In vitro antifungal and cytotoxicity activities of selected Tanzanian medicinal plants

Purpose: To evaluate the antifungal and cytotoxic activities of four medicinal plants from Tanzania, namely, Mystroxylon aethiopicum, Lonchocarpus capassa, Albizia anthelmentica and Myrica salicifolia.Methods: The plant materials were subjected to extraction using dichloromethane, ethyl acetate and distilled water. The minimum inhibition concentration (MIC) of the extracts against Candida albicans and Cryptococcus neoformans was determined by microdilution method. The lowest concentration which showed no fungal growth was considered as MIC. The cytotoxic effect of the extracts was determined using brine shrimp toxicity assay.Results: Lonchocarpus capassa leaf extracts exhibited antifungal activity against test fungal strains with MIC range of 0.78 – 3.13 mg/mL with Lonchocarpus capassa aqueous leaf extract (LCAL) inhibiting C. albicans and C. neoformans at MIC value of 0.78 mg/mL. Cytotoxicity assay revealed that LCAL extract which displayed good antifungal activity, was cytotoxic against brine shrimp larvae with halfmaximal lethal concentration (LC,sub>50) value of 17.86 μg/mL. Interestingly, 33 % of plant extracts exhibited high cytotoxicity with LC50 values below that of the standard anticancer drug, cyclophosphamide (16.57 μg/mL).Conclusion: The results obtained suggest that LCAL needs to be further investigated for its phytochemical composition to unravel its antifungal secondary metabolites. Furthermore, some of the plant extracts are potential anticancer agents.Keywords: Antifungal, Cytotoxicity, Brine shrimp, Mystroxylon aethiopicum, Lonchocarpus capassa, Albizia anthelmentica, Myrica salicifoli

Biovar 2 of Ralstonia solanacearum Species Complex Causes Tomato Bacterial Wilt Disease in Tanzania

This research article published by Science Alert, 2020Background and Objective: Bacterial wilt disease (BWD) caused by complex species of Ralstonia solanacearum (RSSC) has been categorized as one of the most significant plant diseases in the world. It is a serious problem of tomato and causes significant economic losses of tomato in Tanzania. The purpose of this study was to determine biovars of RSSC causing tomato BWD in Tanzania. Materials and Methods: Tomato stems showing typical symptoms of BWD were collected from main agro-ecological regions and were characterized by pathological and carbohydrate oxidation tests. The least significance difference (LSD) procedure was used for mean separation (p = 0.05) of disease incidence and severity. Results: A total of 29 out 40 RSSC isolates from infected tomato stems produced typical colonies of RSSC on triphenyl tetrazolium chloride medium out of which 19 (52%) were pathogenic on tomato variety Tanya. Carbohydrate oxidation test showed that most (90%) predominating isolates in main agro-ecological regions belong to biovar 3 while the rest (10%) belong to biovar 2 and prevail in the southern zone of Tanzania. This is the first report of prevalence of biovar 2 of Ralstonia in Tanzania and suggests a recent introduction of biovar 2 in tomato fields in Tanzania. Conclusion: Biovar 2 of RSSC is reported for the first time to cause tomato bacterial wilt disease in Tanzania. This alerts plant health regulators to embark on necessary phytosanitary measures to prevent further spread and/or introduction of the disease considering its quarantine status in different countries

Effects of pH and Phosphorus Concentrations on the Chlorophyll Responses of Salvia chamelaeagnea (Lamiaceae) Grown in Hydroponics

Salvia chamelaeagnea (Lamiaceae) is a slow growing water‐wise evergreen shrub originating from the western province of South Africa. It is an attractive landscape, and S. chamelaeagnea is a medicinal plant. It is important to develop enhanced cultivation protocols that could result in high yield and high‐quality medicinal materials. Chlorophyll is a fundamental part of the light‐dependent reactions of the photosynthesis process. This chapter investigates the effects of four phosphorus concentrations and three pH levels of supplied irrigated water on the production of chlorophyll A, chlorophyll B, total chlorophyll, leaf colour and the nutrient uptake of S. chamelaeagnea grown in hydroponics over an 8‐week period at the Cape Peninsula University of Technology. The treatments of pH 4, pH 6 and pH 8 at 31, 90, 150 and 210 ppm of phosphorus were received by 12 groups of plants and were replicated 10 times. The results indicated that at pH 4, P fertilization significantly (P < 0.05) induced a higher chlorophyll production of S. chamelaeagnea grown in hydroponics compared to other pH treatments (pH 8 and pH 6)

Rooting and growth potential of Leucadendron laxum (proteaceae) using different rooting mediums and indoleacetic acid growth regulators

