1-Hydroxybisabola-2,10-dien-4-one

We isolated the novel vasoactive marine natural products, (5E,10E)-14-hydroxy-2,6,10-trimethylpentadeca-5,10-dien-4-one (4) and sargachromenol D (5), from Sargassum siliquastrum collected from the coast of the East Sea in South Korea by using activity-guided HPLC purification. The compounds effectively dilated depolarization (50mMK+)-induced basilar artery contraction with EC50values of 3.52±0.42 and 1.62±0.63μM, respectively, but only sargachromenol D (5) showed a vasodilatory effect on endothelin-1 (ET-1)-induced basilar artery contraction (EC50=9.8±0.6μM). These results indicated that sargachromenol D (5) could act as a dual antagonist of l-type Ca2+channel and endothelin A/B2receptors. Moreover, sargachromenol D (5) lowered blood pressure in spontaneous hypertensive rats (SHRs) 2h after oral treatment at a dose of 80mg/kg dose and the effect was maintained for 24h. Based on our ex vivo and in vivo experiments, we propose that sargachromenol D (5) is a strong candidate for the treatment of hypertension that is not controlled by conventional drugs, in particular, severe-, type II diabetes-, salt-sensitive, and metabolic disease-induced hypertension.

One new bisabolane-type sesquiterpenoid, together with four known bisabolane-type sesquiterpenoid derivatives and seven phenolics, was isolated from the rhizomes of Curcuma longa. Their structures were elucidated by extensive spectroscopic (IR, HR-ESI-MS, and NMR) data analysis. The possible anti-Alzheimer's disease (AD) activities of the isolated compounds were also evaluated using Caenorhabditis elegans AD pathological model, and 1β-hydroxybisabola-2,10-dien-4-one had the highest possible anti-AD activity.