A new diacetylated flavonol triglycoside from the aerial parts of <i>Actinidia polygama</i>

<p>Phytochemical investigation of a methanolic extract of aerial parts <i>Actinidia polygama</i> Miq. led to the isolation of one new diacetylated flavonol triglycoside, kaempferol 3-<i>O</i>-[<i>α</i>-L-rhamnopyranosyl(1→3)-(4-<i>O</i>-acetyl)-<i>O</i>-α-L-rhamnopyranosyl(1→6)-(2-<i>O</i>acetyl)-<i>O</i>-<i>β</i>-D-galactopyranoside] (<b>1</b>) along with 12 known compounds (<b>2</b>–<b>13</b>). The chemical structures were determined using their spectroscopic data including 1D and 2D NMR. To the best of our knowledge, this is the first time that compounds <b>2</b>, <b>4</b>, <b>6</b>, <b>7</b>, <b>8</b>, <b>9</b>, <b>12</b> and <b>13</b> are isolated from this plant. All purified compounds were tested for free radical scavenging effect using DPPH and ABTS assays. Our results showed that compounds <b>4</b>, <b>6</b>, <b>7</b> and <b>13</b> have potential antioxidative effect for scavenging both DPPH^<b>·</b> and ABTS^<b>·+</b> radicals that are comparable with those of ascorbic acid used as positive control, whereas compounds <b>1</b> and <b>2</b>, which are di- and mono- acetylated flavonol triglycoside respectively, were not found to be potent scavengers of free radicals.</p

Cyclocurcumin, an Antivasoconstrictive Constituent of <i>Curcuma longa</i> (Turmeric)

Despite the increasing attention on the therapeutic potential of <i>Curcuma longa</i> (turmeric), the biological activities of curcuminoids other than curcumin are not well understood. Here, we investigated antivasoconstrictive activities of <i>C. longa</i> extract and its ingredients using freshly isolated rat aortic rings. <i>C. longa</i> extract significantly suppressed agonist-stimulated vasoconstriction, and cyclocurcumin was found to be the most potent (IC₅₀ against phenylephrine-induced vasoconstriction: 14.9 ± 1.0 μM) among the 10 tested ingredients including four curcuminoids. Cyclocurcumin significantly inhibited contraction of vascular smooth muscle, which was mediated by the suppression of myosin-light-chain phosphorylation and calcium influx via the L-type calcium channel. The inhibitory effect of cyclocurcumin was observed to be reversible and without cytotoxicity. Taken together, we demonstrated that cyclocurcumin, a bioactive ingredient in <i>C. longa</i>, may have a therapeutic potential as a novel antivasoconstrictive natural product