Abstract
Ultraviolet B radiation has been described as a potential elicitor agent of the synthesis of secondary metabolites in plants. Thus, the present study aimed to investigate the production of betalains and total flavonoids, as well as the antioxidant activity, of Alternanthera sessilis, A. brasiliana, A. tenella and A. philoxeroides exposed to different periods of UV-B radiation (280-315 nm). Plants of these four species were exposed to UV-B radiation for 0, 2, 4, 6, and 8 hours, which amounts to 0, 10, 20, 30, and 40 J cm−2 of radiation, respectively. Significant increases in betacyanin and betaxanthin levels were observed in A. sessilis and A. brasiliana during the period of UV-B exposure, while no differences were observed for the others species. The highest estimated flavonoid levels were for A. sessilis exposed to UV-B radiation for 8 h, followed by a 24-h recovery period. In conclusion, the action of UV-B radiation as an inducer of defence responses in plants is influenced by increasing exposure periods followed by a recovery period. Both increase the levels of these composts, yet this increase is different among the four Alternanthera species, having a greater influence on the species A. sessilis and A. brasiliana.
Highlights
Even though several chemical substances are synthetically produced nowadays, plants still represent an important source of chemical compounds used in the pharmaceutical industry, adding great economic value
Taking into account previous studies, the present study aimed to investigate the elicitor effect of UV-B radiation on the production of betalains and total flavonoids, as well as quantifying antioxidant activity in the species A. sessilis, A. brasiliana, A. tenella, and A. philoxeroides so that they can be used in further studies as an alternative to obtain plants with increased levels of natural pigments and improved antioxidant capacity
The average level of betanidin differed significantly as the period of exposure to UV-B radiation increased for the species A. sessilis and A. brasiliana
Summary
Even though several chemical substances are synthetically produced nowadays, plants still represent an important source of chemical compounds used in the pharmaceutical industry, adding great economic value. It is estimated that 25 % of medicines prescribed are directly or indirectly derived from plants (Zhang & Björn 2009). The use of both biotic and abiotic elicitors is a strategy used to increase the production of secondary metabolites with commercial application. UV-B radiation (290–320 nm) may induce different changes in plant metabolism (Schreiner et al 2009), including the production of secondary metabolites mostly involved in the plant defence system, such as alkaloids and flavonoids (Zhang & Björn 2009; Schreiner et al 2012). The first evidence of the role that flavonoids play in protecting against UV radiation appeared with mutants in the biosynthetic route for this compound, resulting in hypersensitive phenotypes to UV radiation (Winkel-Shirley 2002)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
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 call
