Abstract
Flavonoids are natural polyphenolic compounds produced by many aquatic plants and released in their environments. In this study, the effects of several aquatic flavonoids on cyanobacterial Microcystis aeruginosa, especially in relation to the cell growth, photosynthetic activity, cell morphology, and cell membrane integrity, were investigated. Significant growth inhibition was observed when the cyanobacteria were exposed to three flavonoids, namely, 5,4'-dihydroxyflavone (DHF), apigenin, and luteolin. Luteolin reduced the effective quantum yield, photosynthetic efficiency, and maximal electron transport rate by 70%, 59% and 44%, respectively, whereas 5,4'-DHF and apigenin slightly affected these parameters, which implies that luteolin disrupts the photosynthetic system. Moreover, 5,4'-DHF and apigenin compromised the membrane integrity, and induced membrane depolarization in 52% and 38%, and permeabilization in 30% and 44% of the cells, respectively. The 5,4'-DHF and apigenin showed more pronounced effects on M. aeruginosa morphology and membrane integrity, compared to the luteolin. These results suggest that flavonoids could have significant effects on growth and physiological functions in cyanobacterial species.
Highlights
Flavonoids are low molecular weight natural polyphenolic chemicals that play important roles in various metabolic processes in photosynthesizing cells, and their existence is widespread in the plant kingdom [1]
Microscopic analyses revealed that the three flavonoids showed significant concentration-dependent inhibition of M. aeruginosa growth (p < 0.05) after 5-d incubation (Figure 1)
Apigenin and 10 mg/L luteolin based on the preliminary experiments), and the inhibition rates were
Summary
Flavonoids are low molecular weight natural polyphenolic chemicals that play important roles in various metabolic processes in photosynthesizing cells, and their existence is widespread in the plant kingdom [1]. Over 5000 flavonoids, from different tissues and parts of plants, have been characterized, including leaves, flowers, stems, pollen and seeds [2]. Flavonoids are released into the environment by growing plants especially when they are under physiological stress, or from decomposing parts of plants. Flavonoids have multiple unique biological properties, including antioxidant, anti-inflammatory, antibacterial, antifungal effects just to name a few [12,13]. Many studies focused on the effects of flavonoids on microbes in medicine or the food industry, ; their interactions with aquatic organisms in the natural environment are not adequately studied
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
