Marennine, the still mysterious pigment from Haslea ostrearia

Ilhem. Zebiri 1,2, Pamela. Pasetto1, Jean-Luc. Mouget2, Jens. Dittmer1

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

 

Keywords : Cyclic voltammetry analysis, Haslea ostrearia, marennine

 

Haslea ostrearia is a tychopelagic marine diatom distributed worldwide, which erratically settles in oyster-ponds. This diatom synthesizes and releases into the external medium a blue-green pigment called marennine, which is responsible for oyster greening. Although the pigment has been known and studied for many years, the complete molecular structure has not been fully elucidated yet, but Pouvreau et al.established a protocol to extract and purify the pigment[1], and provided various information regarding the molecular weight, the absorption in the UV-visible region and the chemical nature, possibly polyphenolic[2]. In the present study, we focused on some chemical characteristics of pure marennine. 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 chemical environment, the other is less reactive. The possible presence of quinone groups was confirmed by the colorimetric “inner ring quinone” test[3], which was positive. Additional information about marennine chemical structure were gained carrying out other tests (zeta potential, acetylation and acid-base properties) and trying novel purification procedures.

 

[1] J.-B. Pouvreau, M. Morançais, G. Massé, P. Rosa, J.-M. Robert, J. Florence, and P. Pondaven, J. Appl. Phycol. 2006, 18, 769–781.

[2] J.-B. Pouvreau, M. Morancais, F. Fleury, P. Rosa, L. Thion, B. Cahingt, F. Zal, J. Fleurence, and P. Pondaven, J. Appl. Phycol. 2006, 18, 757-767.

[3] E. Sawicki and W. Elbert, Analytica Chimica Acta 1960, 22, 448-451.