Marennine, the still mysterious pigment with antibacterial activities from Haslea ostrearia

Lila Zebiri 1,2, Charlotte Falaise 2, Cyrille François 3, Marie-Agnès Travers 3, Jens Dittmer1, Pamela Pasetto1, Jean-Luc Mouget2

 

1 Institut des Molécules et Matériaux du Mans, Université du Maine - Avenue Olivier Messiaen - 72085 LE MANS Cedex 9, France,

2 Mer-Molécules-Santé, Université du Maine - Avenue Olivier Messiaen - 72085 LE MANS Cedex 9, France,

3 Ifremer, SG2M-LGPMM, Laboratoire de Génétique et de Pathologie des Mollusques Marins, Avenue Mus de Loup, La Tremblade 17390, France

 

Haslea ostrearia is a tychopelagic marine diatom distributed worldwide, which erratically settles in oyster-ponds. This diatom synthesizes and releases in the external medium a blue-green pigment called marennine, which is responsible for oysters greening. It has also been demonstrated that marennine displays several biological activities such as antiviral1 or antibacterial2,3. Although the pigment has been known and studied for many years, the complete molecular structure has not been fully elucidated yet. Pouvreau et al.established a protocol to extract and purify the pigment4, and provided various information regarding the molecular weight, the absorption in the UV-visible region and the chemical nature, possibly polyphenolic5.

In the present study, chemical characteristics of purified samples of marennine and its antibacterial activities were further investigated.

Cyclic voltammetry (CV) analysis of marennine coupled with UV-visible spectrometry (in NaCl solutions and at different pH values, scanning between 200 and 800 nm) showed the presence of two reversible redox systems similar to those found in quinones: one is in a highly conjugated and easily reducible