Liver–protective Principle of Thujopsis dolabrata Leaves1

Abstract

The protective action of methanol extract of a Japanese folklore medicine „asunaro–yo”, Thujopsis dolabrata leaves, on CCl₄–induced liver damage in mice has been assessed with a liver function test to reveal that some extracts are effective for protection of the experimental liver lesion. One of the extracts has been fractionated, monitored by the serum enzyme assay, furnishing a lignan, desoxypodophyllotoxin, as the active principle. The protective effect of desoxypodophyllotoxin against CCl₄ hepatotoxicity has been shown by liver function tests as well as by pathological examinations. Desoxypodophyllotoxin had no appreciable effect on the serum enzyme activity of normal mice. Remarkable variation has been found in the content of the active principle desoxypodophyllotoxin and consequently the protective activity of the leaves.