Flavonoids in Cucurbitaceae herbs: targeted HPLC-PDA-mS profiling of wild and cultivated Cucumis, Echinocystis, and Melothria species and their pancreatic lipase inhibitory potential.

Green waste from Cucurbitaceae agriculture is a common but underutilised resource. In this study, we performed targeted HPLC-PDA-MS profiling to analyse the flavonoid composition of Cucumis africanus L.f., Cucumis anguria L., Cucumis dipsaceus Ehrenb. ex Spach, Cucumis melo L., Cucumis sagittatus Wawra & Peyr., Echinocystis lobata (Michx.) Torr. & A.Gray, Melothria pendula L., and Melothria scabra Naudin herbs. Fifty-seven compounds were identified, including derivatives of apigenin, luteolin, kaempferol, quercetin, and isorhamnetin, as acylated and non-acylated C-, O-, and C,O-glycosides, many of which were identified for the first time in these genera. Cultivated samples exhibited higher flavonoid content than wild plants, with E. lobata showing the highest values (72.25-120.42 mg/g) and Melothria species the lowest (1.02-6.33 mg/g). Cucurbitaceae extracts demonstrated inhibitory potential against human pancreatic lipase, with IC50 values of 31.16-1000 μg/mL, correlating with flavonoid levels. These findings suggest a new way to utilise agricultural byproducts as a source of bioactive flavonoids with antilipase potential.