Beneficial functions of plant materials used in shodhana process of mercury in Ayurveda Rasashastra

Abstract

Shodhana process in rasashastra is a mandatory process for each material prior to use in herbomineral pharmaceutical preparations. Although different types of mercury (Hg) shodhana”processes are described in rasashastra, in Sri Lanka, Ayurveda herbo-mineral manufacturers use a three-step method with Allium sativum extract, Piper betel extract and the decoction using Terminalia chebula, T. bellerica and Phyllanthus emblica. Although this method is well-known within the Ayurveda community, there are no research evidences available to identify the support and the functions given by the plant materials in the mercury shodhana process. Therefore, this research was carried out to analyse the elemental changes that would occur to commercially available mercury during the shodhana process. Shodhana process was carried out as mentioned in the Rasa Jala Nidhi textbook (volume I) of rasashastra literature under the mercury section (eighth process). As the shodhana process involves three steps, there were four samples to be analysed namely, crude mercury, first step completed Hg, second step completed Hg and final step completed Hg. Samples were microwave digested using HNO3: HCl in 3:1 ratio and diluted prior to the Inductive Coupled Plasma Mass Spectroscopy (ICPMS) analysis. These four Hg samples were then, subjected to ICPMS analysis. Standard 2A was performed to check Ag, Al, As, Ba, Be, Cd, Co, Cr, Cs, Cu, Fe, Ga, K, Li, Mg, Mn, Ni, Pb, Rb, Se, Sr, Tl, U, V, Zn elements and standard 2A Hg was performed to check Hg element. Cu, As and V were measured in He gas mode and rest were measured in no gas mode. The analysis was carried out in triplicate. Origin and R software were used for the comparison. According to the results obtained, Mg, Al, Fe, Co, Zn, Cd, Ba and Pb were present in the crude mercury as noticeable elements, but the element levels were changed with each shodhana step. Most importantly, it clearly shows the reduction of Pb level from 2347.25 ± 0.01 ppb to 173.20 ± 0.02 ppb. Furthermore, trace elements such as Li, Ni, Ga and U were completely removed from mercury after the completion of shodhana process. The reason for the reduction of metal ions can be attributed to metal iron chelation, detoxification procedures with plant bioactive compounds such as organic sulphides, polyphenols and flavonoids. Therefore, these results reflect the benefit of shodhana process and clearly explains the use of plant extracts as a removal agent of unwanted metal ions, which are trapped in Hg.