Microscopic, physicochemical and chromatographic fingerprints of leaves of Nigerian <i>Cassia tora</i> Linn

Abstract

Introduction: Cassia tora Linn (Leguminosae–Caesalpinioideae), commonly known as Fotid in English and Tafasa in Hausa, is a perennial tree native to Africa. It has been reported to be used to manageskin infections, haemorrhoids, stomach ache and coughtraditionally. C. Tora leaves have been shown to possess anti-hepatotoxic, anti-allergic, anti-mutagenic, anti-fungal, radical scavenging, and anti-microbialactivities. Compounds such as anthraquinones, including chrysophanol, emodin, rhein have been isolated from C. tora.

Objective: To investigate the pharmacognostic and physicochemical characteristics of the leaves of Cassia tora Linn.

Methods: Pharmacognostic investigations including microscopy, chemomicroscopy, proximate analysis and phytochemical investigations including Thin Layer Chromatographic finger-printing were conducted.

Results: The macro and microscopic studies revealed the leaves to be simple, papery, cordate and pinnately-veinnated. Both the adaxial and abaxial epidermal surfaces were characterized by abundant diacytic and anomocytic stomata respectively. Polygonal epidermal cells and numerous uniseriate, unicellular trichomes were also present. Quantitative leaf analysis revealed the following: stomata number on abaxial surface 445, stomata index 30.7, palisade ratio 17.1, vein- islet number 17.3 and vein- termination number 14.2. Chemomicroscopic characters present included lignin, tannin, mucilage, starch, oil and calcium oxalate crystals. The physicochemical parameters evaluated were: moisture content 4.6%, total ash 7.9%, acid-insoluble ash 1.5%, sulphated ash 19.6%, water-soluble ash 6.8%, alcohol-soluble extractive 9.5% and water-soluble extractive 24.1%. Chromatographic fingerprints of ethanol(70 %) extract showed major spots at Rf = 0.76 daylight (light green), UV366 (brown), spray reagent at 100°C (brown); Rf = 0.85 daylight (green), UV366 (red), spray reagent at 100°C (brown); Rf = 0.90 daylight (yellow), UV366 (brown), spray reagent at 100°C (brown).

Conclusion: The results of this research provide information which can be included in official monograph of the plant for its proper identification and quality control.

Keywords: Cassia tora, Pharmacognostic studies, proximate analysis, Chromatographic fingerprints