AU2018100981A4

AU2018100981A4 - Sweet potato sitosterol glucoside saturated fatty acid ester, extract, preparation methods and application thereof

Info

Publication number: AU2018100981A4
Application number: AU2018100981A
Authority: AU
Inventors: Xuegang LI; Yanlin Li; Yasong Li; Xiaoli Ye
Original assignee: Southwest University
Current assignee: Southwest University
Priority date: 2017-12-21
Filing date: 2018-07-10
Publication date: 2018-08-16
Anticipated expiration: 2026-07-10
Also published as: CN109942648A; WO2019119675A1

Abstract

The present invention relates to the field of medical chemistry and particularly relates to a sweet potato sitosterol glucoside saturated fatty acid ester and extract as well as preparation methods and application thereof. The sweet potato sitosterol glucoside 5 saturated fatty acid ester extract has a certain inhibition effect on MCF-7, and the inhibition effect is very weak under low concentration; the sweet potato sitosterol glucoside saturated fatty acid ester has a good inhibition effect on MCF-7, wherein sweet potato sitosterol glucoside palmitate has the highest inhibition effect on MCF-7 breast cancer cells, and the anti-tumor activity is reduced to a certain degree due to 10 increase and decrease of carbon chains; and the inhibition effect of the sweet potato sitosterol glucoside palmitate on tumors is obviously higher than that of sweet potato sitosterol glucoside linoleate and sweet potato sitosterol glucoside. -28-

Description

SWEET POTATO SITOSTEROL GLUCOSIDE SATURATED FATTY ACID ESTER,

EXTRACT, PREPARATION METHODS AND APPLICATION THEREOF

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to the field of medical chemistry and particularly relates to a sweet potato sitosterol glucoside saturated fatty acid ester, extract as well as preparation methods and application thereof 2. Description of Related Art [0002] Tumors are malignant diseases that seriously threaten human health. In China, tumors have become the leading cause of death, and the morbidity rate and the death rate are still increasing. In 2015, China is expected to have 4.292 million new cases of tumors, which is equivalent to an average of 12,000 new cases of cancers per day and 2.814 million death cases, equivalent to an average of 7,500 deaths per day from cancers. Search and development of anti-tumor medicines with exact curative effects and low toxic and side effects are the hotspot and difficulty for innovation and research of medicines. Due to the unique advantages of traditional Chinese medicines, extraction of safe and effective parts from traditional Chinese medicines for prevention and/or treatment of cancers is always the hotspot for chemotherapy research of tumors.

[0003] Sweet potatoes are one of the grain crops in China, and both the planting area and the yield of the sweet potatoes are ranked first in the world. According to the records of Compendium of Materia Medica, the sweet potatoes are sweet in taste, neutral in nature and nontoxic, are mainly used for tonifying deficiency, invigorating vigor, strengthening the spleen and stomach and reinforcing kidney yin, and are same with Chinese yams in terms of its functions. Modern research results show that (Wang

Hongyun et al., Food and Nutrition in China, 2013, 19(12):59-62) the sweet potatoes have multiple effects of resisting cancers, enhancing immunity, reducing blood fat, reducing blood glucose, inhibiting thrombosis, preventing and treating arteriosclerosis, cardiovascular diseases and the like. The recent research proves that the sweet potatoes have a good anti-tumor effect (Meimei Wang etc. Bioassay-guided isolation of glycoprotein SPG-56 from sweet potato Zhongshu-1 and its anti-colon cancer activity in vitro and in vivo. Journal of Functional Foods. 35, (2017), 315-324). However, at present, in some cases, development and utilization of the sweet potatoes mainly refer to the primary processing for production of sweet potato starch, and in the production process of the sweet potato starch, multiple health care components (including anti-tumor components) such as sweet potato proteins, polysaccharides and vitamins are lost together with the sweet potato starch mother liquor (commonly known as yellow pulp or starch wastewater), so that the environment is polluted and resources are greatly wasted; and on the other hand, active monomers in the sweet potatoes are difficult to separate and identify, and the components with anti-tumor effects cannot be determined. Therefore, separation and identification of the active monomers of the sweet potatoes as well as research of sweet potato extract of different processes for prevention and/or treatment of tumors have important significance so as to find potential anti-tumor medicines or health foods which are better in anti-tumor effect, safe, simple in processing and high in yield.

SUMMARY OF THE INVENTION

[0004] The first object of the present invention is to provide a sweet potato sitosterol glucoside saturated fatty acid ester which has obvious anti-tumor activity.

[0005] The second object of the present invention is to provide a sweet potato sitosterol glucoside saturated fatty acid ester extract.

[0006] The third object of the present invention is to provide preparation methods of the sweet potato sitosterol glucoside saturated fatty acid ester extract and the sweet potato sitosterol glucoside saturated fatty acid ester.

[0007] The fourth object of the present invention is to provide the application of the sweet potato sitosterol glucoside saturated fatty acid ester and/or the sweet potato sitosterol glucoside saturated fatty acid ester extract in preparation of medicines and health foods for preventing and/or treating tumors.

[0008] In order to realize the above objects of the present invention, the present invention provides the following technical schemes.

