RESUMO
The effect of solvent polarity on extraction yield and antioxidant properties of phytochemical compounds in bean seeds was studied. Seed flour of three varieties of bean was extracted in a series of organic solvents with increasing polarity (n-hexane, petroleum ether, chloroform, ethyl acetate, ethanol, acetone and water). Preliminary screening of phytochemicals showed the presence of tannins, flavonoids, cardiac glycosides, anthocyanins, terpenoids, carotenoids, ascorbic acid and reducing compounds in all extracts. One way analysis of variance (ANOVA) of results showed that extraction yield, phytochemical content and antioxidant properties were significantly influenced (p<0.05) by the polarity of extracting solvents. The regression analysis of data showed polarity-dependent second order polynomial variations in the extraction yield, phytochemical contents, antioxidant activity, reducing properties and free radical scavenging activity of each variety. Extraction in highly polar solvents resulted in high extract yield but low phenolic and flavonoid content as compared to non-polar ones. The polarity-dependent increase in total antioxidant activity and reducing properties indicates the extraction of strong antioxidant compounds in polar solvents. The study suggests the use of a combination of polar and nonpolar solvents to increase the extraction efficiency of phytochemicals with good antioxidant quality from the bean and other legume seeds.
RESUMO
In this study, we evaluated the effect of the herbicide propyl 4-(2-(4,6-dimethoxypyrimidin-2-yloxy)benzylamino) benzoate (ZJ0273) on barley growth and explored the potential to trigger growth recovery through the application of branched-chain amino acids (BCAAs). Barley plants were foliar-sprayed with various concentrations of ZJ0273 (100, 500, or 1000 mg/L) at the four-leaf stage. Increasing either the herbicide concentration or measurement time after herbicide treatment significantly impaired plant morphological parameters such as plant height and biomass, and affected physiological indexes, i.e. maximal photochemical efficiency (Fv/Fm), quantum yield of photosystem II (ФPSII), net photosynthetic rate (Pn), and chlorophyll meter value (soil and plant analyzer development (SPAD)). Cellular injury of herbicide-treated plants was also evidenced by increased levels of reactive oxygen species (ROS) and antioxidative enzyme activity. Elevated levels of herbicide significantly reduced the activity of acetolactate synthase (ALS)-a key enzyme in the biosynthesis of BCAAs. In a separate experiment, growth recovery in herbicide-stressed barley plants was studied using various concentrations of BCAAs (10, 50, 100, and 200 mg/L). Increasing BCAA concentration in growth media significantly increased the biomass of herbicide-stressed barley seedlings, but had no significant effect on non-stressed plants. Further, BCAAs (100 mg/L) significantly down-regulated ROS and consequently antioxidant enzyme levels in herbicide-stressed plants. Our results showed that exogenous application of BCAAs could reverse the inhibitory effects of ZJ0273 by restoring protein biosynthesis in barley seedlings.