Article: A COMPREHENSIVE REVIEW OF CLASSICAL SHODHANA PROCEDURES AND PURIFICATION MEDIA OF YASHADA IN RASASHASTRA

Article Category: Review articles

DOI: 10.7897/2277-4343.174161

Pages: 189-194

Author: Manish Kumar Saini *, Pradeep Kumar Prajapti

Abstract: Shodhana (purification) is a fundamental preliminary processing procedure in Rasashastra (the Ayurvedic science of mineral and metallic pharmaceutics), used to purify metals and minerals, reduce undesirable properties, and render them suitable for further pharmaceutical use. Yashada (zinc), a low-melting-point metal described in classical Ayurvedic literature, is purified by multiple methods in different texts. This review critically analyses the classical descriptions of Yashada shodhana in Ayurvedic and Rasashastra literature, compares general and drug-specific purification procedures, examines the purification media employed, and situates these classical descriptions alongside available modern analytical evidence. This review was structured in a PRISMA-informed format. Texts listed in Schedule I of the Drugs and Cosmetics Act, 1940, available in physical form, together with other authoritative classical and secondary sources, were screened for procedure type, purification medium, number of repetitions, and textual variation. A PRISMA-style flow diagram, defined eligibility criteria, and a structured data-extraction sheet are reported to improve transparency. Descriptions of Yashada shodhana were identified in 25 classical and secondary texts (9 listed in Schedule I and 16 additional sources). Twenty-one distinct purification media were documented from plant, animal, and mineral sources. Godugdha (cow's milk) was the most frequently cited medium for Vishesha Shodhana, whereas taila, takra, gomutra, kanji, and kulattha kwatha were the media most commonly used for Samanya Shodhana. Repetitions ranged from 3 to 21, depending on the text and procedure. Classical Yashada shodhana represents a deliberate, rationally structured pharmaceutical process. Available modern analytical studies on Yashada bhasma (incinerated ash preparation) lend partial, indirect support to the classical claims of particle-size reduction and phase transformation. Still, direct experimental validation of the shodhana step itself remains limited. The diversity of methods and media reflects a well-developed traditional pharmaceutical rationale and justifies further experimental evaluation.

Keyword: Yashada, Shodhana, Rasashastra, purification media, Ayurvedic pharmaceutics, PRISMA