[0009] In the first aspect, the chemical formula of the sweet potato sitosterol glucoside saturated fatty acid ester is represented by formula I:

Formula I

[0010] wherein R=-CnH2n+i, 12 < n < 18.

[0011] Further, R=-CnH2n+i, n=15.

[0012] Further, R is straight-chain hydrocarbyl, the chemical formula of the sweet

potato sitosterol glucoside saturated fatty acid ester is represented by formula II, and the formula II is sweet potato sitosterol glucoside palmitate.

Formula II

[0013] In the second aspect, the sweet potato sitosterol glucoside saturated fatty acid ester extract provided by the present invention contains a compound represented by formula I, and the compound represented by formula I accounts for 1% or more of the extract by weight.

[0014] The sweet potato sitosterol glucoside saturated fatty acid extract provided by the present invention contains a compound represented by formula II, and the compound represented by formula II accounts for 1% or more of the extract by weight. [0015] Further, the sweet potato sitosterol glucoside saturated fatty acid extract contains the compound represented by formula II, and the compound represented by formula II accounts for 10% or more of the extract by weight.

[0016] Further, the extract is obtained by precipitation, filtration/centrifugation and organic solvent extraction and purification of sweet potato starch mother liquor.

[0017] Further, the extract is dropped on a thin layer chromatography plate, is developed in a developing solvent of a mixed solution of chloroform, methanol and water in a volume ratio of 90:10:1, and performs color development by a color developing agent of sulfuric acid and methanol in a volume ratio of 1:9, and the extract shows mauve color after being heated for 5min at 105°C.

[0018] In the third aspect, a preparation method of the sweet potato sitosterol glucoside saturated fatty acid ester extract provided by the present invention comprises the following steps: [0019] step 1: adding a precipitant with a weight ratio of 0.01% to 5% to the sweet potato starch mother liquor at 50 to 100°C, performing centrifugation or filtration, and taking the solid to obtain a sweet potato crude extract; and [0020] step 2: adding an organic solvent with a weight ratio of 1:1-10 to the sweet potato crude extract, performing stirring and then filtration, and concentrating the filtrate to obtain the sweet potato sitosterol glucoside saturated fatty acid ester extract. [0021] Further, the preparation method of the sweet potato sitosterol glucoside saturated fatty acid ester extract further comprises step 3: performing column chromatography on the sweet potato sitosterol glucoside saturated fatty acid ester extract, collecting an elution solution which takes a mixed solution of chloroform, methanol and water in a volume ratio of 90:10:1 as a developing solvent, takes a solution of sulfuric acid and methanol in a volume ratio of 1:9 as a color developing agent, shows mauve spots after being heated for 5min at 105°C and has the thin layer chromatography Rf of 0.68 to 0.77, and concentrating the elution solution to obtain the sweet potato sitosterol glucoside saturated fatty acid ester extract.

[0022] The preparation method of the sweet potato sitosterol glucoside saturated fatty acid ester provided by the present invention is characterized in that the precipitant used in step 1 is selected from a divalent or trivalent metal salt, organic acid, glucono lactone, sodium alginate, xanthan gum and carrageenan; preferably, the precipitant used in step 1 is selected from calcium salt, magnesium salt, aluminum salt, acetic acid, malic acid, citric acid, tartaric acid, glucono lactone, sodium alginate, xanthan gum and carrageenan; preferably, the precipitant used in step 1 is selected from calcium sulfate, magnesium sulfate, tartaric acid, malic acid, citric acid and gluconolactone. Preferably, the addition weight of the precipitant used in step 1 is 0.05% to 1% of the weight of the sweet potato starch mother liquor.

[0023] The preparation method further comprises a step of performing cooling to 0 to 80°C before the centrifugation or filtration in step 1; and preferably, the preparation method further comprises a step of performing cooling to 20 to 50°C before the centrifugation or filtration in step 1.

[0024] The organic solvent used in step 2 is selected from one or more of water-soluble alcohols or ketones; and preferably, the organic solvent used in step 2 is selected from one or more of methanol, ethanol, propanol and acetone.

[0025] The dosage of the organic solvent used in step 2 is 2 to 5 times the weight of the sweet potato crude extract.

[0026] Step 2 can be repeated for 1 to 5 times; preferably, step 2 can be repeated for 2 to 4 times; and further preferably, step 2 can be repeated for 2 to 3 times.

[0027] The column chromatography in step 3 comprises silica gel column chromatography, macroporous adsorption resin column chromatography, glucose gel column chromatography and high performance liquid column chromatography; and specifically, the column chromatography in step 3 is silica gel column chromatography or high performance liquid column chromatography.

[0028] When the column chromatography in step 3 is silica gel column chromatography, chromatography conditions are as follows: petroleum ether with 1 to 5 times the column volume, ethyl acetate with 1 to 5 times the column volume, ethanol with 1 to 5 times the column volume and methanol with 1 to 5 times the column volume are sequentially used for performing elution.

