Woody Plants of Ghana and Their Uses@@@Woody Plants of Ghana, with Special Reference to Their Uses

Effects of leaf extracts of Ocimum gratissimum and Aframomum melegueta on spore germination and mycelial reduction of the most occurring fungal pathogen causing soft rot of yam tuber were investigated. Fungi isolated from rotted yams were Aspergillus niger, A. flavus, Fusarium oxsporium Rhizopus stolonifer, Botryodiplodia theobromae and Penicillium chrysogenum. The leaf extracts with ethanol extraction were most effective followed by cold-water and hot water extraction. The fungicidal activity with Ocimum gratissimum leaf extracts was more effective. In vitro inoculation of fresh yam with A. niger, A. flavus and F. oxsporum at room temperature for 3 months showed typical rot symptoms characteristic of the disease. The significance of these findings is discussed in relation to plant chemical or non-chemical means of disease control on yams in Africa.

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Antifungal effects of two tropical plant leaf extracts (Ocimum gratissimum and Aframomum melegueta) on postharvest yam (Dioscorea spp.) rot

Medicinal and aromatic plants (MAPS) represent a consistent part of the natural biodiversity endowment of many countries in Africa. The role and contributions of medicinal plants to healthcare, local economies, cultural integrity and ultimately the well-being of people, particularly the rural poor, have been increasingly acknowledged over the last decade. The demands of the majority of the populace for medicinal plants have been met by indiscriminate harvesting of spontaneous flora, including those in forests.  This has resulted in severe loss of habitat and genetic diversity.  The utilization of medicinal and aromatic plants (MAPs) as a source of fuel, building material, food, fodder, and fibre, in African countries has, however, led to a resurgence of natural product- based industries and pharmaceutical products. This had been spurred by the interests of the developed countries for traditional medicine and natural products. Furthermore, many African medicinal plants are well-known in the international markets, e.g. Ancistrocladus abbreivatus, a Cameroun plant with anti-HIV potential. Therefore, sustainable management and conservation of these endangered medicinal plant species are important not only because of their value as potential therapeutics, but also due to worldwide reliance on traditional medicinal plants for health. Effective conservation strategies for medicinal plant should take place within four main areas: in-situ andex-situ conservation, education and research. Saving Africa’s medicinal plant resources from extinction calls for intensive management and conservation, more research and increased level of public awareness about our vanishing heritage.

	 

	Key words: African, health care delivery, medicine, harvesting.

Biodiversity and conservation of medicinal and aromatic plants in Africa

Many human pathogens require serious attention in developing countries like Nigeria. Six pathogens were used for the study of the antimicrobial effect of Cajanus cajan leaf extract on some pathogens. Escherichia coli, Staphylococcus aureus, Proteus mirabilis, Salmonella typhi, and Klebsiella pneumoniae were the bacteria isolates and Candida albicans was the only yeast (fungi) isolate used. Solvents used for the extraction of active ingredients of the plant leaf were water (as the aqueous solvent), petroleum ether, ethanol, and chloroform/methanol mixture (as organic solvents). The antibacterial effect of the plant extract showed that the organic solvent extracts were inhibitory to E. coli, S. aureus, and S. typhi; the aqueous extract was inhibitory to E. coli and S. aureus; while K. pneumoniae and P. mirabilis showed resistance to all the extracts. The minimum inhibitory concentration value of the extracts on the organisms ranged between 0.125 and 0.25 mg/ml for E. coli, 0.125 mg/ml for S. aureus...

Antimicrobial Effect of Leaf Extracts of Pigeon Pea (Cajanus cajan (L.) Millsp.) on Some Human Pathogens

Two pathogens were employed, Streptococcus faecalis and Candida albicans for the study of the antimicrobial effects of Piper guineense and Phyllantus amarus using agar-well diffusion and disc-diffusion methods. Phytochemical screening of ethanol, cold and hot water extracts detected the presence of tannins, saponins, flavonoids, terpenoids and phlobatannins. Antimicrobial effect of the plant extracts showed that the organic solvent and aqueous solvents of P. amarus were inhibitory to S. faecalis while the extracts of Phyllantus amarus were not inhibitory to Candida albicans. Agar-well determined Minimum Inhibitory Concentration (MIC) values ranged between 3.125 mg/ml and 6.25 mg/ml while the disc diffusion determined MIC values ranged between 6.25 mg/ml and 25.0 mg/ml. The agar-well determined MIC values for the ethanolic P. amarus extracts (3.12 mg/ml) were lower than the corresponding disc-diffusion MIC determined values (6.25 mg/ml – 25.00 mg/ml). Bacteriocidal and bacteriostatic effect varied with, solvent type of extract, concentration of the plant extract and the method of the test adopted. The active components of the plant have no antifungal effect on the tested yeast (Candida albicans). These findings are discussed in relation to plant chemicals as a means of disease control and also to the problem of microbial resistance to synthetic drugs.

Antimicrobial effects of Piper Guineense ‘Uziza’ and Phyllantus amarus ‘Ebe-Benizo’ on Candida albicans and Streptococcus faecalis

Investigation was carried out to test the potency of some plant extracts for the control of yam tuber rot caused by Fusarium oxysporum, Aspergillus niger and Aspergillus flavus. Hot water extracts were obtained from leaf and seed of uda (Xylopia aethiopica) and Ginger (Zinigiber officinale), and were found to be fungitoxic against the fungi. The extracts of suppressed the growth of these fungi in culture and reduced rot development in yam tubers.

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I A Nmeka

Papers

Control of yam tuber rot with leaf extracts of Xylopia aethiopica and Zingiber officinale