Chemical components and biological activities of two freshwater green algae from Ordu, Turkey

Abstract

Objective: Scientists are looking for new resources which have biological activities. The present study was planned to evaluate the antioxidant and antimicrobial activity of ethanol and acetone extracts, as well as the volatile compounds of two freshwater green algal species Spirogyra spp. and Zygnema stellinum (Vaucher) C. Agardh belonging to Zygnemaphyceae (Conjugatophyceae) obtained from Ordu University Campus wetlands.

Methods: The extracts were tested in vitro for their antimicrobial effects using disc diffusion method. Total phenolic content and the antioxidative activity according to FRAP and DPPH methods of the extracts were also determined. The secondary metabolites from the investigated extracts were identified using GC-MS.

Results: The extracts dramatically inhibited almost all tested microorganisms. The antimicrobial activity of the acetone extract of the Zygnema against C. albicans was found as more higher than positive control Nystatin. In accordance with antimicrobial activity, the highest total phenolic content was also determined in the presence of the acetone extract of the Zygnema. Furthermore the highest FRAP value and the lowest EC50 (mg/mL) value were calculated for the same extract. The main components of the all consisted of dimethyl and diethyl ester of 1,2-benzenedicarboxylic acid. However, the abundance of these metabolites in the extracts was not associated with antimicrobial or antioxidant activity. Biological activities of these algal species could be attributed to chemicals such as 1-Pentadecene and 1-Tetradecene which were present in smaller amounts.

Conclusion: Investigated algal species can be evaluated to use in biotechnological applications such as food industry and medicine.