Phytochemical analysis of Passiflora quadrangularis L. and its potential role in hypertension and cardiac remodeling

Context: Hypertension is a major risk factor for cardiovascular disease and stroke, contributing significantly contributing to increased morbidity and premature mortality worldwide. Further research into new treatments and the pathophysiology of this disease is necessary. Aims: To isolate and identify bioactive fractions and compounds from Passiflora quadrangularis L., and to evaluate their antihypertensive and anti-remodeling effects in rat models. Methods: The P. quadrangularis extract was fractionated and analyzed through chromatographic and spectroscopic techniques. Various fractions and the total extract were used to treat spontaneously hypertensive rats (SHRs), whose blood pressure was measured weekly using a non-invasive method. Vascular reactivity assays were then performed, and morphometric and morphological parameters were calculated. In Wistar rats, vascular reactivity assays were performed using isolated fractions and compounds. Results: Nine compounds were isolated in the phytochemical analysis. Evaluation of the antihypertensive effect of the treatments revealed significant differences versus the control group. Concentration–response curves of all treatments shifted along the concentration axis, indicating improved EC₅₀ values, with significant differences compared to the control group in both SHRs and Wistar rats. Histological analysis revealed a reduction in cardiac and vascular fibrosis across all treatment groups. Conclusions: Phytochemical analysis identified novel compounds for P. quadrangularis. In vivo studies utilizing SHRs revealed that P. quadrangularis extract and its fractions significantly attenuated systolic blood pressure, improved endothelium-dependent relaxation, and mitigated cardiac hypertrophy and vascular remodeling. Organ bath assays suggested the involvement of multiple pathways, including NO-cGMP signaling, activation of K⁺ channels, and modulation of adrenergic and muscarinic receptors.