Analysis of Metal Ion Levels in Ashwagandha and Thipala Ayurveda Powdered Drugs in Sri Lankan Herbal market

Abstract

Over the years, herbal products have been used in various parts of the world for the cure of human disorders. Although herbal products are often demanded to be beneficial and free of side effects there have been reports of acute and chronic toxicity resulting from their use. One of the main causes of toxicity of herbal medicines is the existence of heavy metals. Therefore the main objective of this study is to analyze Ayurvedic powdered drugs, Ashwagandha churna (AC) and Thipala churna (TC) of three different brands available in Sri Lankan herbal market for the quantitative analysis of essential trace and heavy metals. The samples were prepared by wet digestion method using hydrogen peroxide and nitric acid treatment. The presences of metals were analyzed by Flame Atomic Absorption Spectroscopy using a HITACHI ZA3000 Polarized Zeeman Atomic Absorption Spectrometer. The results were compared with the extraneous maximum residue limit recommended by the Food and Agriculture Organization (FAO) /World Health Organization (WHO) for herbal medicines. Lead and cadmium in brand A of AC were not detected in the samples. However cadmium concentrations in other samples were below the extraneous maximum residue limit. The extraneous maximum residue limits of the FAO/WHO have not been established yet for copper, nickel, chromium and zinc in herbal medicine. The results reveal that among the trace elements zinc (33.25 mg/kg) found in highest amount, but this was below the acceptable daily intake limit (60 mg/day). Chromium was not detected in brand C of AC and TC samples. In conclusion, the quality of herbal churna products sold in Srilankan market is safe. However there is need for continuous monitoring of branded herbal churna products sold for human consumption.