WO2000061162A1 - Use of tetrahydrocurcuminoids to regulate physiological and pathological events in the skin and mucosa - Google Patents

Abstract

The present invention is directed to a mixture of tetrahydrocurcuminoids which can be used for regulating random intracellular protein crosslinking, optimizing cell electric potential, treating a premalignant state or a malignancy, increasing intracellular transglutaminase activity, and reducing 'age spots' due to lipofuscin formation.

Description

USE OF TETRAHYDROCURCUMINOIDS TO REGULATE PHYSIOLOGICAL AND PATHOLOGICAL EVENTS IN THE SKIN AND MUCOSA

Background of the invention

A body cell owes its functioning in large part to its cytoskeleton, the structural

framework of the cell. The cytoskeleton is formed by components in the cytoplasm

that maintain cell shape, stabilize cell attachments to neighboring cells, and facilitate

specialized cell functions like endocytosis, exocytosis and cell motility. The

cytoskeleton includes several filamentous structures like microtubules,

microfilaments, intermediate filaments, and microtrabecular lattice. Proteins

participating in the formation of a cytoskeleton, especially microtubular-associated

proteins (MAPS) after being manufactured by the cell, are further adapted to the

cytoskeleton function in a process called post-translational modification, or cross-

linking. This process of proteins cross-linking is essential to stabilizing the

cytoskeleton, the event necessary to maintain cell homeostasis, physiological

processes, and cell development and maturation.

The post-translational modification of proteins involves several chemical

reactions. Protein phosphorylation exemplifies one of the most common

mechanisms of post translation modification of cellular proteins. Other examples

include methylestrification of proteins, ADP-ribosylation, protein glycosylation,

histone acetylation, hypusine formation and transglutaminase-catalyzed reactions.

The electric potential of a cell is an aspect of cellular physiology important to

the understanding of the mechanism of the invention. The electric potential of a cell is maintained by a complex balance between negatively and positively charged

molecules which results in a physiologic resting potential inside the cell of

approximately - 70 mV. This value is indicative of the cell's well-being. On the other

hand, the inability of a cell to maintain an optimal resting potential occurs in

pathological conditions, e.g. physical or chemical assaults, a disease process, and

the wear and tear due to aging. Optimal resting potential is conductive to the

physiological processes including post-translational protein modification and cross-

linking. It also holds true that the intact physiological cross-linking of proteins is

indicative of a cell's ability to maintain optimal resting electric potential,

Positive effects of cross-linking

Cross-linking of proteins, as it has been previously mentioned, is an outcome

of the post translational modification of proteins. Some of the most common cross¬

links identified in proteins forming cytoskeleton are Neee-(ggg-glutamyl)lysine and

N,N-bis(gggglutarnyl)polyamine. The formation of these two types of cross-links is

facilitated by the catalytic activity of a group of enzymes known as

transglutaminases. One of the well known transglutaminases in the body is

coagulation protein Factor XIII. This Factor causes cross-linking of the fibrin, which

acts as a stabilizing agent on blood clot formation. This type of modification is an

example of a life saving mechanism-based on protein cross-linking, that prevent

exsanguination in a cut or a wound.

Transglutaminases are responsible for facilitating a physiological process of

protein cross-linking, which under normal conditions leads to cell differentiation, thus the cell is able to fulfill its purpose, e.g. mucus secreting cell, phagocytic cell,

epithelial and tegumen cell protecting the tissue structure. Transglutaminase

activity, or its absence, plays a critical role in the differentiation of cancer cells,

especially skin cancer melanoma. Melanoma is a rapidly spreading cancer

consisting of undifferentiated skin cells, and the degree of poor cell differentiation

correlates well with the suppressed activity of transglutaminase. On the other hand,

experimental induction of transglutaminase activity led to promising results in

slowing-down or reversing melanoma progression. Examples of transglutaminase

inducers are retinoic acid and methylxantines. It appears that the therapeutic

potential of retinoids in melanoma is related to their ability to activate intracellular

transglutaminases.

Detrimental cross-linking

Cross-linking of intracellular proteins is, however, not always a positive event.

