UPAVISHA DRAVYA AND SHODHANA: A CRITICAL REVIEW OF EXPERIMENTAL EVIDENCE THAT CLASSICAL PURIFICATION REDUCES THE TOXICITY OF VATSANABHA, KUPILU, BHALLATAKA AND LANGALI
Upavisha are plant drugs classified in Rasashastra as semi-poisonous but therapeutically useful, and classical texts prescribe that they be processed by shodhana before use. Shodhana uses media such as cow’s urine, cow’s milk, ginger juice and sour gruel. Whether these procedures reduce toxicity, and how, can now be tested with analytical chemistry and pharmacology. This review appraises the experimental evidence for four upavisha: Vatsanabha (Aconitum spp.), Kupilu (Strychnos nux-vomica), Bhallataka (Semecarpus anacardium) and Langali (Gloriosa superba). For aconite, shodhana in cow’s milk or urine converted toxic diester diterpenoid alkaloids into less toxic monoesters. Depending on species and medium, aconitine fell by 23–91%, with milk more effective than urine. In rats, shodhana-treated aconite lost the cardiac and neuromuscular toxicity of the raw root while largely retaining antipyretic activity. For Kupilu, shodhana in ginger juice reduced strychnine by about 68% and brucine by 40–48%, and sour gruel by about 39% and 18%. For Bhallataka, shodhana reduced oil and phenolic content and changed chemical fingerprints, but quantitative data on urushiol-type toxins are scarce. For Langali, colchicine fell by 30–76% with Thai traditional pretreatments, while Indian shodhana data are limited. The evidence supports the principle that shodhana reduces key toxic constituents, but reductions are partial and variable, and no study links shodhana to clinical outcomes. We recommend marker-based acceptance limits for processed upavisha, standardised procedures, and pharmacovigilance.