Assessment of Bioactive Potential of Aqueous Protein Extracts from Diatoms Nitzschia laevis, Spirulina platensis, and Chlorella vulgaris

ABSTRACT

The bioactivities of protein extracts from Nitzschia laevis, Spirulina platensis, and Chlorella vulgaris were evaluated in vitro. Free radical scavenging potential, reducing power, oxygen radical absorbance capacity, superoxide anion radical, xanthine oxidase inhibition, and potential to inhibit angiotensin 1-converting enzyme (ACE) and acetylcholinesterase enzyme (AChE) were studied. Nitzschia protein extracts showed the highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activities, reducing power, and ACE inhibitory activity. Spirulina’s proteins showed the highest 2,2′-Azino-bis (3 ethylbenzothiazoline-6-sulfonic acid) (ABTS) scavenging activity, xanthine oxidase, and AChE inhibition activities. Aqueous protein extracts from Nitzschia, Spirulina, and Chlorella showed in vitro antioxidant, anti-ACE, and anti-AChE activities, suggesting possible new sources of bioactive proteins of different phyla with nutraceutical and pharmaceutical potentials.

KEYWORDS:

• Nitzschia
• antioxidant
• ACE
• acetylcholinesterase
• Spirulina
• Chlorella

Acknowledgments

The first author acknowledges funding from King Abdullah Scholarships Program and support from the Saudi Arabian Cultural Mission in New Zealand, School of Chemical Sciences, Dr. Angus C. Grey from Biomedical Imaging Research Unit (BIRU) for his help using MALDI-TOF mass spectrometer, and Dr Simon Swift and Mrs Janesha Perera from Department of Molecular Medicine and Pathology, School of Medical Sciences for their ongoing help and support with antimicrobial activity tests conducted at the University of Auckland.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplemental Material

Supplemental data for this article can be accessed at https://doi.org/10.1080/10498850.2019.1571551.