Tannic Acid Content in the Cultured Diatom Skeletonema costatum (Greville) Cleve 1873, Isolated from the Romanian Black Sea Waters

Abstract

Skeletonema costatum is a dominant species in the spring phytoplankton composition of the Romanian Black Sea coastal waters. The species was isolated during a spring bloom and maintained in laboratory conditions for the past 10 years. The biomass was obtained by culturing the species in growth medium for diatoms under continuous light and shaking for four days. The biomass was harvested by vacuum filtration and lyophilized. The tannic acid content was determined by the HPLC method in the methanolic extract of S. costatum biomass. The tannic acid content was 0.46% (4.6 mg tannic acid/g biomass). Also, the chromatogram showed the presence of other separate, but unidentified organic compounds, which may contribute to its therapeutic potential. Our results justify further research to highlight S. costatum antioxidant and antimicrobial activity.