Kinetics and Inhibition of Alpha-Amylase by Curcuma caesia for Antihyperglycemic Potential

Abstract

Curcuma caesia (C. caesia), commonly known as black turmeric, holds a significant place in traditional medicine due to its potent medicinal properties, particularly in managing hyperglycemia associated with diabetes. Despite existing treatments, achieving optimal glycemic control remains a persistent challenge due to their side effects, highlighting the need for additional therapeutic options. Understanding the effects of herbal processing conditions (such as temperature) and the mechanisms of action can lead to the development of more effective treatments with minimal side effects. Knowledge of these mechanisms, using kinetic equations, helps predict and prevent negative interactions with herbal products intended for treatment. This study aims to investigate the antihyperglycemic activity of C. caesia extracts (CC50 and CC60) by targeting the alpha-amylase enzyme, a key player in glucose metabolism, with the goal of elucidating its enzymatic kinetics and mode of inhibition. The methodology involves obtaining C. caesia extract through reflux and subjecting it to drying at 50°C (CC50) and 60°C (CC60). Antihyperglycemic efficacy was evaluated by employing the extract as an inhibitor of alpha-amylase. The effectiveness of the inhibition was measured using DNS reagent to determine the amount of reduced sugar, and results were analyzed using UV-spectrophotometry at 540 nm. The half minimal inhibitory concentration (IC₅₀) values for CC50 (5094.41 ppm) and CC60 (5083.07 ppm) indicate that drying temperatures between 50°C and 60°C are suitable for processing C. caesia. Additionally, the maximum reaction rate (Vmax) for both CC50 and CC60 was 0.0025 mg/min, lower than the uninhibited reaction rate (0.0055 mg/min), suggesting that both CC50 and CC60 cause non-competitive inhibition. Kinetic analysis revealed that both extracts were non-competitive inhibitors, as evidenced by the unchanged Michaelis-Menten constant (K_m). This work enhances the understanding of how to improve the efficacy of C. caesia as an antihyperglycemic agent by targeting alpha-amylase. Advanced knowledge of the enzyme-inhibitory activities of C. caesia and the conditions for processing it supports the clinical application of blood glucose regulation, addressing the shortcomings of contemporary diabetes care and aiming to minimize the adverse effects of current pharmacotherapy.