Extractives of Polygala. Part 5. New trioxygenated xanthones of P. arillata

Abstract

The stems and roots of Polygala arillata have been shown to contain 1-hydroxy-2,3-dimethoxyxanthone (1), 1,2,3-trimethoxyxanthone (2), 1-hydroxy-2,3-methylenedioxyxanthone (3), 1-methoxy-2,3-methylenedioxyxanthone (4), and a compound that yields 1,3,4-trimethoxyxanthone (5) on methylation. Additionally, senegenic acid and large amounts of esters of glucose and of either protocatechuic acid or gallic acid have been isolated. Ring-B oxygen-free xanthones are comparatively rare, and this is the first report of the co-occurrence of the biogenetically related 1,2,3- and 1,3,4-trioxygenated xanthones in nature.