When a random and massive cross-linking is precipitated by an abrupt, non-

physiological stimulus, an accelerated aging of the cell occurs. Due to the nature of

random crosslinking, which defies the purpose of cell organization and

differentiation, this may lead not only to premature cell aging and death, but also can

lead to a pathology including malignancy. For example, the UVA-generated free

radicals in skin cells can cause premature cross-linking of proteins and liberation of

proteolytic enzymes. This latter event leads to the destruction of the cytoskeleton,

and the rapid deterioration of cell organization which compromises cell functioning.

It is of special interest to mention here the term lipofuscin, nicknamed "the aging pigment" or "liver spots", which occurs in the epidermis and mucous

membranes probably as a result of disrupted cellular and systemic metabolism.

Lipofuscin has been shown to result from the oxidative degeneration of mitochondria

and/or lysosomes in the cells. Lipofuscin is postulated to be a result of a metabolic

error which results in hypoanabolism combined with hyperkatabolism. It is

postulated here that lipofuscin formation is in part a manifestation of the disrupted

process of post-translational protein modification, and that this process intensifies

with any systemic disease process, including the aging process.

Related art

As previously mentioned, transglutaminases are responsible for facilitating

the physiological process of protein cross-linking, which under normal conditions

leads to cell differentiation, maturation and timely aging. There is considerable

evidence that intracellular transglutaminase activity may be inhibited in certain

pathology, for example malignancy, e.g. melanoma. It appears that therapeutic

potential of transglutaminase inducers like retinoids and methylxantines in

melanoma is related to their ability to activate intracellular transglutaminases. This

in turn would lead to differentiation of cells, which in clinical practice would lead to a

slow down of the disease process due to a decrease in the number of

undifferentiated malignant cells.

Curcumin derivatives including tetrahydrocurcumin and curcuminoids are well

recognized in literature as a group of phenolic antioxidants (Majeed et al.

Curcuminoid book). Majeed et al., U.S. Patent No. 5,861 ,415 established that the combination of naturally occurring curcuminoids isolated from turmeric root, i.e.

curcumin, demethoxy curcumin and bisdemethoxy curcumin produce a broad range

of antioxidant protection described as bioprotectant action. Bioprotectant action,

characterized by the prevention of free radical formation and intervention in

scavenging free radicals, is exerted by tetrahydrocurcumin(oids) (THC) as well as

curcumin(oids) (Majeed et a\.,Tumeric and the Healing Curcuminoids, Keats

Publications 1996 and Majeed et al., Curcuminoids Antioxidant Phytonutrients,

NutriScience Publishers 1995). However, tetrahydrocurcumin(oids) show superior

free radical scavenging properties, as compared to curcumin or curcuminoids

(Majeed et al. Curcuminoid book). Another advantage of tetrahydrocurcuminoids is

that they are not as highly colored curcuminoids and thus can be applied topically

without significant staining.

Recently curcumin but not tetrahydrocurcumin was found to have a

preventive effect on cross-linking of collagen in diabetic rats. (Sajithlal GB, Chithra

P, Chandrakasan G., Biochem Pharmacol 1998 Dec 15;56(12):1607-14). However,

the anti cross-linking effect of curcumin was attained with a very high oral dose of

the compound (200 mg/kg body wt.). It was also noted that the preventive effect of

curcumin on the advanced cross-linking of collagen was more pronounced than its

therapeutic effect. The authors of this study explained that the anti cross-linking

mechanism of curcumin is due to quenching the free radicals, which in turn would

prevent the accelerated cross-linking of collagen in diabetes. This study supports the

use of curcumin to prevent and to some degree treat excessive cross-linking of

proteins in conditions characterized by accelerated cross-linking such as diabetes. Description of the invention

The mechanism of the invention is in preserving homeostasis and functioning

of cells based on its regulatory, both inhibitory and stimulating, effect on the cross-

linking of intracellular proteins. This regulatory mechanism, previously unknown for

curcumin and its derivatives, is also unrelated to the well researched and described

antioxidant properties of curcumin(oids) and tetrahydrocurcumin(oids). It is a novel

way of accomplishing a broad regulatory effect on biological processes. A

comparable regulatory effect on cross-linking of proteins in the organism was not

described previously with any single compound or with compounded products. In

essence the invention differs from other compounds affecting the cross-linking

process in that the previously described compounds would stimulate or inhibit

intracellular cross-linking, while the invention would act as a cross-linking modifier

(CLM) or "crossregulin". These terms are used here for the first time to describe the

mechanism of the invention. CLM or crossregulin indicates that a composition of the

present invention exerts a positive influence on the post-translational protein

modification and cross-linking process in both physiological and pathological

conditions alike. The CLM effect of the invention is accomplished by using a specific

composition of the product as described in the section "Process of Obtaining THC".

