Determination of alpha-glucosidase inhibitory effects of anthraquinone aglycons by molecular docking and in vitro studies

Rumex acetosella L. (Polygonaceae) has been commonly used for diabetes in traditional medicine [1]. According to World Health Organization, the global prevalence of diabetes was estimated to be 9% among adults in 2014 [2] and 90% of which was type 2 diabetes [3].

Alpha glucosidase inhibitors delaying breakdown of complex carbonhydrates in small intestine and slowing glucose absorbtion are significant to prevent development of hyperglycemia [4].

In this study, anthraquinone aglycons were investigated by molecular docking studies and in vitro α glucosidase inhibition assay to determine whether the effect depends on the compounds or not. According to the docking studies simulated by the docking program AutoDock Vina 4.0, emodin, chrysophanol, physcion, aloe-emodin and rhein had moderate binding energies ranging from -6.8 to -7.5 kcal/mol. Because anthraquinone aglycons showed similar and inconclusive docking results, we in vitro measured the α glucosidase inhibition for each. In comparison to the standard compound acarbose (IC₅₀= 1.75 mg/mL) their activity was low except for chrysophanol (IC₅₀= 0.25 mg/mL). In our further studies, antidiabetic potential of glycosidic 1,8-dihydroxy anthraquinone derivatives will be investigated.

Acknowledgements: This study was supported by grants from Hacettepe University Scientific Research Projects (Project No: 1216).

References:

[1] Kilic O, Bagci E. An ethnobotanical survey of some medicinal plants in Keban (Elazığ-Turkey). J Med Plants Res 2013; 7: 1675 – 84.

[2] Global status report on noncommunicable diseases 2014. Geneva, World Health Organization, 2012

[3] Definition, diagnosis and classification of diabetes mellitus and its complications. Part 1: Diagnosis and classification of diabetes mellitus. Geneva, World Health Organization, 1999 (WHO/NCD/NCS/99.2)

[4] He ZX, Zhou ZW, Yang YX, Yang TX, Pan, SY, Qiu JX. et al. Overview of clinically approved oral antidiabetic agents for the treatment of type 2 diabetes mellitus. Clin Exp Pharmacol P 2015; 42: 125 – 38.