Anti-inflammatory, antinociceptive, antipyretic and antioxidant activities and phenolic constituents from Loranthus regularis Steud. ex Sprague

Loranthus regularis Steud. ex Sprague (Loranthaceae) aerial part is widely used for medicinal purposes. To evaluate its anti-inflammatory, antinociceptive and antipyretic activities, two concentrations of the extract and its fractions were tested in carrageenan-induced rat paw oedema, hot-plate test model in mice and brewer’s yeast-induced pyrexia in mice. The antioxidant power of the extract, its fractions and isolated compounds was studied using DPPH scavenging and β-carotene/linoleic acid tests. The ethyl acetate fraction of a methanol extract was found to be the most active fraction and exhibited the highest inhibition of inflammation (67%) and the highest inhibition of oxidation of β-carotene (92%). Bioassay-guided fractionation of the ethyl acetate fraction was carried out and three flavonoid glycosides were isolated for the first time from this species: (1) quercetin 3-O-β-l-galactopyranoside, (2) quercetin 3-O-β-l-arabinopyranoside and (3) quercetin 3-O-α-l-rhamnopyranoside. The present results confirmed the traditional use of L. regularis and clearly indicate that the plant could be a potential anti-inflammatory and antioxidant agent.

► Loranthus regularis showed significant anti-inflammatory and antioxidant activity. ► L. regularis demonstrated also interesting antinociceptive and antipyretic activity. ► The ethyl acetate fraction of the crude extract was the most active fraction. ► A bioassay-guided fractionation yielded three flavonoids for the first time from this species. ► Quercetin 3-galactoside, quercetin 3-arabinoside and quercetin 3-rhamnoside were isolated.