Bioaccessible compounds from bean (Phaseolus vulgaris L.) landraces activate PPARγ in transiently transfected HepG2 cells

Common beans (Phaseolus vulgaris L.) are a nutrient-dense staple food associated with a reduced risk of noncommunicable chronic diseases. One proposed mechanism involves the modulation of nuclear receptors, particularly peroxisome proliferator-activated receptors (PPARs), which are key regulators of lipid and carbohydrate metabolism. In this study, we evaluated the effects of in vitro digested flours, secondary metabolite-enriched extracts (SMEEs), their fractions, and selected representative phytochemicals from 14 landraces and 2 commercial P. vulgaris samples to directly activate PPARs and other nuclear receptors using a luciferase reporter assay in transiently transfected HepG2 cells. We hypothesized that bioaccessible compounds from the digested landraces would directly activate PPARγ in HepG2 cells. Digested flours from landraces such as Magnum and Peumo significantly activated both PPARγ1 and PPARγ2, reaching values up to 1.54-fold higher than the controls (P < .05). Corresponding SMEEs showed stronger activities, with up to 2.32-fold activation compared to the controls (P < .05). In contrast, none of the polarity-based fractions or the major identified phytochemicals (kaempferol-3-O-glycoside, sojasaponin Ba and Bb) showed significant effects. These findings demonstrate that digested P. vulgaris matrices contain bioaccessible compounds capable of directly activating PPARγ in HepG2 cells, likely through synergistic interactions or unidentified constituents. This mechanistic evidence supports the functional relevance of traditional bean landraces in precision nutrition strategies targeting metabolic health.