Pharmacognostic Studies of the Leaf of Senna siamea (lam.) Irwin & Barneby Family: Caesalpiniaceae

Aims: To establish pharmacognostic standard for S. siamea and provide chromatographic fingerprints with a view to assisting in the quality control of medicinal products from the plant.

Study Design: Pharmacognostic evaluation of the leaf of Senna siamea.

Place and Duration of Study: Pharmacognosy laboratory, department of medicinal plant research and traditional medicine, national institute for pharmaceutical research and development (NIPRD), Abuja, Nigeria.

Methodology: Chemomicroscopic evaluation and determination of physicochemical properties (moisture content, ash values, extractive values) of the powdered leaves, macroscopy and microscopy of anatomical sections of the leaf were carried out using standard procedures.

Results: Evaluation of the macro and microscopic characters showed that the leaves are dark green, simple and entire. The leaf epidermis is polygonal, has paracytic stomata on the lower surface and uniseriate trichomes. Quantitative leaf analysis revealed stomatal number (464.7), stomatal index (38.23), palisade ratio (4.48), vein islet number (21.71) and vein termination number (20.71). Chemomicroscopic characters present include lignins, tannins, mucilage and oils. The physicochemical parameters evaluated are: Moisture content 7.33%, total ash 6.46%, acid-insoluble ash 5.32%, sulphated ash 8.47%, water-soluble ash 1.87%, alcohol-soluble extractive 5.12% and water-soluble extractive 16.71%. Chromatographic fingerprints of ethanol (70%) extract showed major spots at Rf = 0.74 daylight (yellow), UV366 (fluorescent), spray reagent (brown); Rf = 0.91 daylight (green), UV366 (red), spray reagent (brown).

Conclusion: The results from this study have provided information on the morphological, anatomical features and physicochemical parameters of the leaf of Senna siamea. The findings from this study will be useful towards establishing standards which can be included in official monograph of the plant for its proper identification and quality control.