Standardized decoction was prepared as previously described by Samarakoon et al. . Equal portions (20 g each) of N. sativa (seeds), H. indicus (roots), and S. glabra (rhizome) were mixed and boiled gently in 1.6 L of distilled water until a final volume of 200 mL was obtained. The extract was then filtered, freeze dried, and stored in a vacuum desiccator at −4°C. The percentage yield of the freeze dried plant material was 13.6%. For experimental purposes, the required weight of the freeze dried powder was reconstituted in 1% dimethyl sulfoxide (DMSO) and filter sterilized using 0.22 μm disposable filters.