| Objective: To make a systematic study on the chemical constituents of the stems and leaves of male plants in Trichosanthes kirilowii Maxim. This research provided some reference for the comprehensive utilization of the stems and leaves of male plants in Trichosanthes kirilowii Maxim that wasted in production and theoretical basis for further research of Trichosanthes kirilowii MaximMethods: The stems and leaves of male plants in Trichosanthes kirilowii Maxim was separated and purified by many chromatographic methods, including polyamide resin chromatography, Sephadex LH-20, silica gel chromatography, C18 middle-pressure chromatography, High-Speed Counter-Current Chromatography and high performance liquid chromatography and so on. The chemical structures of compounds were determined on the basis of the chemical properties and spectral analysis. Besides, we performed a primary research on the the DPPH radical scavenging activity of seven flavonoids from stems and leaves of male plants in Trichosanthes kirilowii Maxim.Results: 26 compounds were isolated from stems and leaves of male plants in Trichosanthes kirilowii Maxim, and the structures of 21 compounds were successfully elucidated, as loliolide(1), 4-[formyl-5-(methoxymethyl)-1H-pyrrol-1-yl] butanoic acid(3), 4-(2-formyl-5-methoxymethylpyrrol-1-yl) butyric acid methylester(5), 4-hydroxybenzyl methyl ether(6), p-hydroxybenzaldehyde(7), abscisic acid(11), pentanedioic acid, 3-hydroxy-3-methyl-[2-(4-carboxy-3-methyl-1,3-butadienyl)-2-hydroxy-1,3-dimethyl-5-ox o-3-cryclohexen-1-yl]-methyl methyl ester(12), trans-cinnamic acid(13), vanillic acid(14), trans-ferulic acid(15), 3-(hydroxyacetyl) indole(16), p-hydroxybenzoic acid(17), p-hydroxycinnamic acid(18), protocatechuic acid(19), luteolin-7-O-β-D-glucoside(20), chrysoeriol-7-O-β-D-glucoside(21),apigenin-7-O-β-D-glucopyranoside(22),diosmetin-7-O-β-D-glucopyranoside(23), quercetin-3-O-β-D-glucopyranoside(24), luteolin(25), chrysoeriol(26). All compounds except compounds 3, 17 and 20~22 were isolated from stems and leaves of male plants in Trichosanthes kirilowii Maxim for the first time. Compounds 5, 11~13 and 15~16 were separated from the plant of Trichosanthes kirilowii Maxim for the first time.Under the present experimental condition, the order of their DPPH-scavenging capacities is:Ⅰ>Ⅲ>Ⅶ>Ⅱ>Ⅳ>Ⅵ>Ⅴ. The research showed that the ability of scavenging DPPH free radicals of flavonoids with 3′,4′ two adjacent hydroxide groups in B ring is much higher than that of flavonoids only with 4’ hydroxyl in structure. Its scavenging ability decreased significantly because of 3′ or 4′ hydroxyl methylation. In addition, the ability would also decrease if there is a 7 hydroxyl glycosylation in the structure. Above all, the research provided theoretical basis for further research of the structure activity relationship between flavonoids and its DPPH-scavenging capacity.Conclusions: The results of this study showed the necessity to investigate the chemical constituents of stems and leaves of male plants in Trichosanthes kirilowiit Maxim. and the possibility to turn waste into treasure. This study would also provided the theoretical basis for further research of Trichosanthes kirilowii Maxim. |