The mechanism also occurs with modifications of the THC molecule, for example

ether THC, trimethyl ether THC, dimethyl ether THC, benzyl ether THC and

potassium, magnesium and copper salts of THC. The mechanism of the invention

has been demonstrated in in vivo experimental conditions such as preventing UV sunburn and cross-linking (percent of thymine dimer cells) in the skin cells exposed

to UV radiation. The biological properties of the invention were compared with those

of curcuminoids, and despite the fact that the present composition is devoid of

yellow color it still produces comparable protective effects against UV radiation as

that of yellow curcuminoids. This activity appears to be different from the antioxidant

effects characteristic of THC and curcuminoids.

The following describes the mechanism of the invention in detail:

1. It is proposed that in physiologic states characterized by optimal post-

translational protein modification, protein cross-linking, as well as the optimal

cell electric potential, THC would not interfere with the above exemplified

states of cellular well-being.

2. However, in the states, characterized by poor morphological and functional

differentiation of cells, e.g. pre-malignant states or malignancy, THC would

contribute to protein post-translational modification and cross-linking and

optimization of cell electric potential. This would be accomplished by

interaction between phenolic rings and olefinic bonds of THC and NH2 as well

as COO groups of the protein amino acids. The resulting bonds

would act as an "anchor" that would initiate cross-linking with other proteins.

3. In the states of cell aging and in the states where random cross-linking is precipitated by a thermal injury due to the action of UV rays, for example, the

undesired process would be prevented by the invention. THC would prevent

undesired cross-linking by attaching to amino and carboxy groups of the

protein amino acids. This would result in interference with the random cross-

linking, a mechanism comparable to a "buffering" action. This "buffering"

action would effectively stop the chain reaction which otherwise would lead to

deterioration of cell homeostasis, premature aging and premature cell death.

4. The invention also has a supportive mechanism in preventing random cross-

linking of intracellular proteins which is based on the antioxidant properties of

THC, specifically on the invention's ability to scavenge free-radicals. It is

proposed that due to this antioxidant action it would facilitate disruption of the

electric charges of "supercharged" protein molecules, which is one of the

reasons why random cross-linking is accelerated. This combined mechanism

of crossregulin and antioxidant action is particularly applicable in preventing

"age spots" due to lipofuscin formation, and inflammatory conditions such as

psoriasis.

5. The source of oxygen moieties in THC for binding to NH2 or COO groups

would be from the para hydroxy group no longer in conjugation with the olefinic

bond, and from the hydroxy groups of phenolic rings. 6. Unlike the curcumin(oid) compound(s), THC molecule(s) can rotate more

freely, thus providing better access to the reactive groups for "anchor" and/or

"buffering" reactions.

7. Whereas, as previously mentioned, the invention is relatively inactive in

states of cell physiology, its crossregulin mechanism would be gradually

expressed proportionate to the degree of stress acting upon the cell. Thus the

crossregulin mechanism of THC in the biological system would depend on the

kind of injurious action experienced by the biological system.

Process of obtaining THC:

Tetrahydro curcuminoids of the invention are products of the chemical

reduction of curcuminoids, obtained from the rhizomes of Curcuma longa, commonly

known as turmeric, or any other suitable plant from the botanical family

Zingiberaceae.

The prior art teaches that when curcuminoids obtained from Curcuma longa

are catalytically reduced and then isolated in the process of crystallization,

tetrahydrocurcumin (THC) is recovered without a loss, but with substantial losses of

tetrahydrobisdemethoxy curcumin (THBDC) and tetrahydrodemethoxy curcumin

(THDC). As a result, the ratio among tetrahydrocurcuminoids is significantly

changed as compared to tile original ratio of parent compounds, curcuminoids. The

ratio of curcuminoids is preferred, because it correlates with the optimal biological activity of curcuminoids. U.S. Patent No. 5,861 ,415 describes curcuminoids in a

specific and optimal ratio as Bioprotectants, providing maximal protective effect of

the living cell.

