[Difference of effective component content and key enzyme gene expression of biosynthesis in Atractylodes chinensis with different leaf shapes].

In this study, four Atractylodes chinensis(A. chinensis) with different leaf shapes, such as the split leaf, long and narrow leaf, oval leaf, and large round leaf, were used as experimental materials to establish a method for simultaneously determining atractylodin, atractylenolide Ⅰ, ß-eudesmol, and atractylon in the rhizome of A. chinensis. The expression of key enzyme genes for biosynthesis of acetyl-CoA carboxylase(ACC), 3-hydroxy-3-methylglutaryl-CoA reductase(HMGR), and farnesyl pyrophosphate synthase(FPPS) was detected by real-time fluorescence quantitative polymerase chain reaction(qRT-PCR). High performance liquid chromatography(HPLC) was used to compare the difference in the content of four active components in A. chinensis with different leaf shapes, and the correlation between the content of active components and the expression of key enzyme genes in biosynthesis was discussed. The results show that there was good linearity among atractylodin, atractylenolide Ⅰ, ß-eudesmol, and atractylon in the range of 3.30-33.00 µg·mL~(-1)(r =0.999 7), 12.04-120.40 µg·mL~(-1)(r =0.999 5), 29.16-291.60 µg·mL~(-1)(r =0.999 5), and 14.20-142.00 µg·mL~(-1)(r =0.999 5), respectively. The average recoveries were 99.77%(RSD=2.1%), 98.56%(RSD=1.2%), 103.0%(RSD=1.2%), and 100.6%(RSD=1.5%), respectively. The method was accurate and had good reproducibility, which could be used to simultaneously detect atractylodin, atractylenolide Ⅰ, ß-eudesmol, and atractylon. The results showed that there were significant differences in the content of four active components in A. chinensis with different leaf shapes. The content of atractylodin, atractylenolide Ⅰ, and ß-eudesmol in A. chinensis with split leaves was the highest, which were 1.341 9, 5.237 2, and 12.084 3 mg·g~(-1), respectively. The content of atractylon in A. chinensis with long and narrow leaves was the highest(5.470 1 mg·g~(-1)). The content of atractylodin, atractylenolide Ⅰ, ß-eudesmol, and atractylon in A. chinensis with oval leaves was the lowest. The total content of the four effective components in descending order was A. chinensis with split leaves > A. chinensis with long and narrow leaves > A. chinensis with large round leaves > A. chinensis with oval leaves. The gene expression levels of key enzymes ACC, HMGR, and FPPS in A. chinensis with split leaves were the highest(P < 0.05), and the gene expression levels of key enzymes ACC and HMGR in A. chinensis with oval leaves were the lowest(P < 0.05). The gene expression level of key enzyme FPPS in A. chinensis with large round leaves was the lowest. In A. chinensis with different leaf shapes, the key enzyme gene ACC was significantly positively correlated with the polyacetylene component, namely atractylodin(P < 0.01), and the key enzyme genes HMGR and FPPS were positively correlated with the sesquiterpene components, namely atractylenolide Ⅰ, ß-eudesmol, and atractylon. In summary, the quality of A. chinensis with split leaves is the best, and the biosynthesis of atractylodin is significantly correlated with the gene expression of key enzyme ACC, which provides a theoretical basis for screening and optimizing the germplasm resources of A. chinensis and improving the quality of medicinal materials.

Adsorption and desorption characteristics of ginsenosides from Panax ginseng C. A. Meyer on middle-pressure chromatogram isolated gels.

Four types of middle-pressure chromatogram isolated gels are evaluated for adsorption or desorption characteristics of ginsenosides from Panax ginseng. Among them, SP207SS and SP2MGS were selected for dynamic investigations based on their static adsorption or desorption capacity of total ginsenoside. Their adsorption kinetics was better explained by pseudosecond-order model and isotherms were preferably fitted to Langmuir model. Dynamic breakthrough experiments indicated an optimum sample loading speed of 4 bed volume/h for either SP207SS or SP2MGS. Desorption speed was determined to be 2 bed volume/h according to desorption amount of total ginsenoside in their effluents. Eight ginsenosides were identified and quantified by high performance liquid chromatography-triple quadropole-mass spectrometry in total ginsenoside extract and different fractions during stepwise dynamic elution. For SP207SS, 27.62% of loaded ginsenosides was detected in 40% ethanol fraction, while 59.12% of them were found in 60% ethanol fraction. As on SP2MGS, the number went to 53.71 and 44.43%, respectively. Recovery rate of ginsenosides were calculated to 78.65% for SP207SS and 89.53% for SP2MGS, respectively. Intriguingly, content of Rg1 and Re in 40% ethanol fraction from SP207SS became 20.1 and 18.6 times higher than that in total ginsenoside extract by one-step elution, which could be leveraged for the facile enrichment of these two ginsenosides from natural sources.

[Effects of growing time on Panax ginseng rhizosphere soil microbial activity and biomass].

Using the field sampling and indoor soil cultivation methods, the dynamic of ginseng rhizosphere soil microbial activity and biomass with three cultivated ages was studied to provide a theory basis for illustrating mechanism of continuous cropping obstacles of ginseng. The results showed that ginseng rhizosphere soil microbial activity and biomass accumulation were inhibited observably by growing time. The soil respiration, soil cellulose decomposition and soil nitrification of ginseng rhizosphere soil microorganism were inhibited significantly (P <0.05), in contrast to the control soil uncultivated ginseng (R0). And the inhibition was gradual augmentation with the number of growing years. The soil microbial activity of 3a ginseng soil (R3) was the lowest, and its activity of soil respiration, soil cellulose decomposition, soil ammonification and soil nitrification was lower than that in R0 with 56.31%, 86.71% and 90. 53% , respectively. The soil ammonification of ginseng rhizosphere soil microbial was significantly promoted compared with R0. The promotion was improved during the early growing time, while the promotion was decreased with the number of growing years. The soil ammonification of R1, R2 and R3 were lower than that in R0 with 32.43%, 80.54% and 66.64% separately. The SMB-C and SMB-N in ginseng rhizosphere soil had a decreased tendency with the number of growing years. The SMB-C difference among 3 cultivated ages was significant, while the SMB-N was not. The SMB of R3 was the lowest. Compared with R0, the SMB-C and the SMB-N were significantly reduced 77.30% and 69.36%. It was considered by integrated analysis that the leading factor of continuous cropping obstacle in ginseng was the changes of the rhizosphere soil microbial species, number and activity as well as the micro-ecological imbalance of rhizosphere soil caused by the accumulation of ginseng rhizosphere secretions.