Pharmacognostic and Phytochemical Studies of Leaves of Psydrax horizontalis Schum. and Thonn (Rubiaceae)

Introduction: Psydrax horizontalis Schum. and Thonn; is used traditionally in the treatment of malaria, fever, and management of diabetes in Nsukka, South-eastern Nigeria. Owing to its increasing ethno-medicinal relevance, proper identification and evaluation are vital to prevent adulteration. This research article presents a detailed pharmacognostic, physicochemical and phytochemical evaluation on the leaves of Psydrax horizontalis which will be used in its identification and consequent standardization. Methods: The fresh and powdered leaves were evaluated for their macroscopic and microscopic features. Physicochemical properties and phytochemical screening were carried out based on standard procedures by World Health Organization (WHO). Results: Psydrax horizontalis is a petiolate, stipulate and compound bi-pinnate leaf with reticulate venation, entire margin, chordate base and has opposite leaf arrangement. Microscopic diagnostic characters observed were paracytic stomata, unicellular covering trichomes, microsphenoidal shaped calcium oxalate crystals, lignified vessels and fibres as well as numerous starch grains. The total ash, water soluble ash, sulphated ash, acid insoluble ash compositions were 6.5, 0.5, 2.75 and 0.5% respectively. The moisture content, alcohol soluble extractive and water soluble extractive values obtained were 8.8, 3.8 and 3.7% respectively. Qualitative and quantitative phytochemical screening showed flavonoids, tannins, steroids, phenols and alkaloids at 100.00±0.035, 22.00±0.036, 19.50±0.024, 15.00±0.032 and 13.00±0.014 mg/g respectively as the major phytochemical constituents. Conclusion: The pharmacognostic standards of the leaves of Psydrax horizontalis were determined and serve as quality control parameters for their purity, identification and standardization.