Extracts of Ficus exasperata leaf inhibit topical and systemic inflammation in rodents and suppress LPS-induced expression of mediators of inflammation in macrophages.

The leaves of Ficus exasperata are mashed and prepared as poultices that are placed on swellings, wounds, and arthritic joints to relieve swelling and pains by the Igede tribal community of Nigeria. The leaf and stalk are also squeezed and used to mitigate itching or inflammation. These claimed benefits inspired this study in which topical and systemic (acute, chronic) anti-inflammatory activities of a methanol/methylene chloride leaf extract of F. exasperata (MFE) were assessed in rodents. Effects of an aqueous leaf extract (AFE) on lipopolysaccharide-induced expression of interleukin-1β (IL-1β), tumor necrosis factor (TNF)-α, and inducible nitric oxide (iNO) were also investigated in murine bone marrow-derived macrophage (BMDM) cultures. Treatment of rats with MFE (200 and 400 mg/kg) led to significant inhibition of acute and chronic inflammation induced by, respectively, agar and formaldehyde in the paws. Topically, pre-application of mice with MFE (5 µg/ear) also significantly inhibited (by up to 21%) ear edema induced by xylene. In vitro, pre-treatment of BMDM with 5-100 µg AFE/ml significantly inhibited IL-1β, TNFα, and iNO production in a dose-related manner. BMDM viability was not significantly affected AFE at concentrations up to 200 µg/ml. Initial studies showed that flavonoids, alkaloids, and terpenoids were the predominant phytoconstituents in each extract. In conclusion, the results of the various investigations indicated that F. exasperata leaf extracts possess anti-inflammatory properties that could underlie the benefits associated with the folklore use of the plant. The results also show that the extracts may be acting through a suppression of mediators of inflammation, such as IL-1β, TNFα, and iNO.