Author(s): Anagha Vishwas Ranade *, Rabinarayan Acharya
In Ayurveda, the safety and quality of crude medicinal plants has been quoted to base upon major factors like Desha (habitat), Kala (Time), Guna (properties), etc. Among them, Kala i.e. the time factor (season, lunar period and day) plays a significant role in influencing the pharmacotherapeutic properties. Accordingly, protocol for crude drug collection in six rutus (seasons) according to the parts used has been denoted in Charaka, Sushruta, Sharangdhara samhita and Raja nighantu. In modern pharmaceutics, extensive research has been carried out to assess the role of seasons, diurnal variation, maturing stages on phytoconstituents of different plants parts. Extensive data is available on non- Ayurvedic plants. In this paper, a thorough review was made pertaining to the concept of Kala, in relation to medicinal plants, from available classical literature. Scientific reports have been compiled from the available online scientific journals. On critical analysis, data on seasonal variation was found reported in 36 medicinal plants used in Ayurveda whereas data on diurnal variation was found in 8 medicinal plants. Thus, the concept of Kala in Ayurveda truly holds a scientific stand and plays an essential role in deciding the quality of the crude drug.