[0029] The preparation method of the sweet potato sitosterol glucoside palmitate provided by the present invention comprises the following steps: dissolving the obtained sweet potato sitosterol glucoside saturated fatty acid ester extract in ethanol, performing column chromatography separation through alkylsilane bonded silica gel, taking an alcohol-water solution as an eluent, and collecting the elution solution corresponding to the retention time, thereby obtaining each sweet potato sitosterol glucoside saturated fatty acid ester monomer.

[0030] In the fourth aspect, the present invention provides application of the sweet potato sitosterol glucoside saturated fatty acid ester and the extract thereof in preparation of medicines or health foods for preventing and/or treating tumors.

[0031] The sweet potato sitosterol glucoside saturated fatty acid ester and/or the sweet potato sitosterol glucoside saturated fatty acid ester extract of the present invention can be administrated through modes of oral administration, spraying administration, sublingual administration, intravenous injection, intravenous infusion, intramuscular injection, intraperitoneal administration, intradermal administration and the like.

[0032] The sweet potato sitosterol glucoside saturated fatty acid ester and/or the sweet potato sitosterol glucoside saturated fatty acid ester extract of the present invention can be solely used for preventing and/or treating tumors and can also be used together with other anti-tumor medicines.

[0033] The sweet potato anti-tumor active monomer and/or the sweet potato anti-tumor extract of the present invention are selected from food materials, are very safe to human bodies, can be solely processed and prepared or processed and prepared together with other nutrient substances and/or food additives to obtain foods, beverages, functional foods, functional beverages and the like, exerts a function of food therapy, and can be used for health foods, food processing and other fields.

[0034] The sweet potato sitosterol glucoside palmitate of the present invention has an obvious growth inhibition effect on tumor cells; under the administration concentration of 10 mg/L, the inhibition rate of the sweet potato sitosterol glucoside palmitate monomer of the present invention to MCF-7 cells is 96%, the inhibition rate of the control medicine sweet potato sitosterol glucoside linoleate monomer to the MCF-7 cells is 65%, and the inhibition rate of the control medicine sweet potato sitosterol glucoside monomer to the MCF-7 cells is 55%; and under the administration concentration of 1 mg/L, the inhibition rate of the sweet potato sitosterol glucoside palmitate monomer of the present invention to the MCF-7 cells is 65%, the inhibition rate of the control medicine sweet potato sitosterol glucoside linoleate monomer to the MCF-7 cells is 15%, and the inhibition rate of the control medicine sweet potato sitosterol glucoside monomer to the MCF-7 cells is 10%. Thus, the inhibition rate of the sweet potato sitosterol glucoside palmitate is obviously higher than that of the control medicines.

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] FIG. 1 is a hydrogen spectrogram of the sweet potato sitosterol glucoside palmitate (formula II) monomer.

[0036] FIG. 2 is a carbon spectrogram of the sweet potato sitosterol glucoside palmitate (as shown in formula II) monomer.

[0037] FIGs. 3A-3C are gas chromatography-mass spectrometry combined spectrograms of the sweet potato sitosterol glucoside palmitate (as shown in formula II) monomer, wherein FIG. 3A is a total ion current chromatogram of the sweet potato sitosterol glucoside palmitate, FIG. 3B is a primary mass spectrum of ion current of which the retention time is 23.735min, and FIG. 3C is a secondary mass spectrum of methyl palmitate fragments.

DESCRIPTION OF THE EMBODIMENTS

[0038] The present invention is further described in detail in combination with the following embodiments, and is not limited to the following embodiments. Reagents and raw materials used in the present invention are commercially available or can be prepared by conventional methods in the art.

[0039] The sweet potato starch mother liquor used in the present invention is the mother liquor in which the sweet potato starch is removed, and is commonly known as yellow pulp or starch wastewater. The sweet potato starch mother liquor can be waste liquid obtained in production of the sweet potato starch and can be prepared by a method comprising the steps of pulverizing sweet potatoes together with water, performing sieving to obtain sweet potato pulp, then removing starch and collecting the pulp. For example, the sweet potato starch mother liquor can be prepared by a method comprising the steps of pulverizing sweet potatoes together with 0 to 2 times of water, performing sieving with a 80-mesh sieve to obtain sweet potato pulp, then performing filtration to remove starch, and collecting the pulp.

[0040] Embodiment 1: Preparation of Sweet Potato Sitosterol Glucoside Saturated Fatty Acid Ester Extract [0041] Step 1 : Calcium sulfate of which the weight is 0.01% of the weight of mother liquor is added to 100 L of sweet potato mother liquor at 100°C, uniform stirring is performed, cooling is performed to 80°C, centrifugation is performed, and vacuum drying is performed at 60°C to obtain a sweet potato crude extract.

[0042] Step 2: 10% ethanol (weight/weight) of which the weight is one times the weight of the sweet potato crude extract is added to the sweet potato crude extract obtained in step 1, stirring is performed for lmin, filtration is performed, filter residues are dissolved with 10% ethanol of which the weight is one times the weight of the filter residues, filtration is performed, the processes are repeated for two times, filtrates are collected and mixed, and concentration and drying are performed to obtain the sweet potato sitosterol glucoside saturated fatty acid ester extract, wherein the content of sweet potato sitosterol glucoside palmitate is 1.1%.

