High‐performance thin‐layer chromatography coupled attenuated total reflectance‐Fourier‐transform infrared and NMR spectroscopy‐based identification of α‐amylase inhibitor from the aerial part of Asparagus racemosus Willd

Abstract

Introduction: α-Amylase inhibitors from natural sources are of interest for new drug development for the treatment of diabetes mellitus (DM). High-performance thinlayer chromatography (HPTLC) coupled bioassay guided isolation of bioactive compounds has been improved within last few years.Objective: A microchemical derivatised HPTLC-coupled attenuated total reflectance-Fourier-transform infrared (ATR-FTIR) and nuclear magnetic resonance (NMR) spectroscopy was employed for profiling α-amylase inhibitor from the aerial part of Asparagus racemosus Willd.Methodology: Asparagus racemosus Willd. aerial part extracted with different solvents (n-hexane, chloroform, ethyl acetate, and methanol) and assayed to detect free radical scavengers and α-amylase inhibitor by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and starch-iodine assay method, respectively. HPTLC-coupled ATR-FTIR and NMR spectroscopy was used to identify the α-amylase inhibitor.Results: Methanolic extract of A. racemosus showed highest antioxidant activity (21.99 μg GAE/μL) where n-hexane extract showed lowest antioxidant activity (5.87 μg GAE/μL). The α-amylase inhibition was recorded as highest and lowest in ethyl acetate extract (13.13 AE/μL) and n-hexane extract (3.92 AE/μL), respectively.The deep blue zone of α-amylase sprayed TLC plate of extracts with hR F = 72 analysed for ATR-FTIR and NMR spectroscopy which revealed the presence of stigmasterol is responsible for α-amylase inhibition. Conclusion:The present work establishes the α-amylase inhibiting properties of A. racemosus maintaining its use for the treatment of DM as a traditional medicine.Bioassay guided isolation through HPTLC-coupled ATR-FTIR and NMR spectroscopy offers an effective method for the exploration of bioactive compounds such as α-amylase inhibitor from complex plant extracts.

Comparative assessment of physicochemical properties of plant active molecules having antidiabetic potential

“…The study of pharmacokinetics parameters of active compounds is one of the important aspects to predict the therapeutic potential of phytochemicals [29,30,31]. The analyses of different attributes of pharmacokinetics parameters suggest that half of the targeted active molecules have high propensities for gastrointestinal (GI) absorption (Table 3), which means these molecules will easily be absorbed in the human intestine.…”