Membrane stabilization as a mechanism of the anti-inflammatory activity of methanol extract of garden egg (Solanum aethiopicum)

Abstract

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.