Mosquito control has become more difficult due to the unsystematic use of synthetic chemical insecticides which have inauspicious effect on the environment. Botanical phyto-chemicals with mosquitocidal potential are now recognized as potent alternative insecticides to replace synthetic insecticides in mosquito control programs due to their excellent larvacidal activities. The present study assessed the influence of A. sativum (garlic), Z. officinale (ginger) and S. aromatic (clove) extracts against Aedes mosquitoes. Larvacidal activities of three indigenous plant extracts were studied in the range 5.0 to 30.0mg/l in the laboratory bioassay against fourth instar larvae of Aedes sp. The mortality were subjected to probit analysis to determine the lethal concentration (LC50) to kill 50 percent of treated larvae of Aedes sp. Data obtained were analyzed by Comparing experimental groups and control groups with significance level established at p<0.05. All plants tasted showed effects after 24hrs of exposure at different concentration (mg/l). However the highest mortality was found in A. Sativum (garlic) and Z. officinale (ginger) against larvae of Aedes mosquitoes with LC50 = 42.50% (2.685) and LC50 = 30.01% (4.461) mg/l, while S. aromatic(clove) was found to have lowest mortality at LC50 = 24.50% (5.52) respectively. It is therefore recommended that A. sativum(Gallic), S. aromatic (Clove) has showed larvacidal effects against Aedes mosquitoes and could be served as alternative form of botanical control against mosquitoes .
Keywords: A. sativum (garlic), Z. officinale (ginger) and S. aromatic (clove), Extracts, Aedes mosquitoes
The study was carried using the Botanic Garden of the Kano State Zoological Garden as the control site in comparison with roadside in order to determine the effect of exhaust from vehicles on the number of stomata, epidermal cells, stomatal length, stomata breadth. Results obtained showed an increase in the number of stomata and epidermal cells per unit area in leaf samples collected from polluted sites than those from unpolluted site. However, the length and breadth of stomata, pore length and pore breadth in the polluted sites was lower than that of the control site. Furthermore, there was no significant difference based on the type of stomata in the species studied at the two different sites. An increase in number of stomata of epidermal cells and stomatal density was found in plants growing on the road side both on the abaxial and adaxial surfaces, a decrease was found on the stomatal length, stomatal breadth, pore length, pore breadth and stomatal index of the plant with those in the control site. These changes in stomata and epidermal cells per unit area could be used as an indicator of environmental stress which could be recommended in high traffic density areas for the early detection of urban air pollution.
The in vitro anti coccidial activities of n-butanol and aqueous fractions of Khaya senegalensis, Gueira senegalensis and Tamarindus indica leaves extracts on Eimeria tenella parasite was studied by observing the effects of the plant extracts on the sporulation of the Eimeria tenella oocysts. Drug resistance and consumer demanding decrease in the use of drugs in animals have generated interest in alternative strategies to control the avian disease one of which is herbal intervention studies. Fresh faecal samples were collected from infected birds and their oocysts load determined. Dilutions of the extracts (100mg, 250mg, 400mg, 550mg, 700mg and 850mg per ml) in distilled water were prepared and placed in separate well labelled petri dishes. 100 oocysts were added to each petri dish and the set up was left at ambient temperature on the laboratory table and monitored twice daily (9.00am and 3.00pm) to observe the sporulation of the oocysts over a 72 hours period. Laboratory sporulation medium (2.5% Potassium dichromate) and Amprolium were used for comparison. The phytochemical result implied that the active ingredients were present mainly in the n-butanol and crude extract fractions with the nbutanol fraction of the Khaya senegalensis extract containing phenols and flavonoids which have antioxidant effects. The in vitro study showed that the n-butanol fraction of K senegalensis (100mg/ml) and the aqueous fraction of Tamarindus indica (100mg/ml) extracts had similar effects to those obtained using Amprolium which was considered as the standard by inhibiting the sporulation of Eimeria tenella oocysts. It is therefore recommended that more work needs to be done to determine the anti coccidial activities of these extracts in vivo.
Key words: Eimeria tenella, sporulation, in vitro, extracts
This study was embarked upon to evaluate the efficacy of aqueous extracts of Senna tora leaf against Perenospora parasitica, causing downy mildew on cabbage. Phytochemical analysis of the leaf extracts revealed the presence of some secondary metabolites (Tannins, Saponins, Flavonoid, Glycosides, Alkaloids, Phenolic compounds and Carbohydrates) which have been reported to have antimicrobial effects. Assays were performed using extract concentrations of 1000, 500, 250, 125 mg/ml by agar well diffusion technique. Results obtained, revealed a significant difference in diameter of mycelial zone of inhibition between the concentrations. Highest zone of inhibition was recorded at 1000 and 500 mg/ml (20 and 15 mm) respectively. Minimum Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration (MFC) were determined and recorded at 250 mg/ml. The antifungal screening revealed that the extract exhibited inhibitory activities at varying concentrations against the downy mildew pathogen. These activities observed could be attributed to the presence of active metabolites contained in the extract.Keywords: Aqueous leaf extract, Downy mildew, Perenospora parasitica and Senna tora
Bacterial species have been reported to develop resistance to antibiotics commonly prescribed for respiratory tract infections. Therefore, the need to search for natural products for the remedy of this problem cannot be overemphasized. The extraction of Citrullus lanatus leaves was carried out using cold maceration extraction method. Chemomicroscopical and phytochemical analysis were carried out using the standard methods. Agar well diffusion, agar dilution and spread plate methods were employed to determine the zone of inhibition, minimum inhibitory concentration, minimum bactericidal concentration and rate of kill respectively. Chemomicroscopical evaluation revealed the presence of cellulose, tannins, starch, lignin, calcium oxalate, suberin, aleurone grain and mucilage with the exception of calcium carbonate. Phytochemical screening of Citrullus lanatus revealed the presence of phenolic compounds and flavonoid as secondary metabolites. The antibacterial activity result indicated that S. aureus showed higher zone of inhibition (20 mm and 24 mm) followed by K.pneumoniae (18 mm and 22 mm) and P. aeruginosa (18 mm and 20 mm) at a concentration of 250 mg/ml in aqueous and methanol extract respectively. The two extracts showed broad spectrum of activity and moderate M.I.C and M.B.C values ranging from 15.625 mg/ml – 31.25 mg/ml respectively. LD50 of both extracts was above 5000 mg/kg and did not cause mortality in all the tested rats. The results of this investigation may be useful for deriving doses that are safe for human consumption medicinally.. This study has justified the traditional use of Citrullus lanatus leaf extract in the treatment of respiratory tract infection caused by bacteria.
Keywords: Agar well diffusion, Chemomicroscopical, Minimum inhibitory concentration, Minimum bactericidal concentration, phytochemical, Citrullus lanatus
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