| Liquidambar is an important medicinal plant resource, widely distributed in China, which is well known for its city ecological value of ornamental plants and medicinal and health value of hemostasis, inhibition of cancer, liver protection and anti thrombosis, but the research about its active ingredients and the development of its functional product is less. Through the studies in recent years, it is found that the volatile components in liquidambar leaves have functions as bacteriostatic, anti oxidation of food and fruits freshing, which is a potential source of natural antioxidant and fresh-keeping agent.In this paper, we use the ultrasonic assisted extraction technology to extract the flavonoids from the leaves of liquidambar, discuss the best extraction process of flavonoids by quadratic rotational combination design method, and investigate the ability of flavonoids to clear DPPH·、·O2-·and·OH by chemical method. The results show that the optimal extraction process parameters for flavonoids from leaves of liquidambar are as follows. The proportion of liquid and material is40.1mL.g-1, ethanol concentration is68.7%, ultrasonic temperature is73℃, ultrasonic time is93.5min, and the production of flavonoids is27.6083mg.g-1; The EC50of cleared DPPH·、·O2-·OH and by flavonoids is0.0906mg/mL,0.0593mg/mL and0.4891mg/mL. Compared with the EC50of Vc, it is1.4and2.2times more in removing·O2-·and·OH. Although the removing ability of flavonoids from liquidambar leaves on free radicals like DPPH·、·O2-·and·OH is weaker than that of Vc, but the former one still shows a higher activity in scavenging free radicals in vitro.To find the strongest antioxidant activity components in liquidambar leaves, this paper intends to use liquidambar leaves as raw material, divides ethanol extract of liquidambar leaves into petroleum ether, chloroform, ethyl acetate, n-butanol and water through organic solvent extraction, and investigate the total reducing ability and scavenging effect on DPPH·、·O2-·and·OH, then make a comparison of antioxidant effects of different extraction. The results show that, in the experiment scavenging free radicals in vitro, except for that the reduction ability of O2-·is slightly lower than the n-butanol phase, the rest’s ability of scavenging the free radical and reduction show a similar trend, which is VC>ethyl acetate>n-butanol>BHT> chloroform. It shows that the ethyl acetate in ethanol extract of liquidambar leaves has strong antioxidant activity and capacity of scavenging free radical with phase, and antioxidants mainly exist in the phase of ethyl acetate in weak polarity.In this paper, we use column chromatography, thin layer chromatography, recrystallization,high performance liquid chromatography and mass spectrometry techniques to make a further separation and purification on the ethyl acetate extracts of liquidambar leaves, and make a evaluation of the antioxidant activity of the monomer. The results show that we can get two monomer from the separation of the ethyl acetate, after which is identified as rutin and astragalin. Through the antioxidant activity detection, we find they both have a strong ability in scavenging free radicals. At the concentration of10-50μg/mL, the effect to remove DPPH of sample1is stronger than that of sample2.Study on treatment with ethyl acetate of Liquidambar leaves on post-harvest preservation of Pruns salicina.Ethyl acetate of Liquidambar leaves is used as fruit antiseptic agent to explore the effects of Liquidambar leaves’ Ethyl acetate in different potency (8mg/100mL and15mg/100mL) immersing on post-harvest physiological and biochemical characteristics of Pruns salicina which storage in a low temperature(6℃)every5days. Result shows that different concentrations of the Ethyl acetate can all effectively maintain the storage characteristics of plum fruit. After25days storage, the decrease of the content of plum soluble solids, fruit titratable acid, fruit relative SSC/TA ratio and fruit hardness are inhibited by processings with significant difference to the control. The processing has remarkable effect to inhibit the rise of decay index, permeability of cell membrane, the content of MDA and the rise of POD activity. After25days storage, A significant difference between the test indexes in the processing and the control (P<0.05), while most index between the two treatments is not significant. |
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