Case Studies in Chemical and Environmental Engineering (Dec 2023)
Untargeted metabolomics analysis of Rhinachantus nasutus (L.) Kurz stem bark using HRMS UHPLC-Q-Orbitrap and evaluation of antioxidant capacity and α-glucosidase inhibitory activity
Abstract
Preparations of the roots, stems, and leaves of Rhinachantus nasutus (L.) Kurz (RNK) have been used empirically in traditional medicine to treat diabetes, eczema, pulmonary tuberculosis, herpes, hepatitis, and hypertension for centuries. This study seeks to identify compounds that have antioxidant and antidiabetic properties by inhibiting alpha-glucosidase activity in RNK stem bark through metabolomics and molecular docking approaches based on ultrahigh-performance liquid chromatography-mass spectrometry (UHPLC MS/MS). The results of the alpha-glucosidase inhibition activity test showed that fraction A of stem bark was active with an IC50 value of 20.04 ± 0.05 mg/L, while fractions B and C were very active with IC50 values of 6.67 ± 0.04 and 6.99 ± 0.03 mg/L, respectively. The EC50 value obtained in testing the antioxidant activity of fractions A, B, and C using the FRAP method was in the range 9.79–11.33 mg/L, while using the CUPRAC method was in the range 8.98–17.05 mg/L. The antioxidant properties of fractions A, B, and C are very strong. This metabolomics approach yielded nine compounds that play an important role as antioxidants (the FRAP method) and 19 compounds (the CUPRAC method), while 11 compounds play an important role as inhibitors of alpha-glucosidase activity. Molecular docking verification of 11 significant compounds as alpha-glucosidase inhibitors revealed that the ΔG values of all compounds were negative, with the exception of compound (10) tangeretin, which had an almost identical ΔG value to acarbose. RNK stem bark is a possible source of anti-diabetic and antioxidant compounds, according to the findings of this study. Therefore, RNK stem bark may be utilised in the future for the advancement of anti-diabetes research and the preparation of medicinal constituents. Besides that, it can better utilise stem bark which was originally an agricultural or plantation waste, to become a source of antidiabetic drugs.
