Study On The Sulfur Fumigation And Alternative Drying Technology Of Radix Paeoniae Alba

Radix Paeoniae Alba(BS),the roots of Paeonia lactiflora Pall.,is a commonly used medicinal herb in oriental traditional medicine,with the efficacies of nourishing blood and regulating menstruation,astringing Yin to check sweating,emolliating the liver and relieving pain,as well as pacifying and repressing the liver Yang.At present,sulfur-fumigation is widely applied to change color,prevent molds and kill insects during post-hanvest handling of BS.However,extensive studies showed that sulfur-fumigation could induce chemical transformation and could lead to the accumulation of sulfites and harmful heavy metals,thus may have potential risk to human health.In this study,the effects of sulfur-fumigation on quality and absorption of BS were investigated so as to evaluate the practicability of sulfur-fumigation for BS.Furthermore,the technology alternative to sulfur-fumigation for drying BS was developed.The main contents of this study are as follows:1.Effects of sulfur fumigation on the quality of BSFirst,the effect of sulfur-fumigation on major bioactive components in BS was investigated.A improved high performance liquid chromatography-diode array detector(HPLC-DAD)method for simultaneous quantification of twelve major components belonging to three chemical types(including monoterpene glycosides,galloyl glucoses and phenolic compounds)was developed,and was applied to quantitatively compare the quality of BS purchased from commercial herbal markets.It was found that paeoniflorin sulfonate was detectable in 59%commercial BS samples,suggesting that sulfur-fumigation is currently still a common post-harvest handling method of BS.And owing to the sulfur-fumigation,the consistency of BS samples was obviously decreased.In addition,the content trend of 12 major components in BS samples versus sulfur-fumigation duration was clarified,it was found that the contents of oxypaeoniflorin,paeoniflorin,benzoylpaeoniflorin and paeonol decreased,whereas that the contents of paeoniflorin sulfonate increased obviously with the extending of sulfur-fumigation duration.Moreover,the content of paeoniflorin and paeoniflorin sulfonate appear in an obvious negative correlation.Second,the effect of sulfur-fumigation on the SO2 residues contents in BS was assessed.The SO2 residues content in BS was detetmined by the method(distillation)documented in Chinese Pharmacopoeia(CP).It was found that the contents of SO2 residue were not positively correlated with that of paeoniflorin sulfonate.The reliability of SO2 residues analytical method was further validated,on account of an unacceptable repeatability.It was found that paeoniflorin sulfonate could not be transformed to SO2 completely,which result in poor repeatability of SO2 residues determination.And the conversion rate of paeoniflorin sulfonate to SO2 residues was only 50%,even the distillation time last 2 h.Moreover,the SO2 residues contents would be reduced gradually with the time elapsed,and the antiseptic activity was eventually lost.Third,microbial limit,sulfur and heavy metal residues in sulfur-fumigated Radix Paeoniae Alba(S-BS)were determined by the methods documented in the CP.It was found that sulfur fumigation could reduce the number of bacteria in BS.However,sulfur fumigation did not exhibit significant inhibitory effects on the growth of Escherichia coli and molds.,Except for sulfur,the contents of heavy metal residues in S-BS samples were not significantly different from that in products processed with other methods,indicating that sulfur fumigation does not obviously influence the heavy metal residues as long as the superor grade sulfur was used.2.Effects of sulfur fumigation on the absorption and metabolism of BSFirst,a improved HPLC-TQ-MS/MS method for simultaneous quantification of five major components including paeoniflorin sulfonate was established and validated,and was applied to compare the pharmacokinetic properties of the five major components between S-BS and non-fumigated Radix Paeoniae Alba(N-BS).The mass spectrometer was operated in negative mode using multiple reaction monitoring(MRM)to detect the analytes.It was found that the AUC(0-t),AUC(0-∞),MRT(0-t)of paeoniflorin and the AUC(0-t),AUC(0-∞),t1/2,Cmax of oxypaeoniflorin were significantly different(P<0.05),whereas the those pharmacokinetic parameters of albiflorin were not between the two groups.And compared to N-BS,the Cmax and AUC(0-∞)values of paeoniflorin in S-BS decreased very significantly,whereas its t1/2 values increased obviously.All these results suggested that sulfur fumigation can significantly affect thepharmacokinetic properties of N-BS.Second,the difference of all metabolites was comprehensively analyized by UPLC-QTOF-MS/MS-based metabonomics approach between two groups.The MS datasets were analyzed by the principal component analysis(PCA),and then the orthogonal partial least squared discriminant analysis(OPLS-DA)to explore the the differential components contributed most to the difference of these two groups.In total,7 differential components(1 in plasma,3 in bile,3 in urine,4 in faeces)were tentatively assigned.The differential components,except for 2 unknowns and 1 endogenous substance,which were only found in the biological samples of S-BS group,were elucidated to be paeoniflorin sulfonate and its metabolites.At the same time,there was a significant difference in mass spectra between the paeoniflorin sulfonate and the sulfur-containing metabolite of paeoniflorin produced by the phase Ⅱ metabolism in vivo,suggesting that the paeoniflorin sulfonate and its metabolites in biological samples should be from the absorption and metabolism of paeoniflorin sulfonates in S-BS samples,not from the phase Ⅱ metabolism of paeoniflorin.All these suggested that sulfur fumigation could significantly affect the the absorption and metabolism of BS.3.Innovative technology alternative to sulfur fumigation for drying BSThe combined hot air-microwave technique was newly established alternative to sulfur fumigation for drying BS.Evaluated with contents of active ingredients,characters,the degrees of moisture index,practibility and costs,different drying techniques were comparatively investigated.It was found that hot air combined with microwave was more reasonable for drying N-BS.Then the pilot-scale experiments for combined hot air-microwave drying method were validated.With the optimized process parameters,the established technique was proved to be stable and feasible,and the quality of dried BS successfully meets the requirements of CP.In order to evaluate the quality stability of the samples dried with the new technique,the dried samples were stored with different package(including woven bags,plastic bags and vacuum bag)for different durations.The results showed that the traditional woven bag stored in a dry ventilated place is the best package and storage condition.The quality evaluation standards and technical specifications of combined hot air-microwave drying method of BS were established according to the above study.This study could provide technical support for the ensurence of the quality consistency,and thus the safety and efficiency of BS.