Characterization of compounds of Hordeum vulgare (Poaceae) and Tridax procumbens L. (Asteraceae) in the control of cyanobacteria cyanotoxins producer and weeds

Author(s)

Gustavo Franciscatti Mecina

• Document type: Doctoral Thesis
• Press: Araraquara. 2018-09-12.
• Institution: Universidade Estadual Paulista (Unesp). Instituto de Química. Araraquara
• Defense date: 0000-00-00
• Advisor: Maria do Carmo Bittencourt de Oliveira; Regildo Márcio Gonçalves Silva

Abstract

The eutrophication of aquatic environments is a serious environmental problem, mainly due to the consequent increase in blooms of toxic cyanobacteria, which can negatively affect animal and human health. As an alternative to commonly used synthetic algaecides, chemical compounds from plants are employed to control microorganisms that are of public health importance. This study aimed to evaluate the effect of extract, fractions and isolated compounds of Tridax procumbens L. and Hordeum vulgare L. (barley) on the growth of Microcystis aeruginosa (Kützing) Kützing. (strain BCCUSP232), as well evaluating the alterations in the antioxidant metabolism by the determination of the H2O2 content, lipid peroxidation and of the enzymes of the antioxidant metabolism to establish the possible mechanism of action. It was found that the different extracts interfered with cell density, reducing the same on the first reading after of its application and in its different concentrations, similar response was observed for the fractions 3 of the T. procumbens extract and for the three flavonoid compounds isolated from the same, already for fractions 1 and 2 of the extract of H. vulgare, a significant reduction when compared to the control was observed only for the highest concentration on the 10th day of the bioassay. The production of reactive oxygen species (ROS), lipid peroxidation, and antioxidant enzyme activities was altered when the colonies were exposed the different concentrations of extract and fraction 3 of T. procumbens and extract and fractions 1 and 2 of H. vulgare. The MCs content of the cyanobacterium was negatively affected by the presence of the extract, fractions and isolated flavonoids. The results of the present study show that T. procumbens and H. vulgare has secondary metabolites that are capable of interfering with the physiology and microcystins production of M. aeruginosa. These characteristics are promising for the control of this noxious cyanobacterium in aquatic ecosystems. (AU)

• FAPESP's process: 14/17126-0 - Characterization of compounds Hordeum vulgare (Poaceae) and Tridax procumbens L. (Asteraceae) for the development of alternative control method of cyanobacteria cyanotoxins producer
• Grantee: Gustavo Franciscatti Mecina
• Support Opportunities: Scholarships in Brazil - Doctorate