[0043] Embodiment 2: Preparation of Sweet Potato Sitosterol Glucoside Saturated Fatty Acid Ester Extract [0044] Step 1 : Aluminum sulfate of which the weight is 1% of the weight of mother liquor is added to 100 L of sweet potato starch mother liquor at 50°C, uniform stirring is performed, cooling is performed to 20°C, centrifugation is performed, and vacuum drying is performed at 60°C to obtain a sweet potato crude extract.

[0045] Step 2: 50% propanol (weight/weight) of which the weight is five times the weight of the sweet potato crude extract is added to the sweet potato crude extract obtained in step 1, stirring is performed for 20min, filtration is performed, filter residues are dissolved with 50% propanol of which the weight is five times the weight of the filter residues, filtration is performed, the processes are repeated for four times, filtrates are collected and mixed, and concentration and drying are performed to obtain the sweet potato saturated fatty acid ester extract, wherein the content of sitosterol glucoside palmitate is 1.2%.

[0046] Embodiment 3: Preparation of Sweet Potato Sitosterol Glucoside Saturated Fatty Acid Ester Extract [0047] Step 1: Acetic acid of which the weight is 0.1% of the weight of mother liquor is added to 100 L of sweet potato starch mother liquor at 70°C, uniform stirring is performed, cooling is performed to 20°C, centrifugation is performed, and vacuum drying is performed at 60°C to obtain a sweet potato crude extract.

[0048] Step 2 : 80% acetone (weight/weight) of which the weight is three times the weight of the sweet potato crude extract is added to the sweet potato crude extract obtained in step 1, stirring is performed for lOmin, filtration is performed, filter residues are dissolved with 80% propanol of which the weight is three times the weight of the filter residues, filtration is performed, the processes are repeated for three times, filtrates are collected and mixed, and concentration and drying are performed to obtain the sweet potato sitosterol glucoside saturated fatty acid ester extract, wherein the content of sweet potato sitosterol glucoside palmitate is 1.3%.

[0049] Embodiment 4: Preparation of Sweet Potato Sitosterol Glucoside Saturated Fatty Acid Ester Extract [0050] Step 1: Citric acid of which the weight is 0.05% of the weight of mother liquor is added to 100 L of sweet potato starch mother liquor at 90°C, uniform stirring is performed, cooling is performed to 30°C, centrifugation is performed, and vacuum drying is performed at 60°C to obtain a sweet potato crude extract.

[0051] Step 2 : 95%% ethanol (weight/weight) of which the weight is seven times the weight of the sweet potato crude extract is added to the sweet potato crude extract obtained in step 1, stirring is performed for lOmin, filtration is performed, filter residues are dissolved with 95% ethanol of which the weight is seven times the weight of the filter residues, filtration is performed, the processes are repeated for two times, filtrates are collected and mixed, and concentration and drying are performed to obtain the sweet potato sitosterol glucoside saturated fatty acid ester extract, wherein the content of sweet potato sitosterol glucoside palmitate is 1.2%.

[0052] Embodiment 5: Preparation of Sweet Potato Sitosterol Glucoside Saturated Fatty Acid Ester Extract [0053] Step 1: Malic acid of which the weight is 0.5% of the weight of mother liquor is added to 100 L of sweet potato starch mother liquor at 80°C, uniform stirring is performed, cooling is performed to 40°C, centrifugation is performed, and vacuum drying is performed at 60°C to obtain a sweet potato crude extract.

[0054] Step 2 : 80% ethanol (weight/weight) of which the weight is two times the weight of the sweet potato crude extract is added to the sweet potato crude extract obtained in step 1, stirring is performed for 30min, filtration is performed, filter residues are dissolved with 80% ethanol of which the weight is two times the weight of the filter residues, filtration is performed, the processes are repeated for two times, filtrates are collected and mixed, and concentration and drying are performed to obtain the sweet potato sitosterol glucoside saturated fatty acid ester extract, wherein the content of sweet potato sitosterol glucoside palmitate is 1.4%.

[0055] Embodiment 6: Preparation of Sweet Potato Sitosterol Glucoside Saturated Fatty Acid Ester Extract [0056] Step 1: Glucono lactone of which the weight is 2% of the weight of mother liquor is added to 100 L of sweet potato starch mother liquor at 60°C, uniform stirring is performed, cooling is performed to 25°C, centrifugation is performed, and vacuum drying is performed at 60°C to obtain a sweet potato crude extract.

[0057] Step 2: 60% ethanol (weight/weight) of which the weight is three times the weight of the sweet potato crude extract is added to the sweet potato crude extract obtained in step 1, stirring is performed for 30min, filtration is performed, filter residues are dissolved with 60% ethanol of which the weight is three times the weight of the filter residues, filtration is performed, the processes are repeated for two times, filtrates are collected and mixed, and concentration and drying are performed to obtain the sweet potato sitosterol glucoside saturated fatty acid ester extract, wherein the content of sweet potato sitosterol glucoside palmitate is 1.3%.

[0058] Embodiment 7: Preparation of Sweet Potato Sitosterol Glucoside Saturated Fatty Acid Ester Extract [0059] Step 1: Sodium alginate of which the weight is 2% of the weight of mother liquor is added to 100 L of fresh sweet potato starch mother liquor at 60°C, uniform stirring is performed, cooling is performed to 25°C, centrifugation is performed, and vacuum drying is performed at 60°C to obtain a sweet potato crude extract.

