Bioactive Diels-Alder Type Adducts from the Stem Bark of Morus macroura

Abstract

Five new compounds, named guangsangons A (1), B (5), C (6), D (7), and E (8), along with four known compounds, albafuran C (2), kuwanon X (3), kuwanon P (4), and kuwanon Y (9) were isolated from Morus macroura Miq.. Their structures were determined by means of spectroscopic analyses and chemical methods. These compounds were regarded biogenetically as Diels-Alder type adducts, and ¹H-NMR variable temperature experiments suggested that they all existed as an equilibrium mixture of conformational isomers in solution. Compounds 1 - 3 and 5 - 9 showed good anti-oxidation activity, with the inhibitory rate of malondialdehyde being from 90.1 % to 102.7 % at a concentration of 10^-4 mol/L and from 70.9 % to 88.1 % at a concentration of 10^-5 mol/L. Compounds 1, 5, and 7 showed anti-inflammation activity, with the inhibitory rates of release of lysosome enzyme from polymorphonuclear leukocytes of rats being 19.0 % (P > 0.05), 57.3 % (P < 0.001) and 24.3 % (P < 0.05) at concentrations of 10^-5 mol/L, respectively.

Key words

Morus macroura - Moraceae - anti-oxidation - anti-inflammation - guangsangons A - E

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