Antimicrobial Properties of Some Medicinal Plants of the Luo Community of Kenya

Background: The Luo community of Kenya rely mostly on ethno-medicine to manage human ailments. This study was set to survey, record and report the medicinal plant species they use to manage infectious conditions. Objective of this study was to screen the plants used by this community to treat microbial infections, to demonstrate their in-vitro antibacterial and antifungal activities. Methodology: Eight plants namely Lannea stuhlmanii, Carissa edulis, Combretum fragrans, Conyza sumatrensis, Ormocarpum trichocarpum, Sida cuneifolia, Plumbago zeylanica, and Rhoicissus revoilii, used by the Luo for treatment of microbial infections, were studied. Observations and semi-structured interviews were used to gather ethno-botanical data for each plant. About 3 kg of suitable specimens were harvested, with leaves pressed and preserved for identification at University of Nairobi’s Department of Botany Herbarium. Voucher specimens were also deposited at the University’s School of Pharmacy Herbarium and excess material powdered and kept dry. The pressed specimens were dried at 20 0C to 25 0C using plant blower. Their ethanolic extracts were screened for their antimicrobial activity against Candida albicans, Escherichia coli, Staphylococcus aureus and Bacillus pumulus. Results: Extracts from Conyza sumatrensis, C. fragrans, C. edulis, S. cuneifolia, R. revoilii and leaf C. sumatrensis had good activity against E. coli. Activity against B. pumulus was observed in all extracts except those of L. stuhlmanii bark and R. revoilii tubers. Good activity against S. aureus was observed with C. fragrans, S. cuneifolia and L. stuhlmanii. Rhoicissus revoilii, L. stuhlmanii, C. fragrans and C. edulis exhibited good antifungal activity against Candida albicans. Conclusion: This work partially supports the traditional antimicrobial use of the various plants, and it is hoped that the results will form the basis for further research that could lead to isolation and/or development of antibacterial and antifungal medicines for use in primary health care. The results also confirm that plants are a potential source of antimicrobial compounds. Key words: Luo; Antimicrobial; Ethanolic extracts; screenin

Microbial Quality of Unregulated Herbal Medicinal Products in Kenya

Background: The use of herbal medicines is global, with the majority of the world’s population depending on traditional medicines, particularly herbal remedies for their primary healthcare needs. In Kenya, it is estimated that conventional healthcare system provides for approximately 30 % of the population, while nearly 70 % rely on herbal remedies. Herbal medicines, however, present safety concerns as they carry a relatively high risk of contamination by pathogenic microbes, organic and inorganic pollutants including toxic metals and non-metals, organic, mycotoxins, endotoxins, and agrochemical residues. Objective: This study was designed to assess the microbial quality of regulated and unregulated herbal medicinal products in diverse Kenyan markets, such as the supermarkets, roadside vendors, retail pharmacies and herbal clinics, for levels of microbial contaminants. Materials and Methods: Thirty samples of registered and unregistered herbal medicinal products were collected by purposive sampling from five Kenyan provinces.  Microbial load analysis was performed in accordance to pharmacopoeial methods (BP and USP). Microorganisms were further isolated and characterized using differential and selective media and by biochemical analyses. Results: All registered products had microbial load below 100 cfu/ml, and complied with BP and USP requirements. However, none of the unregistered samples complied with pharmacopoeial limits for either or both bacterial and fungal load limits. Most of the unregistered samples had microbial loads ranging from 3.00×106 to 1.56 × 1010 cfu/ml, thus exceeding by far BP or USP standards. The microbial isolates belonged to fifteen (15) different bacterial genera and seven (7) fungal genera.  Escherichia coli was the most frequently isolated bacteria from 75 % of the unregistered product samples while Klebsiella pneumoniae, Enterobacter aerogenes, and Staphylococcus aureus followed in 70 %, 60 % and 45 % of the samples, respectively. Salmonella spp was isolated in 40 % of the samples while Shigella spp was found in 20 % of the samples. Conclusion: Unregulated herbal medicinal products that are available in diverse Kenyan markets show poor microbial quality and exhibit contamination by pathogenic microorganisms.  There is need to extend regulatory control by the drug authorities to herbal medicinal products to enhance microbial quality and safety. Keywords: Microbial contaminants, herbal medicines, microbial loa

