Chemical Constituents from the Alcohol Extract of Root Bark of Celastrus Angulatus
|Keywords||Celastrus angulatus β-dihydroagarofuran chemical constituents isolation and identification NMR assignment|
Celastrus angulatus Maxim is a perennial woody vine plant of Celastraceae, Celastrus L. It is a valuable resources of botanical insecticide, widely distributed over the basin of Yellow River and Yangtze river. And its insecticidal ingredients were a series of sesquiterpene polyol esters bearing P-dihydroagarofuran skeleton. It has the insecticidal action, antifeedant action, insect narcosis on the pests. In order to find more active compounds, establishing fingerprint of insecticidal ingredients and further study on structure-activity relationship, we have undertaken a systematic investigation on the chemical constituents of the root bark of Celastrus angulatus.In this paper, studies the chemical constituents from the alcohol extract of root bark of C. angulatus. After further divided the extracts, then crossed the atmospheric pressure chromatography column, with petroleum ether-ethyl acetate as eluant. Prepared by thin-layer examination and preparative HPLC. The compounds structures were confirmed by NMR spectra (including 1H NMR,13C NMR, DEPT,1H-1H COSY, NOESY, HSQC, HMBC) as well as consulting document. Twenty compounds were isolated. They were:(+)-Catechin (H-1),(-)-Epicatechin (H-2),3β-hydroxyolean-9(11),12-diene (H-3),β-Sitosterol (H-4), Celahin B (H-5), 1β,2β,6α,15-tetraacetoxy-9a-benzoyloxy-8P-isobutanoyloxy-β-dihydroagrofuran (H-6), Celastrine A (H-7), Celahin D (H-8), 1β,2β,6α,8β,15-pentaacetoxy-9p-benzoyloxy-β-dihydroagrofuran (H-9), angulatin E (H-10), angulatin A (H-11), Celangulatin C (H-12), Celangulin XIX (H-13), angulatin P (H-14), angulatin H (H-15), 1β,2β,8α, 15-tetraacetoxy-9β-benzoyloxy-4a,6a-dihydroxy-β-dihydroagrofuran (H-16), Celan-gulin III (H-17), Chinese Bittersweet Alkaloid B (H-18), angulatin J (H-19) and Wilforsinine B (H-20). Four of them, H-6, H-9, H-16, H-18, are new compounds; H-5, H-7, H-8, H-20 were first found in C. angulatus. Finally, four compounds, H-5, H-7, H-10, H-15, were completely assigned using a combination of 1D NMR and 2D NMR.