<i>In vitro</i> inhibition of Hepatitis C virus protease and antioxidant by flavonoid glycosides from the Saudi costal plant <i>Sarcocornia fruticosa</i>

<p>A new flavonol triglycoside, rhamnazin 3-O-2<sup>G</sup>-rhamnorutinoside or rhamnazin 3-<i>O</i>-(2″,6″-<i>O</i>-α-di-rhamnosyl)-β-glucoside (<b>1</b>) was isolated along with known flavonols, rhamnazin 3-<i>O</i>-rutinoside (<b>2</b>), rhamnazin 3-<i>O</i>-(6″-<i>O</i>-α-rhamnosyl)-β-galactoside (<b>3</b>), isorhamnetin 3-<i>O</i>-(6″-<i>O</i>-α-rhamnosyl)-β-galactoside (<b>4</b>), isorhamnetin 3-<i>O</i>-(2″,6″-<i>O</i>-α-di-rhamnosyl)-β-galactoside (<b>5</b>), and isorhamnetin (<b>6</b>), and allantoin (<b>7</b>) from the aqueous methanol extract of <i>Sarcocornia fruticosa</i> leaves. Spectral analyses (UV, MS, and NMR) and acid hydrolysis were used to determine the structures. These compounds in this study except <b>6</b> were reported for the first time from the genus <i>Sarcocornia</i>. The extract and flavonol glycosides (<b>1–5</b>) were evaluated for antioxidant and inhibition of HCV protease enzyme. Rhamnazin triglycoside (<b>1</b>) was shown to have a potent HCV protease inhibitor with IC<sub>50</sub> value 8.9 μM, while isorhamnetin di- and triglycosides (<b>4</b> and <b>5</b>) were effectively scavenged DPPH radicals with IC<sub>50</sub> values 3.8 and 4.3 μM, respectively.</p>