Antibacterial and cytotoxic activity of Kenyan medicinal plants

Abstract

(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...

Ethnobotany, ethnopharmacology, and phytochemistry of traditional medicinal plants used in the management of symptoms of tuberculosis in East Africa: a systematic review

“… Asteraceae Ekoutapem Herb Roots, Leaves Uganda [ 10 ] Harrisonia abyssinica Oliv. Simaroubaceae Mutagataga (Meru), Osiro (Luo), Orongoriwe (Kuria), Lushaike Shrub Stem bark Uganda, Kenya [ 10 , 50 , 51 ] Harungana madagascariensis Lam.ex Pior Hypericaceae Mukabiiransiko (Luganda) Tree Stem bark, Leaves Uganda [ 8 ] Helichrysum odoratissimum (L.) Asteraceae Lweza (luganda) Herb Leaves Uganda [ 10 ] Heterotis canescens Melastomataceae Umusomaw’a-bungere, Herb Leaves Burundi [ 38 ] Hibiscus fuscus Garcke Malvaceae Lusaala (Luganda) Herb Leaves Uganda [ 7 ] Hoslundia opposita Vahl Lamiaceae Cheroronit, Cherungut (Nandi), Nfodo (Lusoga) Shrub Leaves Uganda, Kenya [ 10 , 31 ] Hypericum revolutum Vahl Clusiaceae Mushungwa Tree Leaves Uganda [ 10 ] Hypoestes verticillaris (L.f.) Sol. Acanthaceae Narubat (Ogiek) Herb Roots Kenya [ 46 ] Iboza multiflora (Benth.)…”

Analysis of Peganum harmala, Melia azedarach and Morus alba extracts against six lethal human cancer cells and oxidative stress along with chemical characterization through advance Fourier Transform and Nuclear Magnetic Resonance spectroscopic methods towards green chemotherapeutic agents

“…The effects of the plant species are consistent with the phytochemical data of these plants as a source of active cytotoxic and antitumor compounds ( Bastos et al, 2009 ). So, our findings indicated BSLT as convenient bioassay to screen natural products in drug discovery process ( Cyrus et al, 2008 ). The LC 50 values of the plant extracts (at 24 h) were achieved through a plot of proportion of the shrimps killed alongside the concentrations of extracts and best-fit line was acquired from the statistics by means of regression analysis to calculate LC 50 value ( Roy et al, 2011 ).…”

Efficacy of Avicennia marina (Forsk.) Vierh. leaves extracts against some atmospheric fungi

“…Bhosale et al (1999) screened seventeen floral and faunal organisms for their antifungal activity, out of seventeen species, twelve exhibited significant activity against all the three species of food spoilage strains of Aspergillus. Similarly, the cytotoxic activity of mangrove plants was observed by Cyrus et al (2008). The presence of these plants in high salinity habitat might have caused the toxic microbial compounds with increased resistance and tolerance in these plants.…”