AU2018102089A4 - Method of treating endotoxemia - Google Patents

Abstract

A method of treating a subject suffering from endotoxemia comprising administering an effective amount of a compound comprising a structure of Formula I or a pharmaceutically acceptable salt thereof to the subject. A method of inhibiting the activation of p38MAPK pathway in a colorectal cell comprising contacting said compound to the cell. , C- 0 0 0. 0. .22 t b o 0~~. 07u~4 -. 0) tf In 4' 4-3 w ~~ (D 0-Cc: -6 : 0 m 0 >0 -e

Description

METHOD OF TREATING ENDOTOXEMIA

TECHNICAL FIELD

The present invention relates to a method of treating endotoxemia, particularly but not 5 exclusively relates to a method of treating diabetic endotoxemia.

BACKGROUND OF THE INVENTION

Endotoxins released or secreted by bacterial species play a role in acute or chronic infections. The endotoxins circulated in the blood are usually translocated from 10 microbiota in the gut when a subject is infected by bacteria or suffering from a disease.

Recently, there are reports stating that metabolic endotoxemia resulting from absorption of endotoxins from energy-enriched diets may lead to inflammation. Metabolic endotoxemia has also been recognized as a risk factor that is closely accompanied with both the onset and the progress of Type 2 diabetes mellitus 15 (T2DM). There are reports discussing that gut dysbacteriosis might be the source of diabetic endotoxemia as dysbiosis of gut microbiota may contribute to the increase of gut permeability which finally leads to metabolic endotoxemia and higher plasma lipopolysaccharide (LPS). Although it is still uncertain about the cause of endotoxemia, it is believed that inhibition of endotoxemia can help to prevent or attenuate the 20 development of T2DM. Accordingly, it would be important to preserve gut integrity so as to treat endotoxemia. However, there are currently no drugs found to have satisfactory effect on preserving gut integrity particularly when the subject is at the same time suffering from T2DM.

Accordingly, there is a strong need for new compounds which are able to treat endotoxemia such as metabolic endotoxemia, and able to protect the gut integrity.

SUMMARY OF THE INVENTION

The first aspect of the present invention relates to a method of treating a subject 30 suffering from endotoxemia comprising administering an effective amount of a compound comprising a structure of Formula I or a pharmaceutically acceptable salt thereof to the subject,

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Formula I wherein Ri, R2, R3 and R4 are independently selected from a hydrogen atom, a straight-chain or branched C1-C3 alkyl group, or a glycosyl group.

Preferably, the compound comprises a structure of Formula II, Formula III, Formula IV or Formula V:

Formula II,

Formula III,

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Formula IV, or

The second aspect of the present invention pertains to a method of inhibiting the activation of p38MAPK pathway in a colorectal cell comprising contacting a compound comprising a structure of Formula I or a salt thereof to the cell,

Formula I wherein Ri, R2, R3 and R4 are independently selected from a hydrogen atom, a straight-chain or branched C1-C3 alkyl group, or a glycosyl group.

In a third aspect, the present invention pertains to use of the compound comprising a structure of Formula I in treatment of endotoxemia particularly diabetic endotoxemia.

Furthermore, the present invention pertains to use of said compound in the preparation of a medicament for treating endotoxemia.

Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. 20 The invention includes all such variations and modifications. The invention also includes all steps and features referred to or indicated in the specification, individually or collectively, and any and all combinations of the steps or features.

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Other features and aspects of the invention will become apparent by consideration of the following detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 refers to a schematic diagram showing the Ex Vivo Intestinal Perfusion Alive Cell Immobilized Chromatography.

Fig. 2 refers to bar charts of blood HbA1c and AGEs levels in db/db mice of different 10 treatment groups. Fig. 2A shows a bar chart of blood HbA1c level in db/db mice of different treatment groups. Fig. 2B shows a bar chart of blood AGEs level in db/db mice of different treatment groups. DM: diabetic group; Met: metformin group; CM (L, Μ, H) indicated diabetic mice administrated with Low, Medium, or High dose of Cortex Mori water extract. *p<0.05, **p<0.01, vs. normal mice; ^#p<0.05, ^##p<0.01, vs. DM; 15 ^$$p<0.01, vs. Met; ^&p<0.05, vs. CM (M).

Fig. 3 refers to bar charts of alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN), creatinine (Cr) and microalbuminuria (mAlb)/Cr levels in db/db mice of different treatment groups. Fig. 3A 20 shows a bar chart of ALT level in db/db mice of different treatment groups. Fig. 3B shows a bar chart of AST level in db/db mice of different treatment groups. Fig.3C shows a bar chart of BUN level in db/db mice of different treatment groups. Fig.3D shows a bar chart of Cr level in db/db mice of different treatment groups. Fig.3E shows a bar chart of mAlb/Cr level in db/db mice of different treatment groups. DM: 25 diabetic group; Met: metformin group; CM (L, Μ, H) indicated diabetic mice administrated with Low, Medium, or High dose of Cortex Mori water extract. *p<0.05, **p<0.01, vs. normal mice; ^#p<0.05, ^##p<0.01, vs. DM; ^$p<0.05, ^$$p<0.01, vs. Met.

Fig. 4 refers to bar charts of white blood cells (WBC), atypical lymphocytes (ALY), 30 inflammatory cytokine monocyte chemoattractant protein-1 (MCP-1) and lipopolysaccharides (LPS) levels in blood of db/db mice of different treatment groups as determined by kits. Fig. 4A shows a bar chart of WBC level in db/db mice of different treatment groups. Fig. 4B shows a bar chart of ALY level in db/db mice of different treatment groups. Fig. 4C shows a bar chart of MCP-1 level in db/db mice of 35 different treatment groups. Fig. 4D shows a bar chart of LPS level in db/db mice of different treatment groups. DM: diabetic group; Met: metformin group; CM (L, Μ, H)

2018102089 18 Dec 2018 indicated diabetic mice administrated with Low, Medium, or High dose of Cortex Mori water extract. *p<0.05, **p<0.01, vs. normal mice; ^#p<0.05, ^##p<0.01, vs. DM; ^$p<0.05, ^$$p<0.01, vs. Met.