The present invention provides a new, more efficient method of recovering

THCs. This process prevents the loss of TBDMC and TDMC, and provides a

Bioprotectant composition of THCs.

THCurcuminoids % content prior art % content invention

Tetrahydro curcuminoids 90 75 - 85

Tetrahydro demethoxy curcumin 9 10 - 20

Tetrahydro bisdemethoxy curcumin 1 2 - 4.5

Brief outline of the prior art process for producing THCs

Natural curcuminoids (95 %) - 100 gm

Acetone - 1 liter

Pd-C (catalyst) 5% - 2.5 gm

The solution of natural curcuminoids was charged into a hydrogenator. The

catalyst was added carefully and the pressure of hydrogen was maintained at about

2 Kg/cm2. This reaction is completed in 3 to 4 hrs. The catalyst is then filtered out and removed. The acetone solution is concentrated under vacuum. The residue is

crystallized from toluenes. The tetrahydro compounds are crystallized out as a

creamy white powder having a melting point of 92-94°C.

Process of the Present invention

This process utilizes a novel method of saturation of two olefinic bonds in

curcuminoids in the catalytic hydrogen transfer reaction known as a hydride transfer

reaction. The following is an example of a hydride transfer method.

1. A 3 liter round bottom flask with a stirrer and a reflux condenser is charged

with 1 liter ethyl acetate;

2. The solution is charged with 250 gm of natural curcuminoids in a previously

described Bioprotectant composition, i.e. curcumin (C) 70-80%, Demethoxy

curcumin (DMC) 15-20% and Bisdemethoxy curcumin (BDMC 2.5-6.5% and

stirred to uniformity at room temperature;

3. This mixture is charged with 1 liter of triethylamine followed by 12 gm of

Palladium carbon and 80 ml of formic acid; 4. The mixture was stirred and subsequently refluxed at 80 deg. Celsius for

12 hours.

5. Periodically formic acid in 5 ml aliquots was charged at 2 hours intervals

while a reflux was carried on;

6. TLC was checked to monitor the completion of the reaction, (system: Silica

Precoated 0.25 mm thick plates/chloroform : methanol = 9: 1 );

7. After completion of the reaction, the reaction mixture was cooled to room

temperature. It was filtered to remove palladium catalyst and washed with 50

ml of ethyl acetate;

8. Ethyl acetate and triethylamine were distilled off ( 2 liters of distillate was

collected);

9. The crude mass was then extracted with toluene (3 x 500 ml);

10. The toluene extract was washed with 200 ml of 5% HCI and 3 x 500 ml of

water and dried over sodium sulphate; 11. The solvent was removed under vacuum to get a pale yellow paste

approximately 200 gm.

12. The paste was slurred with 200 ml of ether, filtered and dried under

vacuum to obtain a pale yellow powder of tetrahydrocurcuminoids, Yield 175

gm (70%).

Assay:

THC 75 to 85%

THDHC 10 to 20%

THBDMC 2 to 4.5%

In another variation of hydride transfer reaction, curcuminoids were treated

with ammonium formate or sodium dihydrogen phosphite (as a catalytic hydrogen

transfer reagent) in the presence of Pd/C and acetic acid. The reduction is complete

in 20 to 30 minutes at 100 to 110 Celsius degrees. This method yields 50% of

tetrahydrocurcuminoids.

THC can be administered topically in a suitable vehicle or with an application

device, e.g. a transdermal patch, in a concentration ranging from 0.025% to 5%; in

the form of subcutaneous injections or a transdermal patch in a concentration ranging from 0.025% to 5%; or in orally administered dosage form in a concentration

ranging from 5 mg to 500 mg per dose or 0.083 - 8.3 mg/kg of body weight. THC is

suitable for human and animal use.

Other routes of administration include but are not limited to: aerosol or other

device for delivery to the lungs, nasal spray, intravenous, intramuscular,

intraperitoneal, intrathecal, vaginal, and rectal. Excipients which can be used as a

vehicle for the delivery of the phage will be apparent to those skilled in the art.

