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

Spectrometric Detection of Organic Compounds and Toxicity of Ethanolic Leaves Extracts of Prosopis Juliflora

Spectrometric detection of saponins, tannins and alkaloids in Prosopis juliflora using Fourier Transform Infrared (FTIR) spectroscopy is reported in this paper. Crude dry plant powders and corresponding ethanolic extracts were mixed with potassium bromide (KBr) powder and compressed to a thin pellet for infrared examination. The plant powders, ethanolic extracts and leaves ethanolic extract (LEE) fractions  exhibited characteristic infrared spectra due to various functional groups –OH, -C=O, C-H, and C=C absorptions. Phytochemical analysis confirmed the presence of saponins, tannins and alkaloids in the tested specimens. Prosopis juliflora whole plant parts were used as a reference sample. Toxicity and safety levels of P. juliflora were also investigated. Acute and sub-acute toxicity of P. juliflora ethanolic leaves extract was evaluated using Swiss albino rats. All clinical signs and symptoms were recorded within 24 hours. These results indicated that direct detection of bioactive compounds was possible by infrared analysis. Toxicity symptoms were moderately observed and post mortem did not show any major gross effects on the internal organs. Keywords: Prosopis juliflora, infrared examination, potassium bromide, acute and sub-acute toxicity, clinical signs, doses, symptoms

Phytochemical and antimicrobial evaluation of selected medicinal plants in Meru community of Kenya

Background: Increased resistance against antimicrobial medication used to combat bacterial infection necessitates the need for alternative medication.   Objective: This study seeks to evaluate the antimicrobial potential and phytochemical profiles of 10 medicinal plants collected from Chuka, Tharaka-Nithi County of Kenya. Plant samples were collected, dried, pulverised into fine powders and extracted with distilled water.   Methodology: Qualitative phytochemical screening and disc-agar diffusion methods were used according to standard method to determine phytochemical profile and antimicrobial activity of the aqueous extracts against four bacterial strains and a fungus.   Results: Phytochemical investigation revealed the presence of terpenoids, tannins and reducing sugars in all the plants except one. Saponins were found to be present in Albizia anthelmintica, Entada leptostachya, Raponae rhododendroides and Warbugia ugandensis. Steroids were present in seven plants while alkaloids were present in five. Albizia anthelmintica, E. leptostachya and W. ugandensis extracts were active against Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, Escherichia coli and Candida albicans. Escherichia coli was the most susceptible bacteria against all the plant extracts tested, except Harrisonia abyssinica. Vernonia lasiopus and Uvariodendron anisatum were the least active extracts. Susceptibility against E. coli and C. albicans was significantly comparable to benzathine penicillin and streptomycin.   Conclusion: The type of ailments the plants are claimed to treat can be attributed to the presence of various classes of phytochemicals. In conclusion, the plants evaluated were found to be active against the microorganisms tested

Antioxidant activity and antimicrobial properties of <i>Entada leptostachya</i> and <i>Prosopis juliflora</i> extracts

Background: Natural phytoconstituents produced by plants for their sustenance have been reported to reduce disease. Objectives: This study determined the phytoconstituents, antioxidant and antimicrobial activity of crude methanolic extracts of Entada leptostachya and Prosopis juliflora extracts. Methodology: Antioxidant activity was determined using 2,2-diphenyl-1-picrylhydrazyl and β-carotene assays; the total phenolic and flavonoid were estimated using Folin–Ciocalteau and aluminium chloride, whereas antimicrobial activity was determined using the zone of inhibition method. Results: Screening of the extracts revealed the presence of terpenoids, flavonoids, saponins and phenols. Fourier transform infrared spectra of the extracts revealed presence of hydrogen bonded –OH functional group. E. leptostachya barks had the highest antioxidant activity followed by P. juliflora roots, E. leptostachya roots and P. juliflora leaves [μg/mL]. Prosopis juliflora (roots) had the highest bleaching effect, whereas E. leptostachya (barks) had the lowest bleaching effect. The total flavonoids were determined to be 0.15 ± 0.02 mg/g, 1.18 ± 0.18 mg/g, 0.39 ± 0.05 mg/g and 0.64 ± 0.03 mg/g for E. leptostachya roots, E. leptostachya barks, P. juliflora leaves and P. juliflora roots extracts, respectively. The total phenols were determined to be 0.93 ± 0.18 mg/g, 2.69 ± 0.41 mg/g, 0.62 ± 0.08 mg/g and 0.62 ± 0.08 mg/g for E. leptostachya roots, E. leptostachya barks, P. juliflora roots and P. juliflora leaves extracts. All plant extracts exhibited moderate activity against the growth of selected microorganisms. Conclusion: Antimicrobial and antioxidant activity of the two plants was as a result of secondary metabolites found in the crude extracts