Fig. 5 refers to histological diagrams of the gut of db/db mice of different treatment groups with hematoxylin-eosin (HE) staining and immunohistochemistry treatment. Fig. 5A shows the histological diagrams of the gut of db/db mice of different treatment groups with hematoxylin-eosin (HE) staining. Fig. 5B shows the histological diagrams of the gut of db/db mice of different treatment groups illustrating the inflammatory 10 protein ICAM-1 expression as determined by the immunohistochemistry method. DM: diabetic group; Met: metformin group; CM (L, Μ, H) indicated diabetic mice administrated with Low, Medium, or High dose of Cortex Mori water extract. Representative pictures were shown. (Magnification: 200)

Fig. 6 refers to HPLC-DAD chromatograms of CM water extract by ex-vivo intestinal perfusion alive cell immobilized chromatography, in which plot a shows the chromatogram of the sample washed with D-hank’s solution for 10 times before CM water extract intestine perfusion; plot b shows the chromatogram of the culture solution of CM-perfused intestine; plot c shows the chromatogram of the CM sample 20 washed with D-hank’s solution for 10 times, followed by being dissociated in the acetose solution from intestine lumen; plot d shows the chromatogram of the last washing solution from the aforementioned intestine lumen; plot e shows the chromatogram of the fully homogenated intestine sample after CM perfusion and dissociation; plot f shows the chromatogram of the CM water extract.

Fig. 7 refers mass spectra of indicated component from CM. Fig. 7A shows the HPLC-ESI-MS¹ spectra of indicated component from CM. Fig. 7B shows the HPLCESI-MS² spectra of indicated component from CM.

Fig. 8 refers to a diagram showing the proposed fragmentation of mulberroside A (MBA).

Fig. 9 refers to chromatograms of mulberroside A (MBA), in which the upper chromatogram shows the HPLC-DAD chromatogram of MBA standard sample; and 35 the lower chromatogram shows the HPLC-DAD chromatogram of CM water extract.

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Fig. 10 refers to mass spectra of MBA, in which the upper mass spectrum shows the ESI-mass spectrum of MBA standard sample, and the lower mass spectrum shows the ESI-mass spectrum of CM water extract.

Fig. 11 shows the evidence of MBA binding with intestinal wall in db/db mice as determined by ex-vivo intestinal perfusion alive cell immobilized chromatography, in which line a shows the chromatogram of D-hank’s solution control; line b shows the chromatogram the sample washed with D-hank’s solution for 10 times before CM water extract intestine perfusion; line c shows the chromatogram of D-hank’s solution 10 incubated with dissociation solution control; line d shows the chromatogram dissociation solution control; line e shows the chromatogram of intestine lumen sample being fully washed with D-hank’s solution after CM perfusion and dissociation; line f shows the chromatogram of CM sample being dissociated by acetose solution from intestine lumen; line g shows the chromatogram of CM water extract control; line 15 h shows the chromatogram of MBA standard sample control.

Fig. 12 shows the evidence of MBA entering into intestinal wall in db/db mice as determined by ex-vivo intestinal perfusion alive cell immobilized chromatography, in which line a shows the chromatogram of D-hank’s solution control; line b shows the 20 chromatogram of the intestinal sample after CM components were dissociated from intestinal wall; line c shows the chromatogram of supernatant after the intestine sample was perfused with D-hank’s solution, followed by fully homogenization; line d shows the chromatogram of supernatant after the intestine sample was perfused with CM water extract, followed by fully homogenization; line e shows the chromatogram 25 of CM water extract sample control; line f shows the chromatogram of MBA standard sample control.

Fig. 13 refers to bar charts showing the viability and levels of IL-Ιβ, TNF-α and IL-8 of Caco-2 cells in the absence or presence of LPS and/or MBA. Fig. 13A shows the bar 30 chart of viability of Caco-2 cells in the absence or presence of LPS and/or MBA as determined by MTT. Fig. 13B shows the bar chart of relative level of IL-Ιβ of Caco-2 cells in the absence or presence of LPS and/or MBA as determined by kits. Fig. 13C shows the bar chart of relative level of TNF-α of Caco-2 cells in the absence or presence of LPS and/or MBA as determined by kits. Fig. 13D shows the bar chart of 35 relative level of IL-8 of Caco-2 cells in the absence or presence of LPS and/or MBA

2018102089 18 Dec 2018 as determined by kits. CTL: normal control; LPS: lipopolysaccharides group. *p<0.05, **p<0.01, VS CTL; ^ρΟ.ΟΊ, vs LPS+MBA (70uM).

Fig. 14 refers a bar chart showing the MDA level of Caco-2 cells in the absence or presence of LPS and/or MBA. CTL: normal control; LPS: lipopolysaccharides group; ROS: reactive oxygen species. *p<0.05, vs CTL; ^##p<0.01, vs LPS.

Fig. 15 refers to fluorescence microscopy images showing the ROS level of Caco-2 cells in the absence or presence of LPS and/or MBA. CTL: normal control; LPS: 10 lipopolysaccharides group; ROS: reactive oxygen species. *p<0.05, vs CTL; ^##p<0.01, vs LPS.

Fig. 16 refers to bar charts of Trans-epithelial electrical resistance (TEER) of Caco-2 cells and LPS permeability across the gut epithelial barrier in the absence or 15 presence of LPS and/or MBA. Fig. 16A shows the bar chart of TEER of Caco-2 cells in the absence or presence of LPS and/or MBA as measured by a Millicell-ERS electric resistance system. Fig. 16B shows the bar chart of LPS permeability across the gut epithelial barrier to the lower chamber in the absence or presence of LPS and/or MBA. CTL: normal control; LPS: lipopolysaccharides group. **p<0.01, vs CTL;

^#p<0.05, vs LPS.