Compositions of tetrahydrocurcuminoids for topical administration should be

essentially colorless. The term "essentially colorless" is intended to mean that the

composition contains no color or such a small amount of color that the composition

does not stain the skin upon topical administration.

The term "color removed curcumin" refers to the tetrahydrocurcuminoid

mixture according to the present invention.

THC molecule acting as an "anchor" for amino acids of proteins, to initiate protein crosslinks. This mechanism would contribute to the physiological cross-links.

Legend amino acid/protein

THC molecule acting as a buffer in preventing random cross-links in UN precipitated cross-links. This mechanism would contribute to die prevention of pathological crosslinks.

THC

Legend

-amino acid protein INTRODUCTION

The study was designed to determine the acute oral toxiάty of Colour Removed Curcumin to Sprague Dawiey rats. The guideϋnes followed were as prescribed by die Gaitonde Committee Guidefines, CH, New Delhi

PROJECT N0.4952

MATERIALS AND METHODS

TEST SUBSTANCE

Sponsor Sa i Chemicals and Extracts LtcL, Bangalore.

Label on Sample : Colour Removed Cαrcnmin Batch No.- CRC/65 ARNo. - BL8C 0445

Description Creamy white crystalline powder

Identification IR Spectrum : Complies

Solubility Soluble in methanol

Purity by HPLC 99.0%

PROJECT N0.4 52

SUMMARY

The study now reported was designed to determine die acute oral toxiάty of Colour Removed Curcumin to Sprague Dawiey rats. The test substance suspended in co oil was administered by oral route to rats. The rats were observed for 14 days after treatment for the product related symptoms. The test snbstance caused salivation all animals and polyurea in two animals with onset at 2 hours after the treatment. AH *t n_. survived through the study period of 14 days and were free of intoxicating signs 24 hours after the treatment.

The LD50 value of Colour Removed Curcumin in rats by oral route was found to be greater than 5000 mg/kg. TEST SYSTEM

Species Rat

Strain Sprague Dawiey

Source LIT. Animal house

Sex Male and Female

Age 6 to 8 weeks

Weight range 120.5 to 141.9 gms

No. of animals per dose 5 per sex

Randomization Randomly selected in groups of five of like sex at the time of initiating the study.

Accfimatiσn Not done as the animals were bred and reared in die same Institute.

Identification of antmqls By cage number and individual marking on for. Diet Pelleted feed supplied by Nav Maharashtra Chakan Oil Mills Ltd., Pune.

Water Aquaguard pure water in glass bottles ad libitum.

Management The rats were housed S each, of the same sex in polypropylene cages provided with bedding of husk. The temperature was maintained between 20 &-24 °C and relative humidity between 50 and 60%; 12 hours each of dark and light cycle was maintained.

Route Oral gavage

Vehicle used Com oil

Dose volume 10 ml/kg The test substance, suspended in coin oil was administered once each by oral gxvage in rats of both saxes. The rats were starved for 16 hours before and 2 hours after the administration of the test substance. The animals woe observed for 14 days after the dosing for the product related toxic symptoms and mortality. Necropsy was carried out animals died during the observation period. At the end of the observation period the surviving test animals were sacrificed, dissected and examined for gross pathological abnormality, if any.

Ten rats (5 male and 5 female) was allocated to treatment as follows.

Group No._ No.of rats per sex Dosc ft/ty

1 5000

PROJECT NO.4 52

RESULTS

LDso in rats

Group No. Dose (mg kg) No. of aiiml. _ Mortality

No. of animals treated

5000 0/10

Symptoms :

Group 1 ^• Salivation in all animals and polyurea in two animals were observed with onset at 2 hours after the treatment. All animals survived through the study period of 14 days and were free of intoxicating signs 24 hours after the treatment.

Necropsy findings : No significant changes could be seen with naked eye.

SUMMARY

The study was deagned to determine the primary skm irritation potential of Colour Removed Cuxαmin supplied by Sami Chemicals and Extracts Ltd* Bangalore. The test substance in die amount of 500 mg was applied to shorn back dm both intact and abraded site of three rabbits per sex. Each site of application was carefhHy observed and the reaction evaluated according to Drake's method at 24 and 72 hours. Colour Removed Curcumin did not cause irritation to skin in rabbits. Primary skin irritation score - 0.00.

