Estimation of antinociceptive and anti-inflammatory activity on Geranium pratense subsp. finitimum and its phenolic compounds

To obtain experimental evidence on the therapeutic efficacy of Geranium species and its phenolic compounds for inflammatory diseases, we examined the effects of the aqueous extract of the aerial parts of Geranium pratense subsp. finitimum (Woronow) Knuth, its fractions and isolated compounds, the mixture of quercetin 3-O-α-arabinopyranoside, kaempferol 3-O-β-galactopyranoside (1), the mixture of quercetin 3-O-β-glucopyranoside, quercetin 3-O-β-galactopyranoside (2), kaempferol 3-O-β-glucopyranoside (3), (-)-6-chloroepicatechin (4), the mixture of quercetin 3-O-(2″-O-galloyl)-β-glucopyranoside, quercetin 3-O-(2″-O-galloyl)-β-galactopyranoside (5) and myricetin 3-O-(2″-O-galloyl)-β-glucopyranoside (6), on carrageenan-, PGE₂- and TPA-induced inflammation in mice and p-benzoquinone-induced writhing reflex to assess anti-inflammatory and antinociceptive activities. The effective dose of materials for the inhibition of carragenan-induced hind paw edema assay was determined to be 100 mg/kg, which was also used in the assays with the extract, its fractions and isolated compounds in all other experiments. The aqueous extract, 1, 2 (100 mg/kg), as well as indomethacin (10 mg/kg) inhibited significantly the formation of the carrageenan-induced hind paw edema. There was also a significant reduction in PGE₂-induced hind paw edema and TPA-induced ear edema models with 5, in addition to the aqueous extract and the other active components 1 and 2. In the antinociceptive assay, the aqueous extract and its fractions, as well as 1, 2, and 5 diminished significantly the number of writhings. Based on the results obtained it is suggested that the aqueous extract of Geranium pratense subsp. finitimum and its phenolic compounds display anti-inflammatory activity, supporting the folkloric use.