HMGR and CHS gene cloning, characterizations and tissue-specific expressions in Polygala tenuifolia Willd.

Triterpenoid saponins and flavonoids have several pharmacological activities against P. tenuifolia. The 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) and chalcone synthase (CHS) are the rate-limiting enzymes of triterpenoid saponin and flavonoid biosynthesis, respectively. In this study, HMGR and CHS genes were cloned from P. tenuifolia, and their bioinformatics analyses and tissue-specific expression were investigated. The results showed that the HMGR and CHS genes were successfully cloned, separately named the PtHMGR gene (NCBI accession: MK424118) and PtCHS gene (NCBI accession: MK424117). The PtHMGR gene is 2323 bp long, has an open reading frame (ORF) of 1782 bp, and encods 593 amino acids. The PtCHS gene is 1633 bp long with an ORF of 1170 bp, encoding 389 amino acids. PtHMGR and PtCHS were both hydrophobic, not signal peptides or secreted proteins, containing 10 conserved motifs. PtHMGR and PtCHS separately showed high homology with HMGR and CHS proteins from other species, and their secondary structures mainly included α-helix and random curl. The tertiary structure of PtHMGR was highly similarity to that the template 7ULI in RCSB PDB with 92.0% coverage rate. The HMG-CoA-binding domain of PtHMGR is located at 173-572 amino acid residues, including five bound sites. The tertiary structure of PtCHS showed high consistency with the template 1I86 in RCSB PDB with 100% coverage rate, contained malonyl CoA and 4-coumaroyl-CoA linkers. The expression of PtHMGR and PtCHS is tissue-specific. PtHMGR transcripts were mainly accumulated in roots, followed by leaves, and least in stems, and were significantly positively correlated with the contents of total saponin and tenuifolin. PtCHS was highly expressed in the stems, followed by the leaves, with low expression in the roots. PtCHS transcripts showed a significant positive correlation with total flavonoids content, however, they were significantly negatively correlated with the content of polygalaxanthone III (a type of flavonoids). This study provided insight for further revealing the roles of PtHMGR and PtCHS.

Identification of potentially suitable areas for nucleosides of Pinellia Ternata (Thunb.) Breit using ecological niche modeling.

Pinellia ternata, a traditional Chinese medicine, is well-renowned for its effectiveness in treating sickness such as coughs with excessive phlegm, vomiting, and nausea. The nucleoside components of P. ternata have been shown to have antitumor activity. Identifying potential growth areas of high-quality P. ternata based on the content of five nucleoside components and the identification of climatic features suitable for the growth of P. ternata will help to conserve P. ternata resources with targeted bioactive compounds. Using high-performance liquid chromatography (HPLC), we determined five nucleoside components, uridine, guanosine, adenosine, inosine, and thymidine, at 27 sampling points of P. ternata collected from 21 municipalities of 11 provinces in China. We used ecological niche modeling to identify the major environmental factors associated with the high metabolite content of P. ternata, including precipitation of the warmest quarter, annual mean temperature, annual precipitation, and isothermality. Areas with high suitability for the five nucleosides were found in Hebei, Shandong, Shanxi, Gansu, Sichuan, Guizhou, and Hubei Provinces. Under the RCP 2.6, RCP 4.5, and RCP 8.5 scenarios, the areas with a suitable distribution decreased and some areas with high suitability became areas with low suitability. Overall, our findings advance our knowledge of the ecological impacts of climate change and provide a valuable reference for conserving and sustainably developing high-quality P. ternata resources in the future.

Responses of soil nutrients and rhizosphere microbial communities of a medicinal plant Pinelliaternata to vermicompost.

Vermicomposting is an important strategy for restoring soil function and fertility. However, information on the effects of vermicompost application in intensive Pinellia ternata planting systems has rarely been reported. Here, we focus on the effects of different vermicompost levels and chemical fertilizer (CF) strategies on soil chemical properties, soil enzymes, and soil rhizosphere microbial communities (bacteria and fungi) in a field experiment. Compared to no added fertilizers (CK), vermicompost was more effective than the CF treatment in increasing P. ternata yield. We found that the 5 t ha-1 vermicompost treatment (VC2) significantly increased the tuber yield by 44.43% and 6.55% compared to the CK and CF treatment, respectively, and water-soluble exudates by 6.56% and 9.63% (P < 0.05). The vermicompost and CF treatments significantly increased the total phosphorus (TP), urease (Ure), and soil catalase (Cat) contents (P < 0.05). Compared to the vermicompost and CK treatments, the CF treatment significantly decreased soil organic carbon (SOC), C/N ratio, and soil acid phosphatase (Pac) (P < 0.05). Redundancy analysis (RDA) showed that Ure and total potassium (TK) were the major drivers in the bacterial community, whereas TP, total nitrogen (TN), Pac, and TK were the major drivers in the fungal community. We also found a positive correlation between soil enzyme activities, including between Ure and bacterial genera (Clostridium, Pseudoclavibacter, Stella, Hyphomicrobium, Mesorhizobium, and Adlercreutzia). In summary, vermicompost application promotes P. ternata soil microecosystems and improves soil fertility, soil enzyme activities, and rhizosphere microbial structure and function. Vermicomposting is a novel and promising approach to sustainable ecological cultivation of Chinese herbs via the promotion of soil properties and beneficial organisms.

Phytochemical profile and biological activities of the essential oils in the aerial part and root of Saposhnikovia divaricata.

