ABSTRACT
From the acetone extract of Teucrium tomentosum, a new antifeedant neo-clerodane diterpenoid teuctosin (1) was isolated along with teuflin (2), teucrin-H(2) (3), 6beta-hydroxyteuscordin (4), 6beta-acetylteuscordin (5) and montanin-D (6). The structure of the new compound was elucidated comprehensively using 1D and 2D NMR methods and confirmed by X-ray crystallography. All the compounds showed effective antifeedancy against Plutella xylostella and Spodoptera litura at 10 mug/cm(2) of leaf area.
Subject(s)
Diterpenes, Clerodane , Diterpenes/chemistry , Diterpenes/pharmacology , Teucrium/chemistry , Animals , Crystallography, X-Ray , Diterpenes/isolation & purification , Feeding Behavior/drug effects , Insecticides/chemistry , Insecticides/isolation & purification , Insecticides/pharmacology , Molecular Structure , Moths/drug effects , Nuclear Magnetic Resonance, Biomolecular , Plant Extracts/chemistry , Spodoptera/drug effectsABSTRACT
A new diterpene, viz. 3beta-acetoxy-4alpha,18:15,16-diepoxy-6beta,12-dihydroxyneocleroda-13(16),14-dien-19,20-olide, C(22)H(28)O(8), exhibiting antifeedant activity against Spodoptera litura was isolated from the aerial parts of Teucrium tomentosum and its structure is reported. One of the two fused rings has a distorted-chair conformation and the other has a chair conformation. The molecules in the crystal are stabilized via O--H...O and C--H...O hydrogen bonds.
