Two new flavones, 5‐hydroxy‐8‐hydroxymethyl‐7,4′‐dimethoxy‐flavone ( 1 ) and 6‐hydroxy‐8‐hydroxymethyl‐7,4′‐dimethoxy‐flavone ( 2 ), together with six known flavones ( 3–8 ), were isolated from the bark of Lindera caudata . The structures of 1–8 were elucidated by spectroscopic methods including extensive 1D and 2D NMR techniques. Compounds 1–8 were evaluated for their anti‐tobacco mosaic virus (anti‐ TMV ) activity. The results showed that Compounds 1 and 2 showed high anti‐ TMV activity with inhibition rates of 31.2 and 28.8%, respectively. These values are close to those of positive control.
Cassia fistula L., (Leguminosae) is an ornamental tree with beautiful yellow flowers 1 .In China, it has been used as traditional Chinese medicine by people of Dai nationality (who lived in Xishuangbanna, Yunnan province) for treatment of diarrhea, gastritis, ringworm and fungal skin infections 2,3 .Previous phytochemical studies of C. fistula have shown the presence of anthraquinones 4,5 , steroids 6 , chromones 7,8 and flavonoids 9 .Motivated by a search for new bioactive metabolites from this plant, our group has investigated the chemical constituents of the bark and stem of C. fistula, which led to the isolation and characterization of a new chromone (Fig. 1).This paper deals with the isolation, structural characterization and anti-tobacco mosaic virus (anti-TMV) activities of this compound.UV spectra were obtained on a Shimadzu UV-2401A spectrophotometer.A Tenor 27 spectrophotometer was used for scanning IR spectroscopy with KBr pellets.1D and 2D NMR spectra were recorded on a DRX-500 NMR spectrometer with
Three new xanthones, 1-hydroxy-3-hydroxyethyl-5-methoxy-6-methoxycarbonylxanthone (1), 1,4-dihydroxy-3-hydroxyethyl-5-methoxy-6-methoxycarbonylxanthone (2), and 1-hydroxy-3-hydroxyethyl-4-methoxy-8-methoxycarbonylxanthone (3), together with five known xanthones (4-8) were isolated from the fermentation products of an endophytic fungus Phomopsis sp.. Their structures were elucidated by spectroscopic methods including extensive 1D- and 2D-NMR spectroscopic techniques. Compounds 1-3 and 7 were also tested for their cytotoxicity against five human tumor cell lines (NB4, A549, SHSY5Y, PC3, and MCF7) by the MTT method, with paclitaxel used as the positive control. Compound 1 showed cytotoxicity against A549 and PC3 cells with IC50 values of 3.2 and 2.5 μM, respectively, 2 showed potential cytotoxicity against NB4 cells, with an IC50 value of 3.6 μM, and 3 showed cytotoxicity against A549 cells with an IC50 value of 3.5 μM.
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