In vitro anthelmintic activity of Albizia gummifera, Crotalaria axillaris, Manilkara discolor, Teclea trichocarpa and Zanthoxylum usambarense using sheep nematodes

Background: Albizia gummifera, Crotalaria axillaris, Manilkara discolor, Teclea trichocarpa and Zanthoxylum usambarense are used to treat different ailments in many parts of the world. For instance, A. gummifera is used to treat stomach pains, malaria, diarrhoea and sleeping sickness while C. axillaris treats ophthalmic disorders and kidney problems. Manilkara discolor stem bark infusion is used to treat stomach disorders and as an astringent while T. trichocarpa has been used to treat malaria, helminth infections and fever. Zanthoxylum usambarense is used to treat rheumatism, backache, painful joints, fever, sore throat, tonsillitis, chest pains, malaria, abscesses and wounds. Objective: The aim was to determine whether the crude plant extracts have in vitro anthelmintic activity. Materials and methods: Different parts of the plants were acquired from Ngong Hills forest, Kajiado County, Kenya in May 2012, dried and macerated to exhaustion with dichloromethane: methanol (1:1, v/v) solution. Nematode eggs (Haemonchus Spp, Trichostrongylus Spp and Oesophagostomum Spp) were obtained from infected sheep rectums at Department of Vet Farm, University of Nairobi based at Kabete. Varying concentrations of water solutions of the dry crude extracts were prepared. Egg hatch (EHA) and larvae development assays (LDA) were used to test the extracts’ effects on nematode egg hatching and larvae development, respectively Results: Albizia gummifera (root bark) and Zanthoxylum usambarense (stem bark) showed high activity (IC50 below 300 μg / mL) in both tests.  Albizia gummifera (root, stem bark and pods), Zanthoxylum usambarense root bark, Crotalaria axillaris twigs and Teclea trichocarpa root and stem bark showed high activity in LDAbut moderate activity (300 μg / mL < IC50 < 500 μg / mL)  in EHA. Teclea trichocarpa twigs showed moderate activity in LDA but low (IC50 > 500 μg / mL) activity in EHA. Manilkara discolor extracts showed low activity in both tests. Conclusion: Different extracts of the plants tested may inhibit nematode growth and development and hence warrant in vivo tests would support their ethnomedicinal application. Key words: Anthelmintic activity, egg hatch, larval development, Haemonchus, Trichostrongylus, Oesophagostomu

A 56-Day Oral Toxicity Study of the Aqueous Extract of Rapanea melanophloeos (L.) Mez in Rats

Rapanea melanophloeos is a tropical tree that is extensively utilized in African traditional medicine to treat helminthiases, tuberculosis, and heart-water. As with many other medicinal plants, there is insufficient information regarding the safety of therapeutic R. melanophloeos extracts. An aqueous extract of R. melanophloeos stem bark was administered to Sprague Dawley rats at doses of 100 mg/kg, 300 mg/kg, and 1000 mg/kg for 56 days to characterize its potential toxicity after prolonged dosing. Blood samples were obtained fortnightly for serum chemistry and hematology, while organs were collected at the end of the study. The extract caused an increase in organ weight indices of the kidneys and testis at 300 mg/kg and 1000 mg/kg. Hematological and biochemical examination revealed a drop in leukocyte counts and the hematocrit at 1000 mg/kg dose level, while there was a general but nondose-related elevation in alkaline phosphatase activity. There were time-associated variations in the hematological and clinical chemistry parameters at days 28, 42, and 56 in all dose levels, but most values remained within physiological limits. No pathological lesions were evident at histopathology after treatment with the extract. Our data shows that the aqueous extract of R. melanophloeos is not likely to be toxic at the doses tested and provides support to its medicinal use

Antibacterial and Antifungal Activity of Dombeya torrida (J.F. Gmel) and Hydnora abyssinica (A. Braun)