[0060] Step 2 : 30% ethanol (weight/weight) of which the weight is three times the weight of the sweet potato crude extract is added to the sweet potato crude extract obtained in step 1, stirring is performed for 30min, filtration is performed, filter residues are dissolved with 30% ethanol of which the weight is three times the weight of the filter residues, filtration is performed, the processes are repeated for two times, filtrates are collected and mixed, and concentration and drying are performed to obtain the sweet potato sitosterol glucoside saturated fatty acid ester extract, wherein the content of sweet potato sitosterol glucoside palmitate is 1.4%.

[0061] Embodiment 8: Preparation of Sweet Potato Sitosterol Glucoside Saturated Fatty Acid Ester Extract [0062] Silica gel column chromatography is performed on the sweet potato sitosterol glucoside saturated fatty acid ester extract obtained in embodiment 1 with silica gel according to a weight ratio of 1:10, elution is performed sequentially with petroleum ether with 5 times the column volume, ethyl acetate with 5 times the column volume, ethanol with 5 times the column volume and methanol with 5 times the column volume, an elution solution part which takes a solution of sulfuric acid and methanol in a volume ratio of 1:9 as a color developing agent, shows mauve color after being heated for 5min at 105°C and has the thin layer chromatography Rf of 0.68 to 0.77 is collected, and concentration is performed to obtain the sweet potato sitosterol glucoside saturated fatty acid ester extract, wherein the content of sweet potato sitosterol glucoside palmitate is 11%.

[0063] Embodiment 9: Preparation of Sweet Potato Sitosterol Glucoside Saturated Fatty Acid Ester Extract [0064] Silica gel column chromatography is performed on the sweet potato sitosterol glucoside saturated fatty acid ester extract obtained in embodiment 2 with silica gel according to a weight ratio of 1:100, elution is performed sequentially with petroleum ether with 2 times the column volume, ethyl acetate with 2 times the column volume, ethanol with 2 times the column volume and methanol with 2 times the column volume, an elution solution part which takes a solution of sulfuric acid and methanol in a volume ratio of 1:9 as a color developing agent, shows mauve color after being heated for 5min at 105°C and has the thin layer chromatography Rf of 0.68 to 0.77 is collected, and concentration is performed to obtain the sweet potato sitosterol glucoside saturated fatty acid ester extract, wherein the content of sweet potato sitosterol glucoside palmitate is 12%.

[0065] Embodiment 10: Preparation of Sweet Potato Sitosterol Glucoside Saturated Fatty Acid Ester Extract [0066] Silica gel column chromatography is performed on the sweet potato sitosterol glucoside saturated fatty acid ester extract obtained in embodiment 3 with silica gel according to a weight ratio of 1:50, elution is performed sequentially with petroleum ether with 3 times the column volume, ethyl acetate with 3 times the column volume, ethanol with 3 times the column volume and methanol with 3 times the column volume, an elution solution part which takes a solution of sulfuric acid and methanol in a volume ratio of 1:9 as a color developing agent, shows mauve color after being heated for 5min at 105°C and has the thin layer chromatography Rf of 0.68 to 0.77 is collected, and concentration is performed to obtain the sweet potato sitosterol glucoside saturated fatty acid ester extract, wherein the content of sweet potato sitosterol glucoside palmitate is 14%.

[0067] Embodiment 11: Preparation of Sweet Potato Sitosterol Glucoside Saturated Fatty Acid Ester Extract [0068] Silica gel column chromatography is performed on the sweet potato sitosterol glucoside saturated fatty acid ester extract obtained in embodiment 4 with silica gel according to a weight ratio of 1:500, elution is performed sequentially with petroleum ether with 2 times the column volume, ethyl acetate with 2 times the column volume, ethanol with 2 times the column volume and methanol with 2 times the column volume, an elution solution part which takes a solution of sulfuric acid and methanol in a volume ratio of 1:9 as a color developing agent, shows mauve color after being heated for 5min at 105°C and has the thin layer chromatography Rf of 0.68 to 0.77 is collected, and concentration is performed to obtain the sweet potato sitosterol glucoside saturated fatty acid ester extract, wherein the content of sweet potato sitosterol glucoside palmitate is 13%.

[0069] Embodiment 12: Preparation of Sweet Potato Sitosterol Glucoside Saturated Fatty Acid Ester Extract [0070] Silica gel column chromatography is performed on the sweet potato sitosterol glucoside saturated fatty acid ester extract obtained in embodiment 5 with silica gel according to a weight ratio of 1:200, elution is performed sequentially with petroleum ether with 3 times the column volume, ethyl acetate with 3 times the column volume, ethanol with 3 times the column volume and methanol with 3 times the column volume, an elution solution part which takes a solution of sulfuric acid and methanol in a volume ratio of 1:9 as a color developing agent, shows mauve color after being heated for 5min at 105°C and has the thin layer chromatography Rf of 0.68 to 0.77 is collected, and concentration is performed to obtain the sweet potato sitosterol glucoside saturated fatty acid ester extract, wherein the content of sweet potato sitosterol glucoside palmitate is 14%.

