Phenolic profile, antioxidant, anti-inflammatory and cytotoxic activities of small yellow onion (Allium flavum L. subsp. flavum, Alliaceae)

Abstract

The objectives of this study were to define the phenolic profile, antioxidant, anti-inflammatory and cytotoxic properties of edible Allium flavum subsp. flavum (small yellow onion), which has never been comprehensively examined before. The presence and content of 44 phenolic compounds in methanol extracts of A. flavum were investigated by LC-MS/MS, where 25 compounds were found, the most dominant being: ferulic, p-coumaric, caffeic, p-hydroxybenzoic, vanillic, protocatechuic and syringic acid, rutin, quercetin-3-O-glucoside and kaempferol-3-O-glucoside. Antioxidant activity, determined through several assays, was low in comparison to the synthetic antioxidant butylated hydroxytoluene, but comparable to onion (Allium cepa L.) extract. Anti-inflammatory potential was studied by measuring the inhibitory effect on cyclooxygenase-1 (COX-1) and 12-lipoxygenase (12-LOX) activity, where A. flavum expressed high inhibitory potential, especially on 12-LOX activity (IC50 = 0.078 mg mL−1). Treatment of four human cell lines resulted in a considerable inhibition of cell growth, where the extract of A. flavum expressed selective inhibitory action towards cervix epithelioid carcinoma and colon adenocarcinoma cells (IC50 = 71 μg mL−1 and IC50 = 81 μg mL−1, respectively). To conclude, these results support use of A. flavum as a functional food and indicate that it could be a potent source of health-beneficial phytochemicals.