Metabolomics and Biological activities of Chlorella vulgaris grown under modified growth medium (BG11) composition

Abstract

The aim of this work was to determine the biochemical compounds and evaluate the biological activities of Chlorella vulgaris cultivated under a biotic stress condition (various Zinc and Cupper conc.). The growth rate was recorded as well as determination of active compounds, pigments and defense enzymes, in addition to the biological activities as antioxidant, antimicrobial and anticancer. The obtained results revealed that, higher copper concentrations [0.632 mg /L (Cu)] showed an inhibitory effect to growth while 1.76 mg /L (Zn) enhanced growth which reached its maximum at 25th day of cultivation. Furthermore, combination of 0.88mg/L (Zn) and 0.316mg /L (Cu) induced an increase in growth rate, catalase, tannins, lipid peroxidation and glutathioneS-transferase and a decrease in flavonoids, phenolic content, protein and antioxidant activity. Also, the results of antioxidant activity showed that, elevation of Zn conc. induced an augmentation of antioxidant activity either by DPPH(2, 2 diphenyl-1-picrylhydrazyl) or ABTS (2, 2’- azino-bis ethylbenzthiazoline-6-sulfonic acid), with maximum activity at 0.88 mg/L Zinc conc. (89.91%) even exceeded those of control (85.62%). While more elevated Zn conc. (1.76 mg/L) induced lower activity when compared with synthetic antioxidant standard (Butylated hydroxyl toluene, BHT). Concerning antimicrobial activity, Gram +ve bacteria, Staphylococcusaureus recorded moderate activity in sulfur-contained extract. Cytotoxicity of three cancer cell lines was inversely proportional to extracts conc. used, where the higher conc. (500µg/ml) showed the lowest cell viability of the tested cell lines which ranged from 22.06 to 69.89%. 0.316 mg/L (Cu) of conc. 500 µg/ml recorded the lowest cell viability of (32.166 %) in breast cell line , (22.06%) in colon cell line, and 27.18 06%) in cervical cell line.