A. Extracts of Neem, Tulsi, Calotropis and Tobacco leaves 50 g of powdered botanicals from each was weighed and transferred to a cellulose extraction thimble (Whatman, UK). These materials were extracted using 250 ml ethanol (78 oc) for 5 hours in a Soxhlet apparatus (250 ml) and the extracts were decanted from the flask separately. Then the volume of each abstract was measured and each was made to a final volume of 200 ml and transferred separately into round bottom flasks. The flasks were fitted with the Rotatory evaporator (Buchi; R-114; Switzerland) individually and evaporated to dryness at a temperature not exceeding 85 oc. Then the flasks with dried materials were removed and weighed. The weight of the dried extract was calculated by subtracting the weight of the empty flask. Thereafter few milliliters of ethanol were added to each flask to aid the dissolution of the extract with water. Finally 50 ml of distilled water was added to the extract to get 1gml-1 (100% w/v) concentration. Further dilutions were made for further experiments