Radioprotection Imparted by Four Spices in a Bacterial System

Introduction: A wide variety of substances derived from herbs and spices have been shown to possess potent antioxidant, anti-inflammatory, anti-mutagenic and anticarcinogenic activities. The study of the modulation of genotoxicity by the extracts of some such spices would thus be meaningful and interesting. Objective: Aqueous extracts of four extensively used spices viz. Trachyspermum copticum (Ajwain), Piper nigrum (Black pepper), Syzyquim aromaticum (Clove) and Pimenta dioica (Allspice) have been employed to study the modulation of genotoxicity, if any, induced by a potent DNA damaging agent viz. ultraviolet radiation (UV C), in Salmonella typhimurium cells. Methods: Induction of umu-gene was assayed in Salmonella typhimurium cells in presence or absence of varying amounts of the spice extract after a fixed dose of UV C exposure. The percentage survival of the Salmonella typhimurium cells exposed to UV C was computed by the study of the colony forming units on LB-Agar plates. Results: All the aqueous extracts of Ajwain, Black Pepper, Clove and Allspice was found to impart radioprotection to Salmonella typhimurium cells against UV C induced DNA damage in a dose–dependent manner. Clove has been found to impart a very high degree of radioprotection as compared to the other spice extracts and also at a much lower concentration. This has been reflected by both the assay methods mentioned above. Conclusions: Our results indicate that aqueous extracts of all four spices studied, impart radioprotection against UV induced DNA damage in Salmonella typhimurium cells in a dose-dependant manner. All the spice extracts mentioned above, excepting clove, presumably due to its antibacterial activity, were found to support the growth of the Salmonella typhimurium cells. This may be indicative that the extracts are imparting protection by effectively reducing the UV dose upon absorption of a part of UVC by the constituents of the spice extracts excepting clove.