Fig. 17 refers to fluorescence microscopy images showing the levels of intercellular adhesion molecules proteins, phosphor-p38MAPK and total-p38MAPK of Caco-2 cells in the absence or presence of LPS and/or MBA. Fig.17A is fluorescence 25 microscopy images showing the levels of intercellular adhesion molecules proteins including ZO-1 and Occludin of Caco-2 cells in the absence or presence of LPS and/or MBA. Fig. 17B is fluorescence microscopy images showing the levels of phosphor-p38MAPK and total-p38MAPK of Caco-2 cells in the absence or presence of LPS and/or MBA. phosphor-p38MAPK was stained by Cy3-conjugated secondary 30 antibody (RED), and total-p38MAPK was stained by FITC-conjugated secondary antibody (GREEN); the cell nucleus was stained with DAPI. CTL: normal control; LPS: lipopolysaccharides group. **p<0.01, vs CTL; ^#p<0.05, vs LPS.

DETAILED DESCRIPTION OF THE INVENTION

Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by one skilled in the art to which the invention belongs.

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As used herein, “comprising” means including the following elements but not excluding others. “Consisting of’ means that the material solely consists of, i.e. is formed by the respective element. As used herein, the forms “a,” “an,” and “the”, are 5 intended to include the singular and plural forms unless the context clearly indicates otherwise.

In the first aspect of the present invention, the present invention pertains to a method of treating a subject suffering from endotoxemia. Endotoxemia refers to a condition 10 where an individual has abnormal presence of endotoxins in the blood compared to a healthy individual. The term “endotoxins” used herein refers to lipopolysaccharides secreted by bacteria or released from bacteria when the bacterial wall is destructed. The destruction of the bacterial wall may be caused by damages to endothelial layer of blood vessels, damages to gut integrity, or triggered by immune system.

The presence of endotoxins in the blood of a subject can be detected by performing Limulus Amebocyte Lysate (LAL) assay. LAL can react and coagulate with endotoxins in a sample. The resulting coagulation can then be detected. Alternatively, ELISA tests may also be applied to detect the presence of endotoxins and in turn confirming 20 whether the subject is suffering from endotoxemia. It would be appreciated that other suitable diagnostic methods can also be used.

In an embodiment of the present invention, the subject suffering from endotoxemia may be at the same time suffering from diabetes particularly type 2 diabetes mellitus 25 (T2DM). The endotoxemia may be therefore considered as diabetic endotoxemia, i.e.

associated with diabetes. The characteristics of diabetic endotoxemia generally include, but are not limited to, epithelial cell loss and intestinal inflammation.

The method of the present invention comprises the step of administering the subject 30 suffering from endotoxemia comprising administering an effective amount of a compound of Formula I or a pharmaceutically acceptable salt thereof to the subject,

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Formula I.

Preferably, Ri, R2, R3 and R4 are independently selected from a hydrogen atom, a straight-chain or branched C1-C3 alkyl group, or a glycosyl group. The alkyl group 5 may be methyl, ethyl, propyl, isopropyl, or cyclopropyl. The glycosyl group may be based on a monosaccharide, a disaccharide or a polysaccharide, preferably a monoor di-saccharide. Monosaccharide may be a hexose selected from, but not limited to, glucose, fructose, galactose, mannose, allose, talose, or gulose. Disaccharide may be, but not limited to, sucrose, lactose, maltose, trehalose, cellobiose, or chitobiose.

Polysaccharide, may be, but not limited to, starch, glycogen, cellulose, or chitin.

In one embodiment, the compound is of Formula I, and R1 and R2 are respectively a glycosyl group, R3 and R4 are respectively a hydrogen atom or a straight-chain C1-C3 alkyl group. Preferably, R1 and R2 are monosaccharide based glycosyl group as 15 described above. In a preferred embodiment, the compound may comprise a structure of Formula II, Formula III, Formula IV or Formula V:

Formula II,

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Formula III,

Formula V.

In a further embodiment, the compound of the present invention may comprise a structure of Formula VI:

The compound of Formula VI is identified as mulberroside A (abbreviated as MBA). The inventors found that the compound of Formula VI is capable of acting against oxidative stress, for example by reducing the level of malondialdehyde (MDA) and 15 reactive oxidative species (ROS) in cells. Also, the compound of Formula VI can enhance the expression of tight junction proteins including ZO-1 and occludin in colorectal cells to protect the gut integrity. It is also found that the compound of

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Formula VI is capable of inhibiting the activation of p38MAPK. Accordingly, the compound of Formula VI can treat endotoxemia by protecting the gut integrity and reducing the damages caused by oxidative stress. The compound of Formula VI is thus useful to treat endotoxemia in particular diabetic endotoxemia.

Since the compound of the present invention has advantageous effects on protecting the gut integrity like protecting the endothelial layer of tissues, the release of endotoxins into the blood can be significantly reduced. Therefore, the method of the present invention also pertains to a method of lowering the level of endotoxins 10 particularly bacterial endotoxins in the blood of a subject. It would be appreciated that said method comprises the step as described above, i.e. administering an effective amount of a compound of Formula I as described above to the subject.

It would be appreciated that the compound of Formula I may also exhibit protective 15 effects on gut microflora and thus can be used in promoting health in a subject.

Also contemplated by the present invention are any pharmaceutically acceptable salts, of the compound of the present invention. Suitable pharmaceutically acceptable salts are those which are suitable to be administered to subjects, in particular mammals 20 such as humans and can be prepared with sufficient purity and used to prepare a pharmaceutical composition.

The expression effective amount generally denotes an amount sufficient to produce therapeutically desirable results, wherein the exact nature of the result varies 25 depending on the specific condition which is treated. In this invention, endotoxemia is the condition to be treated and therefore the result is usually a reduction of the amount of endotoxins in the blood of the subject, reduction of inflammation associated with endotoxemia, or amelioration of symptoms related to endotoxemia.

The effective amount of the compound of Formula I may depend on the species, body weight, age and individual conditions and can be determined by standard procedures such as with cell cultures or experimental animals. The concentration of the compound of Formula I, such as the compound of Formula VI, effective for treating the subject may, for example, be at least 50μΜ, at least 60μΜ, or in particular at least

70μΜ. As shown in the detailed example embodiments below, the compound of

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Formula VI can exhibit protective effects in epithelial colorectal cells at a concentration of about 70μΜ.

