VOLUME 14 (Supplement)

Chemical Composition and In vitro Antioxidant and Antibacterial Properties of the Edible Cyanobacterium, Nostoc commune Vaucher

The nutritional composition of the edible cyanobacterium, Nostoc commune Vaucher, was evaluated, including its potential antioxidant and antibacterial properties. Results showed that the elemental composition were in decreasing order as: Ca > Fe > Mg > Na > K > Mn > Zn > Cu > Cr > Pd > Cd. Proximate composition of N. commune showed high carbohydrate and protein content with estimated value of 65.27 ± 0.09% and 21.51± 0.06%, respectively. The Nostoc commune (NC) methanolic crude extract had an average total phenolic content of 88.2 mg, as gallic acid equivalent (GAE)/ 100 g, and a mean value of 17.45 mg as quercetin equivalent/100 g for total flavonoids. Relative antioxidant efficiency of N. commune exerted potent copper reducing activity with IC50 value of 10.84 ± 0.015 μg GAE/mL. The tested algal extract exhibited antioxidant activity that is dose-dependent and positively correlated to its phenolic content. Acidified methanolic extract of N. commune showed an extended spectrum of inhibitory activity against Gram-positive bacteria, Staphylococcus aureus, Staphylococcus epidermidis and Bacillus cereus with MIC (minimum inhibitory concentration) of 125 and 250 μg/mL, respectively. Also, it is moderately active against Bacillus cereus with MIC and MBC (minimum bactrericidal concentration) of 500 and 1000 μg/mL. This study is useful in the context of improved utilization of N. commune as alternative source of functional products possessing multi-bioactivities with potential use in food and pharmaceutical industries, being not only economically advantageous but also environmentally friendly.