Research Article: Evaluation of antioxidant and antibacterial activities of bioactive compounds extracted from the green microalgae (Dunaliella salina) on Enterococcus faecalis, Bacillus cereus, and Pseudomonas aeruginosa

The marine microalgae are producing modern technological compounds. Nowadays, algae are the most important natural resource of carotenoids. The production of strategic products in the modern pharmaceutical industry depends on these compounds. In this study, ethanol, aqua, and ethanol extracts: aqua (۵۰:۵۰) Dunaliella salina were extracted under different temperature (۱۰, ۳۰, and ۵۰°C) and times (۱۵ and ۳۰ min) with ultrasound waves. Also, the minimum inhibitory concentration (MIC) of antibiotics and the minimum bacterial concentration (MBC) of the extracts were obtained on Gram-positive and Gram-negative bacteria using the microdilution broth method. The results of antioxidant activity of D.salina showed that the highest antioxidant capacity was based on DPPH and IC۵۰ tests for microalgae (D. Salina) in ethanol and ethanol: water extraction (۱۵ minutes at ۳۰°C). ethanol (۳۰ min / ۳۰°C), ethanol: water and water (۱۵ min / ۱۰°C) and water (۳۰ min / ۱۰°C), respectively. IC۵۰ values ​​of ۰.۰۴۵, ۰.۰۹۶, ۰.۴۵, ۰.۴۸, ۰.۴۸ and ۰.۴۸۱ were measured as the highest antioxidant activity.  MIC in Gram-positive bacteria is related to ethanolic extract (۱۵ min/۳۰°C) and ethanol/water extract (۳۰ min/۳۰°C). MIC was obtained in gram-negative bacteria in ethanol/water (۳۰ min/۳۰°C) and water extract (۳۰ min/۱۰°C). The results of DPPH inhibition in the studied treatments (temperature and time) showed that the antioxidant activity in ethanol, ethanol: water (۱۵ minutes / ۳۰°C) and ethanol: water (۳۰ minutes / ۳۰°C) showed the best results A significant difference was observed in the MIC obtained from the aqueous ethanol treatments compared to other treatments (p≤۰.۰۵). Also, no significant difference was observed in the minimum MIC levels in the water treatments (p≥۰.۰۵). The concentration of MIC and MBC in this bacterium in all extracts are equal to each other. The best MIC in Gram-negative bacteria (P. aeruginosa) was observed in AE (۳۰ min/۳۰°C), and EWE (۳۰ min/۱۰°C) extracts at the rate of ۶.۲۵ μg/ mL; investigations showed that equal times in the extraction process Extracts with different temperatures do not have significant differences. According to the results of this study, the halophyte green microalga D. salina can be used as a potential source of antioxidant and antibacterial activity in the food and pharmaceutical industries.

کلیدواژه ها:

Dunaliella salina ، Antioxidant ، Anti-Bacterial ، Extracts ، Free Radical