engleski

Duration of light intervals changes antioxidant response of industrial hemp

Industrial hemp (Cannabis sativa L. subsp. sativa) is one of the oldest cultivated plants used for many purposes throughout centuries. It has been valued for its nutritional and medicinal properties. Industrial hemp is primary a short-day plant but it can endure great changes in daylight intensity and length which can promote oxidative damage. Therefore, plants must modify their antioxidative responses to combat this stress. In this study, the antioxidative response of two hemp cultivars (USO and Finola) grown under violet light (250 mol m-2 s- 1) and different light/dark intervals (18/6, 20/4 and 24/0) was investigated. To determine antioxidative potential, ferric reducing antioxidant power (FRAP) and scavenging effect on the 1, 1-diphenyl-2-picrylhydrazyl free radical (DPPH) assays were employed. The content of total polyphenols was determined spectrophotometrically using Folin-Ciocalteu reagent. Highest FRAP values were observed at 20/4 in both cultivars. DPPH assay showed similar results as FRAP, except that no statistical difference was observed between 16/8 and 20/4 values for the Finola cultivar. The total phenolic content in both cultivars showed the highest values at 20/4 as well, correlating with other two methods and suggesting that phenolic compounds are likely to contribute to radical scavenging activity. All results indicate that 20/4 light interval causes the most stress in plants possibly inducing free radical formation and consequent increase in overall nonenzymatic antioxidant response in order to preserve important bioactive components.

industrial hemp, antioxidative response, DPPH, FRAP, total phenolic content

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