355 PHYTOLOGIA BALCANICA 17 (3): 355 – 359, Sofia, 2011 Pharmacognostic study of two medicinal species of Rytigynia (Rubiaceae) from Nigeria Glory O. Ajayi 1 , Akeem B. Kadiri 2 , Mabel E. Egbedi1 & Oluwakemi O. Oyeyemi 2 1 Department of Pharmacognosy, Faculty of Pharmacy, University of Lagos, Akoka, Lagos, Nigeria 2 Department of Botany, Faculty of Science, University of Lagos, Akoka, Lagos, Nigeria, e-mail: akadiri@unilag.edu.ng (corresponding author) Received: August 16, 2011 Accepted: December 16, 2011 Abstract. Micromorphological studies and phytochemical screening of the leaves of Rytigynia nigerica and R. umbellu- lata were carried out. The epidermal cells of both adaxial and abaxial surfaces have irregular shape, and the anticlinal cell wall patterns are either curved or undulate. Some remarkable diagnostic features of the two plants, which in a way justify their grouping in the same genus, are: paracytic stomatal type, hypostomatic leaf and centrally located vascular bundles in the midrib, and spatial deposition of crystals of calcium oxalate in the perivascular tissue. The distinctive features of each species include a higher epidermal cell number in R. nigerica than R. umbellulata; a thin cell wall of 1.0 (1.6 ± 0.2) 3.0 μm on the abaxial surface of R. nigerica; a greater stomatal size of 6.0 (12.4 ± 1.2) 20 μm × 5.0 (13.4 ± 1.3) 20 μm in R. umbellulata, as well as a long and tip-bent trichomes reported on the abaxial surface of R. nigerica and of the multicellular glandular type on the adaxial layer of R. umbellulata. Phytochemical screening has shown that in R. nigerica were present such bioactive compounds as tannins, saponins, reducing compounds, steroids, and flavonoids, whereas anthraquinones, cardiac glycosides, cyanogenetic compounds, phlobatannins and alkaloids were absent. In R. umbellulata, alkaloids, tannins, saponnins, reducing compounds, and flavonoids were present, whereas anthraquinones, steroids, cardiac glycosides, and phlobatannins were absent. These bioactive compounds found in the leaves of these plants contribute greatly to their medicinal potential. The two species are well known plants, used in folk medicine in Nigeria. Key words: anatomy, leaf, pharmacognosy, phytochemistry, Rytigynia Introduction Rubiaceae Juss. is a large family with a wide range of habits, including lianas, trees, shrubs, or more seldom herbs, comprising about 450 genera and 6500 species. It is a family of flowering plants, commonly called Madder, Bedstraw or Coffee family. It is widely dis- tributed but is mainly tropical (Burkill 1985). Plants belonging to this family are known to contain sub- stantial amounts of anthraquinones, especially in the roots. The traditional therapeutic use of the plants has been for skin disorders and against cancer. Further- more, anthraquinones of the Rubiaceae family exhibit in vivo some interesting biological properties, such as antimicrobial, antifungal, hypotensive, analgesic, an- timalarial, antioxidant, antileukemic, and mutagen- ic functions. Apart from their medicinal value, these plants are also used as natural food colourants and as natural hair dyes. Interest in the isolation of natu- ral dyes and colouring substances has been on the in- crease, owing to their application in foods, medicinal drugs and other human usages (Kannan & al. 2009). Two medicinally important species of Rytigynia be- longing in this family – R. umbellulata Robyns and