Common Poisonous Plants of East Africa.

The use of herbal medicine is increasingly finding more relevance today, especially with the recognition that we are facing more challenges in the treatment of some medical conditions such as diabetes and cancer. To date, there are not many publications or records on the traditional herbal medicine use among the various Kenyan communities despite the widespread use. There is therefore an urgent need to document traditional medicines in Kenya for future reference and research. The main objective of this review is to examine the current state of traditional herbal medicine practise in Kenya, the challenges facing the sector and the possible solutions to streamline the practice and maximize on the benefits. The method adopted in this research involved the analysis of the available records on herbal medicine in Kenya from various sources including internet and the available books. This information was then compared with those in other countries with established systems in order to establish the existing inadequacies. The various efforts to document herbal medicine incorporate into mainstream healthcare and the legal framework was also reviewed. Key words: Herbal medicine, documentation, research

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Current trends of Traditional Herbal Medicine Practice in Kenya: A review

Objective:Traditional medicinal plants have long been used to treat various ailments in Keiyo district. However to date there are no records on medicinal plants used by the Keiyo despite threats of rapid disappearance of indigenous knowledge from deforestation, overexploitation among other factors. The purpose of the study was to document medicinal plants used by the Keiyo community in order to preserve traditional medical knowledge for future research and potential development of new drugs. Methods:The research team comprised of professionals from the fields of medicine and botany. Local leaders, community elders, church leaders and other stakeholders were used to identify herbalists and convince them to provide information. Semi structured interviews, group discussions and observations were used to collect information on traditional knowledge from herbalists. Details of the medical conditions treated, herbal preparations used, treatment methods, local plant names and methods of collection of herbs were recorded. 
Results:A total of 73 medicinal plant species belonging to 33 families were identified, used to treat 46 common human and three veterinary diseases. Leucas calostachys was the most widely used (17 medicinal uses) followed by Vachelia xanthophloea (10), Carissa edulis (9), Trimeria grandifolia (8), Terminalia brownii (7) and Rhamnus prinoides (6). Heartburn was treated using the largest number of plants (17) followed by cancer (9). Eight plants were used to either treat infertility in women or arthritis, whereas peptic ulcers, hypertension, headache, chest congestion and colic pains were each treated using seven plants. 
Conclusions:The study provides information on medicinal and healing methods used by the Keiyo community. It also revealed that traditional medicines are still widely used in Keiyo district. Some of the identified plants have been demonstrated to possess pharmacological activities related to those mentioned by the herbalists.

Ethnomedicinal Plants Traditionally Used by the Keiyo Community in Elgeyo Marakwet County, Kenya

Synaptolepis alternifolia is a commonly used fish poison plant in Zimbabwe. Root methanolic extracts of S. alternifolia were screened for phytochemicals and tested for cytotoxicity and insecticidal activity. Tests indicated the presence of reducing sugars, terpenoids, flavonoids, saponins, tannins and alkaloids. Cytotoxic effects of the plant were assessed through the Brine shrimp lethality (BSL) bioassay. An LD50 of 0.372 mg/ml was found indicating that the root extract were cytotoxic. Insecticidal activity was assessed by the mosquito larvae test using Culex quinquefasciatus 3rd and 4th instars. LD50 and LD90 of the methanol extract after 24 hr was 5.6 mg/ml and 82.5 mg/ml while the LD50 and LD90 after 48 hr were 0.45 mg/ml and 11.3 mg/ml respectively, showing a higher insecticidal activity after 48 hours of exposure to the extract. The results show a huge potential of S. alternifolia as an insecticide.

https://www.phytojournal.com/archives/2014/vol2issue5/PartA/1.1.pdf

Phytochemical screening, cytotoxicity and insecticidal activity of the fish poison plant Synaptolepis alternifolia oliv. (Thymelaeaceae).

The present study focused on the insecticidal potential of easily available local botanicals using a simple but effective method. Seven indigenous plants (Cinnamomum tamala (taiz pat), Aloe vera (aloe vera), Datura alba (datura), Allium sativum (garlic), Allium cepa (onion), Zingiber officinale (ginger), and Ocimum basilicum (niazbo/basil) were tested for their larvicidal efficacy against Culex quinquefasciatus (Say) under laboratory conditions. The evaluation of a series of five concentrations (1%, 2%, 3%, 4%, and 5%) of aqueous plant extracts against the 4th instar larvae revealed convincing larval mortality effects at 24 and 48 h after exposure. Larval mortality showed a significant concentration-dependent correlation. No mortality was observed in the control. The LC50 values demonstrated garlic as the most effective (1.37%), followed by taiz pat (1.48%) and aloe vera (1.96%), at 24 h. Moreover, the LC50 at 48 h showed high efficiency by aloe vera (0.37%), followed by garlic (0.55%) and taiz pat (0.98%). The sequence of LC50 values for the other plants were onion (2.20%) < datura (2.49%) < niazbo (5.32%) < ginger (7.48%) after 24 h and datura (1.13%) < niazbo (1.17%) < onion (1.24%) < ginger (2.43%) after 48 h. Taken together, the aqueous extracts of all plants exhibited potential efficacy against C. quinquefasciatus larvae and could be considered as potent natural larvicidal agents. These plants may be recommended for use in mosquito management programs as potential alternatives to synthetic insecticides. The simple aqueous extraction method is easy and inexpensive and can be used at the home level for mosquito management.

