| The genus Paulownia, large deciduous tree, has been placed taxonomically in the family Scrophulariaceae. P. fortunei(Seem.)Hemsl, P. tomentose(Thunb.)Steud, P. elongate S.Y.Hu, P. catalpifolia Gong Tong, P. kawakammii Ito, P. fargesii Franch and P. australis Gong Tong are the main species of this genus. They are distributed throughout China, Korea and Japan. The leaves, flowers, bark, root, wood of Paulownia have been used in traditional herb medicine since ancient times for treatment of various diseases, such as cough, phlegm, carbuncle, hemorrhoid, gonorrhea, bronchopneumonia and so on. The research of chemical constituents in flora of Paulownia started from 1930s. Recently, much attention has been paid to the Paulownia genus and its chemical constituents.Objective To investigate the chemical constituents of the fruits of P. tomentosa (Thunb.)Steud, and do some primary researches on the cytotoxicity and anti-oxidand activity of some constituents. The relations of the flavonoids structures with their antioxidant activities were also discussed.Methods The 70% ethanol extract of the fruits of P. tomentosa(Thunb.)Steud were isolated and purifyed by using of silica gel column chromatography, sephadex LH-20 column chromatography, ODS column chromatography, TLC preparation and recrystallization techniques. The constituents’structures were identified on the basis of their chemical and physical properties as well as the spectra data of ESI-MS,’H-NMR,13C-NMR etal, compared with data reported in literatures. The cytotoxicity of five constituents were studied on human lung cancer A549 cell by MTT method, and paucatalinone A was chosen to some research on A549 cell cycle by Flow Cytometry analysis. The antioxidant effect of nine flavonoids were evaluated by DPPH method, by using natural antioxidants ascorbic acid as the comparison.Results Nineteen compounds were isolated and their structures were identified as followes:paucatalinone A (Ⅰ), paucatalinone B (Ⅱ), isopaucatalinone B (Ⅲ), paucatalinone C (Ⅳ), diplacone (Ⅴ),3’-methoxyluteolin-7-O-β-D-glucoside (Ⅵ), tricin-7-O-β-D-glucoside (Ⅶ),3’,4’,5,7-tetrahydroxy-6-[7-hydroxy-3,7-dimethyl-2(E)-octenyl]flavanone (Ⅷ), quercetin (Ⅸ), apigenin (Ⅹ), luteolin (Ⅺ),5,7,4’-trihydroxy-3’-methoxyflavone (Ⅻ), paulownin (ⅩⅢ), sesamin (ⅩⅣ), ursolic acid (XV),2a,3a,19a-trihydroxyurs-12-en-28-oic acid (ⅩⅥ), stigmasterol (ⅩⅦ),β-sitosterol (ⅩⅧ), daucosterol (ⅩⅨ). The investigation on antioxidant effect of the isolated flavonoids showed that nine flavonoids and ascorbic acid have scavenging effect to DPPH free radical, and the dose-effect relationship exists. Quercetin and paucatalinone A have great antioxidand activity, followed by luteolin, diplacone, paucatalinone C, isopaucatalinone B and paucatalinone B. Apigenin and 5,7,4’-trihydroxy-3’-methoxyflavone are less active. The analysis on the structures of flavonoids showed that the pyrocatechol hydroxy group of B ring was necessary for the antioxidant activities. The hydroxymethylation of -OH at B ring and the glycosylation of -OH at A ring were not favorable for antioxidant activities. Five compounds were performed on human lung cancer A549 cell to do the research on cytotoxicity by MTT method, and the results showed that compounds I-V have a strong cytotoxicity.Conclusions Nineteen compounds were isolated from the fruits of P.tomentosa. Compound Ⅰ、Ⅱ、Ⅲ、Ⅳ are new compounds. Compound Ⅶ、ⅩⅥ、ⅩⅦ were isolated from the Paulownia genus for the first time. Compound XIV were isolated from the P. tomentosa for the first time. The investigation on antioxidant effect of nine flavonoids isolated showed that quercetin and paucatalinone A have great antioxidand activity.Compound I-V have strong cytotoxicity, it may be associated with the inhibition of G1 phase of cell cycle that paucatalinone A have cytotoxicity on A549. |
PDF Full Text Request