Abstract
The growth response and biological activity of the cyanobacterium Oscillatoria sancta were investigated in starvation conditions. Oscillatoria sancta growth potential was examined on BG11 and Zarrouk's media. Zarrouk's medium supported the maximum growth of the test cyanobacterium. Zarrouk's medium composition was modified by excluding CaCl2 center dot 2H(2)O, NaCl, EDTA (Na), micronutrients, and replacing sodium nitrate with urea. Using Zarrouk's medium and three different concentrations of modified Zarrouk's media (Treatments 1-3), the growth response of Oscillatoria sancta (MZ366482) was examined and compared. Zarrouk's medium and modified Zarrouk's medium at 12.5% nutrient concentration had non-significant differences in both the dry weight biomass and total protein of Oscillatoria sancta. Oscillatoria sancta crude biomass extracts grown on Zarrouk's and modified Zarrouk's media (T3) inhibited human breast cancer, pathogenic bacteria, and acetylcholinesterase activity. Oscillatoria sancta grown on T3 showed the most potency against MDA-MB-231 cells with an IC50 of 165.2 mu g mL(-1), antibacterial activity only against Bacillus cereus (17.2 mm) and Staphylococcus aureus (15.3 mm), and acetylcholinesterase inhibition activity by 60.7%. Thus, it is advisable to use the 12.5% nutrient concentration of modified Zarrouk's medium as a reduced-cost medium for mass cultivation of Oscillatoria sancta with potential anticancer, antibacterial diseases, and anti-Alzheimer purposes.