Structural Characterization and Anti-HSV-1 and HSV-2 Activity of Glycolipids from the Marine Algae <em>Osmundaria obtusiloba</em> Isolated from Southeastern Brazilian Coast

Abstract

Glycolipids were extracted from the red alga <em>Osmundaria obtusiloba </em>from<em> </em>Southeastern Brazilian coast. The acetone insoluble material was extracted with chloroform/methanol and the lipids, enriched in glycolipids, were fractionated on a silica gel column eluted with chloroform, acetone and then methanol. Three major orcinol-positive bands were found in the acetone and methanol fractions, being detected by thin layer chromatography. The structures of the corresponding glycolipids were elucidated by ESI-MS and ¹H/¹³C NMR analysis, on the basis of their tandem-MS behavior and HSQC, TOCSY fingerprints. For the first time, the structure of sulfoquinovosyldiacylglycerol from the red alga <em>Osmundaria obtusiloba</em> was characterized. This molecule exhibited potent antiviral activity against HSV-1 and HSV-2 with EC₅₀ values of 42 µg/mL to HSV-1 and 12 µg/mL to HSV-2, respectively. Two other glycolipids, mono- and digalactosyldiacylglycerol, were also found in the alga, being characterized by ESI-MS/MS. The structural elucidation of algae glycolipids is a first step for a better understanding of the relation between these structures and their biological activities.

Keywords

• &lt;em&gt;Osmundaria&lt;/em&gt; &lt;em&gt;obtusiloba&lt;/em&gt;
• red alga
• glycolipids
• sulfoquinovosyldiacylglycerol
• anti-herpes simplex activity