Pharmacognostic study of two medicinal species of Rytigynia (Rubiaceae) from Nigeria
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Date
2011
Authors
Ajayi, G. O.
Kadiri, A. B.
Egbedi, M. E.
Oyeyemi, O. O.
Journal Title
Journal ISSN
Volume Title
Publisher
Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences.
Abstract
Micromorphological studies and phytochemical screening of the leaves of Rytigynia nigerica and R. umbellulata
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.
Description
Keywords
anatomy , leaf , pharmacognosy , Phytochemistry , Rytigynia
Citation
Ajayi, G. O., Kadiri, A. B., Egbedi, M. E. and Oyeyemi, O. O. (2011). Pharmacognostic study of two medicinal species of Rytigynia (Rubiaceae) from Nigeria. Pnytologia Balcanica 17(3): 355 – 359