Phytoconstituent screening and in vitro hypoglycemic and antioxidant properties of terpenoid fraction of Kaempferia pulchra extracts in Indian traditional medicine

Abstract

Introduction: The current healthcare system is insufficient to deal with the global impact of rising diabetes, necessitating the development of better alternatives, such as plant-derived natural compounds, to improve glucose tolerance. Therefore, the present study evaluated the phytoconstituents of the aqueous leaf and rhizome extracts of an unnoticed plant species, Kaempferia pulchra. In addition, the in vitro anti-hyperglycemic efficacy and antioxidant activities of the derived terpenoid fraction from the plant extracts were also assessed. Methods: The aqueous extracts of K. pulchra leaves and rhizomes were screened for phytoconstituents using gas chromatography-mass spectrometry. Colorimetric techniques were used to determine the terpenoid fraction’s total phenolic and flavonoid content. Terpenoids’ in vitro antioxidant properties were examined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity (RSA) and ferric reducing power assay, proceeded by α-amylase and α-glucosidase inhibition tests, and anti-hyperglycemic potential was determined utilizing the terpenoid’s fraction. Results: The preliminary phytochemical analysis revealed that the terpenoids obtained from the leaf had the highest total phenol and flavonoid content. Both leaf and rhizome extracts had modest antioxidant capacities compared to ascorbic acid. Similarly, the rhizome extract had significantly higher α-amylase inhibitory activity than the standard acarbose (P < 0.05). Overall, the rhizome extract of K. pulchra outperformed the leaf extract in terms of antioxidant and antidiabetic potential. Conclusion: Kaempferia pulchra is a natural source of terpenoids with several therapeutic qualities, especially for managing diabetes. However, further research is needed to validate some of the claims ascribed to this plant.

Bioassay-guided isolation of the antioxidant constituent from Kaempferia rotunda L.

“…The reducing capacity of isolated compounds was investigated by applying the method reported previously with slight modification (Saravanan et al 2023). Briefly, the FRAP reagent wash was freshly prepared by mixing 300 mM acetate buffer of pH 3.6, 10 mM of 2,4,6tripyridyl-s-triazine (TPTZ) in 40 mM hydrochloric acid (HCl), and 20 mM Ferric (III) chloride hexahydrate (FeCl3.6H2O).…”