Repellent and larvicidal properties of selected indigenous plants in the control of Anopheles mosquitoes.

BACKGROUND OBJECTIVES: Widespread pyrethroid resistance and plastic-feeding behaviour of most malaria vectors across Africa threaten the efficacy of current insecticide-based vector control interventions like Insecticide-Treated Nets (ITNs) and Indoor Residual Spraying (IRS). This study examined the larvicidal activity ofMorinda citrifolia against Anopheles gambiae larvae and the repellent properties of Morinda citrifolia (Noni), Moringa oleifera (Moringa), and Ocimum basilicum (Basil) as complementary vector control tools against Anopheles gambiae sensu lato (s.l.). METHODS: Noni, Basil, and Moringa oil extracts were obtained with the extraction techniques; Soxhlet, steam distillation and maceration respectively, using hexane and ethanol. The effectiveness of the extracts was assessed using the WHO standard larval susceptibility bioassay and guidelines for repellent efficacy. Following bioassays, effective doses (ED) and lethal concentrations (LC) were determined. Gas Chromatography-Mass Spectroscopy analysis was performed to identify the bioactive chemical components of the extracts of Moringa oleifera and Ocimum basilicum. RESULTS: Emulsified Morinda citrifolia seed oil had LC50=68.3, LC90=130.9 and LC99.9=222.5, and ED99. 9=308.3%v/v, the ethanolic extract of Moringa oleifera leaves had ED99.9= 1.25g/ml, and essential oil of Ocimum basilicum leaves had ED99.9=0.28g/ml against Anopheles gambiae. INTERPRETATION CONCLUSION: The results obtained indicated that seed oil of Morinda citrifolia, essential oil of Ocimum basilicum, and crude extract of Moringa oleifera have repellent activity against An. gambiae s.l. The complete protection time (CPT) of Morinda citrifolia, Moringa oleifera, and Ocimum basilicum was 120 min, 72 min and 84 min at ED99.9 respectively. Morinda citrifolia oil exhibited larvicidal effects against the larvae of An. gambiae s.l. The results provide valuable information for the use of the plants as biocides.

In-vitro antioxidant, antimicrobial and phytochemical properties of extracts from the pulp and seeds of the African baobab fruit (Adansonia digitata L.).

Adansonia digitata, commonly known as the African Baobab plant is used widely in traditional medicine for treating of many diseases. The current study investigates the antioxidant and antimicrobial properties, and nutritional composition of the pulp and seeds from the fruit of African Baobab plant. Matured fruits were harvested and processed by separating the fruit pulp and seeds. Water, 70 % Ethanol/water mixture, and Hexane were used as solvents for extraction. Antioxidant properties of extracts in this study were investigated using the 2,2-diphenyl-1-picrylhydrazyl, hydrogen peroxidescavenging assays., Total Flavonoid Content, Total Phenolic Content, Total Tannin Content, and Total Antioxidant Capacity were also investigated. Agar Well Diffusion and Broth Dilution methods were used to estimate the antimicrobial properties of the extracts. The proximate composition of the seeds and fruit pulps was also determined. GC-MS was employed to determine the fatty acid composition. Results obtained showed the presence of Total phenolics (range 4.1-5.5 mg GAE/g), Total flavonoids (range 10.1-16.5 mg QE/g), Total Tannins (range 1.7-15.6 mg CE/g), and Antioxidants (range 2.0-14.5 mg AAE/g). The H2O2 and DPPH assays gave IC50s in the ranges of 300-1800 mg/L and 700-1600 mg/L respectively. Extract from the fruit pulp was found to inhibit the growth of a panel of 2 g-positive bacteria, 2 g-negative bacteria, and two fungi microorganisms. Fatty acids such as myristic acid, palmitic acid, and stearic acid were found to be present in oil from the seeds. Proximate components such as crude protein, crude fat, and crude fibre were found to be high. From the results, seeds and the fruit pulp of the African Baobab plant have significant antioxidant properties and can inhibit microbial growth.

Antioxidant and anti-inflammatory properties of "Limolanii" grass and perceptions of locals on its survival in the era of changing climate.

The aromatic Spear grass Hyparrhena rufa (locally called "Limolanii") found in the Saboba District of the Northern Region of Ghana is ingeniously used for dietary, medicinal, and other purposes. Focus group discussions were conducted in communities where "Limolanii" grows to assess the local perception of the importance of the grass and changing climate impacts on its continued existence. Findings indicated that the plant is of immense importance to the locals but has not been validated scientifically and reported for its current use. The communities are also hopeful of future socio-economic benefits of "Limolanii" but expressed concern about the lack of remediation practices to address issues of climate change, increased use of agrochemicals, urbanization, etc., which can lead to the extinction of the grass. "Limolanii" was therefore evaluated for its nutritional and anti-nutritional content by proximate analysis and ethanolic extract evaluated for some medicinal properties. The extract was assessed for its anti-inflammatory property using the carrageenan-induced oedema in chicks' model while antioxidant property evaluated using DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity, Phosphomolybdenum (Total Antioxidant Capacity), Total Phenol (Folin-Ciocalteu), and Total Flavonoid Content (Aluminium-chloride colorimetric) assays. The plant showed good nutritional content, extract exhibited a dose-dependent inhibition of oedema with maximal percentage inhibition of 41.05% at 300 mg/kg body weight and noticeable antioxidant activities. Flavonoids, coumarins, and other phytochemicals detected in the plant could be responsible for these activities, however, at certain levels, these phytochemicals could act as anti-nutrients. "Limolanii" exhibits medicinal properties backing its use traditionally as food supplements and herbs, hence the need to explore its possible commercial cultivation and embark on community sensitization to encourage people to protect and expand its production.

