Investigation into the biological activities and chemical composition of Calendula officinalis L. growing in Tunisia

Calendula officinalis (Marigold) was characterized in respect to its chemical composition, antioxidant potential and antimicrobial activities. Five compounds were identified and quantified by LC/MS and HPLC in leaves and flowers of aqueous-methanolic extracts. Total flavonoids ranged between 44.91 and 76.44 mg QE/g dry weight in leaf and flower extracts, respectively. Rutin, quercetin-3-O-glucoside, scopoletin-7-O-glucoside, isorhamnetin-3-O-glucoside and gallic acid were tentatively identified in this plant. The highest antioxidant activities using two methods, DPPH and FRAP assays were obtained with aqueous-methanol flower extract from C. officinalis (0.35 mg.mL^-1 and 28.37 mM of Trolox). The potential antimicrobial activity of the leaf and flower aqueous-methanol extracts from the C. officinalis was screened against three bacteria and two pathogenic fungi, using the cellulosic disc method. A strong inhibited activity against the five microorganisms is obtained. This study could provide useful information for industry to produce potentially bioactive plant extract.