Study On The Bioactive Components From Twigs And Leaves Of Kopsia Hainanensis

Kopsia hainanensis Tsiang (Apocynaceae) is a species of the genus Kopsia, which is widely distributed over Southeast Asia, comprises about26species, four of which grow in China. Plants belonging to this genus are prolific producers of a wide variety of indole alkaloids, many of which have intriguing carbon skeletons. These alkaloids have interesting biological activities such as antitussive, antitumor, and antileishmanial activites. Kopsia hainanensis was used for the treatment of rheumatoid arthritis, pharyngitis, tonsillitis, and dropsy in Chinese folk medicine. Previous chemical investigations on this plant have led to24alkaloids, but there is no more further study on the biological activity and other active constituents of this plant. In an effort to search for more bioactive compounds, chemical constituents from K. hainanensis were studied under bioassay guidance of antitumor and antimicrobial for the purpose of developing this plant resource.Twenty-one constituents were isolated from the ethanol extract of the twigs and leaves of K. hainanensis by column chromatography and semipreparative HPLC on the guidance of activity-tracking, and their structures were identified by physicochemical and spectroscopic methods (including MS, IR, UV, ID,2D-NMR and X-Ray etc) as kopsihainin D (1), kopsihainin E (2), kopsihainin F (3), kopsinine (4), tubotaiwine (5),19(s)-methoxytubotaiwine (6), kopsiflorine (7), kopsinarine (8),(2/β,5β)-aspidofractinin-16-ol (9), kopsinilam (10),5,22-dioxokopsan (11), kopsifine (12),(-)-leuconolam (13), O-methylleuconolam (14),8-hydroxypinoresinol (16), dihydrodehydrodiconiferyl alcohol (17), β-amyrin (18), ursolic acid (19),2a,3β-dihydroxyursolic acid (20), and β-sitosterol (21) respectively; The structure of compound15was determined by single crystal X-ray diffractometry to be alkaloid A (15). Compounds1-3were new indole alkaloids, and compounds1-3,6-9, and12-21were isolated from this species for the first time.The antimicrobial activites against Staphylococcus aureus and Methicillin-resistant Staphylococcus aureus (MASR) of all compounds were measured using paper disco diffusion method, among them, compounds1-3,5, and7had inhibitory activities against Staphylococcus aureus, and compounds4,5,17, and19had inhibitory activities against MASR.The cytotoxicities of compounds1-21were evaluated in vitro using the MTT method. Compound19showed inhibitory activities towards chronic myelogenous leukemia (K562), human gastric carcinoma (SGC-7901) and human hepatoma (SMMC-7721) cell lines.