Determination of the various extraction solvent effects on polyphenolic profile and antioxidant activities of selected tea samples by chemometric approach

In this study, the effect of solvent type and solvent concentration on the ultrasound assisted extraction (UAE) of polyphenols from popular tea samples (black, green, mate, blackberry and black mulberry) which have high antioxidant activities were investigated by chemometric approaches. For this purpose, green extraction method was preferred and hydroalcoholic solvents for applied this system in industry. Water, MeOH 100%, MeOH 75%, MeOH 50%, EtOH 100%, EtOH 75%, EtOH 50% were used as extraction solvent. Multivariate calibration analytical technique preferred for quantification of individual phenolic compounds in tea samples and the relationship between total phenolic content (TPC), total flavonoid content (TFC) and total antioxidant activity (TAA) and individual phenolics was determined by chemometric approaches. The results of the study suggest that only spectroscopic comparisons based on TPC, TFC and TAA correlations are insufficient or even incorrect, and this is due to the fact that in tea samples different molecules besides different flavonoid structures are sensitive to spectroscopic techniques. The determination of the appropriate type and the concentration of solvent would contribute the usage of the herbal plants as a source of natural antioxidants in foods and pharmacology in large-scale industrial applications.