Antioxidant furofuran lignans from Premna integrifolia

Two new furofuran lignans premnadimer (1) and 4β-hydroxyasarinin-1-O-β-glucopyranoside (2) along with 9 known compounds have been isolated from the stem bark of Premna integrifolia. Their chemical structures were elucidated using detailed spectroscopic studies. Their relative configurations were established using analysis of NOESY correlations and coupling constants observed in 1H NMR. Compounds 1 and 2 together with four known iridoid glycosides (3–6) were evaluated for radical scavenging and ferric reducing antioxidant power. Radical scavenging activity was found maximum in 4″-hdroxy-E-globularinin (4) followed by 10-O-trans-p-coumaroylcatalpol (3) and new dimer (1). In FRAP assay, premnosidic acid (5), 10-O-trans-p-coumaroyl-6-O-α-l-rhamnopyranosyl catalpol (6) showed maximum ferric reducing ability supported by high reducing power.

Two new furofuran lignans premnadimer (1), 4β-hydroxyasarinin-1-O-β-glucopyranoside (2) were isolated from the stem bark of Premna integrifolia and their structures were elucidated largely from their 1D and 2D NMR data.Figure optionsDownload as PowerPoint slideHighlights
► Two new lignans, (1 and 2) were isolated from Premna integrifolia (Verbenaceae).
► Structure elucidation of the novel ones and known nine compounds were made based on 1D and 2D NMR and mass spectroscopic analyses.
► Lignans and iridoid glycosides were observed for antioxidant activity.