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Oxyfadichalcones A (I) and B (II) are unprecedented chalcone dimers fused by head-to-tail [2 + 2] cycloaddition, that has never been found previously in nature.

Oxyfadichalcones A (I) and B (II) are unprecedented chalcone dimers fused by head-to-tail [2 + 2] cycloaddition, that has never been found previously in nature.

Oxyfadichalcones A and B, two unprecedented chalcone dimers fused through a cyclobutane ring by head-to-tail [2+2] cycloaddition of two chalcones that had never been found previously in nature, along with oxyfadichalcone C, a new head-to-head [2+2] cyclized chalcone dimer, were simultaneously obtained from Oxytropis falcata. Structural elucidation was succeeded by spectroscopic and single-crystal synchrotron radiation analysis. Additionally, the photosynthesis of the chalcone dimers was performed and the plausible biosynthesis was discussed. (C) 2013 Elsevier Ltd. All rights reserved.

Objective: To study the chemical constituents of the Tibetan medicine Caryopteris toroetii.; Method: The crude drug was extracted with 95% EtOH and isolated by repeatedly chromatographic methods. The structures of the isolated compounds were elucidated by spectral analysis.; Result: Six compounds were yielded and identified as: phenethyl cinnamide (1), 1-hydroxy-2, 3, 4, 5-tetramethoxy-xanthone (2), 1-hydroxy-2, 3, 5-trimethoxy-xanthone (3), (2S)-5-hydroxy-7-methoxyflavanone (4), 2', 4'-dihydroxydihydrochalcone (5) and rutin (6).; Conclusion: All the above compounds were obtained from C. toroetii for the first time.;

Four different extracts of Oxytropis falcata, including the aerial aqueous extract, and the underground aqueous extract, the aerial lipophilic extract, and the underground lipophilic extract were prepared and then administrated orally to mice at the maximum dose (50 g x kg(-1) x d(-1) calculated by raw material) for fifteen days respectively. Compared with the control group, which was administrated of 1.0% tween-80, the treatment groups did not show significant differences in appearance and behavior. However, the organcoefficient, blood biochemical indicator and pathological section results showed that the lipophilic extracts of the aerial and underground parts of O. flacata showed mild injury to the liver of mice, while the aerial and underground aqueous extracts and the underground lipophilic extract showed mild toxicity to the kidney of male mice. Chemical analysis showed that the lipophilic extracts of the aerial and underground parts, especially aerial lipophilic extract, consisted of large amount of flavonoid aglycones with little amount of polysaccharides and proteins, while the aqueous extracts contained much polysaccharides and proteins with almost no flavonoid aglycones detected.