A CRITICAL REVIEW ON LD50 OF SOME MEDICINAL PLANT

Eric Omo Irinmwinuwa*, Godwin Oyate Benard, Mbah Chikodili Adolphus, Raymond Emiakpo Opute, Njoku Charles Cherechi and Juliet Orugbala Chinedu

ABSTRACT

Traditionally, humans have used herbal medicines for remedying various diseases since time immemorial. One major and overriding criterion in the selection of herbal medicines utilized in health care provision is safety. The LD50 for a particular substance is the amount that can be expected to cause death in half of animals (mice/rat). The objective of the paper was to comprehensively review the literature on the toxicity (LD50) of commonly used medicinal plant. We reviewed relevant articles and books published over the years on botany/ ethnopharmacology for their toxic effect; Vitex madiensis Oliv, Aquilaria malaccensis, Aristolochia longa, Psidium guajava, Annona squamosa, Lagerstroemia speciosa, Combretum micranthu, Ficus deltoidea, Peganum harmala, Rhizophora racemosa, Mangifera indica, Warburgia ugandensis, Alysicarpus glumaceus, Abrus precatorius, Aloe barbadensis and Tephrosia vogelii. We searched several scholarly publication. LD50 method of determining toxicity was mainly by OECD's and Lorke's, crude plant extracts were the most commonly used, Water and methanol were common solvent used, Biochemical, haematological and histopathology studies were the assay carried out to ascertain lethality (LD50) of the plant extract. The LD50 value varied with the type of cells, extracts and solvent used, making direct comparison of the plant species difficult. Most of the plant had tolerated LD50, two of plant species were toxic, namely; Abrus precatorius and Peganum harmala (2345 mg/kg and 1.8, 2.4 and 2.5mg/kg) respectively in animal models, the remaining fourteen plant species were non toxic. W. ugandensis decoctions were reported to cause adverse effect in humans by herbalist.

Keywords: Acute toxicity; Chronic toxicity; Hematological parameters; Biochemical parameters; Safety.