[0071] Embodiment 13: Preparation of Sweet Potato Sitosterol Glucoside Saturated Fatty Acid Ester Extract [0072] Silica gel column chromatography is performed on the sweet potato sitosterol glucoside saturated fatty acid ester extract obtained in embodiment 6 with silica gel according to a weight ratio of 1:600, elution is performed sequentially with petroleum ether with 2 times the column volume, ethyl acetate with 2 times the column volume, ethanol with 2 times the column volume and methanol with 2 times the column volume, an elution solution part which takes a solution of sulfuric acid and methanol in a volume ratio of 1:9 as a color developing agent, shows mauve color after being heated for 5min at 105°C and has the thin layer chromatography Rf of 0.68 to 0.77 is collected, and concentration is performed to obtain the sweet potato sitosterol glucoside saturated fatty acid ester extract, wherein the content of sweet potato sitosterol glucoside palmitate is 15%.

[0073] Embodiment 14: Preparation of Sweet Potato Sitosterol Glucoside Saturated Fatty Acid Ester Extract [0074] Silica gel column chromatography is performed on the sweet potato sitosterol glucoside saturated fatty acid ester extract obtained in embodiment 7 with silica gel according to a weight ratio of 1:600, elution is performed sequentially with petroleum ether with 2 times the column volume, ethyl acetate with 2 times the column volume, ethanol with 2 times the column volume and methanol with 2 times the column volume, an elution solution part which takes a solution of sulfuric acid and methanol in a volume ratio of 1:9 as a color developing agent, shows mauve color after being heated for 5min at 105°C and has the thin layer chromatography Rf of 0.68 to 0.77 is collected, and concentration is performed to obtain the sweet potato sitosterol glucoside saturated fatty acid ester extract, wherein the content of sweet potato sitosterol glucoside palmitate is 13%.

[0075] Embodiment 15: Preparation of Sweet Potato Sitosterol Glucoside Saturated Fatty Acid Ester Monomer [0076] The sweet potato sitosterol glucoside saturated fatty acid ester extract obtained in embodiment 14 is dissolved in methanol, treatment is performed with a C18 preparative column (the particle size of silica gel is 25pm), detection is performed with a 200nm wavelength, elution is performed with ethanol, and an eluting peak near 50min is collected to obtain sweet potato sitosterol glucoside dodecanoate of which the yield is I. 3%; an eluting peak near 85min is collected to obtain sweet potato sitosterol glucoside tetradecanoate of which the yield is 2.4%; an eluting peak near 115min is collected to obtain sweet potato sitosterol glucoside hexadecanoate of which the yield is 12.5%; and an eluting peak near 150min is collected to obtain sweet potato sitosterol glucoside octadecanoate of which the yield is 1.6%.

[0077] A hydrogen spectrogram and a carbon spectrogram of the sitosterol glucoside hexadecanoate (sitosterol glucoside palmitate) are as shown in FIG. 1 and FIG. 2, and the spectrogram data is as follows: [0078] H-NMR(600MHz, CDC13)5.3O((H, m, H-6), 4.4O(1H, d, J=6Hz, H-6’), 4.3O(1H, d, J=6Hz, H-l’), 4.22(1H, d, J=12Hz, H-l’), 3.36-3.56(m, H-3, 2’-5’), 2.28(2H, t, J=6Hz , -CH2CO-)1.30[m, -(CH2)n-], 0.94(3H, s, CH3-19), 0.85(3H, d, J=6Hz, CH3-21), 0.81(3H, t, J=6Hz, CH3-18”), 0.79(9H, m, CH3-26, CH3-27CH3-29, ), 0.61(3H, S, CH3-18,).

[0079] 13C NMR (600 MHz, CDC13)37.28(C-1), 29.65(C-2), 79.56(C-3), 38.92(C-4), 140.32(C-5), 122.15 (C-6), 31.95 (C-7), 31.91 (C-8), 50.83 (C-9), 36.75 (C-10), 21.08 (C-ll), 39.79 (C-12), 42.35(C-13), 56.79(C-14), 24.29(C-15), 28.22(C-16), 56.13(C-17), II. 85(C-18), 19.33(C-19), 36.14(C-20), 18.78(C-21), 33.99(C-22), 26.19(C-23), 45.89(C-24), 29.18(C-25), 19.04(C-26), 19.78(C-27), 23.11(C-28), 11.97(C-29), 101.21(C-l’), 73.65(C-2'), 76.05(C-3’), 70.15(C-4’), 73.98(C-5), 63.18(C-6’), 174.59(C-1"), 34.23(C-2"), 24.95(C-3"), 29.22(C-4"), 29.34(C-5"), 29.51(C-6"), 29.70(C-7"-12"), 29.30(C-13"), 31.89(C-14"), 22.67(C-15"), 14.07(C-16").

[0080] Embodiment 16: Tumor Cell Inhibition Activity Test of Sweet Potato

Sitosterol Glucoside Palmitate Monomer of the Present Invention [0081] Experimental materials: MCF-7 breast cancer cells and HCT8 colon cancer cells are purchased from Army Medical University, and other biochemical reagents such as bovine serum and cell culture materials are purchased from Beijing Dingguo

Biotechnology Co., Ltd.