The subject can be a human or animal, in particular the subject is a mammal, preferably a human. The subject is, thus, preferably a human suffering from endotoxemia. The subject may also include human suffering from diabetes particularly T2DM.

According to the present invention, the compound according to the present invention can be provided in form of a composition. The composition may be administered by an oral, injective, rectal, topical, parenteral, transdermal or inhalative route to a subject. In a preferred embodiment, the composition is administered by oral route to the subject.

In some embodiments, the composition of the present invention may further comprise a pharmaceutically acceptable excipient in addition to the compound of Formula I which acts an active ingredient, and optionally one or more active compounds for ameliorating the symptoms of endotoxemia. The “pharmaceutically acceptable excipient” may include pharmaceutically acceptable carriers, diluents, preserving agents, solubilizing agents, stabilizing agents, disintegrating agents, binding agents, lubricating agents, wetting agents, emulsifiers, sweeteners, colorants, odorants, salts, buffers, coating agents and antioxidants. Suitable excipients and techniques for formulating pharmaceutical composition are aware by a skilled person in the art. Preferably, the composition may comprise water as a carrier to deliver the composition to the subject, especially when the composition is administered to the subject via oral route.

In a particular embodiment, the composition of the present invention is derived from Cortex Mori. Preferably, said composition is derived from a water extract of Cortex

Mori. Said composition comprising the compounds as described above is found to be effective in protecting intestinal epithelial cells, thereby preserving gut integrity. Said composition may be administered to the subject at a dose of from 0.5g/kg to 1 g/kg, from 1.1g/kg to 1.5g/kg, from 1.6g/kg to 2.0g/kg, from 2.1g/kg to 2.5g/kg, from 2.6g/kg to 3.0g/kg, from 3.1 g/kg to 3.5 g/kg, from 3.6g/kg to 4g/kg, if the subject is a mammal such as a mouse. Preferably, said composition is administered to the subject at a dose of from 1.6g/kg to 2.0g/kg, or from 3.6g/kg to 4.0g/kg. In an embodiment where

2018102089 18 Dec 2018 the subject is a human, said composition may be administered to the subject at a dose of from 40mg/kg to 90mg/kg, from 91mg/kg to 140mg/kg, from 141mg/kg to 190mg/kg, from 191mg/kg to 240mg/kg, from 241mg/kg to 290mg/kg, or from 291mg/kg to 340mg/kg. Preferably, said composition is administered to the subject at 5 a dose of from 141mg/kg to 190mg/kg, or from 291mg/kg to 340mg/kg.

In another aspect, the present invention pertains to use of the compound of Formula I as described above in treatment of endotoxemia as discussed above, and use of said compound in the preparation of a medicament for treating endotoxemia particularly 10 diabetic endotoxemia.

In a still further aspect, the present invention pertains to a method of inhibiting the activation of p38MAPK pathway in a colorectal cell comprising contacting the compound comprising a structure of Formula I as described above or a salt thereof to 15 the cell. It is found that the compound of the present invention, particularly the compound comprising the structure of Formula VI is capable of inhibiting the activation of P38MAPK pathway and thereby decreasing the expression and secretion of inflammatory cytokines. Also, the tight junction proteins expression of the cells can be enhanced after incubation with the compound.

The experiments as described below further support the effect of the composition and compound according to the present invention.

EXAMPLES

Materials, reagents and animals

Cortex Mori (CM) was bought from Bozhou Chinese Medicinal Herb market (Anhui, China) and the voucher specimen was deposited in Consun Pharmaceutical Group (Guangzhou, China). HPLC-grade acetonitrile and formic acid were derived from Merck Company (Darmstadt, Germany). Deionized water was prepared by a Millipore 30 Synergy UV water purification system (Billerica, MA, USA). Citric acid - disodium hydrogen phosphate buffer (pH 4.0) were prepared by ourselves. All other chemicals were derived from commercial sources and were of analytical grade. And all solvent and samples were filtered through 0.45 pm nylon membranes before use.

Metformin was purchased from GBCBIO technology (Guangzhou, China); Lipopolysaccharide (LPS) was purchased from Sigma (St. Louis, MO, USA). ELISA

2018102089 18 Dec 2018 kits for advanced glycation end products (AGEs) and LPS were purchased from Cheng Lin biotechnology company (Beijing, China). Kits for alanine aminotransferase (ALT), glutamic oxaloacetic transaminase (AST), HbA1c and Creatinine (Cr) are from Jiancheng (Nanjing, Jiangsu, China). 3-(4,5-dimethylthiazol-2-yl)-2,55 diphenyltetrazolium bromide (MTT), primary antibodies for Zona Occludens protein-1 (ZO-1), occludin, ICAM-1, p-p38MAPK, and p38MAPK were purchased from Santa Cruz (USA). Kit for mAlb is derived from Westang (Shanghai, China). Kits for IL-1 β, IL-8, MCP-1, and TNF-α were purchased from Neobiosicience (Shenzhen, China). MDA and ROS detection kits were from Beyotime Biotechnology (Beijing, China).

Dulbecco’s modified eagle medium (DMEM), Fetal Bovine Serum (FBS), trypsin, MEM Non-Essential Amino Acids Solution, and L-Glutamine were obtained from Gibco (Big Cabin, OK, USA). DAPI, Cy3- and FITC-conjugated secondary antibodies were supplied by Boster (Wuhan, China). In addition, 24-well Transwell cell culture plates (hanging insert well diameter 6.5 mm, membrane area 0.3 cm²) were obtained from Corning (Corning, NY, USA). The electrical resistance detection system (Millicell ESR-2) was bought from Millipore (Billerica, MA, USA). The other reagents and kits are from commercial sources.

Male C57BL/6 and db/db mice weighing 20-30 g were supplied by Cavens Lab 20 Animal Co. Ltd. (Changzhou, China), and normal chow diet or high-fat diet was respectively administrated to the animals. All animal care and investigation conformed to the Guide for the Care and Use of Laboratory Animals published by the US National Institutes of Health (NIH Publication No. 85-23, revised 1996), and were approved by both Consun Group and our University. The animals were kept on a 25 12/12 h light/dark cycle. All animals were kept in animal house for 3 days before treatment.

