Optimization of the solvent mixture for extraction of phenolic compounds with antioxidant activity from Byrsonima basiloba Juss.

The antioxidant activities from Byrsonima sp. leaves are usually attributed to their phenolic acids, flavonoids and tannins1. By a selection of mixture of 15 extraction solvents (H2O, EtOH and MeOH), via an experimental i-optimal design of mixture (Design Expert 10.1, Stat-Ease Corporation), we found a proportion of solvents with maximum phenolics compounds extraction with the most efficient antioxidant activity. For each extract was used 5 g of dried and crushed leaves of B. basiloba/50 ml of the mixture of solvents (collected in Assis-SP). The solution was kept under dynamic maceration for 2h and filtered. The residue was reextracted twice more. The extracts were analyzed to concentration of total phenolics and flavonoids2and antioxidant activities3,4. Statistical analyzes were made with levels of 95% significance. The best solvent mixtures obtained for phenol and for flavonoid content were EtOH:MeOH 55:45 v/v (157.92± 5.35 mg galic acid/g extract) and 79:21 EtOH:MeOH v/v (12.57±6.89 mg quercetin/g extract), respectively. But, the best antioxidant activity was observed for solvent ratio of 33:34:33 EtOH:MeOH:H2O v/v/v (EC50, 8.86 ± 2.53 mg extract/ml and 3.64±7.24 μM Trolox/mg dry extract). In this mixture of solvent, phenolic and flavonoid content were 130,97±1,99 mg galic acid/g extract and 8,17±4,49 mg quercetin/g extract, respectively. All the parameters tested, the linear model had a significant result (phenol p=0,0443, F=4,33) (flavonoids, p=0,0443, F=4,33) (EC50: p<0.0196, F=5.56; ABTS p<0.0433, F=4,37). (Equation 1-4) (Figure 1 A-D). These results, compatible with the literature, were corroborated by the mathematical model proposed for this project.