Nicholas K. Gikonyo

Constituents of the Essential Oil of Suregada Zanzibariensis Leaves are Repellent to the Mosquito, Anopheles Gambiae s.s.

Abstract In traditional African communities, repellent volatiles from certain plants generated by direct burning or by thermal expulsion have played an important role in protecting households against vectors of malaria and other diseases. Previous research on volatile constituents of plants has shown that some are good sources of potent mosquito repellents. In this bioprospecting initiative, the essential oil of leaves of the tree, Suregada zanzibariensis Verdc. (Angiospermae: Euphobiaceae) was tested against the mosquito, Anopheles gambiae s.s. Giles (Diptera: Culicidae) and found to be repellent. Gas chromatography (GC), GC-linked mass spectrometry (GC-MS) and, where possible, GC-co-injections with authentic compounds, led to the identification of about 34 compounds in the essential oil. About 56% of the constituents were terpenoid ketones, mostly methyl ketones. Phenylacetaldehyde (14.4%), artemisia ketone (10.1%), (1S)-(-)-verbenone (12.1%) and geranyl acetone (9.4%) were the main constituents. Apart from phenylacetaldehyde, repellent activities of the other main constituents were higher than that of the essential oil. The blends of the main constituents in proportions found in the essential oil were more repellent to An. gambiae s.s. than was the parent oil (p < 0.05), and the presence of artemisia ketone in the blend caused a significant increase in the repellency of the resulting blend. These results suggested that blends of some terpenoid ketones can serve as effective An. gambiae s.s. mosquito repellents.

Growth disruption activity of polar extracts from Kotschya uguenensis (Fabaceae) against Anopheles gambiae s.s. (Diptera: Culicidae) larvae

Studies on the larvicidal properties of extracts and fractions from Kotschya uguenensis Verdc. were done by long-term exposure of Anopheles gambiae s.s. larvae. The cumulative mean percentage mortalities and deformities at different concentrations for the extracts and fractions were recorded after every 24 h. Treatment of A. gambiae s.s. larvae with K. uguenensis extracts showed growth disruption by forming elongated guts and resulting in eventual death. Larvae treated with the methanol extracts from the stem and root barks, and fractions of the former extract attained complete mortality in 6–8 days at 50 and 100 ppm. More deformed larvae were observed from the methanol extract of the stem bark (40%) and methanol-soluble fraction (88%) than those treated with water-soluble fraction (22%) and methanol extract of the root bark (5%). The growth disruption may be associated with constituents in the plant that interfere with the normal endocrine system functions.

Efficacy of amaranth sorghum grains porridge in rehabilitating moderately acute malnourished children in a low-resource setting in Kenya: A randomized controlled trial

In Kenya, wasting levels among children under five years reduced between 2010 (7%) and 2014 (4%), but the number of wasted children is still high. Thin porridge, mainly from cereals and starchy tubers is a popular complementary food, though inadequate for children`s nutritional requirements. It is low in energy, nutrient density and high in antinutrients. Traditionally, fortified blended foods such as corn-soy blend has been used to treat moderately acutely malnourished (MAM) children with limited effectiveness due to its low nutritive profile and relatively high level of anti-nutrients. Therefore nutrient-dense complementary foods are needed. This study aimed to determine the efficacy of amaranth sorghum grains product in rehabilitating MAM children. Villages in Kiandutu slums, were randomly assigned to two study groups; Treatment (TG) and control (CG). Mothers and their moderately malnourished children (6-23 months old) were recruited at a health centre and assigned to groups depending on their village of residence. Children in TG received germinated amaranth sorghum grains flour, those in CG received a blend of sorghum and maize grains flour, for a maximum period of 6 months. Each month, children`s morbidity status and anthropometric measurements were taken. The primary outcome was nutritional status judged by wasting. At baseline the groups’ characteristics were similar. At month 5, 35.3% and 12.9% of children in CG and TG were wasted respectively (Relative Risk [RR] RR=1.35 (95% CI: 1.03-1.77; p=0.030) and at month 6, 62.1% and 15.6% of the children CG and TG were wasted respectively RR=2.23 [(95% CI: 37-3.61; p<0.001). Germinated amaranth sorghum grains may offer an alternative to treatment of MAM children. Nonetheless, it took longer than WHO recommended 90 days for rehabilitation of MAM children. Introduction In Kenya 4%, 26% and 11% of children under five are wasted, stunted and underweight respectively [1]. Poor quality complementary foods with low nutrient density and inappropriate feeding practices are among the major causes of malnutrition in young children [2]. In sub Saharan Africa moderately wasted children are treated with cornsoy blended flour (CSB) through targeted supplementary feeding programmes. However there have been doubts on the effectiveness of CSB in treating malnutrition [3,4]. Ready to use therapeutic food (RUTF) has also been used to treat moderate acute malnutrition (MAM) [3,5]. However, milk in RUTF (25-35% w/w) makes them too expensive for sustainable use in resource-poor settings. Also, the high nutrient concentration in RUTF may make them unsafe for MAM children. It has been suggested that lipid-based ready to use foods could prevent/treat MAM [4]. There is concern that MAM children may be susceptible to immunological reactions since their immune system is intact [4]. Therefore, there is a need for alternative nutrient dense foods that are affordable by most families that could prevent undernourishment. Amaranth grain has a higher nutrient content compared to staple cereals [6,7]. It was complemented with sorghum in this study. Sorghum is drought tolerant and its nutritional profile is comparable to that of maize [8,9]. The study, aimed at evaluating the efficacy of amaranth sorghum grains product in improving the nutritional status Correspondence to: Okoth JK, Department of Food Science and Technology, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya, Tel: 254714408057/254733950524; E-mail: judithokoth@agr.jkuat.ac.ke/ kanensi@gmail.com