This research article published by Sabinet African Journals, 2009Leucadendron laxum (Proteaceae) is a South African plant species with a high commercial value as a flowering potted plant. Limited research information on the culture and propagation of this species is available in South Africa. The application of rooting hormone indole acetic acid (IAA) in various rooting mediums in L. laxum was tested. The treatments included: control, 500, 1000, 2000 and 4000 ppm, and four rooting mediums: a) bark / polystyrene; b) peat moss / polystyrene; c) bark / river sand / polystyrene; and d) perlite / river sand. A randomised block design with three replicates was used. Compared with other mediums, bark and polystyrene had the highest significant results in root and shoot growth, and the percentage that callused, rooted and survived. The IAA treatments at different concentrations had significant effects on rooting, callusing, shoot growth, root lengths and numbers of roots per cutting

Environmental and genotypes influence on seed iron and zinc levels of landraces and improved varieties of common bean (Phaseolus vulgaris L.) in Tanzania

This research article published by Elsevier, 2020Phaseolus vulgaris L. (common bean) is a grain legume rich in proteins and micronutrients particularly iron and zinc. This study determined the concentration of iron and zinc in 99 common bean genotypes (landraces and cultivars) grown in Tanzania. The bean genotypes were planted in three different agro-ecologies in Tanzania following alpha lattice design with 3 replications each with five blocks of 20 plots. Adaptability and stability of common bean genotypes on seed iron and zinc contents were assessed using the additive main effect and multiplicative interaction (AMMI) analysis, genotype stability index (GSI) and genotype main effect plus genotype-by-environment interaction (GGE). Highly significant effects of bean genotypes, environments, and genotype by environment interaction were observed for both seed iron and zinc contents. The AMMI analysis of variance showed that genotype contributed 69.5% of the total sum of squares for seed iron and 28.6% of seed zinc contents. Environmental effects contributed 1.7% and 39.7% of the total sum of squares for seed iron and zinc contents respectively. Genotype by environment interaction effects contributed 26.3% and 28.6% of the total sum of squares for seed iron and zinc contents respectively. Among individual weather and soil parameters of the experimental sites, total rainfall, soil available phosphorus, iron, silt %, and exchangeable potassium positively significantly influenced the contents of seed iron, while temperature, total soil nitrogen, and manganese influenced negatively and significantly seed iron contents. Twelve most high and stable seed iron-containing bean genotypes identified by both GSI and GGE, includes SMC 18, Selian 94, Urafiki, Kyakaragwe, CODMLB 033, Kikobe, Malirahinda, ACC 714, Jabeyila, Mwamikola, Kasukari and Wifi nygela. These bean genotypes can be used for iron biofortification and or further tested for seed iron contents and other agronomic traits in more bean growing environments involving farmers and seed certifying institutes for release as varieties

Socio-Economic Factors for Anthill Soil Utilization by Smallholder Farmers in Zambia

This research article published by MDPI, 2019In this study, we surveyed two districts of Zambia—Choma and Pemba. The aim of this study was to obtain the perspective of farmers on anthill soil utilization practices for key information that could contribute towards the development of an anthill soil based research agenda. The study employed both a qualitative and quantitative method approach to gather data from the respondents, which included farmers and key informants. Qualitative data was analyzed using the triangulation method and Computer Assisted Qualitative Data Analysis Software (CAQDAS), Nvivo version 10, while data generated from quantitative interviews with a smart phone Application (Open Data Kit) were analyzed using Statistical Package for Social Sciences (SPSS). Results revealed that the key hurdles to the utilization of anthill soil lay in agro-climatic, biophysical, technological, land and institutional constraints. Broadly, farmers reported poor rainfall patterns (95%), decreasing soil fertility (70%), limited farm products (69%), finance (66%), limited access to research and extension services (55%) and security of land tenure (48%) as major constraints. We therefore advocate for strengthenedinstitutional linkages between research and extension for information dissemination, which would aid in decision-making used to promote integrated soil fertility management for improved agriculture production and productivity of rural households

Maize (Zea mays) Response to Anthill Soil (Termitaria), Manure and NPK Fertilization Rate under Conventional and Reduced Tillage Cropping Systems

This research article published by MDPI, 2021Soil fertility management has been described by many scholars as fundamental and a major hindrance to food production amongst smallholder farmers in the developing world. To counteract this challenge, some farmers have been reported to use anthill soil as analternative fertilizer to improve soil fertility for supporting crop growth. Against this background, a study was undertaken with the aim of ascertaining the effect of anthill soil application alone, cattle manure, and/or their combination with commercially available NPK fertilizer on the growth and yield parameters of three maize varieties under field conditions involving conventional (CONV) and conservation agriculture (CA) tillage systems. Results revealed that anthill soil alone (5000 kg/ha) or in combination with either manure (10,000 kg/ha) or half rate of commercially available fertilizer (NPKS: 10% N, 20% P2O5, 10% K2O, 6% S at 100 kg/ha) competed favourably in terms of response to growth parameters. Furthermore, pH and P levels changed significantly (p < 0.05) at harvest. We conclude that resource-constrained smallholder farmers in less developed countries utilizing anthill soil for fertility improvement purposes should judiciously apply it in CA planting basin structures compared with conventional methods, which appeared to be less effective and leads to sub-optimal yields

Identification and Management Challenges Associated with Ralstonia solanacearum (Smith), Causal Agent of Bacterial Wilt Disease of Tomato in Sub-Saharan Africa.

