Standardisation Parameters for Neem (Azadirachta indica) Leaf Drug Material in Accordance with WHO Guidelines: A Case Study in Kogi State, North Central Nigeria

The establishment of standardisation parameters for herbal drug materials is a fundamental prerequisite for ensuring product quality, safety, and efficacy within the rapidly expanding Nigerian herbal medicine industry. Azadirachta indica (neem) is one of the most widely used medicinal plants in Nigeria, yet standardised monograph data specific to Nigerian-grown specimens remain insufficiently documented. This study establishes physicochemical standardisation parameters for neem leaf drug material harvested from Kogi State, North Central Nigeria. Leaf samples were collected from five different farms across Lokoja, Okene, and Kabba, air-dried under shade, and powdered for analysis. Parameters evaluated in accordance with WHO guidelines for the quality control of herbal medicines included moisture content, total ash, acid-insoluble ash, water-soluble ash, alcohol-soluble extractive, water-soluble extractive, swelling index, and foaming index. Phytochemical screening was also performed. The moisture content ranged from 9.2% to 11.8%, total ash from 7.4% to 8.9%, and alcohol-soluble extractive from 12.6% to 15.2%. Phytochemical analysis confirmed the presence of terpenoids, flavonoids, alkaloids, and tannins. The parameters established provide reference data for inclusion in a local pharmacopoeial monograph and quality control standards applicable to neem-based herbal product manufacturers in Nigeria. Keywords: Azadirachta indica, standardisation, WHO guidelines, quality control, Kogi State