Secondary Metabolites from Higher Plants

Abstract

The leaf surface chemicals of green tobacco (Nicotiana tabacum L.), derived mostly from the trichomes, consist primarily of α and β -4, 8, 13-duvatriene-1, 3-diols, α and β -4, 8, 13 duvatrienols, (DVT diols, ols), docosanol, hydrocarbons and sucrose esters. Of these, the DVT diols, DVT ols, and sucrose esters, significantly inhibit the growth of wheat coleoptiles. In addition, DVT diols and ols are ovipositional stimulators for the tobacco budworm Heliothis virescens and experiments show that egg numbers and DVT concentration are logarithmically proportional. Gram positive bacteria, Bacillus subtilis and B. cereus, are inhibited by α-DVT diol:gram negative bacteria and the fungi Curvularia lunata and Aspergillus flavus are not inhibited. Sucrose esters, wherein the acyl groups are mixtures of C2-8 fatty acids, also inhibit growth of wheat coleoptiles, but the 3-methylvalerate sucrose ester is the most inhibitory. The 3-methylvalerate sucrose ester also inhibits gram positive B. subtilis, B. cereus, and Mycobacterium theromosphactum, but does not inhibit gram negative bacteria, or the fungi C. lunata and A. flavus. Neither 3-methylvalerate glucose, nor methylvaleric acid, nor the K+ salt have biological activity. Combinations of high levels of DVT diols, and sucrose esters, inhibit budworm larval development.