Eleven medicinal plants used by traditional healers in Machakos and Kitui District were screened, namely: Ajuga remota Benth, Aloe secundiflora Engl, Amaranthus hybridus L, Cassia didymobotrya Fes, Croton macrostachyus Del, Entada leptostachya Harms, Erythrina abyssinica DC, Harrisonia abyssinica Oliv, Schkuhria pinnata O. Ktze, Terminalia kilimandscharica Engl and Ziziphus abyssinica Hochst for potential antibacterial activity against four medically important bacterial strains, namely: Bacillus cereus ATCC 11778, Escherichia coli ATCC 25922, Micrococcus lutea ATCC 9341 and Pseudomonas aeruginosa ATCC 27853. The antibacterial activity of methanol extracts was determined as the minimum inhibitory concentration (MIC). The plant extracts were more active against Gram-positive (G+) than Gram-negative (G-) bacteria. The positive controls were streptomycin and benzylpenicillin for G- and G+ bacteria, respectively, both had a significant MIC at <1 mg/mL. The most susceptible bacteria were B. cereus, followed by M. lutea, while the most resistant bacteria were Ps. aeruginosa, followed by E. coli. The present study supports the use of these plants by the herbalists in the management of bacterial ailments. H. abyssinica and T. kilimandscharica showed the best antibacterial activity; hence these plants can be further subjected to phytochemical and pharmacological evaluation.
(Miaron et al. 2004, Kareru et al. 2007, Njoroge & Bussman 2007. The high cost of imported conventional drugs and/or inaccessibility to western health care facilities has led to overreliance on traditional medicine since it is affordable and available to rural people. On the other hand, even when western health facilities are available, traditional medicine is viewed as an efficient and an acceptable system from a cultural perspective (Munguti 1997, Miaron et al. 2004.Infections associated with bacterial pathogens are among some of the indications treated using traditional remedies in Kenya (Njoroge & Bussman 2007). Bacterial infections are prevalent due to various factors such as the HIV/AIDS pandemic, poor hygiene, overcrowding and resistance to convectional antimicrobials. Natural products of higher plants may provide a new source of antimicrobial agents with possibly novel mechanisms of action (Adenisa et al. 2000).The aim of this study was to screen methanolic medicinal plant extracts traditionally used for the management of infectious diseases in Kenya. Brine shrimp (Artemia salina Leach) lethality test (BSLA) was used to systematically evaluate the cytotoxic effects of extracts. Broth dilution assays using Gram-negative bacteria Escherichia coli (ATCC 25922) and Pseudomonas aerugenosa (ATCC 27853) and Gram-positive bacteria Staphylococcus aureus (ATCC25923) and Bacillus cereus (ATCC 11778) was utilized to obtain the minimal inhibitory concentrations (MIC) of the plant extracts.
MATERIALS AND METHODSPlant materials -Plants were collected during dry season from January-March 2006 in Machakos and Kitui areas of the Eastern province, Kenya, based on ethnopharmacological use through interviews with traditional health practitioners. The plants were identified by Mr. Ochung, a plant taxonomist, and voucher specimens (Table I) were deposited at the Department of Land Resource Management and Agricultural Technology Herbarium, University of Nairobi.Extraction -The plant parts (whole plant, bark, root, leaves, tubers or a mixture) were chopped into small pieces, air dried at rt (25°C) under shade and pulverized using a laboratory mill yielding 300-400 g. The fine powders were separately soaked in 70% methanol (3 × 500 mL) for four days at rt to produce extracts. The extracts were filtered and concentrated using rota vapor at 50°C and 100 mbar. Further preparation was done according to Gebre-Mariam et al. (2006). The lyophilized extracts were kept at +4°C until they were screened. The yields of the methanol extracts were between 5%-8.4%. The methanolic extract yields were obtained as follows: leaves of Ajuga remota Benth (320 g) yielded 7.5%, leaves of Amaranthus hybridus L. (350 g) yielded 4.2%, leaves of Cassia didymobotrya Fres. (320 g) yielded 8.4%, a mixture of leaves and roots of Croton macrostachyus Del. (400 g) yielded 5.2%, tubers of Entada leptostachya Harms (300 g) yielded 6%, mixture of leaves and bark of Harrisonia abyssinica Oliv (360 g) yielded 6.5% and bark of Terminalia kilimandscharica Engl. (370...
The chemical composition and in situ dry matter (DM) and organic matter (OM) degradability of seven different cereal crop residues were evaluated in this study.They included the Sorghum stovers (SS) and its threshed head residues (STH), millet stovers (MS) and its threshed head residues (MTH), corn stover (CS), wheat (WS) and barley (BS) straws. A legume crop residue (lentil, Lens esculanta, straw; LS) was included for comparison with the cereal crop residues. The CS was high (P < 0.05) in crude protein (CP) and acid detergent lignin (ADL) and the lowest (P < 0.05) in Neutral Detergent Fibre (NDF) and acid detergent fibre (ADF) when compared to the amounts in SS and MS. It was found out that LS had higher (P < 0.05) CP, ADL, ME and low (P < 0.05) NDF and ADF than the cereal crop residues. There were differences in digestible DM (DMD) at various incubation times both between and within the feed samples. The DM and OM a, c fraction were highest (P < 0.05) for LS when compared to all the cop residues evaluated. The BS and MS had the lowest effective degradability (ED) DM at 0.02 and 0.05 (P < 0.05) rates of passage, while the LS had the highest. The chemical composition and degradability of different crop residues found in Eritrea indicate the potential the residues have in supplementing grazing animals.
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