Investigation of Antioxidant and Elastase Inhibitory Activities ofGeum urbanumAerial Parts, Chemical Characterization of Extracts Guided by Chemical and Biological Assays

Abstract

This study presents the bioguided chemical investigation of the 80% aqueous methanol extract of Geum urbanum aerial parts. Liquid–liquid partitioning of this extract in solvents of increasing polarity combined with biological screening showed that the ethyl acetate (EtOAc) soluble fraction was the most active part of the extract. This fraction was chemically profiled by a 13C nuclear magnetic resonance (NMR)-based dereplication method, resulting in the identification of 14 compounds. The dereplication process was followed by the purification of unknown and minor compounds of the EtOAc fraction. A new glycosylated phenol, namely, 3-(3,4-dihydroxyphenyl)propyl-α-l-rhamnopyranoside, together with 6 known compounds were isolated. Their structures were elucidated by spectroscopic methods including NMR and high-resolution electrospray ionization mass spectrometry. The antioxidant activity of fractions and isolated compounds were evaluated by 2,2,1-diphenyl-1-picrylhydrazyl and hydroxyl radical scavenging, and by cupric ion reducing antioxidant capacity assays. In parallel, their enzyme inhibitory property against human neutrophil elastase was assessed. Four subfractions, essentially containing polyphenols and triterpenes, exhibited a significant elastase inhibitory activity and an ellagitannin showed a very high radical scavenging activity.

Bio-guided Studies of Lotus maritimus Aerial Parts and Investigation of their Antioxidant, Tyrosinase and Elastase Inhibitory Activities

“…1 H-, 13 C-NMR and 2D-NMR spectra were recorded on a Bruker Avance AVIII-600 spectrometer equipped with a 5 mm TCI cryoprobe (Karlsruhe, Germany). ESI-MS spectra were recorded using a Micromass Q-TOF micro instrument (Manchester, UK).…”

“…As a first step of 13 C NMR-based dereplication [18], structures and names of metabolites already described in the genus Lotus (n=14) were collected from the literature. The structures and the predicted 13 C NMR chemical shifts were stored into a database (NMR Workbook Suite 2012, ACD/Labs, Ontario, Canada). Then, all dry CPC fractions were dissolved in 600 μL of DMSO-d6 (δ 39.8 ppm) and analyzed by 13 C NMR.…”

“…The structures and the predicted 13 C NMR chemical shifts were stored into a database (NMR Workbook Suite 2012, ACD/Labs, Ontario, Canada). Then, all dry CPC fractions were dissolved in 600 μL of DMSO-d6 (δ 39.8 ppm) and analyzed by 13 C NMR. A standard zgpg pulse sequence was used with an acquisition time of 0.9 s, a relaxation delay of 3 s and 1024 scans [12].…”

“…In the continuation of our investigation of local plants with anti-aging potential [12,13], we investigated the chemical composition of Lotus maritimus L. also known as Tetragonolobus siliquosus L., a perennial herb species in the subfamily Faboideae [14,15]. L. maritimus grows in Europe, Asia, Middle East and Maghreb [16].…”

“…L. maritimus leaf extract was described as active cosmetic ingredient in Canada as antiaging and anticellulite [17] due in part to their antioxidant property but their chemical profile was not study so far. This work presents the chemical characterization of L. maritimus aerial parts using a 13 C NMR-based dereplication method combined with a bio-guided fractionation and purification process. Antioxidant, tyrosinase and elastase inhibitory activities were evaluated on the crude MeOH extract, fractions and purified compounds.…”