In vitro and in vivo assessment of meadowsweet (Filipendula ulmaria) as anti-inflammatory agent

Ethnopharmacological relevance: Meadowsweet (Filipendula ulmaria (L.) Maxim, Rosaceae) has been traditionally used in most European countries for the treatment of inflammatory diseases due to its antipyretic, analgesic, astringent, and anti-rheumatic properties. However, there is little scientific evidence on F. ulmaria anti-inflammatory effects regarding its impact on cyclooxygenases enzymatic activity and in vivo assessment of anti-inflammatory potential. This study aims to reveal the anti-inflammatory activity of methanolic extracts from the aerial parts (FUA) and roots (FUR) of F. ulmaria, both in in vitro and in vivo conditions. Materials and methods: The characteristic phenolic compounds in F. ulmaria extracts were monitored via high performance thin layer chromatography (HPTLC). The in vitro anti-inflammatory activity of F. ulmaria extracts was evaluated using cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) enzyme assays, and an assay for determining COX-2 gene expression. The in vivo anti-inflammatory effect of F. ulmaria extracts was determined in two doses (100 and 200 mg/kg b.w.) with hot plate test and carrageenan-induced paw edema test in rats. Inflammation was also evaluated by histopathological and immunohistochemical analysis. Results: FUA extract showed the presence of rutoside, spiraeoside, and isoquercitrin. Both F. ulmaria extracts at a concentration of 50 mu g/mL were able to inhibit COX-1 and -2 enzyme activities, whereby FUA extract (62.84% and 46.43% inhibition, respectively) was double as effective as the root extract (32.11% and 20.20%, respectively). Extracts hardly inhibited the level of COX-2 gene expression in THP-1 cells at a concentration of 25 mu g/mL (10.19% inhibition by FUA and 8.54% by FUR). In the hot plate test, both extracts in two doses (100 and 200 mg/kg b.w.), exhibited an increase in latency time when compared with the control group (p < 0.05). In the carrageenan-induced acute inflammation test, FUA at doses of 100 and 200 mg/kg b.w., and FUR at 200 mg/kg, were able to significantly reduce the mean maximal swelling of rat paw until 6 h of treatment. Indomethacin, FUA, and FUR extracts significantly decreased inflammation score and this effect was more pronounced after 24 h, compared to the control group (p < 0.05). Conclusions: The observed results of in vitro and, for the first time, in vivo anti-inflammatory activity of meadowsweet extracts, provide support of the traditional use of this plant in the treatment of different inflammatory conditions. Further investigation of the anti-inflammatory compounds could reveal the mechanism of anti-inflammatory action of these extracts.