This research article published Science Alert, 2017Tomato is the world's most consumed vegetable crop after potato and it is source of vitamins, minerals, fiber, lycopene, β-carotene and income. Despite its significant importance tomato can heavily be attacked by different pathogens including Ralstonia solanacearum that incites bacteria wilt disease. The disease is very devastating causing a considerable yield loss worldwide. The pathogen can survive in plant debris, infected plants and host weeds and spread from one field to another by irrigation or flood water, soil, farm equipment and workers and weeds which usually grow along waterways and it is difficult to manage due to complication in biology, nature of infestation and wide host range. In areas like the Sub-Saharan Africa where there exists a wide diversity of plant species, the pathogen becomes even more difficult to manage. It is on this basis that this review article, clearly discusses challenges for bacterial wilt disease identification and management in tomato farming systems with respect to the diagnosis methods used, pathogen genetic diversity and host range and pathogen survival mechanisms under different environment. The information will empower the responsible personnel involved in tomato production chain to have clear information about the pathogen and management options available against the disease in Sub-Saharan Africa

Effects of Selected Pesticidal Plants on Termites Affecting Maize Production in Arusha, Tanzania

This research article published by Scientific Research Publishing Inc., 2020Investigations under laboratory and field conditions were carried out with purpose of understanding the effects of pesticides of Cupressus lusitanica, Tephrosia vogelii, Eucalpytus dalrympleana, Lantana camara and Azadirachta indica in the control of termites which affect maize production in Arusha, Tanzania. Termites were collected before and during maize season of 2018 and identified at the Tropical Pesticides Research Institute (TPRI) laboratory. A total of 5279 out of 5307 termite species identified belong to genus Macrotermes, 23 species to genus Odontotermes and 5 species were unknown. The results entailed that the area is rich in species of genus Macrotermes. Moreover, concentrations i.e. 5 g, 10 g and 20 g of each botanical were tested for Macrotermes spp. mortality and repellency ability in the laboratory using a completely randomized design (CRD) with three replicates. The results showed that 98.33% Macrotermes spp. mortality was caused by T. vogelii followed by 93.33% recorded from E. dalrympleana after 24 hours. Besides, C. lusitanica repelled Macrotermes spp. by 97% followed by 95% recorded from T. vogelii and E. dalrympleana each. For field trials, 20 g of each botanical was applied using randomized complete block design (RCBD) with four replicates. The results obtained from field indicated that T. vogelii was more effective to protect maize with an average of 6 maize stands and 3.4 kg of dry total weight of maize grains next to positive control per plot. Also, average of 4 maize stands and 3 kg dry total weight of maize grains were recorded from treatments of E. dalrympleana and C. lusitanica each. Such results highlight the potential of developing bio-termiticides from T. vogelii, C. lusitanica and E. dalrympleana to control Macrotermes spp

Importance of common bean genetic zinc biofortification in alleviating human zinc deficiency in sub-Saharan Africa

This research article published by Taylor & Francis Online, 2021Zinc deficiency is among the leading risks to human health in sub-Saharan Africa, its adverse exposure leads to diarrhea, pneumonia, and malaria. Furthermore, it is the leading cause of stunting in children and negatively influences the human immune system, body iron, and vitamin A and D. High zinc deficiency in sub-Saharan Africa is due to the consumption of staple foods with low zinc contents. Genetic zinc biofortification of common bean among staple food crops is the best approach for alleviating zinc deficiency, as it is cost-effective and can easily reach low-income households. Genetic zinc biofortification by conventional breeding coupled with marker-assisted selection is the best strategy for sub-Saharan Africa, as the selection of crosses is precise and takes short time to develop high zinc-containing varieties. Zinc content increase in common bean seeds has a high impact on alleviating zinc deficiency as it is consumed whole compared to cereal grains which undergo milling, the process that removes zinc-rich parts before being consumed. This review explains the current status of zinc deficiency in sub-Saharan Africa, conventional methods for alleviating the problem, current and potential of modern genetic approaches for zinc biofortification of common bean in alleviating zinc deficiency in the region