Phytochemical analysis and biological activity evaluation of the hydromethanolic extract of Fenugreek (Trigonella foenum-graecum L.) seeds locally cultivated In El-Oued Region, Algeria

Abstract

Fenugreek (Trigonella foenum-graecum L., Fabaceae) is a leguminous spice and medicinal plant traditionally cultivated in many regions of the world and in North African countries and Algeria, yet the phytochemical and biological value of locally grown seeds remains insufficiently documented. The aim of this work was to characterise the hydromethanolic extract of T. foenum-graecum L. seeds harvested in the El-Oued region (Hassani Abdelkrim, southeast Algeria) and to evaluate its in-vitro antioxidant, antidiabetic and anti-Alzheimer potential. Air-dried, ground seeds were macerated in methanol/water (75:25, v/v) to obtain the crude extract, which was used to determine total phenolic, total flavonoid and condensed tannin contents by the Folin–Ciocalteu, aluminium chloride and vanillin–HCl methods, respectively. The phenolic and bioactive profile was established by ultra-performance liquid chromatography coupled to electrospray ionisation tandem mass spectrometry (UPLC–ESI–MS/MS), and biological activities were assessed through DPPH and ABTS•+ radical-scavenging assays, the o-phenanthroline reducing assay, and inhibition of α-amylase, α-glucosidase and acetylcholinesterase. The extract was particularly rich in polyphenols (88.57 ± 1.10 mg GAE/g), flavonoids (47.33 ± 3.90 mg QE/g) and condensed tannins (13.62 ± 1.59 mg CE/g), and twenty-two bioactive compounds, including phenolic acids and flavonoid glycosides, were identified by LC–MS/MS out of forty targeted standards. Significant radical-scavenging activity was recorded against DPPH• (IC50 = 77.37 ± 1.80 µg mL⁻¹) and ABTS•+ (IC50 = 29.49 ± 1.11 µg mL⁻¹). Notably, the extract inhibited α-amylase (IC50 = 264.03 ± 23.87 µg mL⁻¹) and α-glucosidase (IC50 = 245.14 ± 26.63 µg mL⁻¹) more strongly than the reference inhibitor acarbose, and exhibited measurable acetylcholinesterase inhibition (IC50 = 237.82 ± 35.25 µg mL⁻¹) compared with galantamine. These findings demonstrate that locally cultivated El-Oued fenugreek seeds constitute a promising antioxidant, antihyperglycaemic and neuroprotective phytotherapeutic and functional-food resource that could effectively replace imported material; nevertheless, the present results are restricted to in vitro models, and further in vivo, toxicological and clinical investigations are required to confirm efficacy, safety and optimal conditions of use.