| This study takes the areca shell as raw material, A series of studies on areca polyphenols were carried out, including extraction conditions optimization, hydrolysis treatment, identification by LC-MS, antioxidant analysis and so on, The main results are as follows:To optimize the areca catechu polyphenol extraction process, extraction effect of polyphenols extracted by different solvent systems were compared to exploring the optimal combination of extraction solvent, material/liquid ratio and extractive grades was designed according to the theory of Multistage cross flow extraction process, in addition, the orthogonal test of interaction was carried to optimize other conditions. The results show that the optimal conditions for the extraction of Areca catechu polyphenol were as follows: extraction solvent, the mixed solvent (methanol:acetone:water=1:2:2); material/liquid ratio, 1:20(g:ml); pH 4.0; extraction time 100 min; extraction temperature 70 ?; extractive stages 2. The extraction efficiency is 34.46 mg/g.The hydrolysis conditions of tannin from Areca catechu and antioxidant activity of polyphenols from areca before and after hydrolysis were studied. With the acetic acid as hydrolysis medium, the content of tannin from areca as index, the hydrolysis technology of tannin from areca was optimized and studied by orthogonal array design. The results showed that at 70 ?, the content of tannin, which were hydrolyzed with 2.5 times the volume of acetic acid for 40 min, was decreased from 36.80% to 28.86% of the content of total phenolics. In vitro antioxidant activity of polyphenols exhibited a dose-effect relationship relevant to the content of total phenolics. After the tannin from areca had been hydrolyzed, the total deoxidization capability of the extract was slightly decreased, superoxide anion radical scavenging capacity and hydroxyl radical scavenging capacity were significantly enhanced, DPPH radical scavenging capacity was not changed obviously. Therefore, it can be considered that the antioxidant activity of areca polyphenols was improved after hydrolysis.The major phenolic compounds of smoked areca shell were identified by high performance liquid chromatography of quadrupole time of flight-tandem mass spectrometry (HPLC-Q-TOF-MS). And antioxidant activity in vitro of phenolic compounds were evaluated by their DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity and total reducing power. The preliminary analysis results show that the extract contains chlorogenic acid, protocatechuic acid, p-hydroxy benzoic acid, vanillic acid and quercetin; antioxidant activity in vitro analysis showed that the five kinds of phenolic compounds have antioxidant activity in a certain degree. Protocatechuic acid is a major component with antioxidant action of polyphenols in smoked areca shell.DPPH radical scavenging activity and total reducing power were used as evaluation indicators. In vitro antioxidant activities of polyphenol mixtures consists of 4 kinds of polyphenols including the structure of C6-C3 type of chlorogenic acid and protocatechuic acid and the structure of C6-C3-C6 type of quercetin and catechin in any combination were investigated to evaluate synergistic, antagonistic, and additive effects of polyphenol mixtures. The results show that interaction of polyphenol mixtures on antioxidant activities related to the structure types, quantity and proportion of polyphenols in mixtures, and the same component also had different antioxidant parameters in different reaction systems, The antioxidant capacity difference of polyphenol mixture in monomer state is bigger, the synergistic effect is stronger, but there is no direct link between the synergistic effect with concentration. |
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