INFLUENCE OF HARVESTING TIME AND LUNAR CYCLES ON DRAVYA POTENCY: AN INTEGRATIVE REVIEW OF BṚIHATTRAYĪ AND CONTEMPORARY SCIENTIFIC EVIDENCE

The potency (vīrya) and therapeutic efficacy of medicinal plants (dravya) are influenced by multiple intrinsic and extrinsic factors, among which kāla (time) holds a central position in Ayurveda. The Bṛihattrayī Saṃhitās—Charaka Saṃhitā, Suśruta Saṃhitā, and Aṣṭāṅga Hṛdaya/Saṅgraha—systematically describe the importance of appropriate season (ṛutu), harvesting time, plant maturity, and lunar phase (tithi) for achieving optimal drug action. Among these, the Moon (Chandra) is regarded as a primary regulator of Soma, nourishment, and biological rhythm. Contemporary pharmacognostic and phytochemical studies increasingly validate these principles by demonstrating temporal variations in sap flow, secondary metabolite accumulation, and metabolic activity regulated by seasonal, diurnal, and lunar rhythms. This review critically integrates classical Ayurvedic doctrines with modern scientific evidence to elucidate the role of harvesting time and lunar cycles in determining dravya potency, highlighting their relevance in herbal drug standardization, quality control, and Good Agricultural and Collection Practices (GACP).