Preparation of Cortex Mori Water Extract (ECM)

Dry powder of Cortex Mori (abbreviated as “CM” herein) (CM, 300 g) was immersed 30 with double distilled water (3,000 ml) and continuously boiled on thermostat for 2 h.

The water extraction mixture was filtered and concentrated to 150 ml by using R2002 rotary evaporator. The stock solution for water extract of CM (ECM) was obtained at a concentration of 2 g/ml. The crude drug solution was filtered through a 0.45 pm membrane. Finally, the stock solution was diluted with water to 1.25 g/ml (high dose), 35 0.58 g/ml (medium dose) and 0.31 g/ml (low dose), and then the diluted solutions were stored at 4 °C until use.

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Intestinal Perfusion and Extraction db/db mice underwent fasting for 12 h, but with free access to water, before the experiment. For ex vivo intestinal perfusion, the mice were executed by cervical dislocation and 10 cm of the intestine was isolated from the abdominal cavity under sterile conditions. The intestinal content was gently washed away with D-Hanks solution (pH 7.4). Then the isolated intestine was gently placed in the ALC-M TissueOrgan Bath System filled with D-Hanks solution, and the intestinal lumen was perfused with 2 ml of the ECM sample solution as mentioned above. With reference 10 to Fig. 1, after co-incubating the intestine with ECM sample solution for 2 h, the intestine content (CM sample after incubation) was collected and the intestinal lumen was gently washed with D-Hanks solution for 10 times. Then 2 ml of citric acid disodium hydrogen phosphate buffer (pH 4.0) was used to disassociate the potential CM bioactive components in the intestinal lumen. All the samples and solutions were 15 collected for further chemical analysis.

Chromatographic and Mass Spectrometric Conditions

An agilent 1200 LC system with a Zorbax SB-C18 reserved-phase column (100 mm x

2.1 mm i.d., 3.5 pm) (Agilent company, USA) and thermofisher LCQ-Fleet ion trap mass spectrometer system (Thermofisher company, USA) were employed for the sample analysis. The mobile phase consisted of acetonitrile (A) and water-0.1% formic acid (B), and the gradient elution conditions were: 0-25 min, 5-20% A; 25-45 min, 20-55% A; 45-55 min, 55-90% A. Flow rate was 0.2 ml/min. The column temperature was set at 30 °C, and the injection volume was 20 pl.

Electrospray in the positive mode was used for ionization. Ultra-high purity helium (He) and N2 were applied as the collision gas and nebulizing gas respectively. Mass parameters in the positive ion mode were optimized to obtain maximum yields of [M+H]⁺ or [M+Na]⁺ ions of the compounds as follows: ion spray voltage, 4.5 kV;

sheath gas (N2) pressure: 40 arbitrary units; auxiliary gas (N2) pressure: 10 arbitrary units; capillary temperature, 300 °C; capillary voltage: 5 V. Spectra were recorded in the range of m/z 80-1200 for full-scan MS analysis. Liquid chromatography and tandem mass spectrometric analysis were realized by using a data-dependent program. The collision energy for MSn was 45% and the isolation width of the 35 precursor ions was 1.5 Th.

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Animals Grouping and Drug Administration

Diabetic animals (db/db mice) were randomly divided into 5 groups as follows:

(1) diabetes animal model group (n=6);

(2) positive control group in which animals were administrated with metformin (0.15 g/kg, n=6);

(3) low dose Cortex Mori group (0.91 g/kg, n=6);

(4) medium dose Cortex Mori group (1.82 g/kg, n=6); and (5) high dose Cortex Mori group (3.64 g/kg, n=6).

In addition, eight C57BL/6 mice were set as normal control. All animals were daily 10 administrated with drugs as mentioned above or 0.45 ml normal saline (for normal and model group animals) by gavage for 5 continuous weeks. At the end of the experiment, blood samples were collected for biochemical examination, all animals were sacrificed and colon samples were collected for histological evaluation.

Blood Assay

Blood cell count was done by the clinical laboratory of Jihua Hospital affiliated to Jinan University (Guangzhou, China). Blood HbA1c, AGEs, AST, SLT, BUN, Cr, LPS and MCP-1 were determined by kits according to the protocol provided by the manufacturers.

Hematoxylin-Eosin Staining and Immunohistological Evaluation of Colon

Colon was fixed in 4% paraformaldehyde for 24 h and then paraffinized. For observation, colon sections (0.4 pm) were stained with Hematoxylin-Eosin (HE) solution for 5 min, and the histopathological images of colon were obtained under a 25 light microscope (Olympus, Tokyo, Japan). For immunohistological evaluation of the colon, colon sections were firstly incubated with a primary antibody for ICAM-1 (1:200), then biotin-conjugated secondary antibody and streptavidin-biotin-enzyme complex were added to the sections to develop brown deposit (positive staining).

Cell Culture

Human epithelial colorectal adenocarcinoma (Caco-2) cell was purchased from the American Type Tissue Collection (Manassas, VA, USA). The cells were maintained in DMEM with 10% fetal bovine serum (FBS), 1% penicillin/streptomycin, 1% MEM nonessential amino acids and L-Glutamine in a cell culture incubator.

MTT assay

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To evaluate influence of LPS and Mulberroside A (MBA) on cell viability, cells were treated with MTT (5 mg/ml) for 4 h followed by dimethyl sulfoxide (DMSO) incubation. The absorbance at 490 nm was determined by a spectrophotometer.

Cell Anti-Oxidant Activity Experiment

Cell anti-oxidant activity was evaluated by determining levels of malondialdehyde (MDA) and reactive oxygen species (ROS) after drugs intervention according to the manufacturer’s instruction.

