Study On The Chemical Constituents And Biological Activities Of The Pericarp Of Garcinia Mangostana

Objective:In this paper,the chemical composition of the ethyl acetate part of the pericarp of Garcinia mangostana was studied systematically in order to clarify its chemical composition and carry out the structural identification and preliminary activity evaluation of the isolated compounds,initially screening out the anti-MRSA(Methicillin-resistant Staphylococcus aureus,MRSA)or the active ingredient that inhibits Histone Lysine Specific Demethylase 1,LSD1,providing science for further research and development of the medicinal value of mangosteen peel.Methods:(1)Extraction,separation,and identification of chemical constituents:The pericarp of Garcinia mangostana was first extracted with 80%ethanol,and then the ethanol extract was extracted with ethyl acetate.The chromatographic separation technique was used to separate and purify the chemical components of the ethyl acetate portion,combined with the spectrum Chemical analysis method to characterize the isolated monomer compounds.(2)Evaluation of the activity of anti-drug resistant strain MRSA:Kirby-Bauer method and micro broth dilution method were adopted for the drug sensitivity test.The active monomer compounds were preferably selected by the presence or absence of the inhibition zone,combined with the size of the MIC(minimum inhibitory concentration)value.(3)LSD1 inhibitory activity test:All the obtained monomer compounds were conducted preliminary screening through the established LSD1 screening platform,and compounds with certain activities are subjected to further activity tests and IC50 values are calculated by SPSS software.Finally,the compounds with LSD1 inhibition activity were selected.Results and conclusion:1.A total of 18 monomers were isolated,all of them were xanthones,including 17-ethoxy-garcinone D(1),garcinone D(2),garcinone C(3),mangaxanthone B(4),12-hydroxy-1-isomangostin hydrate(5),1,6-dihydroxy-7-methoxy-8-(3-hydroxy-3-methylbutyl)-6',6'-dimethyl-4',5'-dihydropyrano[2',3':3,2]xanthone(6),garcimangosxanthone E(7),1,7-dihydroxy-2-(3-methylbut-2-enyl)-3-methoxyxanthone(8),garcinone E(9),?-mangostin(10),?-mangostin(11),?-mangostin(12),cratoxylone(13),1-isomangostin(14),8-deoxygartanin(15),gartanin(16),ananixanthone(17),morusignin J(18).Among them,17-ethoxy-garcinone D(1)and 12-hydroxy-1-isomangostin hydrate(5)are new compounds which have not been reported in the literature.Cratoxylone(13),ananixanthone(17)and morusignin J(18)were isolated from the pericarp of Garcinia mangostana for the first time.2.Evaluation of anti-MRSA activity:A total of 17 monomer compounds participated in the evaluation.The screening result of K-B paper diffusion method(selecting the standard strain of Staphylococcus aureus ATCC29213)showed that 12 of the compounds had activity,and further determined their MIC value(selecting Staphylococcus aureus ATCC29213).Due to the limited solubility of the compound,the first well concentration was set to 16 ?g/mL.In the end,8 compounds(compounds 1,3,4,7,10,11?13)were screened with good anti-MRSA activity.Among them,compound 17-ethoxy-garcinone D(1)is a new compound and has good anti-MRSA activity(MIC value is 2 ?g/mL,MBC value is 2?8 ?g/mL),compound 4(mangaxanthone B)and 7(garcimangosxanthone E)anti-MRSA activity is the first time discovery.3.Evaluation of LSD 1 inhibitory activity:A total of 17 monomer compounds(except compound 9)participated in the test.The results showed that compound 10(?-mangostin),compound 11(?-mangostin),and compound 16(gartanin)had certain inhibitory LSD1 activity,IC50 are 2.210 ?M,1.052 ?M,and 5.158 ?M,respectively.Among them,the LSD1 inhibitory activity of compounds 11 and 16 was discovered for the first time.