Pharmacognostic, Acute Toxicity Profile and Comparative Leaf Characteristics of Desmodium velutinum, Mallotus oppositifolius and Synedrella nodiflora

Abstract

Plant leaf parameters such as stomatal index, stomata type, leaf microscopic features, and leaf powder microscopy are important taxonomic parameters used to properly identify species and to differentiate one species from another and these is a vital keys in the pharmacognostic study of the medicinal plants because leaf parameters play a vital role in distinguishing crude drugs even when they are fragmented or powdered. Also, extractive index, retention factor, ash value, and phytochemical parameters are vital in the standardization of crude drugs for the establishment of pharmacopeia and monograms. Therefore, the study seeks to validate the use of the phytochemistry and molecular systematics among Asteraceae, Euphorbiaceae, and Fabaceae to support their circumscription and therefore evaluated the pharmacognostic profile of Desmodium velutinum, Synedrella nodiflora and Mallotus oppositifolius folklorically used in South East Nigeria using standard laboratory protocols. The result of the leaf microscopy showed that Desmodium velutinum, Synedrella nodiflora, and Mallotus oppositifolius all had irregular shaped leaf epidermis, and stomata was present only in the abaxial surface respectively. The result showed both D. velutinum and S. nodiflora powder showed the presence of lignin, starch, cystoliths, tannin, and Oil body while calcium oxalate was absent whereas, Mallotus oppositifolius showed the presence of lignin, starch, tannin, and Oil body while calcium oxalate, and cystoliths were absent. Also the result of the TLC showed that M. oppositifolius had 3 visible spots with retention factors (RF) of  0.363, 0.425, and 0.5 in that order  respectively, D. velutinum had 4 visible spot with retention factor (RF) of  0.425, 0.5, 0.550 and 0.66 in that order  respectively  while S. nodiflora had 6 visible spot with retention factor (RF) of  0.255, 0.363, 0.438, 0.538, 0.600 and 0.688 in that order  respectively. The result also showed that methanol exhaustible extracted the phytochemicals in the crude dried plant. The acute toxicity studies showed that Desmodium velutinum, Synedrella nodiflora and Mallotus oppositifolius individually had LD50 greater than 5000mg/kg. This study validates the claim that leaf parameters such as stomatal index, stomata type, leaf powder microscopy are important parameters used for the identification of crude drugs.