| Oxidative stress has a close relationship with the occurrence of diseases of the human body system. However, antioxidants can reduce the occurrence of oxidative stress. Traditional Chinese medicine is an important source of antioxidants, and the pharmacological effect of it is associated with oxidative stress. But the composition of Traditional Chinese medicine is very complex, and there is no accurate and simple system to evaluate the antioxidant activity. It is often combined with many kinds to evaluate of antioxidant activity. So the research purpose of this topic: Based on the different antioxidant principles, a simple and convenient in vitro antioxidant evaluation system was established to evaluate the antioxidant activity of traditional Chinese medicine. And then,the system was combined with other methods to expand its application in the field of traditional Chinese medicine.1. Antioxidant activity of the different polar solvent extracts of Magnolia officinalis leaves and purification of main active compounds.The leaf of Magnolia officinalisis abundant in natural resources as a novel potential antioxidant and has great commercial value. In this study,the contents of total phenolics, total flavonoids, magnolol and honokiol in different solvent extracts(acetone, methanol and water) were measured.Meanwhile, the antioxidant activity of extracts from M. officinalis leaves were evaluated using DPPH, ABTS free radical scavenging assay, FRAP assays and β-carotene/linoleic acid system. In addition, the correlation between the antioxidant activity and the contents of the active compounds was analyzed. Experimental results indicated that three extracts exhibited antioxidant effects in a concentration-dependent manner, and acetone extracts had the highest antioxidant activity, next methanol and water.There was an intimate relativity between the contents of magnolol and honokiol in different solvent extracts and the antioxidant capability of them.So the magnolol and honokiol of M. officinalis leaves as a representative of the active compounds were extracted and purified by using the macroporous resin column. The purity of depurated sample could reach82.6%, which indicates the M. officinalis leaves have the potential to substitute the production of magnolol and honokiol in M. officinalis. The results of this study can provide theoretical and technical references for the reasonable use of the M. officinalis leaves and alleviate the shortage of M.officinalis resources.2. Antioxidant activity and optimization of extraction of polysaccharide from the roots of Dipsacus asperoides.Polysaccharide extraction from Dipsacus asperoides roots(DAP) was proved to possess strong antioxidant activities, including DPPH, ABTS radical scavenging activities, inhibiting β-carotene bleaching and strong reducing power. Cell assay demonstrated that the crude DAP possessed antioxidant activity and were effective against H2O2-induced L02 cells injury. Then, response surface methodology(RSM) was applied to optimize the ultrasonic extraction of DAP. The optimum variables given by central composite design(CCD) were as follows: ratio of water to raw material,38.61 m L/g; ultrasonic power, 308.68W; extraction time, 38.61min; and extraction temperature, 89℃. Under these conditions, the maximum yield of DAP obtained was 7.12 ± 0.45%. Moreover, high performance liquid chromatography(HPLC) analysis suggested that the monosaccharide compositions of DAP contained primarily mannose, ribose, glucose,galactose, xylose and arabinose, with a molar ratio of0.22:0.48:2.29:0.34:1.39:1.41. The results of the present study showed that DAP could be considered as potential sources of natural antioxidants.3. Evaluation of antioxidant, anti-inflammatory activity and identification of active compounds of Humulus scandens.In this study, Humulus scandens was extracted using different solvent extraction and divided into four groups, and then evaluate its antioxidant ability by scavenging free radicals, reducing power assay antioxidant experiment. Experimental results show that the Humulus scandens ethyl acetate and n-butanol extracts have good antioxidant effect, and water and chloroform antioxidant effect is weak.Mouse ear swelling and granuloma experiment showed that Humulus scandens chloroform extract has significant anti-inflammatory effect, and can improve the SOD, CAT enzyme activity. So it may be related to the chloroform extract can reduce oxidative stress in mice. Finally, 15 compounds were identified from the extracts of butanol. The results of this study can provide theoretical and technical references for the reasonable use of the Humulus scandens. |
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