MATERIALS AND METHODS

TEST SUBSTANCE

Sponsor Sami Chemicals and Extracts Ltd_*, Bangalore.

Label on Sample : Colour Removed Curcumin Batch No.- CRC/65 ARNo. - BL8C 0445

Description Creamy white crystalline powder

Identification IR Spectrum : Complies

Solubility : Soluble in methanol

Purity by HPLC : 99.0% TEST SYSTEM

Species Rabbit

Strain New Zealand White

Source Serum Institute of India Ltd., Pane.

Sex Male and Female

Age Healthy adult

Weight range 2.00 to 2.40 kg

No. of animals per dose 3 per sex

Randomization Randomly selected in groups of three of like sex at the time of initiating the study.

Acclimation Seven days prior to treatment.

Identification of animals By cage number and individual marking on ear.

Diet Pelleted feed supplied by Nav Maharashtra Chakan Oil Mills Ltd., Pone.

Water Aquaguard pure water in glass bottles ad libitum.

Management The rabbits were housed individually each, in stainless steel cages provided with stainless steel mesh bottom. The temperature was maintained between 20 & 23 "fiend relative humidity between 50 and 60 ; 12 hours each of dark and light cycle was maintained.

Route Dermal

Dose volume 500 tog/she. EXPERIMENTAL PROCEDURE

Three rabbits per sex were used for this study. The hair on both die sides were removed by electric clippers one day before the treatment The test snfwtmrr in die amount of 500 mg was applied to the intact and abraded slrin sites of each test animaL Care was taken to note that the abrasions penetrate die Stratum coπieum but not he dezmis. A gauze patch was secured over each treated area by means of adhesive tape. The animals were housed singly with plastic collar around their necks for 24 hours α order to avoid die mgestion of test substance. The patch and unabsorbed test substance was removed after 24 hours. Each site of application was carefully observed and reaction evaluated according to Draize's method at 24 and 72 hours.

Braize Evaluation of Skin Reactions -

Grading of skin reaction

1. Erythema and Eschar Formation

No erythema 0

Very slight erythema (barely perceptible) I

Well defined erythema 2

Moderate to severe erythema 3

Severe erythema (beet redness) to slight eschar formation (injuries in depth) 4

Total n -r miiTT- possible erythema scor : 4

2. Edema Formation

No edema 0

Very slight edema (barely perceptible) 1

Slight edema (edges of area well defined by definite raising) 2

Moderate edema (raised approximately 1 mm 3

Severe edema (raised more than 1 mm and extending beyond area of exposure) 4

Total maximum possible edema score : 4 RESULTS

Summary of mdividual dermal irritation score following appScatiøn of Colour Removed Curcumin on rabbits.

Primary skin irritation score 0.00 / 4 = 0.00.

CONCLUSION

It is concluded based on the presem study that of the test substance Colour Removed Curcumin supplied by Sami Chemicals and Extracts Ltd., Bangalore did not cause irritation to skin in rabbits. Primary skin irritation score : 0.00.

*NTC: natural STC: synthetic.

O 00/61162

Effect of topical application of curcumin and tetrahydrocurcumin on ultraviolet B light-induced formation of thymine dlmers in mouse epidermis

Treatment Number of Percent of Percent of per group thymine dimer cells protection

1. No UVB 3 0

2. Acetone +UVB 7 8.9 ± 0.02 0

3. THC (10 μ ol) + UVB β 7.3 * 0.03 24.7

4. THC (20 μmol) + UVB 6 1.6 ± 1.30 82.0 δ. Curcumin (10 μmol) + UVB 5 1.6 ± 0.01 82.0 6. Curcumin (20 μmol) + UVB 5 1.2 * 1.69 86.5

Female SKH-1 mice (8-9 weeks old) were treated topically with 100 μl acetone, or test compound in 100 μl acetone. Five minutes later, the mice were irradiated with a βlnglβ dose of UVB (30 mJ/cm2). The mice were killed one hour later, and the skin samples were stored in a 10% formalin-phosphate buffer for thymine dimβrs assay.

