Study On Bioactive Components From The Twigs Of Trigonostemon Heterophyllus

Trigonostemon heterophyllus Merr. belongs to the genus Trigonostemon of family Euphorbiaceae. The genus of trigonostemon has been used in Thai and chinese traditional medicine as an antidote, expectorant, and laxative agent. Previous chemical investigations on this genus have led to the isolations of a number of structurally interesting compounds such as daphnane diterpenoids, phenanthrenes, and alkaloids, some of which showed various bioactivities, such as anti-HIV, antibacterial, and cytotoxic activities. Tigonostemon heterophyllus is a shrub endemic to Hainan province. To search for more bioactive constituents from the twigs of Tigonostemon heterophyllus, chemical constituents and bioactivities were studied under bioassay guidance of antitumor and antimicrobial for the purpose of developing this plant resource.Fifteen compounds were isolated from the ethanol extract of the twigs of T. heterophyllus by column chromatography, and their structures were indentified by physicochemical properties and spectral data (UV, IR, MS,1D and2D NMR) as trigonoheterene (1), trigonoheterene B (2), trigonoheterone (3), trigonoheteran (4),3,4-seco-sonderianol (5), trigonochinene E (6),(+)-lyoniresinol (7), acareubin (8), protocatechuic acid methyl ester (9),3-hydroxy-4-methoxybenzoate (10),4-hydroxy-3-methoxybenzoic acid (11), trans-p-hydroxycinnamic acid methyl ester (12), epilotaustralin (13),β-daucosterol (14), and β-daucosterol (15) respectively. Compounds1-15were isolated form T. heterophyllus for the first time, compounds1-4were new compounds.The cytotoxic activities of compounds1-13were tested by MTT method. Compound6possessed strong activity against K562with an IC50value of6.4μg/mL, the compound5also had potent activities against K562, SMMC-7721and SGC-7901cell lines, and compound1had weak activity against K562. The antimicrobial activities against Staphylococcus aureus and Methicillin-resistant Staphylococcus aureus (MRSA) of all the compounds were measured using paper disco diffusion method, among them, compounds1,3,5,6, and8exhibited antimicrobial activities in different degrees, and compound3showed the strongest inhibitory activity towards the two pathogenic bacteria. The anti-pathagenic activities also were measured using paper disco diffusion method, among them, compounds1,5,6and8showed inhibition against Ralstonia solanacearum and compound5showed inhibition against Xanthomonas oryzae.