Influence of Topical Application of Acetone Solution of Triterpenes on the Chitin Content in the Body Wall (Integument) of fifth Instar Larvae of Silkworm, Bombyx mori (L).

Abstract

Reduction in the chitin deposition in the insect body wall is one of the distinguishing features of juvenoid compound. Ten microliters ( 10 μL ) of different concentrations of acetone solution of standard solvent: Fernasol Methyl Ether (FME) and ten microliters ( 10 μL ) of different concentrations of acetone solution of each  triterpene compounds (Squalene; Polypodatetraene; Malabaricane; Lanostane; Hopaneand and Oleanane) were utilized through the topical application to individual larval instars of silkworm, Bombyx mori (L) (Race: PM x CSR2) at 48 hours after the 4th moult. The body wall integument chitin of untreated control larvae; acetone treated control; FME treated larvae and triterpene treated larvae was estimated at 120 hours after the fourth moult. Topical application of ten microliters ( 10 μL ) of different concentrations of acetone solution of standard solvent: Fernasol Methyl Ether (FME) and ten microliters ( 10 μL ) of different concentrations of acetone solution of each  triterpene compounds (Squalene; Polypodatetraene; Malabaricane; Lanostane; Hopaneand and Oleanane) to fifth instar larvae of silkworm, Bombyx mori (L) (Race: PM x CSR2) was found reported for the reduction in the deposition of chitin in the larval body wall. The plot, “Punyamayee Baramati Dose Response Curves”of concentrations of acetone solutions of FME and triterepene compounds and percent reduction in the body wall chitin was found exhibiting a characteristic Sigmoid form of displacement. The BCAS₅₀ (Baramati Concentration of Acetone Solution) of Triterpene responsible for fifty percent reduction in chitin deposition in the integument (Body Wall) of the Fifth Instar Larvae of multivoltine Crossbreed Race (PM x CSR₂) of Silkworm, Bombyx mori (L). The BCAS₅₀value of juvenoid contents of FME and selected triterpene compounds can be defined as the specific unit (microgram), which enable fifty percent reduction in  chitin  deposition in the body wall of larvae ( in comparison to untreated control). Accordingly,theBCAS₅₀value calculated from the “Punyamayee Baramati Dose Response Curves” for FME was found measured 0.08 mg/ml. The BCAS₅₀ values for triterpene compounds: Squalene; Polypodatetraene; Malabaricane; Lanostane; Hopaneand Oleananewere found measured: 0.231; 0.257; 0.313; 0.468; 0.479 and 0.504 mg/ml respectively. Sigmoid (S-form) “Baramati  Dose Response Curve”  may help for quantitative estimation of juvenoid contents  of various terpene compounds and their analogues.

Key words: Squalene; Polypodatetraene; Malabaricane; Lanostane; Hopane; Oleanane