Diterpenes from Nicotiana glutinosa and their Effect on Fungal Growth

Abstract

SUMMARY: The diterpenes sclareol and 13-epi-sclareol were isolated as a eutectic mixture from leaves of Nicotiana glutinosa. These compounds were probably present in liquid droplets which occurred on the leaf surface. These diterpenes did not prevent germination of fungal spores but markedly inhibited the radial extension of colonies growing on agar. This inhibition is shown to be due to an effect on the morphology of the fungi in which the degree of hyphal branching is increased. The possibility that sclareol/13-epi-sclareol influence the growth-regulatory processes of fungal hyphae and the potential of these compounds to affect growth of fungi on the surface of leaves of N. glutinosa is discussed.