Abstract
Allium species are revered worldwide as vegetables, condiments, and spices as well as the therapeutic agents in traditional medicine. The bioactive compounds in alliums mainly include organosulfur compounds, polyphenols, dietary fibers, and saponins. Flavonoids, particularly flavonols from alliums, have been demonstrated to have the antioxidant, anticancer, hypolipidemic, anti-diabetic, cardioprotective, neuroprotective, and antimicrobial activities. However, flavonols are mostly characterized from onions and have not been comprehensively reviewed across different species. This article therefore focuses on flavonol profiles from different Allium species, their health effects, underlying molecular mechanisms, and bioavailability. Intriguingly, the functional health effects of flavonols were mainly ascribed to their antioxidant and anti-inflammatory activities involving a cascade of multiple signaling pathways. Although the Allium-derived flavonols offer tremendous potential in preventing chronic disease risks, in-depth studies are needed to translate their clinical application.
Highlights
Chronic diseases pose a huge burden on global health care system and economy accounting for nearly seventy percent of pre-mature mortality en masse [1]
Lagoa et al [169] identified mitochondrial respiratory chain complex-I and cyt c as the major molecular targets of quercetin and kaempferol in alleviating oxidative stress. Another mechanism pertaining to the beneficial effect of flavonols is identified as mitochondrial uncoupling, a regulated proton leak mediated by uncoupling proteins (UCPs) [170], which occurs through aldehydic lipid-peroxidation intermediates such as 4-hydroxy-2-nonenal [85] and AMPK activation [64]
It is noteworthy to mention that only 5–10% of pioneering study by Hollman et al [184] indicated that 52% absorption of onion-derived quercetin the total dietary polyphenols is absorbed in the small intestine, while the remaining 90–95% together glucosides whereas, 24% of quercetin aglycone given as a pure compound was absorbed in the small with their conjugates reaches the colon and undergoes microbial metabolism, intestine of healthy ileostomy volunteers
Summary
Chronic diseases pose a huge burden on global health care system and economy accounting for nearly seventy percent of pre-mature mortality en masse [1]. The complex chemistry of OSCs, due to their highly-volatile and thermally-unstable nature, likely impairs their health benefits [10,11,12,13]. In this context, allium polyphenols, with relatively higher stability than. A range of health-modulating effects of Allium-derived polyphenols, in particular, which governsare their functional properties including anti-inflammatory, antimicrobial, antiglycemic, flavonols, attributed to their antioxidant activity which governs their functional properties andincluding anticancer effects [14,15,16]. Allium species are rich source dietary flavonols, anti-inflammatory, antimicrobial, antiglycemic, and anticancer effects of [14,15,16].
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