Identification of cyclooxygenase-II inhibitory saponins from fenugreek wastes: Insights from liquid chromatography-tandem mass spectrometry metabolomics, molecular networking, and molecular docking.

Abstract

This research explores sustainable applications for waste generated from fenugreek (Trigonella foenum-graecum), a plant with both nutritional and medicinal uses. The study specifically targets waste components as potential sources of nutrients and bioactive compounds. The focus is to conduct detailed metabolic profiling of fenugreek waste, assess its anti-inflammatory properties by studying its cyclooxygenase (COX) inhibitory effect, and correlate this effect to the metabolite fingerprint. Ethanolic extracts of fenugreek fruit pericarp and a combination of leaves and stems were subjected to untargeted metabolic profiling using liquid chromatography-mass spectrometry integrated with online database searches and molecular networking as an effective dereplication strategy. The study also scrutinized the COX inhibitory capabilities of these extracts and saponin-rich fractions prepared therefrom. Molecular docking was employed to investigate the specific interactions between the identified saponins and COX enzymes. The analysis led to the annotation of 81 metabolites, among which saponins were predominant. The saponin-rich fraction of the fruit pericarp extract displayed the strongest COX-II inhibitory activity in the in vitro inhibition assay (IC50 value of 81.64 ± 3.98 μg/mL). The molecular docking study supported the selectivity of the identified saponins towards COX-II. The two major identified saponins, namely, proto-yamogenin 3-O-[deoxyhexosyl (1 → 2)] [hexosyl (1 → 4)] hexoside 26-O-hexoside and trigofenoside A, were predicted to have the highest affinity to the COX-II receptor site. In the present study, we focused on the identification of COX-II inhibitory saponins in fenugreek waste through an integrated approach. The findings offer valuable insights into potential anti-inflammatory and cancer chemoprotective applications of fenugreek waste.