RESUMO
Objective: To study the phytochemistry, anti-asthmatic and antioxidant activities of the aqueous leaf extract of Anchomanes difformis (Blume) Engl. (A. difformis) and to verify claims of use in folk medicine. Methods: For anti-asthmatic activity, male and female guinea pigs with average body weight of (451.4 ± 118.1) g were divided into six groups of six animals each. Group 1 served as control (distilled water); Group 2 was administered with salbutamol (reference drug) only; Group 3 served as ovalbumin sensitized group, Group 4, 5 and 6 were treated with A. difformis extract at doses of 100, 200 and 400 mg/kg, respectively. Described methods were used to test fluid viscosity, fluid volume and quantitative phytochemistry analysis. Absorbance was read using a UV-Vis spectrophotometer and results computed in percentage. Total antioxidant assays [2, 2-diphenyl-1-picrylhydrazyl (DPPH) and lipid peroxidation assay], were carried out using reported procedures. Results: The anti-asthmatic evaluation showed that protection from asthma of the animals in Group 6 (400 mg/kg, 32.7%) were similar to that in Group 2 (salbutamol, 33.0%). Excised trachea was free of mucus secretion in Group 5 (200 mg/kg) as was observed in the control group. Fluid volume increase in Groups 3 and 6 indicated mucus secretion. DPPH radical scavenging activity of extract was effective as ascorbic acid which served as standard at 20 μg/mL. But, the extract elicited low lipid peroxidation activity compared with the reference (tocopherol) at concentrations tested. Conclusions: A. difformis aqueous leaf extract is safe and possesses positive anti-asthmatic and antioxidant activities as claimed by traditional herbal practitioners in Delta State.