Direct Detection of Triterpenoid Saponins in Medicinal Plants

Direct detection of saponins in medicinal plants using Fourier Transform Infrared (FTIR) spectroscopy is reported in this paper. Crude dry plant powders were mixed with potassium bromide (KBr) powder and compressed to a thin pellet for infrared examination. FTIR spectra of the test samples showed -OH, -C=O, C-H, and C=C absorptions characteristic of oleanane triterpenoid saponins. The C-O-C absorptions indicated glycoside linkages to the sapogenins. Phytochemical analysis confirmed the presence of saponins in the tested specimens. Entada leptostachya was used as a reference sample. Dry plant powder was extracted sequentially with hexane, dichloromethane, ethyl acetate and methanol. FTIR spectra of the reference sample powder and its organic solvent extracts showed characteristic saponin absorption peaks. These results indicated that direct detection of saponins in medicinal plants was possible by infrared analysis. Lengthy exhaustive chemical analyses necessary for detection of saponins could be avoided

Traditional Medicines Among the Embu and Mbeere Peoples 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

Antimicrobial Activity of Some Medicinal Plants Used by Herbalists in Eastern Province, Kenya

The aqueous extracts from medicinal plants commonly used by herbalists in Mbeere, and Embu districts of Eastern province, Kenya, were tested for their inhibitory activity against three selected strains of bacteria. All the selected plant extracts (infusions: 1.0g sample in 100 ml water) investigated showed activity against Escherichia coli with inhibition zone diameters ranging from 5.8 – 18.0 mm. Terminalia brownii gave the largest inhibition zones against E. coli and Staphylococcus aureus. Vernonia lasiopus and Tithonia diversifolia were inactive to S. aureus and Bacillus subtilis, respectively. Eighteen and sixteen plants showed sensitivity of greater than 10 mm against S. aureus and B. subtilis, respectively. All control discs gave zones of inhibition of 12 – 24 mm, which were larger than those of the extracts. The present study validated the use of the selected medicinal plants by the herbalists in the treatment of bacterial ailments caused by the strains of bacteria investigated. Medicinal plants used for non-bacterial diseases also exhibited sensitivity towards bacterial strains tested. This implied they could be used as multi-purpose medicinal plants

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

Isolation of cellulose nanofibers from Oryza sativa residues via tempo mediated oxidation

Cellulose nanocrystals (CNCs) or cellulose nanofibers (CNFs) with different morphologies, chemical, mechanical and physical properties can be obtained when microcrystalline cellulose is subjected to enzymatic, chemical or mechanical treatment. With the aim of utilizing cellulose nanofibrils (CNFs) from Oryza sativa, we isolated microcrystalline cellulose using the Kraft process, followed by successive fiber fibrillation using mechanical grinding, then (2,2,6,6-Tetramethylpiperidin-1-yl)oxyl (TEMPO) mediated oxidation. Analysis of pulp fibers obtained after each treatment step revealed that fiber properties such as length, crystallinity and crystal size changed when the pulp was subjected to mechanical grinding, ultrasonication and TEMPO mediated oxidation. The degree of crystallinity of the fibers increased while crystal size and fiber length decreased after each treatment. TEMPO mediated oxidation led to a decrease in fiber length and an increase in degree of crystallinity of the fibers as compared to mechanical treatment and ultrasonication. It further introduced carboxyl functional groups (COOH) on the surface of the fibrils, which implies that the nanofibers obtained in this study could be further functionalized. Hence, TEMPO mediated oxidation offers the possibility of further chemical functionalization of cellulose nanofibers isolated from agricultural residues