Efficacy of Electron Beam Irradiation on Microbial Safety and Medicinal Quality of Ashwagandha

As herbal medicines are natural substances -insect and microbial contamination is unavoidable. If untreated, these herbs will result in rapid spoilage and produces food borne illnesses. Therefore, sterilization is a must. Ashwagandha (Withania somnifera (L.) Dunal) is one of the most widely used herb in Ayurvedic system of medicine. Preliminary studies have shown that the plant is susceptible to microbial contamination. Irradiation as a sterilization method is more advantageous than other methods like Heat, Steam under pressure, flowing steam or Ethylene oxide gases, UV radiation etc. Electron beam irradiation is more eco friendly when compared to other methods. Hence, an attempt was made to irradiate the samples of Ashwagandha using electron beam irradiation and thoroughly investigate its pharmacognostical, physicochemical, phytochemical and microbial parameters.

Authenticated samples of Ashwagandha were subjected to electron beam irradiation at different doses of 0, 2.5, 5, 7.5 and 10 kGY, at Microtron centre, Mangalore University. ‘0kGy’ indicates non irradiated sample. The non irradiated and electron beam irradiated samples of Ashwagandha are then subjected to Pharmacognostic studies (morphological and microscopical analysis), Physicochemical analysis (foreign matter, moisture content, Ash value, extractive values), Phytochemical analysis to identify the constituents present in them and Microbial analysis. The result of non irradiated sample is compared with the electron beam irradiated samples.

Pharmacognostic, Physicochemical and Phytochemical analysis showed that, there were no significant changes in electron beam irradiated samples in comparison to non irradiated samples.

Non irradiated samples of Ashwagandha showed a high level of bacterial and fungal load and also there was presence of specific pathogens like – E.Coli, Salmonella and Staphylococcus aureus. Whereas, there was a drastic reduction in microbial load in electron beam irradiated samples and complete sterility was attained at a dose of 5kGy.

Electron beam irradiation was found to be a suitable sterilization method as it reduced the microbial load and did not produce any significant changes in the pharmacognostic, physicochemical and phytochemical parameters in Ashwagandha samples.