Assessment of Oral Acute Toxicity (LD50) of Aqueous, Ethanol, and Acetone Crude Extracts of Plectranthus Neochilus Leaves on Wistar Albino Rats

The Plectranthus genus, comprising more than 300 species distributed through tropical and subtropical areas of Africa, Asia, Oceania and South America, belongs to the Lamiaceae family, which includes some well-established medicinal genus such as mint (Mentha), sage (Salvia) and thyme (Thymus). Toxicology may be defined as the study of harmful, poisonous and adverse effects of drugs and other chemical constituents found in plants, which may increase the chances of mortality or weakness in the general health, physically as well as mentally. Thus, this work was aimed at assessing the oral acute toxicity (LD50) of aqueous, ethanol, and acetone crude extracts of Plectranthus Neochilus Leaves and to establish its safety on wistar albino rats (160-200g) as per OECD guidelines. Lorke’s method (1983) was used for this study. The results of phase one and phase two of the study showed no acute toxicity or mortality in any of the groups of rats in 24 hours, 72 hours and up to two weeks after single oral administration of 10, 100, 1000, 1500, 2250, 3500 and 5000 mg/kg body weight of the animals. In conclusion, oral administration of the plant extracts did not produce any toxic effect in rats. Oral intake of extracts at dose ≤5000 mg/kg body weight is safe, which implies that the oral LD50 is >5000 mg/kg body weight. Hence, the extract can be utilized safely for therapeutic use in pharmaceutical formulations.