In vitro antidiabetic activity of Cotinus coggygria Scop.

Cotinus coggygria Scop. (Anacardiaceae) is a deciduous and slow growing shrub. It grows mainly in South and Central Europe, South Russia, Crimea, Caucasia, Latakia and Turkey [1]. The leaves are used as an infusion in Turkish folk medicine for its anti-diabetic, antiseptic, anti-inflammatory, antimicrobial, anti-haemorragic and wound healing properties [2 – 3]. According to phytochemical studies, the main group of biologically active constituents from different parts of C. coggygria are polyphenols, flavonoids and tannins. The plant extracts showed antioxidant, cytotoxic, antigenotoxic, antimicrobial, antiviral, hepatoprotective, and anti-inflammatory activities in vivo and in vitro. There are also a few studies about anti-diabetic activity of the plant [4]. In the present study, the methanol extract and its different polarity fractions (petroleum ether, dichloromethane, ethyl acetate, n-butanol) prepared from leaves of C. coggygria were evaluated for in vitro α-glucosidase and α-amylase inhibitory activities. The α-glucosidase of Saccaharomyces cerevisiae is used to investigate the inhibitory activities of the extracts against α-glucosidase by using p-nitrophenyl-α-D-glucopyranoside as a substrate and these were compared with acarbose [5]. The dinitrosalicylic acid method was used for determination of α-amylase inhibition activity and expressed as a decrease in units of maltose released [6]^. The ethyl acetate fraction showed the best α-glucosidase inhibitory activity with 96.06% (IC₅₀= 0.0082 mg/mL) when compared with the standard compound acarbose that displayed 2.17% inhibitory activity (IC₅₀= 3.3642 mg/mL) at 20 µg/mL concentration. The petroleum ether, methanol, n-butanol and dichloromethane extracts showed 15.45% (IC₅₀= 0.0445 mg/mL), 13.87% (IC₅₀= 0.0474 mg/mL), 11.60% (IC₅₀= 0.0494 mg/mL) and 5.81% (IC₅₀= 0.1441 mg/mL) inhibition activity at the same concentration, respectively. However, the extracts showed no inhibition against α-amylase.

Acknowledgements: This work was supported by The Foundation of Atatürk University (2015/327).

Keywords: Cotinus coggygria Scop., anti-diabetic activity, α-amylase inhibition, α-glucosidase inhibition.

References:

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