Cashew nut shell liquid: an agricultural by-product with great potential for commercial exploitation in Kenya

Cashew nut shell liquid (CNSL) is the main by‐product from cashew nuts processing and is obtained during roasting of the nuts by the oil‐bath method. It may also be obtained through expression of residual shells or solvent extraction of the pulverized shells. Kenya has the potential to produce 200,000 Tonnes of cashew nuts and  5,000 Tonnes of CNSL if all the nuts were to be processed locally and with recovery of the liquid. Currently, the country realizes only about 5‐10% of its nuts production potential. Processing of the nuts has been left to small scale processors who in many cases, burn residue shells as fuel or as waste. This practice pollutes the environment profoundly through emission of thick dark smoke with particulate matter. No CNSL is recovered in Kenya currently. The aim of this review paper is to highlight a number of products which can be manufactured in Kenya based on research initially done at Kenya Industrial Research and Development Institute and more recently at Jomo Kenyatta University of Agriculture and Technology Recovery of CNSL and its exploitation in Kenya will not only enhance the economic returns to the cashew industry but also contribute significantly to conservation of the environment. It is recommended that further work be done to scale‐up production of CNSL based products and demonstrate feasibility of the same. Production and local processing of the cashew nuts accompanied by recovery of CNSL should be enhanced.Key words: Cashew nuts, CNSL utilization, cashew nut production, Keny

Evaluation of phenolic contents and antioxidant activity of various solvent extracts of Sonchus asper (L.) Hill

<p>Abstract</p> <p>Background</p> <p><it>Sonchus asper </it>(SA) is traditionally used for the treatment of various ailments associated with liver, lungs and kidneys. This study was aimed to investigate the therapeutic potential of nonpolar (hexane, SAHE; ethyl acetate, SAEE and chloroform, SACE) and polar (methanol, SAME) crude extracts of the whole plant.</p> <p>Methods</p> <p>To achieve these goals, several parameters including free-radical (DPPH^•, ABTS^•+, H₂O₂and ^•OH) scavenging, iron chelating activity, scavenging of superoxide radicals, total flavonoids and total phenolic content (TPC) were examined.</p> <p>Results</p> <p>The SA extracts presented a remarkable capacity to scavenge all the tested reactive species with IC₅₀values being found at the μg ⁄ ml level. The SAME was shown to have the highest TPCs while lowest IC₅₀values for the DPPH^•, ABTS^•+radical scavenging capacities and iron chelating scavenging efficiency, moreover, SAME had best activities in scavenging of superoxide radicals and hydrogen peroxide as well as potently scavenged the hydroxyl radicals.</p> <p>Conclusion</p> <p>These results suggest the potential of <it>S. asper </it>as a medicine against free-radical-associated oxidative damage.</p

GC-MS analysis of pesticidal essential oils from four Kenyan plants

Essential oils are complex mixtures of odours and steam volatile compounds which are deposited by plants in the subcuticular space of glandular hairs, in excretory cavities and canals or exceptionally in heart wood. Essential oils have been found to have no specific biological functions in plants, but constitute many compounds that are insect repellents or act to alter insect feeding behavior, growth and development, ecdysis (moulting) and behavior during mating and oviposition. Others possess antifungal, insecticidal and antiseptic properties. Essential oils of leaves of Tagetes minuta L. (Asteraceae), Fuerstia africana T.C.E. Friers (Labiaae), Tephrosia vogelii  Hook. f. (Leguminosae) and Sphaeranthus ukambensis were obtained by steam distillation using the Clevenger apparatus (Guenter, 1949). Compounds in the essential oils were identified by gas chromatography-mass spectrometry (GC-MS). The characteristic volatiles isolated from the four plants were identified as follows: major constituents of the essential oils from F. africana included the following: limonene (39.1%), (Z)-β-ocimene (30.5%), targetone&lt;dihydro&gt; (26.2%),  E -targetone (59%), λ-terpinene (26.2 %), peripitenone 23.7%, ocimene allo (22.8%) and Z-targetone (100%). The compounds with the highest relative abundance value in the essential oils included Z-targetone, E-targetone and (Z)-β-Ocimene. Analysis of T. minuta also revealed a number of compounds which included mycene (20.1%), verbinene (8.0%), Z-ocimenone (35.2%), E-caryophylene (25.5%), α-Humelene (11.8%), germacrene D (21.4%) and camphene (2%). The major constituent of T. minuta was Z-ocimene, caryophylene E and mycene. Essential oils from T. vogelii as revealed by the GC-MS analysis were pinene α (32.7%), limonene (35.1%), copaene α (22.9%), β -elemene (36.7%), Z-nerolidol (77.7%), δ-cadinene  (67.6%), α humelene (69.6%) and -4-α-ol-(β)copaene (65.7%). The highest proportion of the essential oils constituted Z- nerolidol  δ-cadinene, α-humelene and 4-α-ol-β. Copaene. The compounds in essential oils obtained from S. ukambensis were α-copaene (23.8%), β-bourbonene (25.5%), α-gurjunene (14.3%), cymene&lt;2, 5-dimethoxy-para (87.7%), α -humelene (100%), λ- muurolene (17.9%), λ-cadinene (77.3%), caryophylene oxide (54.7%) and δ-cadinene (61.9%). The major compounds contained in essential oils from S. ukambensis were α-humele, λ-cadinene, δ-cadinene and cymene&lt;2, 5-dimethoxy-para.  The compounds which were  common in the four test plants included: α-pinene, α-humele, ocimene allo and (E) β-ocimene. Each of the test plant secreted essential oils constituting numerous volatiles known to exhibit acaricidal, insecticidal and/or arthropod repellent properties. These plants may be useful sources of compounds for use in the control of arthropods of medical, veterinary and agricultural importance.Key words: Essential oils, GC-MS, Tagetes minuta, F. africana, T. vogelii, S. ukambensis

