Browsing by Author "Ademosun, Ayokunle O."

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    Comparative effect of quercetin and rutin on α-amylase, α-glucosidase, and some prooxidant-induced lipid peroxidation in rat pancreas
    (Springer, 2014-12-10) Oboh, Ganiyu; Ademosun, Ayokunle O.; Ayeni, Peluola O.; Omojokun, Olasunkanmi S.; Bello, Fatai
    This study was designed to investigate the effect of quercetin, its glycosylated conjugate rutin and various combinations of the two flavonoids on carbohydrate-hydrolyzing enzymes associated with type 2 diabetes (α-amylase and α-glucosidase) in a bid to understand the possible mechanisms of action by which quercetin and rutin could be used in the prevention/management of the degenerative condition. The aim of this study is to investigate the effect of quercetin, rutin, and various combinations of the two flavonoids on α-amylase and α-glucosidase activities and the ability of the flavonoids to inhibit some pro-oxidants-induced lipid peroxidation in rat pancreas. The effect of the flavonoids on α-amylase and α-glucosidase activities as well as pro-oxidant (Fe2+ and SNP)-induced lipid peroxidation in rats’ pancreas homogenates was investigated. Rutin (IC50 = 0.048 μΜ) exhibited a significantly (P < 0.05) higher inhibition of Fe2+-induced lipid peroxidation than quercetin (IC50 = 0.075 μΜ). Furthermore, rutin had a stronger inhibition of α-amylase (IC50 = 0.043 μM) and α-glucosidase (IC50 = 0.037 μM) activities than quercetin [α-amylase (IC50 = 0.061 μM); α-glucosidase (IC50 0.038 μM)]. A combination of 25 % quercetin and 75 % rutin showed the strongest inhibition (P < 0.05) of α-amylase activity (IC50 = 313.87 μg/L) while 100 % quercetin showed the least inhibition of α-amylase (IC50 507.61 μg/L) activity and same trend was followed for α-glucosidase activity. This study revealed that glycosylation increased the inhibitory ability of quercetin on key enzymes linked to type 2 diabetes (α-amylase and α-glucosidase), and combination of quercetin and rutin had higher synergistic inhibitory abilities on the enzymes than the individual flavonoids, suggesting that a combination of food sources rich in these flavonoids could be very effective in the management/prevention of type 2 diabetes.
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    In Vitro Studies on the Antioxidant Property and Inhibition of 𝛼-Amylase, 𝛼-Glucosidase, and Angiotensin I-Converting Enzyme by Polyphenol-Rich Extracts from Cocoa (Theobroma cacao) Bean
    (Hindawi, 2014) Oboh, Ganiyu; Ademosun, Ayokunle O.; Ademiluyi, Adedayo O.; Omojokun, Olasunkanmi S.; Nwanna, Esther E.; Longe, Kuburat O.
    This study sought to investigate the antidiabetic and antihypertensive mechanisms of cocoa (Theobroma cacao) bean through inhibition of 𝛼-amylase, 𝛼-glucosidase, angiotensin-1 converting enzyme, and oxidative stress. Methodology. The total phenol and flavonoid contents of the water extractable phytochemicals from the powdered cocoa bean were determined and the effects of the extract on 𝛼-amylase, 𝛼-glucosidase, and angiotensin-1 converting enzyme activities were investigated in vitro. Furthermore, the radicals [1,1-diphenyl-2 picrylhydrazyl (DPPH), 2,2..-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS), hydroxyl (OH), and nitric oxide (NO)] scavenging ability and ferric reducing antioxidant property of the extract were assessed. Results. The results revealed that the extract inhibited 𝛼-amylase (1.81 ± 0.22 mg/mL), 𝛼-glucosidase (1.84 ± 0.17 mg/mL), and angiotensin-1 converting enzyme (0.674 ± 0.06 mg/mL [lungs], 1.006 ± 0.08 mg/mL [heart]) activities in a dose-dependent manner and also showed dose-dependent radicals [DPPH (16.94 ± 1.34 mg/mL), NO (6.98 ± 0.886 mg/mL), OH (3.72 ± 0.26 mg/mL), and ABTS (15.7 ± 1.06 mmol/TEAC⋅g] scavenging ability. Conclusion. The inhibition of 𝛼-amylase, 𝛼-glucosidase, and angiotensin-1 converting enzyme activities by the cocoa bean extract could be part of the possible mechanism by which the extract could manage and/or prevent type-2 diabetes and hypertension.
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    Starch composition, glycemic indices, phenolic constituents, and antioxidative and antidiabetic properties of some common tropical fruits
    (No longer published by Elsevier, 2016-06-01) Oboh, Ganiyu; Ademosun, Ayokunle O.; Akinleye, Margareth; Omojokun, Olasunkanmi S.; Boligon, Aline A.; Athayde, Margareth L.
    Background Studies have supported the protective effect of high fruit consumption in the management of chronic diseases such as diabetes. Methods Thirteen fresh tropical fruits were sourced for and the fruits juices were extracted, freeze dried, and then reconstituted for analysis. The sugar, starch, amylose, and amylopectin contents as well as glycemic indices, antioxidant properties, and the ability of the fruits to inhibit starch-hydrolyzing enzymes were determined. Also, the phenolic constituents of the fruits were characterized using high-performance liquid chromatography coupled with diode array detector. Results The starch, sugar, amylase, and amylopectin contents were 3.01–3.89 g/100 g, 35.34–60.91 g/100 g, 0.84–1.46 g/100 g, and 1.68–2.86 g/100 g, respectively, while the glycemic indices were 28.01–68.34, with African star apple (28.01) having the lowest and watermelon (68.34) the highest. Furthermore, the fruits exhibited high antioxidant properties as exemplified by their DPPH, ABTS+, OH, and NO radical scavenging abilities. Likewise, the fruits also demonstrated α-amylase and α-glucosidase inhibitory property with Soursop (IC50 = 18.52 μg/mL), guava (IC50 = 19.77 μg/mL), and African star apple (IC50 = 20.86 μg/mL) showing the highest inhibitory potential among the 13 fruits. Similarly, the same trend was followed for α-glucosidase inhibitory activity. Conclusion The fruits' low glycemic indices, strong antioxidant properties, and inhibition of α-amylase and α-glucosidase activities could be possible mechanisms for their use in the management and prevention of type-2 diabetes.