Abstract

Nine species of sponges (Orders: Keratosida, Hadromerida, Haplosclerida and Poecilosclerida) of the class Demospongiae were tested for antifungal activity. In general, only trace and moderate activity was observed against the fungal pathogens tested. However, the encrusting Keratosida sponges depicted strong antifungal activity than the other sponges. In vitro antifungal activity of sponge extracts was determined against six species of pathogenic fungi (Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus, Penicillium sp., Candida albicans, Cryptococcus sp.). Stock cultures of fungi were maintained in Czapex Dox agar. On the surface of the medium, discs inoculated with the extract (20 µl/6 mm disc) were placed. The inhibition zone was measured after 72 h of incubation and the antifungal activity has been expressed as inhibition zone in mm. In the present investigation, four solvents viz; ethanol, methanol, acetone and chloroform were used to obtain crude extracts from sponges. Of these, only chloroform and ethanol extracts showed activity against the fungi. There was higher activity against Cryptococcus sp. (10 mm) in the crude extracts of chloroform and minimum activity against A. fumigatus (5 mm) in the crude extract of ethanol. From the present study, it could be understood that the sponges might be used for the extraction of useful drugs that have antifungal activity against the important human pathogenic fungal species. Besides, the result of the present study is providing baseline data for the future researches in this line of work and is also throwing more light on the use of sponges by the pharmaceutical technologies for the extraction of useful drugs.

Key words: Demospongiae, solvents, antifungal activity, Palk Bay.