Involvement of the NO-sGC/cGMP signaling pathway in the vasodilator and hypotensive effects of the ethanol-soluble fraction from Citrullus lanatus (Thunb.) Matsum. & Nakai seeds in rats.

The therapeutic management of hypertension involves both pharmacological and non-pharmacological interventions. However, control remains inadequate despite effective treatments, often due to poor adherence. In this context, herbal medicines offer a complementary approach to conventional therapy. Citrullus lanatus (watermelon) seeds, frequently discarded as agricultural byproducts, represent a promising source of bioactive compounds. This study evaluated the cardiorenal properties of three extracts obtained from dried C. lanatus seeds, including an ethanol-soluble fraction from an aqueous extract (ESCL), a hydroethanolic extract, and an aqueous extract obtained by turbolysis. These extracts were chemically characterized using liquid chromatography coupled with diode array detection and mass spectrometry. Diuretic and hypotensive activities were assessed in vivo in normotensive female Wistar rats, while vasodilatory mechanisms were investigated ex vivo in isolated mesenteric vascular beds. Among the preparations screened, only the ESCL fraction displayed significant cardiorenal activity, reducing blood pressure and peripheral vascular resistance. Mechanistic investigation revealed that this vascular response is mediated via the nitric oxide/soluble guanylate cyclase/cyclic guanosine monophosphate signaling cascade. These findings highlight the pharmacological potential of ESCL as a candidate for the development of novel hypotensive agents.