4-Hydroxybenzyl isothiocyanate as a novel hydrogen sulfide-releasing antihypertensive agent

Naturally occurring isothiocyanates can release hydrogen sulfide (H₂S), a cardioprotective gasotransmitter involved in vascular tone regulation; however, the vascular actions of 4-hydroxybenzyl isothiocyanate (HBITC), derived from benzyl glucosinolates, have not been functionally characterized. We investigated whether HBITC exerts vasorelaxant, coronary vasodilatory, and antihypertensive effects through H₂S-dependent signaling mechanisms, including Kv7 channel activation, transient receptor potential ankyrin 1 stimulation, and modulation of endogenous H₂S-producing enzymes (cystathionine γ-lyase, cystathionine β-synthase, and 3-mercaptopyruvate sulfurtransferase). H₂S release was quantified fluorometrically in human aortic smooth muscle cells using Washington State Probe-1, membrane hyperpolarization was assessed with bis (1,3-dibutylbarbituric acid) trimethine oxonol, and vasorelaxation was examined in isolated rat aortic rings under intact, endothelium-denuded, and Nω-nitro-L-arginine methyl ester-treated conditions. Coronary flow was measured in Langendorff-perfused hearts, and the effects of blood pressure were evaluated in normotensive and spontaneously hypertensive rats. HBITC induced concentration-dependent intracellular H₂S release and robust membrane hyperpolarization, comparable to the large-conductance Ca²⁺-activated K⁺ channel (Kv) opener. It produced direct, endothelium-independent vasorelaxation, potentiated by intact endothelium and attenuated by nitric oxide synthase inhibition, reversibly suppressed noradrenaline-evoked vasoconstriction, restored angiotensin II-impaired coronary flow, and selectively reduced systolic blood pressure in spontaneously hypertensive rats. Collectively, these findings identify HBITC as a novel H₂S-releasing vasorelaxant with antihypertensive potential and support its development as a dietary-derived scaffold for vasoprotective therapeutics. SIGNIFICANCE STATEMENT: This study identifies 4-hydroxybenzyl isothiocyanate as a previously uncharacterized dietary hydrogen sulfide donor that produces potent vasorelaxation, restores coronary flow under vasospastic conditions, and selectively lowers blood pressure in hypertensive animals. By engaging Kv7 channels, transient receptor potential ankyrin 1 signaling, and endothelial nitric oxide-hydrogen sulfide crosstalk, 4-hydroxybenzyl isothiocyanate highlights a promising natural scaffold for next-generation antihypertensive and vasoprotective therapies.