Molecularly imprinted solid-phase extraction method for the gas chromatographic analysis of organochlorine fungicides in ginseng.

A highly selective molecularly imprinted solid-phase extraction coupled with gas chromatography method was developed for the simultaneous isolation and determination of four organochlorine fungicides (pentachloronitrobenzene, pentachloroaniline, methylpentachlorophenyl sulfide, and hexachlorobenzene) in ginseng samples. A novel molecularly imprinted polymer with pentachloronitrobenzene as template was synthesized by precipitation polymerization employing butanone/n-heptane (6.5:3.5, v/v) solution as porogen. The limit of detection of the method was 0.001 mg/kg, and the limit of quantification was 0.002 mg/kg. The different spiked levels of ginseng samples were 0.05, 0.5, 2.0 for pentachloronitrobenzene and pentachloroaniline, and 0.01, 0.1, 1.0 for methylpentachlorophenyl sulfide and hexachlorobenzene. The average recoveries of four organochlorine fungicides were 87.6-92.3% of pentachloronitrobenzene, 79.3-95.2% of pentachloroaniline, 80.3-90.4% of methylpentachlorophenyl sulfide, and 83.5-91.7% of hexachlorobenzene, respectively. This new method could be applied to direct determination of four organochlorine fungicides in ginseng samples.

Effects of high hydrostatic pressure-assisted organic acids on the copigmentation of Vitis amurensis Rupr anthocyanins.

Natural anthocyanins are safer and nutritious as compared to synthetic pigments; however, their stability is poor. They can produce spontaneous copigmentation with organic acids, leading to the improvement of colour stability, albeit slowly. Box-Behnken experimental design was used to elucidate the mechanism of copigmentation between Vitis amurensis Rupr anthocyanins (0.1 mg/mL) and organic acids (0.87 mg/mL, ferulic acid:d-gluconic acid:caffeic acid:vanillic acid = 1.5:2.5:2.5:0.5, w/w/w/w) promoted by high hydrostatic pressure (HHP; 300 MPa, 2 min). The copigmentation effect and antioxidant activity of anthocyanins were also evaluated. The structure of anthocyanins was analysed using ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, high-performance liquid chromatography, and mass spectrometry. The results of HHP copigmentation showed that the following anthocyanins were newly formed-delphinidin-3-O-catechol, petunidin-3-O-catechol, delphinidin-4-vinyl-catechol, petunidin-3-O-guaiacol, malvidin-4-vinyl-guaiacol, cyanidin-3-O-(6″-O-caffeoyl)-glucoside, peonidin-3-O-(6″-O-caffeoyl)-glucoside, delphinidin-3-O-(6″-O-caffeoyl)-glucoside, malvidin-3-O-glucoside-4-vinyl-guaiacol, and malvidin-3-O-(6″-O-feruloyl)-glucoside-owing to appropriate modifications that increased the copigmentation rate (R = 42.12%), photo-thermal stability (R > 45%), and potential antioxidant activities expressed in vivo (p < 0.01 vs. Model Group).

Two new fatty acids esters were detected in ginseng stems by the application of azoxystrobin and the increasing of antioxidant enzyme activity and ginsenosides content.

Panax ginseng C.A. Meyer is a valuable herb in China that has also gained popularity in the West because of its pharmacological properties. The constituents isolated and characterized in ginseng stems include ginsenosides, fatty acids, amino acids, volatile oils, and polysaccharides. In this study, the effects of fungicide azoxystrobin applied on antioxidant enzyme activity and ginsenosides content in ginseng stems was studied by using Panax ginseng C. A. Mey. cv. (the cultivar of Ermaya) under natural environmental conditions. The azoxystrobin formulation (25% SC) was sprayed three times on ginseng plants at different doses (150ga.i./ha and 225ga.i./ha), respectively. Two new fatty acids esters (ethyl linoleate and methyl linolenate) were firstly detected in ginseng stems by the application of azoxystrobin as foliar spray. The results indicated that activities of enzymatic antioxidants, the content of ginsenosides and two new fatty acids esters in ginseng stems in azoxystrobin-treated plants were increased. Azoxystrobin treatments to ginseng plants at all growth stages suggest that the azoxystrobin-induced delay of senescence is due to an enhanced antioxidant enzyme activity protecting the plants from harmful active oxygen species (AOS). The activity of superoxide dismutase (SOD) in azoxystrobin-treated plants was about 1-3 times higher than that in untreated plants. And the effects was more significant (P=0.05) when azoxystrobin was applied at dose of 225ga.i./ha. This work suggests that azoxystrobin plays an important role in delaying of senescence by changing physiological and biochemical indicators and increasing ginsenosides content in ginseng stems.

A molecularly imprinted polymer for the selective solid-phase extraction of dimethomorph from ginseng samples.

A molecularly imprinted polymer (MIP) was synthesized and evaluated to selectively extract dimethomorph from ginseng samples. Dimethomorph molecularly imprinted polymers with template to monomer molar ratios were contrived and developed via precipitation polymerization employing methacrylic acid as functional monomer, ethylene dimethacrylate as cross-linker and butanone:N-heptane (7:3, v:v)as porogen. The LOD (limit of detection) of this method was 0.002 mg kg(-1), and the LOQ (limit of quantification) was 0.005 mg kg(-1). The different spiked level of ginseng was 0.1 mg kg(-1), 1.0 mg kg(-1), 5.0 mg kg(-1), and the average recovery of dimethomrph was 89.2-91.6%. Under the optimized condition, good linearity was obtained from 0.01 to 5 mg kg(-1) (r(2) ≥ 0.9997) with the relative standard deviations of less than 3.20%. This proposed MISPE-GC procedure eliminated the effect of template leakage on quantitative analysis and could be applied to direct determination of dimethomrph in ginseng samples.