In vitro antidiabetic evaluation of Siddha medicine: Pavala Silasathu Parpam by alpha-amylase enzyme inhibition assay

Abstract Background: Type 2 diabetes mellitus is a widespread chronic metabolic disorder marked by persistently elevated blood glucose levels, primarily caused by insulin resistance and/or insufficient insulin secretion from pancreatic β-cells. Managing post-meal glucose spikes is essential in diabetes care, and one key strategy involves inhibiting the enzyme alpha-amylase (α-amylase), which breaks down dietary starch. Pavala Silasathu Parpam (PSP), a traditional Siddha formulation made from Pavalam (purified coral), Karpoora Silasathu (purified selenite), and Pirandai ( Cissus quadrangularis L.). It is traditionally used for diabetes-related conditions, but scientific validation behind this usage is limited. This study aimed to evaluate the in vitro α-amylase inhibitory effect of PSP to substantiate its antidiabetic potential. Materials and Methods: PSP was formulated following classical Siddha purification and calcination techniques. The α-amylase inhibition assay was conducted using a spectrophotometric method with 2-chloro-4-nitrophenyl-α-maltotrioside as the substrate. Acarbose served as the standard reference drug. Various concentrations of PSP (100–500 μg/mL) were tested, and inhibition percentages and the inhibitory concentration 50 (IC 50 ) values were computed. Results: PSP demonstrated a concentration-dependent inhibition of α-amylase, reaching a maximum of 58.12 ± 7.14% at 500 μg/mL with a half maximal inhibitory concentration (IC 50 ) of 434.1 ± 120.7 μg/mL. The standard drug acarbose showed 97.64 ± 0.42% inhibition with an IC 50 of 30.19 ± 5.769 μg/mL. Despite lower potency than acarbose, PSP showed significant enzyme inhibition. Conclusion: The findings suggest that PSP possesses measurable α-amylase inhibitory activity, aligning with its traditional use in Siddha medicine for metabolic disorders.