Abstract
Background: Conventionally, Ayurvedic herbs are being used to treat various diseases. These medicinal compounds have to be evaluated for their safety and presence of therapeutic compounds for the clinical application.

Aims and Objectives: The present study was designed to obtain the scientific knowledge on the safety profile as well as to assess the presence of pharmacologically active principles in the Pterocarpus marsupium heartwood.

Materials and methods: The aqueous extract of P. marsupium heartwood was subjected to an acute toxicity in albino rats. The animals were divided into four groups (n = 6) and fed with graded doses (1000, 2000, and 5000 mg/kg p.o.) of plant extract, respectively, whereas control group had received 2 ml distilled water orally. Animals were continuously observed for the toxicological symptoms for 2 h and intermittently for 48 h and latter once in a day for 14 days. The body weight of the animals was recorded. In addition, the qualitative phytochemical investigations were conducted to identify the presence of active principles.

Results: The animals fed with aqueous extract of P. marsupium heartwood did not exhibit any toxic symptoms and the mortality. However, there was a significant (P < 0.05) dose-dependent change in the weight gain observed in comparison to the control group. The median lethal dose (LD50) of the plant extract was considered as >5000 mg/kg. Furthermore, the phytochemical investigations of the plant extract showed the presence of carbohydrates, flavonoids, triterpenoids, saponins, tannins and phenols.

Conclusion: The aqueous extract of P. marsupium heartwood was found to be safe and well tolerated even at a large dose of 5000 mg/kg. Furthermore, the plant extract found to possess pharmacologically active principles having wide pharmacological spectrum. Hence, it can be preferred in various therapeutic conditions.

Key words: Acute Toxicity; Pterocarpus marsupium; Median Lethal Dose; Phytochemicals; Aqueous Extract