Free Radical Scavenging Properties and Induction of Apoptotic Effects of FA Fraction Obtained after Proteolysis of Bioactive Peptides from Microalgae Synechococcus sp. VDW

Abstract

SUMMARYThis study aims to determine the antioxidant activity of bioactive peptides derived from Synechococcus sp. VDW cells cultured for 21 days. Synechococcus sp. VDW protein hydrolysates were prepared with trypsin and purified by ultrafiltration with molecular mass cut-off membranes of 10, 5 and 3 kDa. The M<3 kDa (FA) fraction had the highest 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and 2,2’-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities, with IC50 values of (11.5±0.3) and (13.6±0.2) µg/mL, respectively. The FA fraction was separated by reversed phase HPLC to yield four subfractions (F1–4). The F4 subfraction showed the highest maximum ABTS radical scavenging activity (3.55±0.61) % and it was selected for further analysis by electrospray ionisation quadrupole time-of-flight mass spectrometry (ESI-Q-TOF-MS/MS) based on de novo peptide sequencing. Five antioxidant peptides were identified, of which AILESYSAGKTK had the highest ABTS radical scavenging activity. Furthermore, the FA fraction showed high cytotoxic activities against human cancer-derived cell lines, especially the colon cancer cell line (SW620) with an IC50 value of (106.6±21.5) µg/mL, but not the untransformed Wi38 cell line. The FA fraction activated the apoptotic pathway in SW620 cells after treatment for 24, 48 and 72 h, with the highest activities of caspases-3, -8 and -9 being observed after treatment for 72 h. These findings suggested that microalgae Synechococcus sp. VDW may be used to develop natural anticancer drugs.

Microalgae-based wastewater treatment for developing economic and environmental sustainability: Current status and future prospects

“…Microalgae are high in nutritional value because they contain all of the essential amino acids that mammals are unable to produce. Recently, peptides derived from the enzymatic hydrolysis of various dietary proteins have been shown to have a wide range of bioactivities, and there have been numerous papers on anti-oxidants and anti-cancer properties ( Sheih et al, 2010 ; Ko et al, 2012 ; Zhu et al, 2017 ; Suttisuwan et al, 2019a ; Suttisuwan et al, 2019b ; Moaveni et al, 2022 ). For example, Angiotensin-converting enzyme (ACE) inhibitory and antioxidant properties from microalgae C. vulgaris were reported by Sheih et al, 2010 ) and they then discovered that the peptide fraction isolated from pepsin hydrolyzed algae protein waste had strong dose-dependent antiproliferation and induced post-G1 cell cycle arrest in human gastric cancer cell lines AGS.…”

Exploring the potential applications of biopeptides from seaweeds, insects, and food wastes: mechanisms, utilisation, and industry implications

“…The proteins of seaweeds are also diverse along with different compositions and contents according to species, environmental conditions, and seasons, thus affecting the functionality of generated peptides (Cermeño et al ., 2020). Functional food development can incorporate seaweed peptides (based on their obtainment from Synechococcus , Tetradesmus , and Spirulina ) because they have been documented to possess antioxidant, anticancer, antihypertensive, and immunomodulatory bio‐functions (Indumathi & Mehta, 2016; Fan et al ., 2017; Zheng et al ., 2017; Ovando et al ., 2018; Suttisuwan et al ., 2019; Zhang et al ., 2021; MubarakAli et al ., 2022). This is described in Table S1.…”