Immunofluorescence Assay

Caco-2 cells were seeded on the slide. After being treated with vehicle, LPS (100 pg/ml), or LPS + MBA (70 μΜ), cells were fixed with 4% paraformaldehyde. Then primary antibodies including ZO-1 (1:100), Occludin (1:100), p-p38MAPK (1:100) or p38MAPK (1:100) were added to the cultured cells; DAPI was used for nuclear 15 staining, FITC- or Cy3-conjugated secondary antibodies were applied to observe proteins’ expression or activation under a fluorescence microscope (Olympus, Tokyo, Japan).

Inflammatory Related Cytokines Assay

Levels of LPS and inflammatory cytokines including IL-1 β, TNF-α and IL-8 after drugs intervention were determined according to the manufacturer’s instruction.

Gut Epithelial Barrier Evaluation

An in vitro gut epithelial barrier model was developed according to Guo, H. et al. 25 Molecules 21(11), pii: E1597 (2016). In brief, Caco-2 cells at the density of 1*10⁵ were seeded on the upper well membrane of the Transwell system and further cultured for 21 days, then a confluent monolayer was obtained for which transepithelial electrical resistance (TEER) would exceed 400 Ω-cm². After drug administration for 24 h, the upper well was added with LPS; finally, level of LPS in the 30 lower chamber of Transwell was determined.

Statistical Analysis

The data were expressed as mean ± standard deviation (SD). SPSS 19.0 software with one-way ANOVA method was applied for data analysis, p value of 0.05 or less 35 was considered to be statistical significant.

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EXAMPLE 1

Blood Glycated Proteins

High blood glucose is the most significant phenomenon in diabetic population. Longterm exposure of hemoglobin and other forms of proteins to plasma glucose will 5 promote a non-enzymatic glycation pathway and generate glycated proteins, namely

HbA1c or advanced glycation end products (AGEs). Therefore, level of glycated proteins can reflect average plasma glucose concentration over prolonged periods of time. To identify if CM administration could affect this glycation, levels of HbA1c and AGEs were detected by kits. As shown in Figs. 2A and 2B, drug administration with 10 either metformin or CM could significantly decrease HbA1c and AGEs levels as compared with diabetic model group; and CM at medium dose had more effect on lowering AGEs level as compared with high or low dose (Fig. 2B).

EXAMPLE 2

Liver and Renal Function

To evaluate influence of CM water extract on target organs of diabetes, liver and renal functions were determined. As depicted in Figs. 3A and 3B, CM administration at low and medium dose would not deteriorate liver function because levels of ALT and AST were not significantly higher than that of DM group. Regarding renal function, with 20 reference to Figs. 3C to 3E, the inventors determined urine BUN, Cr, and ratio of mAlb/Cr. The inventors found that renal function in DM mice was dramatically damaged in that all of the three indicators were significantly elevated, while administration with CM at low or medium doses could significantly decrease the renal function indicators.

EXAMPLE 3

CM Ameliorated Diabetic Endotoxemia in db/db Mice

T2DM has now been recognized as a low-grade inflammatory disease and inflammatory cell infiltration is one of the characteristic. In the present study, we found 30 that the amount of white blood cell (WBC) was dramatically increased compared with normal mice (Fig. 4A), and administration with either low or medium dose of CM could significantly decrease level of WBC. More importantly, medium dose of CM possessed more significant effect compared with its low or high dose. The inventors also observed that the number of abnormal lymphocytes (ALY) was significantly 35 increased in diabetic animals and this elevation could be decreased by any drug intervention in this experiment (Fig. 4B). The data reveal that CM at medium dose has

2018102089 18 Dec 2018 beneficial effect on ameliorating both diabetes and diabetic-inflammatory cell infiltration.

Inflammatory cell infiltration relies on inflammatory chemoattractant protein’s 5 expression. MCP-1 is well studied for its role in mediating inflammatory cell infiltration.

The inventors observed in the study that MCP-1 was significantly increased in diabetic model group compared with normal mice, and administration with metformin or low/medium dose of CM could significantly decrease level of MCP-1 (Fig. 4C, p < 0.01, vs. diabetic group).

Lipopolysaccharides (LPS), also known as endotoxin, may be elevated in diabetic population and may have an important role in diabetic endotoxemia. In the present study, the inventors found that the serum level of LPS in diabetic mice increased by about 7 times compared with normal mice (Fig. 4D); metformin and CM treatment 15 significantly decreased level of LPS (p<0.01, vs. diabetic group); more importantly, low or medium dose of CM administration had more significant effect compared with that of metformin on decreasing serum LPS (p<0.01). LPS is an important component of the cell wall in gram-negative bacteria. Accordingly, gut-sourced Gram negative bacteria (or the so-called bad-microbiota) over-proliferation accompanied with gut 20 barrier integrity damage may be involved in diabetic endotoxemia.

EXAMPLE 4

CM Preserved Gut Integrity and Decreased Proinflammatory Cytokine’s Expression

To verify if CM intervention could preserve gut integrity and inhibit “gut-leak” mediated 25 diabetic endotoxemia, the inventors carried out hematoxylin-eosin (HE) staining and immunohistological evaluation on gut. As shown in Fig. 5A, the gut physical barrier in DM model group was severely damaged as large amounts of gut epithelial cells were detached from the basal lamina. After the treatment with metformin or CM, gut integrity was significantly recovered. Medium dose of CM exhibited stronger 30 protective effect on preserving gut integrity. Based on the results, the medium dose of CM could restore gut integrity back to the normal state.

As inflammatory cell infiltration was significantly reduced by CM administration at medium dose, the inventors then investigated which inflammatory protein was 35 involved in the process. The expression of ICAM-1 was determined by immunohistochemistry method. As shown in Fig. 5B, ICAM-1 expression

2018102089 18 Dec 2018 accompanied with inflammatory cell infiltration was dramatically increased in diabetic mice, and medium dose of CM significantly reversed both expression of ICAM-1 and infiltration of WBC. Converging from above findings, the inventors concluded that oral administration of CM has protective effects against diabetic endotoxemia, and the 5 potential mechanism may attribute to its function on preserving gut barrier integrity.

The inventors then investigated components in CM possessing this protective effect via chemical analysis.

