The correlation of in vitro antioxidant potentials with the various biochemical responses of salinized basil leaves

Abstract

One of the environmental sustainability issues is salinity. Basil seedlings (Ocimum basilicum L.) were treated using NaCl solutions of three different concentrations prepared using irrigation (40, 80, and 130 mM), and various biochemical analyses were performed on basil leaves. The number of leaves, leaf area, moisture, weights, and MDA content of basil decreased significantly as salinity levels increased from 40 to 130 mM; however, dry matter increased. As well, the current study investigated a significant increase in osmolytes (including total soluble sugars and proline) and Na+ contents. The highest activities of CAT and SOD in the leaf tissues of basil were recorded after treatment with 130 mM NaCl, whereas the polyphenol and total flavonoid contents were negatively influenced.  On the other hand, the highest ABTS scavenging activity was observed in the 40 mM-treated leaves at a concentration of 1000 µg/mL; however, the DPPH scavenging potential increased significantly in the 80 mM-treated leaves at 3000 µg/mL. Furthermore, the correlation between in vitro antioxidant potentials and biochemical responses was described. A strong correlation was identified between the in vitro antioxidant capacities of salinized O. basilicum leaves and SOD activity, total flavonoids, and the presence of phenolic acids, particularly p-hydroxybenzoic and o-coumaric acids at various concentrations. As a result, this is the first study to explain how basil may resist salinity by producing specific antioxidant compounds; therefore, our research recommends use of salinity issue to obtain a better plant material for producing dietary supplements or herbal drugs.