Variations in the essential oil composition of <i>Persea bombycina </i>(King ex Hook. f.) Kost and its effect on mug a silkworm (<i>Antheraea assama </i>Ww) — A new report

Abstract

<i>Persea bombycina, </i>with the local name 'Som', is a primary food plant for the 'muga' silk worm (<i>Antheraea assama </i>Ww). Hydrodistillation of the fresh green leaves of <i>P. bombycina </i>gives a clear and sweet scented oil in 0.02 to 0.054%<i> </i>(w/w)<i> </i>yield. The oil composition is investigated by GC and GC/MS<i>. </i>A total of 79 compounds have been identified. Substantial

differences in the composition of the oils from 9 leaf samples are noticed. Aldehydes constitute a major portion of the oil (28.0 to 53.2%) followed by acids (11.4 to 40.8%) and alcohols (7.4 to 14.8%).Dodecanal (3.1 to 25.8%), decanal (2.4 to 25.8%), 11-dodecenal (1.5 to 16.3%) and undecanal (1.3 to 9.5%) are present at extremely variable concentrations. Vari ations of (E)-nerolidol is quite conspicuous (0.5% to 21.9%). Out of the two oxides, caryophyllene oxide is a major component (3.0 to 12.1%). Experiments on rearing performances of muga silkworm on nine different collections of 'som', their most favoured host plant, reveal that growth of the worms are influenced unevenly by the different chemical constituents present in the essential oil. Correlation studies indicated that aldehyde per cent in the essential oil has positive influence on the growth of silkworm and cocoon quality, while increased ac id per cent in the oil is found to be detrimental for growth and cocoon quality.