EXAMPLE 5

Bioactive compound extracted by ex-vivo Intestinal Perfused alive cell Immobolized Chromatography (IPIC)

As shown in Fig. 6, one peak was found in the extraction of IPIC (plot c in Fig. 6) by comparing the HPLC fragmentation behavior and retention time with ECM (plot f in Fig. 6), while this peak was not found in the last elute of D-hank’s solution (plot a in 15 Fig. 6). Therefore, it is presumed that the bioactive compound was dissociated from cell membrane in the analogical physiological condition in that when the IPIC extract was eluted with dissociation solution (pH 4.0), it was denatured and the compound was released from its binding site on cell membrane. Interestingly, when the inventors detected possible existence of this compound outside intestinal lumen (plot b in Fig. 6) 20 and on the intestinal wall tissue (plot e in Fig. 6), it was also detectable, suggesting the compound could enter the intestinal tissue and be absorbed by the intestine.

Results from HPLC-ESI-MS² spectrum analysis are as shown in Fig. 7A and 7B, as well as the table below.

RT (min)	MS	MS2	MW	Suggested compound
6.74	569 [M+H]+	407	568	Mulberroside A

It is suggested that the bioactive compound is Mulberroside A (MBA). The proposed fragmentation of MBA is shown in Fig. 8. In order to further verify the chemical structure of this compound, a standard sample of MBA and HPLC-ESI-MS² were used. As depicted in Figs. 9 and 10, the retention time and fragmentation behavior of this compound are well matched between CM water extract (ECM) and MBA standard 30 solution.

EXAMPLE 6

Mulberroside A (MBA) can bind with and/or enter into intestinal wall in db/db mice

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With reference to Fig. 6, the indicated compound was detected outside the intestinal lumen (plot b in Fig. 6) and on the intestinal wall tissue (plot e in Fig. 6). To further verify the presence of MBA in these tissues, MBA was perfused into the intestinal wall according to the method for IPIC. As shown in Fig. 1, MBA can either be dissociated by the acetone solution (line f in in Fig. 11) or be detected in the intestinal wall tissue (line d in Fig. 12), as the un-conjugated compounds were fully washed out from the intestinal samples.

EXAMPLE 7

Effect of Mulberroside A (MBA) on LPS-induced Inflammatory Cytokines Secretion

Some in vitro studies were carried out to determine if MBA has any effects on diabetic endotoxemia. Firstly, the inventors applied LPS to induce Caco-2 cells so as to trigger gut barrier dysfunction and gut-leak. As depicted in Fig. 13A, 100 pg/mL LPS significantly decreased viability of the cells as compared with the control group 15 (p<0.01). Then MBA was added with different concentrations ranging from 5 μΜ to

500 pM after LPS induction. Unexpectedly, the inventors found that MBS does not have significant effect on reversing LPS-damaged cell viability. The cell viability decreases when 500pM MBA was applied to the cells, compared to the cell viability after treatment with 70pM. In view of the results, the inventors applied 70 pM MBA in 20 the following in vitro study.

In order to determine if MBA exhibits any effects on reducing LPS-induced inflammatory cytokines’ secretion, the inventors determined the levels of cytokines by ELISA. As shown in Figs. 13B and 13C, LPS dramatically increased expression of 25 pro-inflammatory cytokines’ expression including IL-Ιβ and TNF-α. Although MBA incubation after LPS stimulation slightly decreased their levels, there is no statistical significance. IL-8 is a well-known chemotactic factor which involves in neutrophil cell infiltration and activation, and low level of IL-8 often results in dysfunction of neutrophil cells and thereafter infection expansion. Referring to Fig. 13D, the 30 inventors found that LPS incubation could significantly decrease IL-8 secretion in

Caco-2 cells, and MBA treatment further inhibited its expression. Based on the above findings, the inventors conclude that MBA does not exhibit any direct effects on LPSinduced inflammatory cytokines secretion in Caco-2 cells.

EXAMPLE 8

Mulberroside A (MBA) Enhanced Anti-oxidative Activity of the Cells

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Oxidative stress damage is believed to be involved in the development of gut-leak and diabetic endotoxemia. In order to determine if MBA has any anti-oxidative activities against oxidative stress damage, Caco-2 cells were used. Caco-2 cells were subject to MBA treatment for 24 h. The culture supernatant was collected for MDA 5 detection and the level of ROS in the cells was observed by using immunofluorescence method. As shown in Figs. 14 and 15, LPS stimulation significantly elevated both MDA and ROS levels in Caco-2 cells, and MBA administration is capable of decreasing their levels, i.e. back to normal.

EXAMPLE 9

Mulberroside A (MBA) Increased Gut Integrity

To determine the effect of MBA on gut epithelial barrier, the inventors constructed a Caco-2 cell monolayer by a Transwell cell culture system. Trans-epithelial electrical resistance (TEER) across the monolayer was measured with a Millicell-ERS electric 15 resistance system, and the amount of LPS from the upper chamber to the lower chamber across the monolayer was determined. As shown in Figs. 16A and 16B, LPS significantly decreased TEER which was accompanied by higher permeability of LPS across the monolayer to the lower chamber (p<0.01), and treatment with MBA strengthened the monolayer integrity.

Two pivotal factors including cell viability and tight junction between cells contribute to the integrity of gut barrier. The inventors would like to know the tight junction condition after drug administration. The expressions of two tight junction proteins including ZO1 and Occludin were studied. With reference to Fig. 17A, these junction proteins are 25 highly expressed in normal Caco-2 cells, LPS administration strikingly decreased their expressions. MBA administration ameliorated this decrease.

To further investigate the potential mechanism, the intracellular signaling pathway activation status was observed. p38MAPK signaling pathway has been well studied in 30 its role on development of diabetic endotoxemia. As shown in Fig. 17B, the amount of total-p38MAPK in normal, LPS and LPS+MBA group were at the similar level; LPS incubation significantly activated p38MAPK, as its phosphor-form (p-p38MAPK) was dramatically increased; when the cell was further administrated with MBA after LPS, activation of p38MAPK was significantly inhibited.

