Résumé
Objective:To isolate the chemical constituents from lipid-soluble parts of Tibetan Tinospora sinensis and identify the structure of the monomer compounds. Method:Eighty kg of dried rhizomes of T. sinensis were soaked by 80% ethanol (5 times of the dose of crude drug) for 1 hour, boiled under reflux for 1 hour,then and filtered. The above steps were repeated. The two extracts were combined,and the solvent was recovered to obtain a total extract. The obtained extract was extracted with a conventional solvent,and the solution was recovered to obtain petroleum ether extract,methylene chloride extract,ethyl acetate extract,n-butanol extract and water extract. Methylene chloride extract was isolated and purified by silicagel column chromatography,semi-preparative liquid chromatography and SephadexLH-20 chromatography; the chemical structure was identified on the basis of ESI-MS,nuclear magnetic resonance (1H-NMR and 13 C-NMR) spectroscopy data and literatures. Result:Fifteen compounds were isolated and identified respectively as n-dodecanol (1),n-hexacosanol (2),palmitic acid (3),dibutyl phthalate (4),vanillic acid (5),vanillin (6),apocynin (7),tinocordifolioside (8),medioresinol (9),isolariciresinol (10),aurantiamide (11),aurantiamide acetate (12),berberine (13),daucosterol (14),β-sitosterol (15). Conclusion:Except for 3,4,6,14,15,the other 10 compounds were isolated from the plant for the first time.
Résumé
The crude extracts of the fermentation broth from a marine sediment-derived actinomycete strain, Saccharothrix sp. 10-10, showed significant antibacterial activities against drug-resistant pathogens. A genome-mining PCR-based experiment targeting the genes encoding key enzymes involved in the biosynthesis of secondary metabolites indicated that the strain 10-10 showed the potential to produce tetracenomycin-like compounds. Further chemical investigation of the cultures of this strain led to the identification of two antibiotics, including a tetracenomycin (Tcm) analogs, Tcm X (1), and a tomaymycin derivative, oxotomaymycin (2). Their structures were identified by spectroscopic data analysis, including UV, 1D-NMR, 2D-NMR and MS spectra. Tcm X (1) showed moderate antibacterial activities against a number of drug-resistant pathogens, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci (VRE) pathogens, with the MIC values in the range of 32-64 microg x mL(-1). In addition, 1 also displayed significant cytotoxic activities against human cancer cell lines, including HL60 (leukemia), HepG2 (liver), and MCF-7 (breast) with the IC 50 values of 5.1, 9.7 and 18.0 micromol x L(-1), respectively. Guided by the PCR-based gene sequence analysis, Tcm X (1) and oxotomaymycin (2) were identified from the genus of Saccharothrix and their 13C NMR data were correctly assigned on the basis of 2D NMR spectroscopic data analysis for the first time.