ABSTRACT
Insecticide resistance in mosquitoes is increasing amidst growing cases of global malaria, leading to high fatality in mostly Africa. To overcome the resistance as well as environmental effects of the synthetic insecticides, preliminary insecticidal and botanical potentiating effects of sub-lethal concentration (LC25) Ficus sycomorus active fraction (AFFS) and its synergistic potential with standard insecticide permethrin were evaluated against malarial vector Anopheles coluzzii (Coetzee & Wilkerson) populations. The glutathione-S-transferase (GST) inhibitory activity of the AFFS was also investigated compared to standard GST inhibitor, diethyl meleate (DEM). The WHO standard protocol for adult bioassay was used to expose the adult mosquitoes with sub-lethal concentration (LD25=0.49 mg/ml) of the plants' active fraction and permethrin (0.75%). The permethrin susceptibility screening result showed high level of resistance to permethrin in the field populations of A. coluzzii from Kano with 50.29 ± 2.14% average mortality after exposure to WHO diagnostic dose 0.75% permethrin. Post hoc Fisher's exact test showed that combination of sub-lethal concentration of AFFS with permethrin (mortality=73.02±12.10%; p=0.00352; RR=0.6923 and 95% CI = 0.5358-0.8946) was statistically significant, while the combination of sub-lethal concentration of AFFS with DEM showed no statistical difference (mortality=63.22±5.03; p=1; RR=0.6667 and 95% CI=0.4470-0.8438). This potentiation effect was signified to be additive effects with co-toxicity factor (CTF) of - 12.66. There was significant reduction of GST activities in the AFFS- and permethrin -exposed groups compared to unexposed populations of A. coluzzii (p < 0.05). The AFFS additively potentiate the permethrin activities by inhibiting GSTs, bio-transformational enzymes implicated in pyrethroids resistance. This study finding generally signifies the potential for bio-rational insecticide approach for malarial vector control.
Subject(s)
Anopheles , Ficus , Insecticides , Animals , Ficus/chemistry , Insecticide Resistance , Insecticides/pharmacology , Mosquito Vectors , PermethrinABSTRACT
BACKGROUND: Some observations and reports show that people with high consumption of Solanum aethiopicum (African garden egg) have relief in arthritic pains and swelling. We aimed at assessing the effect of methanol extract of Solanum aethiopicum in experimentally induced inflammation using leukocyte mobilization and vascular permeability tests in rats and human red blood cell (HRBC) membrane stabilization as studies. METHODS: Twenty five (25) adult Wistar rats of either sex (120 g - 200 g) divided into five groups of five rats each were used for each of the animal models. Groups 2, 3 and 4 were administered varied doses of the extract (100, 200 and 400 mg/kg), while groups 1 (vehicle control) and 5 (treatment control) received normal saline and indomethacin (50 mg/kg) respectively. Vascular permeability was induced by the intra-peritoneal injection of 1 ml of acetic acid and monitored using 0.5 ml intravenous injection of 1% Evans blue solution. Leukocyte mobilization was induced by the intra-peritoneal injection of 0.5 ml of 3% agar suspension in normal saline. Heat and hypotonicity induced heamolysis of HRBC membrane was used to assess membrane stabilization. RESULTS: The methanol extracts of garden egg significantly and dose dependently reduced (p≤0.05) the acetic acid induced vascular permeability and agar induced leukocyte mobilization in rats. The percentage inhibitions of induced vascular permeability were 21 ± 3.39, 25 ±1.92 and 60 ± 3.81 for the 100, 200 and 400 mg/kg of the extract while the inhibitions of the agar induced leucocyte migration were 23 ± 2.17, 26 ± 1.58 and 32 ± 1.58 for the 100, 200 and 400 mg/kg of the extract respectively. The extract also, at doses of 100, 200, 400, 600 and 800 µg/ml significantly inhibited heat induced lysis of the human red cell membrane with values of 66.46 ± 2.89, 65.14 ± 4.58, 46.53 ± 2.52, 61.88 ± 4.51and 86.67 ± 3.06 respectively. CONCLUSIONS: These results show that methanol extract of Solanum aethiopicum has anti-inflammatory properties and can reduce inflammatory injury and tissue damage.
ABSTRACT
OBJECTIVE: To evaluate the possible anti-inflammatory effect of garden egg [Solanum aethiopicum (S. aethiopicum)] using experimentally induced inflammatory models in rats. METHODS: Oedema was induced on the rat hind paw by the injection of 0.1 mL undiluted fresh egg albumin (philogistic agent) into the subplantar surface of the rat paw. Tissue granuloma was induced in the rats by the implantation of two autoclaved cotton pellets (30 mg) under the flank of previously shaved back of anaesthetised rats. Garden egg extract doses were administered to the rats for seven consecutive days. On day 8, the animals were killed and the pellets surrounded by granuloma tissue were dissected out and dried. RESULTS: Extracts of garden egg significantly (P<0.05) reduced the fresh egg albumin-induced rat paw oedema and also significantly (P<0.05) reduced the granuloma tissue formation in the treated groups when compared to the control. CONCLUSIONS: This study shows that the fruits of garden egg (S. aethiopicum) have anti-inflammatory activity in the models studied.
