Flavonoids as benign substitutes for more harmful synthetic chemicals - effects of flavonoids and their transformation products on algae

Publikation: Beiträge in ZeitschriftenZeitschriftenaufsätzeForschungbegutachtet


Flavonoids, a group of plant secondary metabolites, are seen as chemicals for pharmaceutical, nutraceutical, and pesticidal applications. Due to their natural origin, anticipated low ecotoxicity and non-persistence in the environment, they are considered as benign substitutes for synthetic chemicals. However, data on ecotoxicity is still scarce. Therefore, this study aimed for a better understanding of the bioactivity of flavonoids and thus allowing a better evaluation of their potential as benign substitutes. The growth inhibition of the microalgae Raphidocelis subcapitata induced by 13 flavonoids, 10 flavonoid mixtures, and 4 flavonoid transformation products was determined according to the OECD guideline 201. EC50 values of flavonoids ranging from 0.7 to 22 mg/L were moderate in comparison to the synthetic algaecides terbutryn and diuron. Mixtures of flavonoids behaved in a dose-addition manner. Moreover, the fate of 11 selected flavonoids during the growth inhibition test was analyzed by analytical methods (HPLC-UV/vis and HPLC-HRMS). Concentration monitoring revealed fast but incomplete degradation of 8 flavonoids. Overall, 25 transformation products of the degrading flavonoids were identified including 5,7-dihydroxychromone. Comparison of structural features indicate that the combination of a methoxy group and a lacking hydroxy group at C3 decreased degradation rates. Growth inhibition of the 4 tested transformation products was weaker than of their respective parent flavonoids. Taken together, the results suggest low ecotoxicity of flavonoids and promote further research towards their utilization as benign substitutes.
ZeitschriftSustainable Chemistry and Pharmacy
Anzahl der Seiten19
PublikationsstatusErschienen - 01.04.2024