Background: The decoction of Dombeya torrida bark is used to treat indigestion while its roots are used for treatment of chest pains and colds. Hydnora abyssinica decoction is used as a cure for throat complaints, as an astringent in dysentery, for treatment of typhoid, anthrax, and East Coast Fever. Objectives: The present study was aimed at investigating the antibacterial and antifungal activities of D. torrida and H. abyssinica. Methodology: The D. torrida stem-bark and leaves and H. abyssinica whole plant were collected from Kiambu County and Embu County, respectively. Extraction of the plants was carried out using chloroform, methanol and water. The extracts were screened for activity against Staphylococcus aureus, Staphylococcus epididermis, Bacillus pumilus, Escherichia coli, Saccromyces cerevisiae and Candida albicans using agar diffusion assay and autobioassay. Results: Dombeya torrida bark decoction had the highest activity against S. aureus with an inhibition zone diameter of 16.91 mm. Hydnora abyssinica macerate had least activity against S. aureus with a zone diameter of 8.86 mm. Dombeya torrida bark decoction had the highest activity against S. Epididermis with a diameter of 17.05 mm with Hydnora abyssinica macerate having the least activity. Activity against E. coli was highest for D. torrida bark decoction with zone diameter of 16.56 mm. Hydnora abyssinica chloroform extract had the highest activity against B. pumilus with a zone diameter of 17.04 mm. The highest activity observed against S. cerevisiae was with D. torrida chloroform extract with a zone diameter of 17.69 mm with H. abyssinica macerate having the least activity (7.70 mm). Dombeya torrida chloroform extract was the most active extract against C. albicans with a zone diameter of 20.09 mm. Conclusion: The plants under study, D. torrida and H. abyssinica were chosen on the basis of folklore. Above results support the folklore that H. abyssinica is used as a cure for throat complaints, as an astringent in dysentery, treatment of diarrhoea and amoebic dysentery. Results of D. torrida extracts also supports its folklore use to treat chest pains and colds as many of these conditions are usually caused by bacterial infections. Keywords: antibacterial, antifungal, Dombeya torrida, Hydnora abyssinica, autobioassa

Essential oils composition of Ocimum basilicum L. and Ocimum gratissimum L. from Kenya and their inhibitory effects on growth and fumonisin production by Fusarium verticillioides

This work investigated the constituents and the efficacy against Fusarium verticillioides infection and fumonisin production of essential oils of Ocimum basilicum L. and Ocimum gratissimum L. from different locations in Kenya. The oil of leaves and flowering tops of O. basilicum from Sagana contained mainly linalool (95%). The flowering tops and leaves from Yatta contained mainly camphor (32.6 and 31.0%, respectively) and linalool (28.2 and 29.3, respectively). Eugenol was the main constituent in the oil of O. gratissimum leaves from both Sagana (95.5%) and Yatta (70.1%). The oil of the flowering tops had significantly less eugenol. The main component of the oil of flowering tops from Yatta was Z-â-ocimene (34.1%). Oil from both species had some antifungal activity. The oils of O. basilicum and O. gratissimum from different locations showed chemical variation, antifungal activity, free radical scavenging capacity and antimycotoxicogenic property. These properties are attributed to the phenolic compound eugenol. Industrial relevance: This manuscript gives the chemical composition and some biological effects of essential oil of two Ocimum species in Kenya namely Ocimum basilicum L. and Ocimum gratissimum L. The work reveals that there are chemovarieties of these plants in different locations in the country. Of significance is the presence of very high amounts of linalool in one chemovariety of O. basilicum while geranial and neral are major in another. The third variety contains almost equal amounts of camphor and linalool. The first two containing high quantities of linalool, geranial and neral could be cultivated after agronomic studies to provide essential oils useful in perfumery, soap or food industry while that containing camphor and linalool may find use in medicine. Proper seed selection and good agricultural practice for O. gratissimum containing high amount of eugenol could serve as good substitute for cloves which grows best only in a few islands in East Africa. Clove oil due to its high eugenol content has many biological activities including those demonstrated in the present work, and many applications in medicine and commercial world. There is need for more research on these plants especially on cultivation and commercial exploitation of the herbs.Fil: Dambolena, José Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Zunino, María Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: López, Abel Gerardo. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Ciencias y Tecnología de los Alimentos; ArgentinaFil: Rubinstein, Héctor Ramón. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; ArgentinaFil: Zygadlo, Julio Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Mwangi, Julius W.. University of Nairobi; KeniaFil: Thoithi, Grace N.. University of Nairobi; KeniaFil: Kibwage, Isaac O.. University of Nairobi; KeniaFil: Mwalukumbi, Josphat M.. University of Nairobi; KeniaFil: Kariuki, Samuel T.. Egerton University; Keni