Ethnobotany Articles

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Author: search.filters.author.Abdillahi, Halima Saado

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    Effect of Disturbance On the Population Structure and Regeneration of Trees: A Case Study of Acacia xanthophloea (Benth) Woodland in Ol-Pejeta Conservancy in Kenya
    (International Journal of Science and Research (IJSR), 2018-03) Muhati, Godwin Leslie; Abdillahi, Halima Saado
    Tree damage was assessed in 1540 Acacia species (A. xanthophloea) in Olpejeta Conservancy. Using belt transects measuring (20 x 50 m), trees in the sample sites (closed and open) were counted. Measurements were made of Acacia tree count, recruits count, diameter at breast height, and mortality for both adult trees and seedlings. Densities were significantly higher in enclosed areas (398.3 ± 16.60 trees/ha) than open areas (243.3 ± 10.13) trees/ha. Elephants recorded the highest damage to the sampled trees with 54.55% damage while human beings caused 12.85% of the damage. Browsing was the main form of damage in open areas. Mean height for enclosed and open sites was 3.77 ± 4.61 and 5.35 ± 8.81, respectively. These findings suggest that herbivory damage did not have a significant effect on seedling regeneration but rather had an effect on population structure. Debarking caused by elephants occurred in the open areas with the highest being 96% of the sampled trees in the 11-25% damage class. The diameter class quotients fluctuated, an indication of the unstable population thus suggesting the impact of herbivory on population structure. Key recommendations include the creation of more enclosure zones, winning back more space by controlling the densities of browsers, long-term monitoring and the promotion of recruitment and regeneration rather than reducing mature tree loss.
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    Mutagenicity, antimutagenicity and cytotoxicity evaluation of South African Podocarpus species
    (Elsevier, 2011-12-01) Abdillahi, Halima Saado
    Ethnopharmacological relevance: Four species of Podocarpus are used in traditional medicine both in human and animal healthcare in South Africa. In vitro pharmacological screening of leaf and stem extracts of these species exhibited potent antimicrobial, anti-inflammatory, anti-tyrosinase, anthelmintic, acetyl-cholinesterase inhibitory and antioxidant activities. Aim of the study: To investigate the mutagenicity, antimutagenicity and cytotoxicity effects of leaf and stem extract of South African Podocarpus species. Material and methods: The mutagenicity and cytotoxic effects of extracts from four species of Podocar-pus were tested using the Salmonella/microsome assay with and without metabolic activation, based on the plate-incorporation method and neutral red uptake (NRU) assay respectively. Five Salmonellatyphimurium tester strains; TA98, TA100, TA102, TA1535 and TA1537 were used for mutagenicity test- ing. The relative cytotoxicity of the extracts was assessed by determining their NI50 values (50% inhibition of NRU). Results: The extracts did not show any mutagenic effects against all the tester strains with or without metabolic activation. All extracts demonstrated a strong antimutagenic effect on the mutations induced by 4NQO, decreasing its mutagenic effect in a dose-dependent manner. Strong cytotoxic effects were exhibited by petroleum ether extracts as compared to 80% ethanol extracts. When HepG2 cells were in contact with plant extracts in an increasing concentration, slopes of NRU decreased (highest–lowest %) following a concentration-dependent pattern. For 80% ethanol extracts, the most toxic extract in terms of percentage viability was leaves of Podocarpus falcatus whereby at 0.2 mg/ml, the viability of the cells was38.9%. Stem extract of Podocarpus latifolius was the most toxic among PE extracts, giving a percentage viability of 46.4 at 0.1 mg/ml. Conclusion: Absence of mutagenicity does not indicate lack of toxicity, as was observed from these extracts. These findings will help in assessing the safety measures to be considered in the use of these species and also the need to determine the cytotoxic potential of these species against various forms of human cancer cells.