Studies On Chemical Constituents And Antibacterial Activity Of Pholidota Cantonensis Rolfe.

Pholidota cantonensis Rolfe.,a medicinal plant,mainly distributed in Yunnan,Guangdong,Guangxi,Guizhou,Zhejiang,Fujian,Hunan,Jiangxi Provinces etc.of China,It is a Chinese folk herbal medicine with a long history of safe use for treating sore throat,tonsillitis,cough phlegm asthma,pneumonia,acute soft-tissue trauma and arthritis,etc.However,as for P.cantonensis,one of the typical species in South China,the relevant chemical and pharmacological studies are limited.In order to further research and development the resources of P.cantonensis,Studies have been conducted on the active components leading to antibacterial effects on the herb.The 80%ethanol extract of the whole plant P.cantonensis was separated by chromatography on silica gel,Sephadex LH-20,MCI gel and pre-HPLC.The structures of compounds from P.cantonensis were elucidated on the basis of the chemical evidence and 1H-NMR,13C-NMR,2D-NMR and MS spectral.The minimum inhibitory concentration(MIC)and the inhibition zone of different extracts from P.cantonensis were measured by tube dilution method and agar diffusion method;the MIC and the minimum bactericidal concentration(MBC)of some compounds were determined by the broth microdilution method.31 compounds were isolated from P.cantonensis:Batatasin Ⅲ(1),Gigantol(2),Thunalbene(3),Orchinol(4),Phocantol(5),Ephemeranthoquinone(6),Densiflorol B(7),Phocantone(8),Tanshinone IIA(9),Neo-tanshinlactone(10),Syringaldehyde(11),Syringate(12),3,5-dimethoxy-4-hydroxy-propiophenone(13),Syringin(14),Cinnamic acid(15),Butylcinnamate(16),E-Ferulic acid docosyl ester(17),Syringaresinol(18),Tangshennoside Ⅲ(19),Phocantoside A(20),Phocantoside B(21),24-methylenecycoartanol(22),24-methylenecycloartone(23),24-Methylenepollinastanone(24),Hop-22(29)-ene(25),Ergosterol peroxide(26),β-sitostenone(27),Stigmasterol(28),Daucosterol(29),β-Sitosterol(30),1-docosanol(31).Including 10 stilbenoid compounds,9 phenolic compounds,2 diterpene glycosides,4 triterpenoids,5 steroids and 1 fatty alcohol.there are four new Compounds:Compound 5,8 are new stilbenoid compounds,Compound 20,21 are new diterpenoids,it is the first time that diterpenoids were isolated from the genus Pholidota,and compounds 9-10,12,14-16,19,23-25,27-28,31 were isolated from P.cantonensis for the first time.The extracts of P.cantonensis had more inhibiting effect on Candida albicans and gram-positive bacteria such as Staphylococcus aureus,Staphylococcus epidermidis and Peptostreptococcus micros than that on gram-negative bacteria.MIC of different extracts of P.cantonensis Rolfe.against Candida albicans and gram-positive bacteria were in the range of 80-120 mg/mL,and that of gram-negative bacteria in the range of 100-160mg/mL.Compounds 1,4,18,19 had good inhibitory effect on Candida albicans,the MIC were less than 25 μg/mL;compounds 1,3,4,19 had good inhibitory effect on Pseudomonas aeruginosa,the MIC were also less than 25μg/mL,especially the compound 3 has showed good bacteriostatic action and bactericidal action,and the MIC and MBC of compound 3 against Pseudomonas aeruginosa were 11.67 μg/mL;Compounds 1,3,4,18,19 showed bacteriostatic action and bactericidal actiont against Escherichia coli,the MIC and MBC were about 50 μg/mL;Compounds 1,3,4,19 showed bacteriostatic action and bactericidal actiont against Canidia albicans too,the MIC and MBC were about 50 μg/mL.The finding of the compounds and the research on the antimicrobial activity enriched the chemical compositions of P.cantonensis,laid the foundation for the further study of the effective substance and the quality control for P.cantonensis,the discovery of new compounds enriched the content of natural product,provided the material basis for new bioactive discovery.