Substance Interactions’ Foundation On Antioxidant Activities In Vitro Of Complex Carbohydrates

Polysaccharide is an important class of natural active substance. The biggest advantage of polysaccharide is with less drug side effects and wide variety of sources. Studies have proved that the polysaccharide has some antioxidant activities, particularly complex carbohydrates from natural sources. However, it is not fully clear that the relationship between antioxidant activity and physicochemical properties or structural features of polysaccharide. Its substance interactions’ foundation is uncertain. Different sources, extraction methods can influence the polysaccharide characteristics. Protein and polyphenol usually are retained in polysaccharide in the form of either conjugation or mixture. Currently, these studies about factors of polysaccharide oxidation resistance are not very thorough, but also lack of systematic, need further research. In this paper, antioxidant activity of monosaccharide, oligosaccharide and complex carbohydrates in vitro were systematically evaluated. Meanwhile, dextran standard with adding of protein, polyphenol and metal ions were investigated. The antioxidant activities of dextran before and after added were compared. The substance foundations of complex carbohydrates antioxidant activities in vitro were explored. Main results in the paper were obtained as follows:1. The antioxidant activities of monosaccharide in vitro were evaluated comprehensively. The high purity, commonly pentose, hexose and uronic acid were choosed. Antioxidant activities of monosaccharide were analyzed by six commonly used antioxidant assays, which included 1, 1-Diphenyl-2-picrylhydrazyl(DPPH) radical scavenging, hydroxyl radical scavenging, superoxide radicals scavenging, ferric reducing antioxidant power(FRAP), β-carotene bleaching assay and oxygen radical absorbance capacity(ORAC). Results showed that in the six antioxidant assays, monosaccharides did not exhibit antioxidant activities obviously, except galacturonic acid which exhibited some antioxidant activities.2. The antioxidant activities of oligosaccharide in vitro were evaluated comprehensively. The high purity disaccharide of sucrose and lactose, trisaccharide of raffinose and maltotriose to maltoheptaose were choosed as the research objects. Oligosaccharide with different molecular weight showed extremely weak antioxidant activities. The antioxidant activities were hardly changed with increasing concentration.3. The antioxidant activities of commercially available complex carbohydrates were evaluated in vitro. The high purity, single monosaccharide compositions of various types of complex carbohydrates were choosed for antioxidant analysis. They exhibited relatively low antioxidant activities. Meanwhile, the results showed that the antioxidant activities of complex carbohydrates were mainly attributed to the phenolic and protein composition. In addition, the difference of their antioxidant activities might be ascribed to different galacturonic acid content.4. The antioxidant activities of complex carbohydrates from natural products prepared in the laboratory were evaluated in vitro. Ganoderma atrum polysaccharide, Semen Plantaginis polysaccharide, tea polysaccharide and β-glucan prepared in the laboratory were choosed as the research objects. In different antioxidant systems, the antioxidant activities of Ganoderma atrum polysaccharide and tea polysaccharide were generally higher than Semen Plantaginis polysaccharide and β-glucan. These results were consistent with their physical-chemical properties. The polyphenol and protein contents of the Ganoderma atrum polysaccharide were the highest. The polyphenol and protein contents of tea polysaccharide took second place. And it had the highest uronic acid content. The polyphenol contents of Semen Plantaginis polysaccharide and β-glucan were very low. In addition, their metal ions contents were generally low. However, it is still not clear that polyphenol, protein and metal ions mixture or compound actually played roles on antioxidant activity. More studies are needed to perform.5. The mechanisms of carbohydrates antioxidant activities in vitro were explored preliminarily. The standard dextran T-70 of moderate size molecular was select as the research object. Protein, polyphenol and different metal ions were added to it. In different antioxidant systems, gallic acid, ferulic acid and their dextran mixtures had a certain antioxidant activities. However, gallic acid and ferulic acid did not promote the antioxidant activities of dextran mixture. It suggested that there was no synergy. The antioxidant activities of dextran mixture with BSA and metal ions(except Fe2+) were lower, and did not dose-effect relationship with the sample concentration. Dextran standard(T-70) with adding protein, polyphenol and metal ions were analyzed by antioxidant assays in vitro. They didn’t showed synergistic effect, possibly ascribed to polyphenol, protein and metal ions.