Derris indica is belonging to family Fabaceae, inhabitants of India, Srilanka, Malaysia, North Australia and Polynesia, occurs in the tidal forests, river and canal banks, along the water edge in all districts in Bangladesh. It is a medicinal plant. The dried flowers are used in decoction to quench thirst in diabetes. Extracts of the leaves were active against Micrococcus pyogenes var. aureus (Anon, 1969). The juice of the leaves is prescribed in flatulence dyspepsia, diarrhoea and cough.
Preparation of plant materials for extraction:The fresh leaves, fruit shell, root bark, root wood, seeds, stem bark, and stem wood of D. indica were collected from Rajshahi University Campus.Leaves: After collection the leaves were spread out to dry without heaping the material together under the shade avoiding direct sunshine.Fruit shell: Fruits were picked and the shells were opened to remove the seeds for the collection of fruitshells and spread them out to dry under a shade Root bark: Root bark was collected by striping from the stem and cut into small pieces as thin as possible. After collection barks were dried thoroughly in a wellventilated room.Root wood: The root-wood was collected and cut into small pieces and dried.Seeds: Having peeling out the fruit shells the seeds were cut into small pieces and spread out under a shade to dryStem bark: Stem bark was collected by striping from the stem and cut into small thin pieces and dry thoroughly.Stem wood: The stem-wood was collected and cut into small thin pieces and dried as described above.After drying the plant materials were powdered in a grinder machine.
Chemical extraction of the plant parts:The ground dried D. indica leaves, fruit shell, root bark, root wood, seeds, stem bark, and stem-wood were extracted with sufficient amount of chloroform (500g × 1500ml × 3 times) by the cool method after 72 hours of plunging.Extracts, thus obtained were filtered and concentrated to dry out while only as residue was left and kept in a refrigerator after labeling.
Preparation of doses:A concentration for each of the extracts was selected as 2 g/2ml as the stock dose for surface film application to make other successive doses by serial dilution to give 0.708, 0.354, 0.177-, 0.088 and 0.044 mg/cm 2 for seed extract; 1.769, 0.885, 0.442, 0.221 and 0.110 mg/cm 2 for root bark, stem bark and stem wood extracts and 1.417, 0.708, 0.354, 0.177 and 0.088 mg/cm 2 for root wood extract.
Application of doses:All extracts were diluted with the solvents and the actual amount of extracted material in a dose was recorded and applied by residual film method (Busvine, 1971). For each dose one ml of mixture was dropped on a petri dish (90 mm) in such a way that it made a uniform film over the petri dish. The petri dishes were air-dried leaving the extract on it. The actual extract present in one ml mixture was calculated and dividing the value by the area of the petri dish the dose per square centimeter was calculated. Ten C. maculatus adults (3-5 day old) were released in each petri dish with 3 repli...
