Microcystin accumulation and potential effects on antioxidant capacity of leaves and fruits of Capsicum annuum

ABSTRACT

Surface water, often used for irrigation purposes, may sometimes be contaminated with blooming cyanobacteria and thereby may contain their potent and harmful toxins. Cyanotoxins adversely affect many terrestrial plants, and accumulate in plant tissues that are subsequently ingested by humans. Studies were undertaken to (1) examine the bioaccumulation of microcystins (MCs) in leaves and fruits of pepper Capsicum annuum and (2) examine the potential effects of MCs on antioxidant capacity of these organs. Plants were irrigated with water containing MCs for a period of 3 mo. Data showed that MCs did not accumulate in leaves; however, in fruits the presence of the MC-LR (0.118 ng/mg dry weight) and dmMC-LR (0.077 ng/mg dry weight) was detected. The concentrations of MC-LR in fruit approached the acceptable guideline values and tolerable daily intake for this toxin. Lipid peroxidation levels and flavonoids content were significantly enhanced in both organs of treated plants, while total phenolic concentrations were not markedly variable between control and treated plants. Significant decrease in 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging capacity was noted for both organs. The levels of superoxide anion in fruits and hydroxyl radical in leaves were markedly reduced. Data suggest that exposure to MCs significantly reduced antioxidant capacity of experimental plants, indicating that MCs affected antioxidant systems in C. annuum.

Funding

The authors acknowledge the support of the Ministry of Education, Science and Technological Development of the Serbian Government (project number 176020) and COST Action ES1105, “CYANOCOST—Cyanobacterial blooms and toxins in water resources: Occurrence, impacts and management,” for adding value to this study through networking and knowledge-sharing with European experts in the field. The authors thank Dr. Diana Toivola, Åbo Akademi University, for her comments on the article.

Additional information

Funding

The authors acknowledge the support of the Ministry of Education, Science and Technological Development of the Serbian Government (project number 176020) and COST Action ES1105, “CYANOCOST—Cyanobacterial blooms and toxins in water resources: Occurrence, impacts and management,” for adding value to this study through networking and knowledge-sharing with European experts in the field. The authors thank Dr. Diana Toivola, Åbo Akademi University, for her comments on the article.