Heavy metals and nutritional composition of some selected herbal plants of Soon Valley, Khushab, Punjab, Pakistan

Abstract

Herbal plants and their extracts deserve special attention because of the important influence they have on human health. For the majority of the world population, herbal plants represent the primary source of the health care. According to the World Health Organization (WHO) report, almost 80% of people in marginal communities use only herbal plants for the treatment of various diseases. Although, the effectiveness of the herbal plants is mainly associated with their constituents such as essential oils, vitamins, glycosides and many other products but prolonged intake can cause health problems due to the presence of heavy metals. The human body requires both the metallic and the non-metallic elements within certain permissible limits for growth and good health. Therefore, the determination of element compositions in food and related products is essential for understanding their nutritive importance. The accumulation of some heavy metals in large quantities in the body may have a toxic effect. The concentration levels ( mg/L) of selected heavy metals (Fe, Mn, Cu, Zn and Pb) and macronutrients (Na, Ca, Mg, K and P) in eight useful herbal plants of Soon Valley District Khushab were determined by atomic absorption spectrophotometer and colorimeter. The herbal plants having different growing seasons and uses were collected from different locations. The results revealed that the herbal plants accumulate the elements at different concentrations. The maximum concentrations ( mg/L) of heavy metals in the analyzed samples were 47.25 ± 0.01, 26.6 ± 0.01, 207.6 ± 0.08, 78.90 ± 0.04 and 0.39 ± 0.01 for Zn, Cu, Fe, Mn and Pb, respectively. The maximum concentrations ( mg/L) of macro elements were 728 ± 0.60, 28300 ± 113, 68500 ± 25, 24250 ± 55 and 3700 ± 299 for Na, K, Mg, Ca and P, respectively. The levels of heavy metals determined in the analyzed samples were found below the maximum allowable limit. Hence they were safe for consumption. Fe was accumulated most among the plants analyzed for heavy metals. The analyzed samples were good source of important macro elements.

Keywords: Heavy metals, nutritional composition, medicinal herbs, Soon Valley.