Effect of UVB-lnducβd formation of skin sunburn cells in mouse epidermis

Treetmeπt Number of Percent percent per group of sunburn cells of inhibition

No UVB 0.1

Aoetone + UVB (60 mJ/cm2)

DB + (10 μmol) 5 1 .2 60 DBM + (20 μmol) 5 0.9 70

Tetrahydrocurcumin (10 μmol) UVB 5 1 .6 47 Tetrahydrocurcumin (20 μmol) UVB 5 1 .4 53

Female Sencar mice were irradiated with UVB (80 mJ/cn.2), The mice were treated topically with 100 μl acetone or inhibitor in 100 μl aoetone at 5 min before the UVB irradiation. Eight hours later, the mice were killed and skin samples were removed and kept in 10 % formalin phosphate buffer for sunburn cells assay.

Claims

1. A method for regulating random intracellular protein cross-linking and

optimizing cell electric potential in a patient, comprising administering an effective

amount of a mixture of tetrahydrocurcuminoids to a patient in need of such

regulation.

2. The method according to claim 1 , wherein said random intracellular protein

cross-linking is due to exposure to UV rays.

3. The method according to claim 1 , wherein said random intracellular protein

cross-linking is due to the presence of a malignancy.

4. The method according to claim 1 , wherein said intracellular protein

crosslinking is regulated by bonding said tetrahydrocurcuminoids to amino and

carboxy groups of amino acids.

5. A method for treating a premalignant state or a malignancy in a patient

comprising administering an effective amount of a mixture of tetrahydrocurcuminoids

to a patient suffering from a premalignant state or a malignancy.

6. The method according to claim 5, wherein said malignancy is melanoma.

7. A method for increasing intracellular transglutaminase activity in a cell

comprising administering an effective amount of a mixture of

tetrahydrocurcuminoids to a cell with decreased intracellular transglutaminase

activity.

8. A method for producing tetrahydrocurcuminoids by saturating two olefinic

bonds in a mixture of curcuminoids, comprising the steps of

mixing ethyl acetate and curcuminoids at room temperature;

adding a catalytic hydrogen transfer reagent followed by palladium carbon

and an acid;

stirring and subsequently refluxing the mixture while periodically adding

aliquots of said acid;

cooling the resulting mixture to room temperature;

filtering the mixture to remove any palladium carbon;

washing the mixture in ethyl acetate;

distilling off any ethyl acetate;

extracting the resulting crude mass with toluene to produce a toluene extract;

washing the toluene extract with HCI and water;

drying said extract;

removing any remaining toluene under vacuum to produce a paste;

mixing said paste with ether to produce a slurry, and filtering and drying said slurry under vacuum to obtain tetrahydrocurcuminoids.

9. The method according to claim 8, wherein said curcuminoids comprise

70-80% curcumin, 15-20% demethoxy curcumin, and 2.5-6.5% bisdemethoxy

curcumin.

10. The method according to claim 8, wherein said catalytic hydrogen transfer

reagent is selected from the group consisting of triethylamine, ammonium formate

and sodium dihydrogen phosphite.

11. The method according to claim 8, wherein said acid is selected from the

group consisting of formic acid and acetic acid.

12. A method for producing tetrahydrocurcuminoids by saturating two olefinic

bonds in a mixture of curcuminoids, comprising the steps of

mixing ethyl acetate and curcuminoids at room temperature;

adding a catalytic hydrogen transfer reagent followed by palladium carbon and

an acid;

heating the resulting mixture;

cooling the heated mixture to room temperature;

filtering the mixture to remove any palladium carbon; and recovering any tetrahydrocurcuminoids.

13. A mixture comprising 75-85% tertahydrocurcumin, 10-20%

tetrahydrodemethoxy curcumin, and 2.0-4.5% tetrahydrobisdemethoxy curcumin,

wherein said mixture is substantially colorless.

14. The mixture according to claim 13, wherein said mixture is in a form suitable

for topical administration.

15. A method for reducing "age spots" due to lipofuscin formation in a patient in

need of such treatment, comprising administering an effective amount of a mixture

comprising 75-85% tertrahydrocurcumin, 10-20% tetrahydrodemethoxy curcumin,

and 2.0-4.5% tetrahydrobisdemethoxy curcumin to said patient.

16. The method according to claim 13, wherein said composition is administered

topically.

17. A colorless mixture comprising tertrahydrocurcumin, tetrahydrodemethoxy

curcumin, and tetrahydrobisdemethoxy curcumin.