Antioxidant Activity, and α-Glucosidase, α-Amylase and Lipase Inhibitory Activity of Polyphenols in Flesh, Peel, Core and Seed from Mini Apple

Abstract

Dietary inhibitors of fats and carbohydrates degrading digestive enzymes can reduce obesity and type 2 diabetes. In this study, we investigated and compared polyphenol content, DPPH radical scavenging activity, and inhibitory activity on digestive enzymes, including α-glucosidase, α-amylase and lipase in flesh, peel, core and seed from mini apple (Malu domestica cv. 'Alps Otome'). Polyphenol content was significantly higher in peel and seed extracts than in flesh and core extracts. As comparing with flesh, peel polyphenols exhibited stronger DPPH radical scavenging activity, and α-amylase and lipase inhibitory activity. Oligomeric polyphenols (Fra.II) were the main polyphenols in seed extracts, which exhibited significantly strong DPPH radical scavenging activity and inhibitory activity on digestive enzymes. However, monomeric polyphenols (Fra.I) were the main polyphenols in core extracts, which exhibited weak inhibitory activity on digestive enzymes than the other parts. Moreover, Fra.III of seed and peel extracts had the highest inhibitory activity on α-glucosidase, followed by Fra.II and Fra.I, respectively. It indicated that more highly polymerized polyphenols from peel and seed of mini apple showed more potent inhibitory activities on α-glucosidase. All of the observations suggested that mini apples possess useful properties. Particularly, it has potential applications for the treatment of diabetes and obesity.

(Poly)phenols of apples contribute to in vitro antidiabetic properties: Assessment of Canada's Apple Biodiversity Collection

“…α-Glucosidase inhibition was observed in the greatest number of apple accessions, which indicates that apple (poly)phenol-rich extracts are more effective against α-glucosidase than α-amylase (Figure 1a,b). This finding coincides with the scientific literature (Ci et al, 2018;Yilmazer-Musa et al, 2012), where (poly) phenols demonstrate greater α-glucosidase inhibitory capacity than α-amylase. The variability in carbohydrate-hydrolyzing enzyme inhibition can be explained by the previously reported 100-fold difference in TPC across the ABC apple accessions (Watts et al, 2021).…”

Inhibition of enzymes associated with metabolic and neurological disorder by dried pomegranate sheets as a function of pomegranate cultivar and fruit puree

“…Developed products are characterized by a high content of pectins due to the selected fruit and the ingredients of the formulation. In addition, fat digestion can be delayed through enzyme inhibition (by the presence of hydroxycinnamic acids such as chlorogenic acid and caffeic acid) contained in quinces, jujube and apple fruits 11,12 …”

“…As for pomegranate, inhibitory effects of different pomegranate parts (juice, peel, seed and flower) on mammalian type α‐amylase and α‐glucosidase enzyme activities have been demonstrated, mainly due to gallic acid and ellagic acid presence 9,10 . Regarding apple fruit, starch and fat digestion can be delayed through enzyme inhibition (by the presence of tannic acid, chlorogenic acid and caffeic acid) contained in thinned young apples and mini‐apple because of the high inhibitory activity against α‐glucosidase, α‐amylase and pancreatic lipase 11,12 …”

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“…The cyanogenic glycoside (amygdalin), being cytotoxic, exhibits major effectiveness in preventing the proliferation of malignant cells. This also provides hope in treating human cervical cancer, lung carcinoma, and skin cancer 18,20 .…”

“…Anti-obesity Properties: M. domestica pulp, peel, and especially seeds contain high proanthocyanidin, quercetin, and several triterpenes along with dietary fibres that have helped in oxidating the lipoprotein cholesterol and thus causing hypocholesterolemic mechanism. This helps decrease hepatic cholesterol levels and prevent fats deposition in cardiovascular tissues by keeping the heart and liver healthy 2,5,17,18,20 .…”