Study On The Bioactive Components Of Elephantopus Tomentosus

Elephantopus tomentosus L.(Asteraceae) is a species of the genus of Elephantopus, which is usually used as antifebrile, diuretic, antiviral, and antibacterial agent, especially for treating hepatitis, bronchitis, fever, the cough associated with pneumonia, and arthralgia. Domestic and international phytochemical studies on the plants of this genus indicated that the main chemical constituent was sesquiterpene lactones, which show several pharmacological activities such as antimalarial, antitumor, and antihypertensive, et al. It is reported that the main chemical constituents of E. tomentosus are germacranolides and triterpenoids, but there is no further study on the biological activity. In an effort to search for bioactive compounds, chemical constituents from E. tomentosus were studied under bioassay guidance of antitumor and antimicrobial assay for the purpose of developing this plant resource.The chemical constituents of the liposoluble components from E. scaber and E. tomentosus were compared and analyzed by GC-MS. Forty-four compounds were identified from E. Scaber, accounting for93.72%of the total liposoluble components, and twenty-five compounds were identified from E. tomentosus, accounting for82.08%of the total liposoluble components. It were the significant difference to the component and content of liposoluble components of E. scaber and E. tomentosus, which showed inhibitory bacterial activities against methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus aureus by paper disk diffusion method and the inhibitory activitiy of E. tomentosus was stronger.Compounds1-20were isolated from the ethanol extract of E. tomentosus by column chromatography, and their structures were identified as tomenphantopin H (1), tomenphantopin C (2), tomenphantopin D (3), tomenphantopin E(4), tomenphantopin F (5), molephantin (6),2-deethoxy-2-methoxy-phantomolin (7),2-deethoxy-2-hydroxyphantomolin (8),2β-methoxy-2-deethoxy-8-O-deacylphantomolin-8-O?-tiglinate (9),2,5-epoxy-2/β-hydroxy-4a-methoxy-8a-(2-methyl-propenoyloxy)-10(14),11(13)-germacradien-12,6a-olide (10), epifriedelanol (11), lupeol (12),30-oxo-lupeol (13), butulinic acid (14), ursolic acid (15), ferulic acid (16),3-formylindole (17), pinellic acid (18),6-deoxyisojacreubin (19) and β-daucosterol (20) by physicochemical and spectroscopic methods (including MS, IR, UV,1D and2D NMR, etc). All compounds were obtained from E. tomentosus for the first time, compounds1-5were new compounds. The cytotoxicity of compounds1-20was evaluated in vitro using the MTT method. Compounds1,3,6and8-10showed significant inhibitory activities towards chronic myelogenous leukemia (K562) and human hepatoma (SMMC-7721) cell lines. Compounds15possessed inhibitory effect on K562cell line while compounds7and16possessed inhibitory effects on SMMC-7721cell line. The antimicrobial activities against Staphylococcus aureus and Ralstonia solanacearum of compounds1-20were measured using paper disco diffusion method, among them, compounds1,3,6-10and16-18exhibited antimicrobial activities in different degrees, and compounds6-8showed the strongest inhibitory activities towards the two bacteria, while compounds2,4,5,11-15,19and20exhibited no activities.