The flavonol glycoside- and antioxidant alterations during the flowering stages of cloves (Syzygium aromaticum (L.) Merr

Abstract

The flavonol glycosides belong to a large group of flavonoids diverse in chemical structures and properties. In plants, these compounds are usually in O-glycosides with common quercetin or myricetin aglycon. Quercetin is generally the most abundant and prominent component. Flavonols and flavone glycosides were common cloves chemotypes with potential natural antioxidants. The changes and antioxidant capacities of flavonol glycosides during the flowering stages of clove (FS-1 to FS-4) were investigated. Identifications of flavonol glycosides constituent, total phenolic, flavonoids, and antioxidant capacities were evaluated the extracts generated in every stage of clove flowers formation. The experiment showed various concentrations of flavonols (quercetin, quercetin-3-O-glycoside, myricetin, myricetin-3-Oglycoside) and flavones (luteolin-7-O-glycoside, apigenin-7-O-glycoside), as the highest concentration of quercetin-3-O-glycoside was found during the bloom stage (FS-4) at 110.27 μg/g. The blooming stage also had a significantly higher in-vitro antioxidant capacity than FS1, FS-2, and FS-3. Antioxidant activity was based on 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl radical (OH•), and superoxide radical (•O2) scavenging. It is suggested as the best stage in harvesting the cloves for the natural antioxidant source.