Macroscopic and Microscopic Characterisation of Selected Herbal Drug Materials Sold in Onitsha Main Market, Anambra State

Herbal drug markets serve as critical nodes in the distribution of traditional medicine materials across Nigeria, yet the quality and authenticity of products sold in these markets are frequently unverified. This study undertakes macroscopic and microscopic characterisation of twelve commonly traded herbal drug materials in Onitsha Main Market, Anambra State, South East Nigeria. Samples were purchased from six different vendors for each material to account for inter-vendor variability. Macroscopic parameters assessed included colour, odour, texture, fracture surface, and surface characteristics. Microscopic evaluation involved preparation of transverse sections and surface preparations stained with phloroglucinol and iodine solution, followed by identification of diagnostic cellular elements. Moisture content, ash values, and extractive values were determined in accordance with the methods outlined in the British Pharmacopoeia and WHO guidelines on quality control of herbal medicines. Results revealed significant variability in the quality of samples across vendors, with several materials showing evidence of adulteration, misidentification, or contamination. Three materials failed to meet minimum ash value standards. Microscopic examination identified foreign plant fragments in four of the twelve herbal materials tested. These findings underscore the critical need for regulatory oversight of herbal drug markets and the development of local pharmacopoeial monographs for commonly traded Nigerian medicinal plants. Keywords: herbal drug characterisation, adulteration, Onitsha market, microscopy, quality control