Qualitative Content Analysis of Antioxidant-Centred Mechanisms Reported for Trigonella foenum-graecum: Linking Phytochemical Classes to Disease-Relevant Pathways

Background. Fenugreek (Trigonella foenum-graecum L.) seed extracts and their isolated constituents are credited with a very wide range of health-related effects, but the supporting studies are scattered across models, extract types and endpoints, and it is unclear how antioxidant activity relates to the other effects attributed to the plant.Objective. To examine, by qualitative content analysis, how experimental and clinical studies explain the pharmacological behaviour of fenugreek and its main constituents, with particular attention to antioxidant mechanisms. Methods. A codebook of phytochemical classes and outcome domains was built deductively and extended inductively while reading a corpus of in vitro, animal and human studies. Coded segments were condensed into categories and then themes. Trustworthiness was supported by an audit trail, repeated re-reading of the source texts and a negative-case check.Results. Six themes emerged: (1) redox buffering as the most common upstream explanation; (2) compound-specific signalling; (3) convergence of oxidative, inflammatory and metabolic pathways; (4) dependence of effect on extract type and plant part; (5) a favourable but incompletely characterised safety profile; and (6) translational gaps, above all the scarcity of pharmacokinetic data. Mechanistic explanations rested mainly on two compounds, 4-hydroxyisoleucine and diosgenin, whereas trigonelline, flavonoid C-glycosides, sotolone and galactomannan were comparatively under-examined. Antioxidant claims were usually inferred from enzyme and lipid-peroxidation markers rather than shown at compound level.Conclusions. Antioxidant activity functions in the literature as a connecting explanation rather than a demonstrated cause. Future work should characterise extracts chemically, test single compounds and combinations against defined redox and signalling endpoints, and add pharmacokinetic measurements before clinical claims are extended.