Antimicrobial Activities of Skincare Preparations from Plant Extracts

In this study, Tithonia diversifolia Helms. (A Gray), Aloe secundiflora (Miller) and Azadirachta indica (A. Juss) plant extracts were used to make herbal soaps while Thevetia peruviana (Schum) seed oil was used to make a herbal lotion for skincare. The soaps were tested for the growth inhibition of Escherichia coli, and Candida albicans. The lotion was evaluated against Staphylococcus aureus and E.coli. Although Tithonia diversifolia soap exhibited the highest inhibitory effect on the test bacterial strains, it had the least inhibition against C. albicans. Results from this study indicated that the ‘Tithonia diversifolia’ soap would have superior skin protection against the tested bacteria but would offer the least skin protection against C. albicans. The herbal lotion inhibited S. aureus and E. coli in a concentration dependent manner, however, the inhibitory effect was more pronounced on S. aureus

Traditional medicines among the Embu and Mbeere people of Kenya

Ethnobotanical information and traditional medicines were investigated and documented in Embu and Mbeere districts, Eastern Province of Kenya. Oral interviews were obtained from over 100 herbalists, both men and women aged between 40 and 80 years. All the herbalists interviewed were Christians and had little formal education. Non-Christian herbalists were purported to combine herbal medicines with witchcraft and were not interviewed. Of the 40 commonly used herbal plants 25 were used as multi-purpose medicinal plants (mpmp), while 15 were used to treat one disease type. There was a correlation between the outpatient morbidity data at the local District hospital, and the common incident diseases treated by the herbalists. Generally a decoction or infusion of the herb was recommended for the treatment of internal or external condition of the patients. Malaria and typhoid were treatable with a total of 15 and 12 plants respectively and were among the first two commonest diseases found in the study area. Terminalia brownii was found to be the most used medicinal plant either alone or in combination with other herbs. The second and third most utilized medicinal plants were Ovariodendron anisatum and Wurbugia ugadensis respectively. Keywords: Herbalists; Herbal medicine; Terminalia; Decoction The African Journal of Traditional, Complementary and Alternative Medicines Vol. 4 (1) 2007: pp. 75-8

Usable wild plant species in relation to elevation and land use at Mount Kilimanjaro, Tanzania

We used the broad elevational gradient of Kilimanjaro ranging from warm tropical lowland to cold Afro-alpine temperature regimes and the occurrence of natural, nearly untouched as well as of anthropogenic and heavily disturbed habitats to study how elevation and disturbance by humans affect the proportion of useful plant species in different habitat types. Of the 962 vascular plant species recorded in our 60 study plots, 563 species turned out to be listed as useful in the literature. We classified these species into six usage categories. With linear models we tested for relationships between the proportion of useful species per plot and elevation for natural habitats, and with analysis of variance we compared the proportion of useful species between plots in disturbed and natural habitats at similar elevation. The proportion of useful species for all usage categories increased from 860 to 2500 m asl and decreased with higher elevation. We also found an overall positive correlation between the number of useful plants and the species richness of our plots. Human-influenced habitats had higher proportions of useful species for all usage categories, except for construction and fuel wood usage which were higher in natural savanna and lower montane forest than in used habitats at these elevations. Given the high proportions of useful species, we conclude that preserving the biodiversity of Kilimanjaro ecosystems is indispensable for maintaining the diversity of useful plants species for the local people who rely on it for food, sustainable access to medicinal, fuel, construction and forage material