Optimization of extraction conditions for polyphenols from the stem bark of Funtumia elastica (Funtum) utilizing response surface methodology.

BACKGROUND: The recovery of phenolic compounds is seen as an arduous task because phenolic compounds are available as free aglycones, as sugar or ester conjugates, or as polymers with several monomeric components. This study looks at the optimization of factors that affect the efficiency for the extraction of phenolic compounds from the stem-bark of Funtumia elastica. METHODS: Five independent variables (solvent concentration, time, the temperature, solid-liquid ratio, and pH) of the extraction process were selected. Single factor analysis as well as the response surface method was used to evaluate the impact of the selected factors on the total phenolic content. The effect of the extraction factors on the phenolic content was tested for its statistical significant (p <0.05). For the response surface method, a five/factor, five/level central composite design was used, and a fitted second-order polynomial regression model equation was used to show how the extraction parameters affected the total phenolic recovery. RESULTS: The predicted value (R² of 0.5917) agreed with the adjusted value (R² of 0.7707). The residuals for response predictions were less than 5%. The optimal factors for the extraction were ethanol concentration of 75.99% v/v, extraction time of 193.86 minutes, temperature of 63.66°C, pH of 5.62, and solid-liquid ratio of 1:21.12 g/mL. Actual overall content of the phenolic compounds was validated at 82.83 ± 3.335 mg gallic acid equivalent (GAE) /g weight of extract, which agreed with the predicted response of 89.467 mg GAE/g of the dried extract under the optimal factors. CONCLUSIONS: The rich phenolic content of stem-bark of Funtumia elastica points to its potential as a functional medicinal product to alleviate diseases caused by oxidative stress such as asthma, breathing disorders, inflammation, and cardiovascular diseases. The results obtained indicate that, the studied optimal conditions support effective phenolics extraction of Funtumia elastica.

Levels of selected heavy metals in canned tomato paste sold in Ghana.

Sixty-one samples of canned tomato paste comprising seven brands originating from three countries and sold in local markets in the Kumasi Metropolis of Ghana were analysed for levels of iron (Fe), zinc (Zn), manganese (Mn), cadmium (Cd) and lead (Pb) by flame atomic absorption spectrophotometry and for levels of mercury (Hg) by direct mercury analyzer. Mean heavy metal concentrations varied by brand, ranging from below the limit of detection (Cd) to a maximum concentration range of 1.68 ± 1.63 to 58.6 ± 14.5 µg g⁻¹ (Fe). Estimated mean ranges of other heavy metals are 2.06 ± 0.62 to 8.52 ± 0.68 µg g⁻¹ (Zn), 2.62 ± 0.33 to 5.75 ± 0.47 µg g⁻¹ (Mn), 0.070 ± 0.003 to 0.116 ± 0.012 µg g⁻¹ (Pb) and 0.011 ± 0.001 to 0.102 ± 0.001 µg g⁻¹ (Hg). Assessed metal levels in five brands were below the WHO/FAO permissible levels. Results of the one-way analysis of variance (ANOVA) conducted on the data suggested no significant variations (P > 0.05) in the concentrations of the metals in the same brands of canned tomatoes.

Assessment of the quality of water from hand-dug wells in ghana.

This study focused upon the determination of physicochemical and microbial properties, including metals, selected anions and coliform bacteria in drinking water samples from hand-dug wells in the Kumasi metropolis of the Republic of Ghana. The purpose was to assess the quality of water from these sources. Ten different water samples were taken from different parts of Kumasi, the capital of the Ashanti region of Ghana and analyzed for physicochemical parameters including pH, electrical conductivity, total dissolved solids, alkalinity total hardness and coliform bacteria. Metals and anions analyzed were Ca, Mg, Fe, Mn, NO(3) (-), NO(2) (-), SO(4) (2-), PO(4) (2-), F(-) and Cl(-). Bacteria analysed were total coliform and Escherichia coli.THE DATA SHOWED VARIATION OF THE INVESTIGATED PARAMETERS IN SAMPLES AS FOLLOWS: pH, 6.30-0.70; conductivity (EC), 46-682 muS/cm; PO(4) (3-), 0.67-76.00 mg/L; F(-), 0.20-0.80 mg/L; NO(3) (-), 0-0.968 mg/L; NO(2) (-), 0-0.063 mg/L; SO(4) (2-), 3.0-07.0 mg/L; Fe, 0-1.2 mg/L; Mn, 0-0.018 mg/L. Total coliform and Escherichia coli were below the minimum detection limit (MDL) of 20 MPN per 100 ml in all the samples. The concentrations of most of the investigated parameters in the drinking water samples from Ashanti region were within the permissible limits of the World Health Organization drinking water quality guidelines.