Insecticidal Activity of Crude Extracts of Hyptis suaveolens (Bush Mint) on Anopheles Mosquitoes Collected from Lafia, Nasarawa State, Nigeria

Anopheles gambiae is a vector that is responsible for the transmission of malaria parasites which causes high morbidity and mortality in Nigeria and the world at large. Human-vector contact can be reduced by the use of conventional repellents being sold in the market, though some of these repellent are not environmentally friendly and An. gambiae have developed resistance to some of these repellents. To this end, the phytochemical constituents and insecticidal activity of crude extracts of Hyptis suaveolens (bush mint) was determined on adult An. gambiae mosquitoes collected from Lafia, Nasarawa State, Nigeria to evaluate its effect in controlling them. Here, 70% ethanolic and diethyl ether fat crude extracts were made from H. suaveolens dried leaves and used to carry out the experiment. The phytochemical screening of the ethanol extract revealed the presence of alkaloids, flavonoid, saponins, tannins, steroids and reducing sugar. Glycoside was not detected in the ethanol extract. Only steroids was detected in diethyl ether extract the rest of the phytochemical tested were absent. An. gambiae larvae were collected from the field and were raised to F1 progeny adults that were used for the study. WHO protocol for carrying out human bait repellency cage test was used. Human hand treated with the extracts was exposed to a cage containing 30 female mosquitoes for each of the extracts respectively. The ethanolic crude extract treatment proved to be more effective in repelling mosquitoes with 0% (0/30) mosquito landing than diethyl ether extract which had 40% (12/30) mosquitoes landing and the control hand (untreated left hand) had the highest landing rate 63.3% (19/30) which showed very high significant difference (χ2 = 27.2619, df = 2, P <0.00001) in relation to the treatments. After 24 hours holding period, the mortality rate of exposed mosquitoes was observed to be highest in the ethanolic treatment 73.3% (22/30). In conclusion, H. suaveolens extracts have repellency potential in controlling adult An. gambiae

Anti-trypanosomal Activity of Bufonidae (Toad) Venom Crude Extract on Trypanosoma brucei brucei in Swiss Mice

Trypanosomiasis afflicts about 6 ~ 7 million people globally and to a large extent impedes livestock production in Africa. Naturally, trypanosomal parasites undergo genetic mutation and have developed resistance over a wide range of therapies. The utilization of animals and plants products has presented therapeutic potential for identifying novel anti-trypanosomal drugs. This study evaluated toad venom for anti-trypanosomal potency invivo in Swiss mice. Toads were collected from July to August 2019. The acute oral toxicity and biochemical characterization of the toad venom were determined. The experimental mice were administered various doses (130 mg/kg, 173 mg/kg and 217 mg/kg) of the toad venom crude extract and 0.75 mg/mL of Diamizan Plus standard drug for the treatment of trypanosomiasis, once daily for 3 days. The in-vivo anti-trypanosomal activity was evaluated by a curative test, after infecting the mice with Trypanosoma brucei brucei. The pre-patent period was 72 hours before treatment commenced. The overall results showed that trypanosomal load was highest in the control group while the group treated with Diamizan drug had the least trypanosomal load. As such, the mean trypanosomal load in relation to treatments showed a very high significant difference (P0.05) across treatment groups. The over 50% reduction in the trypanosomal load in the 130 mg/kg group in comparison with the control group brings to bare the anti-trypanosomal potency of the toad venom. The anti-trypanosomal activity demonstrated by the toad venom has provided basis for development of new therapeutic agents from different toad species. The study recommends further studies (both in-vivo and invitro) followed by the characterization of the active compounds present in the toad venom responsible for the anti-tyrpanosomal activity observed alongside the management and conservation of these species