Studies On The Chemical Constituents And Bioactivities Of Dioscorea Bulbifera L. And Alternaria Brassicicola

The main contents of Chapter1focus on the studies on the chemical constituents and biological activities of the medicinal herb Dioscorea bulbifera L.. The main contents of Chapter2are about the investigation on the secondary metabolites of Alternaria brassicicola, an endophytic fungi isolated from Siegesbeckia pubescens, and on the revised structures of compound skeleton of brassicicene C by using quantum chemical calculation methed.Chapter1:Study on the chemical constituents and bioactivities of plant Dioscorea bulbifera L.Dioscorea bulbifera L., a vines plant, which has the effects of expectorant, treating cough, anti-inflammatory, acetanilide detumescence, and blood coagulation, has been used historically as a traditional Chinese medicine to treat cancer and thyroid diseases for thousands of years.41compounds were isolated from Dioscorea bulbifera L. collected in Hubei province by repeated chromatography (silica gel, ODS, Sephadex LH-20, HPLC), and were identified by the physical and chemical properties and various spectroscopic methods including IR, UV, HRESIMS, NMR, MS, X-ray single crystal diffraction, and Mosher’s method.The isolates were diosbulbin N (1), diosbulbin O (2), diosbulbin P (3),12-epidiosbulbin B (4), diosbulbin A (5), diosbulbin B (6), diosbulbin C (7), diosbulbin D (8), diosbulbin F (9), diosbulbin G (10), doisbulbinoside G (11), β-sitosterol (12), stigmasterol (13), diosgenin (14), diosbulbisin A (15), diosbulbisin B (16), diosbulbisin C (17), diosbulbisin D (18), daucosterol (19), prosapogenin A (20), diosbulbiside A (21), diosbulbiside B (22), quercetin (23), caryatin (24),3,5,3’-trimethoxyquercetin (25), kaempferol (26),7,4’-dihydroxy-3,5-dimethoxyflavone (27),3,7-dimethoxy-5,4’-dihydroxyflavone (28),3,7-dimethoxy-5,3’,4’-trihydroxyflavone (29),5,7,3’,4’-tetrahydroxyflavan-3-ol (30),2,5,2’, 3’-tetrahydroxy-3-methoxybibenzyl (31), batatasin Ⅲ (32), thunalbene (33), emodin (34), diobulbinone A (35), isovanillic acid (36), methyl eucomate (37), n-butyl eucomate (38), planchol A (39),1-Linolenoylglycerol (40),1-Linoleoylglycerol (41). Compounds1-11were norclerodane diterpenoids,12-22were steroidal sapogenins and glycosides,23-30were flavonoids,31-33were bibenzyls,34-41were other compounds. Compounds land3were new compounds,2and4were a new naturally occurring compound, and37-41were obtained from the plant for the first time.Their cytotoxic activities for1-4were also evaluated against five human cancer cell lines, including HL-60, SMMC-7721, A-549, MCF-7, and SW-480using MTT method. However, the bioassay results revealed that1-4has no in vitro cytotoxicities against all five cancer cell lines (IC50>40μM).Chapter2:Study on the chemical constituents and bioactivities of Alternaria brassicicola.Alternaria brassicicola, an endophytic fungi isolated from Siegesbeckia pubescens, is belonging to Alternaria species.21compounds were isolated from the EtOAc extracts of rice cultivation of Alternaria brassicicola by repeated chromatography (silica gel, ODS, Sephadex LH-20, HPLC), and were identified by the physical and chemical properties and various spectroscopic methods including IR, UV, HRESIMS, NMR, MS, X-ray single crystal diffraction, ECD, and Mosher’s method.The isolates were tarassicene A (1)、tarassicene B (2)、harassicene A(3)、 brassicicene A (4)、brassicicene L (5)、brassicicene B (6)、tricycloalternarene K (7)、 cinnacidin B (8)、cinnacidin C (9)、cinnacidin D (10)、cinnacidin E(11)、N-[9,10-Dihydrojasmonoyl]-isoleucine (12)、(3S,7S)-N-jasmonoyl-D-isoleucine (13)、N-[9,10-Dihydrojasmonoyl]-valine (14)、infectopyrone (15)、4Z-infectopyrone (16)、 novae-zelandin A (17)、novae-zelandin B (18)、3,5-dihydroxyacetophenone (19)、 alternarienonic acid (20)、desmethylaltenusin (21)、Compounds1-7were diterpenoids,8-14wre amides,15-21were other compounds. Compounds land2contain a new fusicoccane skeleton with5-9-5ring system,3contains another new fusicoccane skeleton with5-7-6-5ring system,4,5,7,8,9,10,11were new compounds,12-21were obtained from the fungi for the first time.Their cytotoxic activities for1-14were also evaluated against five human cancer cell lines, including HL-60, SMMC-7721, A-549, MCF-7, and SW-480using MTT method. However, the bioassay results revealed that1-14has no in vitro cytotoxicities against all five cancer cell lines (IC50>40μM).The antibacterial activity was determined by the2-fold microtiter broth dilution method. The following eight microorganisms were used in this study:Escherichia coli, Klebsiella pneumonia, Pseudomonas aeruginosa, Enterococcus casseliflavus, Staphylococcus aureus, Staphylococcus epidermis, Proteus mirabilis, and Salmonella typhimurium. The experiment shows that the compounds1-5and7-14showed no antibacterial activity towards the tested strains, with MIC>256μg/mL.The structures of the brassicicenes C-H was reassigned on the basis of calculated13C chemical shift data using B3LYP/6-31G*GIAO NMR predictions, an advanced quantum chemical calculation methed.