Antioxidant and anti-inflammatory properties of the methanolic extract of Siphonochilus aethiopicus rhizomes

Siphonochilus aethiopicus is a medicinal plant widely used in the treatment of many inflammatory conditions such as arthritis. The objective of this study was therefore to evaluate the antioxidant and anti-inflammatory properties of methanolic extract of S. aethiopicus rhizomes.

The total phenolic compounds, flavonoid, and tannin content, as well as the in vitro antioxidant activity of the extract, were estimated. The in vivo anti-inflammatory activity was then evaluated in male mice aged 3 to 4 months using the arthritic mouse model induced by carrageenan (0.05 ml; 1%) and monosodium urate (MSU) crystals (26.6 mg/mL). Mice were treated with the methanolic extract of S. aethiopicus (75, 150, 300 mg/kg) and the reference drugs: indomethacin (3 mg/kg) and colchicine (1 mg/kg). The serum, splenic, and hepatic lysosomal enzymes were determined, and oxidative stress biomarkers were estimated. Paws were sectioned for histological analysis.

Results showed that S. aethiopicus extract had non-negligible concentrations of polyphenols, flavonoids, and tannins, which could confer it an antioxidant effect. Further, the methanolic extract of S. aethiopicus at different doses significantly (P<0.05) reduced paw swelling, attenuated joint inflammation, limited the release of lysosomal enzymes, and improved antioxidant enzymes.

The methanolic extract of S. aethiopicus has anti-inflammatory and antioxidant properties, and can be used to treat acute forms of gouty arthritis.