Pharmacognostic evaluation of Daucus carota Linn. Leaf (Apiaceae)

Abstract

The macroscopic, organoleptic features, microscopical and chemo-microscopical characters as well as physico-chemical parameters of the D. carota leaf were evaluated to establish some pharmacognostic standards for its further investigation. The plant material was prepared and evaluated according to standard methods of assessing crude drugs. Findings from the study shows the leaf has alternate covering base, tri-pinnate leaf arrangement, parallel venations, finely divided uniform division, acute leaf shape and also serrated leaf blade. The leaf width ranges between 0.30-0.50 cm, stem height 39.00-42.00 cm, leaf size 1.50-2.80 cm and has a fine hairy surfaces, greenish colour, mint odour and pleasant taste. The microscopical features revealed wavy epidermal cells and several diacytic stomata on lower and upper surfaces. The chemo-microscopy revealed the presence of starch, tannins, lignin, cellulose, starch grains, aleurones, mucilage, suberin, cutins and calcium oxalate crystal was not seen. The quantitative leaf microscopy of the lower epidermal layer revealed stomata number is 14.80±0.97, stomata index 31.22±3.09% and palisade ratio is 6.20±0.37, while the upper epidermal layer revealed stomata number is 10.60±0.87, stomata index is 32.55±1.25%, vein islet number is 12.80±1.98 and veinlet termination is 31.800±2.33. The physico-chemical parameters determined showed that the moisture content (5.56%), alcohol extractive value (15.60%), water extractive value (21.80%), total ash (11.60%), acid insoluble ash (1.00%) and water soluble ash (5.67%). These findings will serve as baseline towards establishing standards for D. carota leaf identity, purity and quality which can lead to its further pharmaceutical utilizations and proper differentiation from similar species.