Assessment of heavy metal content in herbal raw materials traded in India

Abstract

Presence of heavy metals in herbal raw materials exceeding the safety limit have potential security risks and has proven adverse effects and its prolonged consumption may causes serious health problems. The present study was carried out to quantify the heavy metals, content in some of the herbal raw materials traded in Indian market. A total 183 samples belongings to 74 different herbal raw materials and 69 species were sampled and analyzed for the presence of Arsenic (As), Cadmium (Cd), Mercury (Hg), and Lead (Pb). As per the permissible limit of Ayurvedic Pharmacopoeia of India (API), 5.46% samples were failed due to Cd accumulation followed by Hg (3.82%), Pb (1.09%), and As (0.55%). Higher accumulation of Cd was main reason behind higher percent of failed samples as per different safety standards such as 13.11% for World Health Organistion (WHO), 5.46% for United States Food and Drug Administration (USFDA) and 72.13% for Health Science Authority Singapore (HSA). Hg contributed higher percent of failed sample (18.03%) as per the safety standards of Pharmacopoeia of People's Republic of China (CP). The results showed that due to higher accumulation of Cd, Pb, As, and Hg, 9.58 - 12.33%, 0.00 to 10.96%, 1.37 to 2.74%, and 8.22 to 30.14% samples were failed respectively in safety standards of different pharmacopoeias. Bacopa monnieri (L.) Wettst., Caesalpinia bonduc (L.) Roxb., Cedrus deodara (Roxb. ex D. Don) G. Don, Cinnamomum zeylanicum Blume, Croton tiglium L., Curcuma longa L., Mucuna pruriens (L.) DC., Nardostachys jatamansi (D. Don) DC., Piper longum L., Pistacia chinensis Bunge, Senna alexandrina Mill., Tamarindus indica L., Teramnus labialis (L.f.) Spreng. and Valeriana wallichi DC. were among the species which failed in minimum of two or more than two pharmacopoeias due to higher concentration of one or more heavy metals. The quality of the herbal raw materials can be enhanced and the wastage of herbal raw material due to accumulation of heavy metals can be reduced by implementing WHO guidelines on Good Agricultural Practices, Good Field Collection Practice and Good Post-Harvest Processing Practices.