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Evaluation of larvicidal efficacy of indigenous plant extracts against Culex quinquefasciatus (Say) under laboratory conditions

Introduction The medical importance of mosquitoes as vectors for the transmission of serious diseases that cause morbidity, mortality, economic loss, and social disruption such as malaria, lymphatic filariasis, and viral diseases is well recorded (Becker et al, 2003). Aedes aegypti, the main carrier for viruses that cause dengue and dengue hemorrhagic and yellow fevers, is found majorly in the tropics and subtropics. There is no effective vaccine against dengue, and thus the only way of significantly lowering the incidence of this disease is through mosquito control (Malavige et al, 2004). Chemical measures were first tried, but they failed since their overuse led to disruption of natural biological control systems and outbreak of new insect species. In addition, use of insecticides led to the development of mosquito resistance, environmental pollution, and undesirable effect on non-target organisms (Brown, 1986). In a bid to resolve these problems, interest in insecticides of natural origin, specifically plant-derived products has recently received close attention. Several studies have emphasized the importance of research and development of herbal substances for controlling mosquitoes (Shaala et al, 2005). Their results may vary, but natural plant products may be a possible alternative to synthetic substances, as they are effective and compatible with human and animal life and the environment (Chaithong et al, 2006). The genus Mundulea consists of about 15 species, widespread throughout Africa, Madagascar, Mauritius, India, Sri Lanka and Papua New Guinea. Only a single species, Mundulea sericea, is found in Southern Africa. This species occurs in South Africa, Botswana, Namibia and Angola, north to tropical Africa, and east to Madagascar, India, Sri Lanka and Papua New Guinea (Watt and Breyer-Brandwick, 1962). Mundulea sericea is one of the commonest fish poisons where both bark and seeds are used (Neuwinger, 2004). In addition, the Chinese used M. sericea to control tobacco budworm Heliothis virescens (Lepidopteriae: Noctuidae) (Yoshida and Toscano, 1994). The toxic principal of the plant is rotenone, an isoflavonoid (Vedcourt and Trump, 1969). The rotenoids deguelin and tephrosin are the potent active principles which have been isolated from extracts of M. sericea (Luyengi et al, 1994). Deguelin is a natural plantderived rotenoid, most commonly used as an insecticide in Africa and South America (Udeani et al, 1997). Rotenoids from the bark of M. sericea have been commercially used as insecticide. These chemical compounds in the bark, leaves and seed are the active compounds responsible for the fish poison. It is reported that the strength varies geographically (Watt and Breyer-Brandwick, 1962). The current study involved extraction and evaluation of root bark and seedpod of M. sericea for larvicidal activities on Aedes aegypt.

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Larvicidal effect of Mundulea sericea (Leguminosaea) plant extract against Aedes aegypti (L.) (Diptera: Culicidae)

Background: The sand fly, Phlebotomus duboscqi is the vector for zoonotic cutaneous leishmaniasis caused by Leishmania major . No definite control method for P. duboscqi is known. Of the plants known for entomocidal properties, Mundulea sericea is one, with the toxic principle being rotenone. Dried crude M. sericea powder extract mixed with water is used by the Giriama people of Coastal region, Kenya, to kill cat fleas and bedbugs. A recent laboratory study using M. sericea non-polar and polar extracts displayed remarkable entomicidal potential. Against this backdrop, M. sericea was chosen for this study. Objective: To evaluate water extracts of Mundulea sericea leaves for efficacy against P. duboscqi eggs and larvae. Methodology: The plant leaves were ground into fine powder and extracted using water. 1 g leaf powder was extracted using 100 ml distilled water, and then filtered. The eggs were then exposed to 1 ml of the filtered extract.  Further, 0.001 g of leaf powder was mixed with 1 g of larval food and fed to larvae. The eggs were incubated at 25 0 C and 80% relative humidity and observed for eclosion, and larvae for hatching to adult stage. Results: The filtered extracts did not inhibit eggs from hatching. Additionally, all the larvae that were fed on food mixed with ground M. sericea leaves survived. Conclusion: These findings suggest that suggest that M. sericea water extracts do not penetrate the egg chorion, thus the lack of activity. Moreover, the inability of P. duboscqi to digest the chlorophyll of M. sericea so as to release rotenone could be responsible for absence of entomocidal effect. Key words: Mundulea sericea; Phlebotomus duboscqi; Leishmania major.

David K. Siele

Papers

Larvicidal effect of Mundulea sericea (Leguminosaea) plant extract against Aedes aegypti (L.) (Diptera: Culicidae)

The effects of Mundulea sericea (Fabales: Fabaceae) water extracts on Phlebotomus duboscqi (Diptera: Psychodidae) eggs and larvae