Health benefits of onion bioactives on hypercholesterolemia, cardiovascular diseases, and bone mineral density

Abstract

Onion (Allium cepa L.) is widely employed as a food, which contains rich phytochemicals and shows health benefits. Hypercholesterolemia is associated with some health problems, especially cardiovascular diseases. The modulator efficacy of the quercetin-rich onion juice on lipid profile and antioxidant status in mildly hypercholesterolemic subjects was clearly identified. Twenty-four healthy subjects with mild hypercholesterolemia (200 mg/dl) were recruited and divided into two groups, and they consumed 100 ml of onion juice or placebo every day for 8 weeks. Fasting blood samples were collected at initial, 2nd, 6th, 8th, and 10th week for estimating various biochemical assays, as well as anthropometric indices. After 8 weeks of intervention, onion juice greatly decreased (p < .05) waist circumference, total cholesterol, and low-density lipoprotein cholesterol (LDL-c). In addition, it elevated (p < .05) total antioxidant capacity and prolong lag time of LDL oxidation were also noted. To confirm the application of onion on combating cardiovascular diseases , the red wine extract of onion (RO) and red wine (RW) on all the risk factors of cardiovascular disease were determined. In vitro studies evaluated various antioxidant activities (trolox equivalent antioxidant capacity [TEAC], DPPH, and H 2 O 2 scavenging ability) of RO and RW group. Both RO and RW showed the maximum antioxidant capacity. In human studies, 23 healthy hypercholesterolemic volunteers were randomly selected and assigned into two groups, who drank 250 ml of RO (n = 11) or RW (n = 10) for 10 weeks. Both RW and RO extracts elevated (p < .05) antioxidant activity and thereby prolonging the lag time of LDL oxidation. However, RO extract intake substantially decreased (p < .05) the total cholesterol and LDL cholesterol levels comparing to equivalent RW intake, thus indicating the additional hypocholes-terolemic effect of onion. The inflammatory markers such as factor VII were also positively modulated by RO extract. Results indicated that This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. c