[0082] Recovery and culture of cells: A cell cryopreservation tube is taken out of liquid nitrogen, the cell cryopreservation tube is quickly put into warm water with the temperature of 37°C, after the cell cryopreservation tube is completely thawed, the cell cryopreservation tube is quickly transferred into a super-clean bench, a solution is transferred into a 10 mL centrifugal tube after sterilization, 7 mL of RIPM-1640 culture medium (containing 10% FBS and 1% penicillin and streptomycin mixed solution) is added, centrifugation is performed for 5min at 3000 rpm in a centrifuge, then supernatant liquor is removed, 4 mL of RIPM-1640 culture medium (containing 10% FBS and 1% penicillin and streptomycin mixed solution) is added, blowing and beating and uniform mixing are performed, and then culture is performed in a culture bottle under the culture conditions that the temperature is 37°C and the content of CO2 is 5%.

[0083] Administration of cells: MCF-7 cells and HCT8 cells which are normal in form and good in growth vigor are selected, after about 80% of cells grow, the cells are digested with trypsin, a blood medium is added, the cells are blown and beaten down, then adherent culture is performed in a 90mm culture vessel, after the culture is performed for 24h, sweet potato sitosterol glucoside palmitate is added, the final concentration is controlled to be 10 mg/L and 1 mg/L, and culture is performed for 18h.

Sweet potato sitosterol glucoside linoleate and sweet potato sitosterol glucoside are controls, and all experimental parameters are controlled to be consistent with those of

medicines.

[0084] MTT experimental results show that under the administration concentration of 100 mg/L, 10 mg/L and 1 mg/L, the inhibition rates of the sweet potato sitosterol glucoside saturated fatty acid ester extract (1%, embodiment 1), the sweet potato sitosterol glucoside saturated fatty acid ester extract (10%, embodiment 8) and the sweet potato sitosterol glucoside saturated fatty acid ester monomers (sitosterol glucoside dodecanoate, sitosterol glucoside tetradecanoate, sitosterol glucoside hexadecanoate and sitosterol glucoside octadecanoate) to MCF-7 cells are as shown in table 1. Experiments take the sweet potato sitosterol glucoside linoleate and the sweet potato sitosterol glucoside as controls.

[0085] Table 1: Inhibition Rates (%) of Related Monomers to MCF-7 Tumor Cells

[0086] Results in the table 1 show that under high concentration, the sweet potato sitosterol glucoside saturated fatty acid ester extract has a certain inhibition effect on MCF-7, and under low concentration, the inhibition effect is very weak; the sweet potato sitosterol glucoside saturated fatty acid ester has a good inhibition effect on MCF-7, wherein sweet potato sitosterol glucoside palmitate has the highest inhibition effect on MCF-7 breast cancer cells, and the anti-tumor activity is reduced to a certain degree due to increase and decrease of carbon chains; and the inhibition effect of the sweet potato sitosterol glucoside palmitate on tumors is obviously higher than that of sweet potato sitosterol glucoside linoleate and sweet potato sitosterol glucoside, and the sweet potato sitosterol glucoside palmitate has good tumor prevention and/or treatment prospects.

Claims

WHAT IS CLAIMED IS:

1. A sweet potato sitosterol glucoside saturated fatty acid ester, having a chemical formula represented by formula I:

Formula I wherein, R=-CnH2n+i, 12 < n < 18, and n is an integer.
2. The sweet potato sitosterol glucoside saturated fatty acid ester according to claim 1, characterized in that n=15.
3. The sweet potato sitosterol glucoside saturated fatty acid ester according to claim 1, characterized in that R is straight-chain hydrocarbyl, and having a chemical formula represented by formula II:

Formula II.
4. A sweet potato sitosterol glucoside saturated fatty acid ester extract, containing a compound represented by formula I, and the compound represented by formula I accounts for 1% or more of the extract by weight, or the extract contains a

compound represented by formula II, and the compound represented by formula II accounts for 1% or more of the extract by weight;

Formula I wherein, R=-CnH2n+i, 12 < n < 18, and n is an integer;

