Bioactive Compound Potential of Brassicaceae Sprouts and the Effect of UV-B Radiation on their Antioxidant Activity

Abstract

Current trend of climate change and depletion of ozone layer may cause the amount of ultraviolet (UV) radiation in the atmosphere to increase and thus, affecting biodiversity and ecosystem. Plants are one of the most affected organisms due their need of sunlight to carry important process of photosynthesis and the presence of UV radiation may result in detrimental effects on them. However, with controlled amount of UV radiation exposure as abiotic stress condition, plants will be able to develop a plant defense chemical and present an alternative source of drug discovery as natural products. Plant secondary metabolites are important compounds largely used in pharmaceutical industry and commonly found in Brassicaceae family plants such as broccoli sprouts, red cabbage sprouts and kale sprouts. Previous studies suggested that Brassicaceae sprouts is a good source of phytochemicals and reported to exhibit bioactive properties including antioxidative and anti-inflammatory. In this study, an overview of the effect of UV-B radiation exposure as abiotic stress on the amount of Brassicaceae sprouts bioactive compound and antioxidant activities are presented and discussed. Brassicaceae sprouts are grown and exposed to UV-B radiation under different sets of time and fresh samples of the sprouts are extracted with ethanol before undergoing phytochemical analysis for total phenolic content and then proceed with DPPH assays to study its antioxidant activity. Results suggest that UV-B radiation causes increase in double in the amount of total phenolic content for red cabbage sprout from 0.33 to 0.63 mg gallic acid/g^-1 and increase in the antioxidant activity of kale sprout from 0.74 to 0.80 mg Trolox/g^-1 from Brassicaceae species at 5^th-min of exposure. This study is important to understand the increment of UV radiation from ozone layer depletion for plants particularly from Brassicaceae family to adapt to these changes while applying them in different industries including agriculture and health for their bioactive compounds.