Phytochemical characterization, antioxidant, antimicrobial and pharmacological activities of Feijoa sellowiana leaves growing in Tunisia

In this study, headspace solid-phase microextraction coupled to GC–MS was applied to identify the volatile bioactive compounds in the leaves of Feijoa sellowiana growing in Tunisia. Thirty-one components were identified, representing 99.9% of the total volatiles. The major constituents were limonene (36.2%), β-caryophyllene (27.8%), aromadendrene (12.5%), and α-copaene (6.6%). Also, the F. sellowiana leaves extract (FSLE) was phytochemically characterized. Antioxidant activity was estimated by different in vitro assays, such as ABTS cation radicals scavenging, iron-chelating capability, ability to inhibit lipid peroxidation, superoxide inhibition and DNA protection assay. The antibacterial and antifungal activities of FSLE were also investigated by the disc diffusion and microdilution methods. In vitro inhibition of diabetes key enzymes (α-glucosidase and α-amylase) was evaluated. The study of kinetics inhibition showed that the FSLE demonstrated a strong inhibition of both α-glucosidase (IC50=8.0 ± 0.2 μg/ mL) and α-amylase (IC50=70.20 ± 0.8 μg/mL) in non-competitive manner. The acute toxicity of FSLE on Wistar rats at the doses of 200, 500 and 2000 mg/kg body weight (BW) was investigated. Our findings revealed that leaves extract at such doses as up to 2000 mg/kg did not cause any signs of toxicity or deaths in rats. Based on hematological and biochemical analyses of hepato-biliary and renal functions, we concluded that the FSLE is tolerated by rats. The analgesic effect of FSLE was assayed using the acetic acid writhing test in mice. At 100 mg/ kg, the FSLE showed a higher analgesic activity (88.08 ± 0.73%) than that of acetylsalicylic acid (ASL) (62.69 ± 0.26%) used as positive control.