Photostabilization of Azadirachtin - A

Studies have been conducted to stabilize azadirachtin - A with neem oil, neem meliacins and some known stabilizers. Neem oil and butylated hydroxy anisole (BHA) gave maximum stability to aza-A. When methanolic solution of aza-A and neem oil (1:1), and aza-A and BHA (9:1) were exposed to sun light, T_1/2. was found to be 5.68 and 3.67 d respectively while that of aza-A alone was 1.76 d only. Further, the antifeedant activity of aza-A against tobacco armyworm, Spodoptera litura Fab was considerably enhanced following incorporation of BHA and neem oil. Fifty two and 27% antifeedancy were observed with aza-A mixed with neem oil and BHA respectively as compared to 10% antifeedancy observed with aza-A alone. The apparent enhancement in antifeedant activity was attributed to the possible stabilizing effect of neem oil and BHA.