Biological activities anti-feedant

Usnic acid (7.53)—a highly biologically active dibenzofuran—is a phenol oxidation product of an acylphlorogludnol. It is produced by numerous lichens, including several Usnea species. Apart from its antibiotic and anti-leukemic activity, it has insect anti-feedant activity. Its presence may account for the observation that many lichens are resistant to serious insect attack. 

C22H28O6, Mr 388.46, square prisms, mp. 196-197 °C. G., a very bitter-tasting diterpene of the 4a,5/S- cler-odane type from the liverwort Gymnocolea inflata, shows a number of biological activities Thus anti-feedant effects on larvae of Japanese Pieris species, inhibition of root growth (10 -10 Mol) in the cress (Lepidium sativum), and promotion of germination (10 -10" Mol) of wheat seeds have been reported. Ut. J. Hattori Bot. Lab. 39,215 (1975). Zinsmeister Mues (eds.), Bryophytes, their Chemistry and Chemotaxonomy (Proc. Phytochem. Soc. Eur. 29), p. 399,404, Oxford Clarendon Press 1990. 

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