Formula II.
5. The sweet potato sitosterol glucoside saturated fatty acid ester extract according to claim 4, characterized by containing a compound represented by formula II, and the compound represented by formula II accounts for 10% or more of the extract by weight.
6. The sweet potato sitosterol glucoside saturated fatty acid ester extract according to any one of claims 4 to 5, characterized in that the extract is obtained by precipitation, filtration/centrifugation and organic solvent extraction of sweet potato starch mother liquor, and the extract is dropped on a thin layer chromatography plate, is developed in a developing solvent of a mixed solution of chloroform, methanol and water in a volume ratio of 90:10:1, and performs color development by a color developing agent of sulfuric acid and methanol in a volume ratio of 1:9, and the extract shows mauve spots after being heated for 5min at 105°C.
7. A preparation method of the sweet potato sitosterol glucoside saturated fatty acid ester extract according to any one of claims 4 to 6, characterized by comprising the following steps: step 1: adding a precipitant with a weight ratio of 0.01% to 5% to the sweet potato starch mother liquor at 50 to 100°C, performing centrifugation or filtration, and taking the solid to obtain a sweet potato crude extract; and step 2: adding an organic solvent with a weight ratio of 1:1-10 to the sweet potato crude extract, performing stirring and then filtration, and concentrating the filtrate to obtain the sweet potato sitosterol glucoside saturated fatty acid ester extract.
8. The preparation method of the sweet potato sitosterol glucoside saturated fatty acid ester extract according to claim 7, characterized by further comprising step 3: performing column chromatography on the sweet potato sitosterol glucoside saturated fatty acid ester extract, collecting an elution solution which takes a mixed solution of chloroform, methanol and water in a volume ratio of 90:10:1 as a developing solvent, takes a solution of sulfuric acid and methanol in a volume ratio of 1:9 as a color developing agent, shows mauve spots after being heated for 5min at 105°C and has the thin layer chromatography Rf of 0.68 to 0.77, and concentrating the elution solution to obtain the sweet potato sitosterol glucoside saturated fatty acid ester extract.
9. A preparation method of the sweet potato sitosterol glucoside saturated fatty acid ester according to any one of claims 1 to 3, characterized by comprising the following steps: dissolving a sweet potato sitosterol glucoside saturated fatty acid ester extract in ethanol, performing column chromatography separation through alkylsilane bonded silica gel, taking an alcohol-water solution as an eluent, and collecting the elution solution corresponding to the retention time, thereby obtaining sweet potato sitosterol glucoside saturated fatty acid ester monomers.
10. Application of the sweet potato sitosterol glucoside saturated fatty acid ester according to any one of claims 1 to 3 and/or the sweet potato sitosterol glucoside saturated fatty acid ester according to any one of claims 4 to 8 in preparation of Medicines and health foods for treating and/or preventing tumors.
11. The sweet potato sitosterol glucoside saturated fatty acid ester extract according to claim 5, characterized in that the extract is obtained by precipitation, filtration/centrifugation and organic solvent extraction of sweet potato starch mother liquor, and the extract is dropped on a thin layer chromatography plate, is developed in a developing solvent of a mixed solution of chloroform, methanol and water in a volume ratio of 90:10:1, and performs color development by a color developing agent of sulfuric acid and methanol in a volume ratio of 1:9, and the extract shows mauve spots after being heated for 5min at 105°C.
12. A preparation method of the sweet potato sitosterol glucoside saturated fatty acid ester extract according to claim 4, characterized by comprising the following steps: step 1: adding a precipitant with a weight ratio of 0.01% to 5% to a sweet potato starch mother liquor at 50 to 100°C, performing centrifugation or filtration, and taking the solid to obtain a sweet potato crude extract; and step 2: adding an organic solvent with a weight ratio of 1:1-10 to the sweet potato crude extract, performing stirring and then filtration, and concentrating the filtrate to obtain the sweet potato sitosterol glucoside saturated fatty acid ester extract.
13. A preparation method of the sweet potato sitosterol glucoside saturated fatty acid ester extract according to claim 5, characterized by comprising the following steps: step 1: adding a precipitant with a weight ratio of 0.01% to 5% to a sweet potato starch mother liquor at 50 to 100°C, performing centrifugation or filtration, and taking the solid to obtain a sweet potato crude extract; and step 2: adding an organic solvent with a weight ratio of 1:1-10 to the sweet potato crude extract, performing stirring and then filtration, and concentrating the filtrate to obtain the sweet potato sitosterol glucoside saturated fatty acid ester extract.
14. A preparation method of the sweet potato sitosterol glucoside saturated fatty acid ester according to claim 2, characterized by comprising the following steps: dissolving a sweet potato sitosterol glucoside saturated fatty acid ester extract in ethanol, performing column chromatography separation through alkylsilane bonded silica gel, taking an alcohol-water solution as an eluent, and collecting the elution solution corresponding to the retention time, thereby obtaining sweet potato sitosterol glucoside saturated fatty acid ester monomers.
15. A preparation method of the sweet potato sitosterol glucoside saturated fatty acid ester according to claim 3, characterized by comprising the following steps: dissolving a sweet potato sitosterol glucoside saturated fatty acid ester extract in ethanol, performing column chromatography separation through alkylsilane bonded silica gel, taking an alcohol-water solution as an eluent, and collecting the elution solution corresponding to the retention time, thereby obtaining sweet potato sitosterol glucoside saturated fatty acid ester monomers.
16. Medicines for treating and/or preventing tumors, comprising the sweet potato sitosterol glucoside saturated fatty acid ester according to claim 2.
17. Medicines for treating and/or preventing tumors, comprising the sweet potato sitosterol glucoside saturated fatty acid ester according to claim 3.
18. Health foods for preventing tumors, comprising the sweet potato sitosterol glucoside saturated fatty acid ester according to claim 1.
19. Health foods for preventing tumors, comprising the sweet potato sitosterol glucoside saturated fatty acid ester according to claim 2.
20. Health foods for preventing tumors, comprising the sweet potato sitosterol glucoside saturated fatty acid ester according to claim 3.