Discussion

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Oral administration of CM water extract at medium dose possessed significant effect on reducing glycated protein levels (HbA1c and AGEs), ameliorating diabetic nephropathy, and reducing diabetic-inflammation in db/db mice. An important finding was that level of blood LPS was significantly reduced after administration with CM 5 extract. Based on the results, CM may possess protective effects against endotoxemia by inhibiting out-sourced LPS entrance into the body. Histological experiment was carried out to confirm the above finding. By HE staining, the inventors observed that the gut barrier was severely damaged in diabetic mice, and CM administration significantly preserved its integrity. Moreover, CM administration 10 significantly decreased expression of ICAM-1 and inflammatory cell infiltration in gut wall. The results suggest that CM can potentially ameliorate diabetic endotoxemia via enhancing gut integrity.

The inventors then constructed an ex vivo Intestinal Perfusion alive cell Immobilized 15 Chromatography (IPIC) coupled with HPLC-ESI-MSⁿ technique to identify the bioactive component from CM. By this method, the inventors identified a compound of Formula VI - mulberroside A (MBA). IPIC for screening bioactive components of herbal medicines has the following advantages (1) it realizes direct reaction/connection between the component and its target in vivo; (2) it reflects oral 20 administration characteristic of herbal medicines; and (3) it saves time for potential active component analysis.

A series of in vitro studies were performed to determine the effect of MBA on preserving gut integrity. In particular, Caco-2 cell line was adopted and LPS was 25 applied to stimulate Caco-2 cell damage to mimic diabetic gut epithelial barrier damage. The in vitro disease model was supported by a previous report from Song and colleagues that LPS administration will induce gut-leak accompanied with the epithelial cell loss in mice.

In order to determine in vitro effects of MBA on LPS-induced Caco-2 cell damages, the cell viability and inflammatory cytokines secretion were firstly studied. Report has demonstrated that cytokines including TNF-α and IL-1 β promote the recruitment and infiltration of infiltration of inflammatory cells, thereafter exaggerate inflammatory damage. Interestingly, the inventors did not observe any significant effects of MBA on 35 enhancing cell viability and reversing LPS induced inflammatory cytokines secretion

2018102089 18 Dec 2018 in Caco-2 cells. This finding demonstrates that MBA may not have direct effect on inhibiting inflammatory cytokines secretion.

Excessive oxidative stress may directly induce cell loss which may contribute to gut5 leak. The inventors found that MBA has significant effects against LPS-induced oxidative stress by reducing level of MDA and ROS within cells.

As discussed above, gut-leak will result in the paracellular invading of luminal antigens and toxins into blood circulation. Recent understanding depicts the 10 importance of gastrointestinal tract leaky barrier in the development of diabetes. The tight junction between intestinal epithelial cells is a natural barrier against invasion of intestinal toxins and bacteria into blood circulation, and cell quantity and tight junction proteins among cells are two important factors that ensure gut barrier integrity. The inventors then determined the effect of MBA on tight junction proteins. The results 15 show that MBA administration significantly increased expression of tight junction proteins expression, including ZO-1 and Occludin. Accordingly, the permeability of LPS across gut epithelial barrier was decreased and TEER was enhanced after MBA administration.

The inventors further investigated the effect of MBA on inhibiting the activation of p38MAPK pathway. p38MAPK has been well demonstrated to be pivotal cell signaling pathway that mediates both inflammation and tight junction proteins expression. It is reported that its activation will increase inflammatory cytokines expression and secretion, while decrease expression of tight junction proteins among epithelial cells.

In the present study, the inventors found that MBA administration significantly inhibited activation of p38MAPK.

Based on the above experimental data, it is demonstrated that the compound of the present invention is useful in treating endotoxemia, particularly diabetic endotoxemia.

1. A method of treating a subject suffering from endotoxemia comprising administering an effective amount of a compound comprising a structure of Formula I or a pharmaceutically

Claims (15)

1. Formula I wherein Ri, R2, R3 and R4 are independently selected from a hydrogen atom, a straight-chain or branched C1-C3 alkyl group, or a glycosyl group.
2. 2. The method of claim 1, wherein R1 and R2 are respectively a glycosyl group, R3 and R4 are respectively a hydrogen atom or a straight-chain C1-C3 alkyl group.
3. 3. The method of claim 2, wherein R1 and R2 are monosaccharide based glycosyl group.
4. 4. The method of claim 1, wherein the compound comprises a structure of Formula II, Formula III, Formula IV or Formula V:

   Formula II,

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   Formula III,
5. 5. The method of claim 1, wherein the compound comprises a structure of Formula VI:
6. 6. The method of claim 1, wherein the endotoxemia is associated with diabetes.
7. 7. The method of claim 1, wherein the compound is administered to the subject via oral route.
8. 8. The method of claim 1, wherein the compound is administered to the subject at a concentration of at least 50μΜ.

   2018102089 18 Dec 2018
9. 9. The method of claim 1, wherein the level of an endotoxin in the subject is reduced or the amount of reactive oxidative substance is reduced.
10. 10. A method of inhibiting the activation of p38MAPK pathway in a colorectal cell comprising contacting a compound comprising a structure of Formula I or a salt thereof to the cell,

    RtO

    OR₃

    Formula I or₂ wherein R1, R2, R3 and R4 are independently selected from a hydrogen atom, a straight-chain or branched C1-C3 alkyl group, or a glycosyl group.
11. 11. The method of claim 10, wherein R1 and R2 are respectively a glycosyl group, R3 and R4 are respectively a hydrogen atom or a straight-chain C1-C3 alkyl group.
12. 12. The method of claim 11, wherein R1 and R2 are monosaccharide based glycosyl group.
13. 13. The method of claim 10, wherein the compound comprises a structure of Formula II, Formula III, Formula IV or Formula V:

    OH

    OH

    HO.

    OH

    HO'

    ΌΗ

    OH

    Formula II,

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    Formula III,
14. 14. The method of claim 10, wherein the compound comprises a structure of Formula VI:

    2018102089 18 Dec 2018
15. 15. The method of claim 10, wherein the compound is provided at a concentration of at least 50μΜ for contacting with the cell.