Study On Active Components And Mechanism Of Black Sesame Melanin To Blacken Hair

Background and objective:Gray hair is an external expression of aging when the human body reaches a certain age,but the premature appearance of gray hair can cause annoyance and cause social disorders such as inferiority.Nowadays,it has become a common phenomenon in the society that premature hair graying of young people,which not only affects their image,but also increases their psychological pressure.There are many causes in human premature hair graying,often different from person to person.Stress at work or life,genetic or disease factors,lack of nutrition or trace elements can cause early gray hair.At present,modern medicine does not have effective methods and drugs for the treatment of hair graying.Most people choose hair dyes for the sake of beauty to temporarily cover the original color of the hair.However,it can damage the protective film of the hair,damage the scalp and hair follicles,accelerate the keratinization of the hair follicles,and lead to hair thinning.It can also cause hair loss and even major diseases.Tyrosinase is a key rate-limiting enzyme in melanin synthesis,and its activity plays a decisive role in melanin synthesis.The reduced or lost tyrosinase activity in melanocytes is thought to be one of important reasons for the premature hair graying,which can cause the hypopigmentation,even unpigmentation of hair.Studies on the pathology of pigment diseases and drug intervention in pigment metabolism have been focused on the activity of tyrosinase.Black sesame is a black mature seed of Sesamum indicum L.,which is rich in lipids,proteins,melanin,minerals,etc.As the homologous substance of medicine and food,it has significant nutritional health care and medical treatment effects.Traditional Chinese medicine believes that human hair is most closely related to the liver and kidneys,and black sesame not only frequently appears in blacken hair prescriptions because of its effects of tonifying liver and kidney,nourishing blood and moistening intestines,and modern pharmacological researches also show that black sesame has the potential for blackening hair.In addition,melanin in black sesame is a good natural antioxidant resource,and can be extracted from sesame residue after oil extraction.It has broad application prospects,but the current research on black sesame melanin is mainly concentrated on crude extracts.In order to further understand the components of melanin in black sesame,reveal the mechanism of black sesame,screen out the best active components,and find out the new active compounds that activate tyrosinase,the following five parts of the research were carried out.(1)Using 80%ethanol to reflux extract for obtaining the total melanin of alcohol of black sesame,and then separate and purify the ethyl acetate part of melanin by repeating column chromatography,recrystallization etc.The obtained single compound was identified by 1H-NMR and 13C-NMR.(2)The effect of six crude extracts of melanin from black sesame seeds on tyrosinase activity was determined in vitro using the mushroom tyrosinase-DOPA rate oxidation method.(3)The cell model of B16 murine melanoma was used to determine the effect of each component on cell proliferation by MTT assay,the effect of each component on tyrosinase activity in cells was determined by DOPA oxidation assay,and the NaOH lysis assay was used to determine the effect of each component on the amount of melanin produced by cells.(4)Zebrafish was used as an experimental animal.After treatment with different agents,the zebrafish was anesthetized and photographed.Image J software was used to calculate the optical density value of the specific area of the zebrafish,and the effects of crude extract of black sesame seeds and single compound on the melanin metabolism of zebrafish embryos were evaluated.(5)2.5%hydroquinone was applied to the shaved area of the back of C57BL/6 mice to simulate the hair graying by reducing tyrosinase activity.The general state of the mice,organ index and the number of hair follicles containing melanin were analyzed for showing the effects of melanin alcohol extract A(80%ethanol extract of black sesame)and compound samin on the organs of the mice and melanin production in hair follicles.Results:(1)Four single compounds were isolated and purified from the ethyl acetate fraction of black sesame melanin,and were respectively identified as(+)-sesamolin,(+)-sesamin,samin,and pinoresinol.(2)Under the same concentration of the final concentration of 1 mg/mL,the melanin alcohol extract A(80%ethanol extract of black sesame)has the highest activation rate of tyrosinase in the six crude extracts.The ethyl acetate extract and water extract of the melanin alcohol extract A,the melanin water extract A(water extract of black sesame)and the melanin water extract B(black sesame seeds extracted with water after extracted with 80%ethanol)showed no activation effect on tyrosinase activity.The activation effect of the n-butanol extraction part of the melanin alcohol extract A was not obvious.(3)In the concentration range of 25—200 μg/mL,melanin alcohol extract A,melanin alcohol extract B(black sesame seeds extracted with 80%ethanol after extracted with water)and black sesame protein extract increase B16 murine melanoma cell proliferation,intracellular tyrosinase activity and melanin production.(4)In the final concentration of 100μg/mL,among the four single compounds,samin has the strongest promotion effect on melanin production in zebrafish embryos,which has a significant difference compared with the control group.(5)The experimental results show that melanin alcohol extract A and samin have no effect on the spleen,thymus and liver indexes of mice,and melanin alcohol extract A can increase the number of melanin-containing hair follicles in mice.