Characterization of anti-dengue and cytotoxic activity of protein hydrolysates from the exophytic bacteria of brown algae Sargassum sp

The protein of exophytic bacteria Enterobacter agglomerans SB 5 (1) derived from Sargassum sp. was extracted and hydrolyzed by an enzyme to obtain bioactive peptides. The bioactivity of peptides was tested after being hydrolyzed with pepsin. Pepsin peptide fraction <3 kDa showed the activity of antidengue against Vero cells with the percentage of inhibition and CC50 value of 91% and 129 μg/ml, respectively. This fraction was toxic to shrimp larvae in the Lethal Concentration 50 (LC50) value of 1.77 μg/ml. Cytotoxic activity of pepsin peptide fraction <3 kDa against cervical cancer cells showed the LC50 value of 0.749 μg/ml. Protein precursors were identified using liquid chromatography- tandem mass spectrometry by searching for Peptides Mass Fingerprint. Sequence analysis of the peptide showed abundant leucine amino acid residue. This peptide sequence has never been reported so far, including its potential biological function as a new antidengue and anticancer agent.