The dried root of Saposhnikovia divaricata (Turcz.) Schischk. is popular as a good medicinal material, however the abundant aerial part is often discarded, which caused the waste of resources. In order to exploit resources, the essential oils of the plant aerial part and root were extracted, separately called as VOA and VOR, their chemicals were identified. The tumor necrosis factor-α, interleukin-6, nitric oxide and interleukin-1ß were detected to evaluate the oils anti-inflammatory activities. Then, the oils free radical scavenging rates were measured with DPPH, ABTS and hydroxyl free radical. The oils antitumor activities were evaluated with HeLa and HCT-8 cancer cell lines. The results showed the concentrations of VOA and VOR were separately 0.261% and 0.475%. Seventeen components of VOA were identified, accounting for 80.48% of VOA, including phytol, spathulenol, phytone, 4(15),5,10(14)-Germacratrien-1-ol, neophytadiene, etc. Seven components of VOR were determined, representing 90.73% of VOR, consisted of panaxynol, ß-bisabolene, etc. VOA and VOR significantly inhibited the secretion of nitric oxide, interleukin-1ß, interleukin-6 and tumor necrosis factor-α, effectively scavenged the DPPH, ABTS and hydroxyl free radicals, and showed significant antiproliferative activity against HeLa and HCT-8. The two oils presented important biological activity, which provided a hopeful utilized basis, and helped to reduce the waste of the aerial non-medicinal resources of S. divaricata.

Study on the Regularity of Ammonia-Related Refrigeration Accidents in China from 2010 to 2020.

The frequent occurrence of ammonia-related refrigeration accidents (ArRAs) restricts the safety and sustainable development of cold storage. As an essential tool for safety management, accident statistical analysis can provide a crucial decision-making basis for accident prevention and control. The present study combined descriptive statistics and comparative analysis methods to explore the characteristics and regularities of 82 ArRAs in China from 2010 to 2020. The results showed that the annual evolution of ArRAs presents a bimodal "M" mode in which 2013 and 2016 were the peaking years of accidents. The monthly distribution has an agglomeration effect, and the period from June to September had a high incidence period of accidents. The ArRAs mainly occurred in East China and Central China in the spatial dimension. Zhejiang, Shandong, Hubei, and Sichuan are the pivotal provinces for preventing and controlling ArRAs. Human factors and equipment failure are the leading causes of ArRAs. Accident numbers and casualties have inconsistent trends due to the uncertainty and variability of ArRAs' consequences. The safety situation of ammonia-related refrigeration enterprises has improved but still needs to strive to prevent and control major accidents. This study draws valuable references for safety decision-making by ammonia-related refrigeration enterprises and safety regulators.

Effectiveness and safety of hydrogen inhalation as an adjunct treatment in Chinese type 2 diabetes patients: A retrospective, observational, double-arm, real-life clinical study.

Aim: To analyze the effectiveness and safety of hydrogen inhalation (HI) therapy as an adjunct treatment in Chinese type 2 diabetes mellitus (T2DM) patients in a real-life clinical setting. Methods: This observational, non-interventional, retrospective, double-arm, 6-month clinical study included T2DM patients receiving conventional anti-diabetes medication with or without HI initiation from 2018 to 2021. Patients were assigned to the HI group or non-HI group (control group) after 1:1 propensity score matching (PSM). The mean change in glycated hemoglobin (HbA1c) after 6 months in different groups was evaluated primarily. The secondary outcome was composed of the mean change of fasting plasma glucose (FPG), weight, lipid profile, and homeostasis model assessment. Logistics regression was performed to evaluate the likelihood of reaching different HbA1c levels after 6-month treatment between the groups. Adverse event (AE) was also evaluated in patients of both groups. Results: In total, 1088 patients were selected into the analysis. Compared to the control group, subjects in HI group maintained greater improvement in the level of HbA1c (-0.94% vs -0.46%), FPG (-22.7 mg/dL vs -11.7 mg/dL), total cholesterol (-12.9 mg/dL vs -4.4 mg/dL), HOMA-IR (-0.76 vs -0.17) and HOMA-ß (8.2% vs 1.98%) with all p< 0.001 post the treatment. Logistics regression revealed that the likelihood of reaching HbA1c< 7%, ≥ 7% to< 8% and > 1% reduction at the follow-up period was higher in the HI group, while patients in the control group were more likely to attain HbA1c ≥ 9%. Patients in HI group was observed a lower incidence of several AEs including hypoglycemia (2.0% vs 6.8%), vomiting (2.6% vs 7.4%), constipation (1.7% vs 4.4%) and giddiness (3.3% vs 6.3%) with significance in comparison to the control group. Conclusion: HI as an adjunct therapy ameliorates glycemic control, lipid metabolism, insulin resistance and AE incidence of T2DM patients after 6-month treatment, presenting a noteworthy inspiration to existing clinical diabetic treatment.

Concentration of fifteen elements in herbaceous stems of Ephedra intermedia and influence of its growing soil.

Mineral nutrients play important roles in the growth and metabolism of Ephedra intermedia, and are affected by soil factors. Fifteen elements were measured from wild E. intermedia as well as their growing soils using inductively coupled plasma mass spectroscopy to investigate the influences and characteristics of herb elements. The pH, cation exchange capacity, humus and soil mechanical composition were also determined in rhizosphere soils. Results showed that E. intermedia stems contained high N, low P concentrations in macronutrients and high Fe in micronutrients, and enriched N, S, Cl, P and Sr from soils. The 15 herb elements were affected by one or more soil factors, and K, P, Zn, Fe and Mn were important soil elements that influenced the mineral accumulation of E. intermedia. This study was useful for the artificial cultivation of wild E. intermedia.

Piperine as a neuroprotective functional component in rats with cerebral ischemic injury.

Long pepper (Piper longum L.) and black pepper (Piper nigrum L.) plants are commonly used as spices around the world and have also been postulated to have medicinal effects. Piperine, as the major alkaloid of P. nigrum and P. longum, has gained wide attention of the medical community and culinary enthusiasts. This study seeks to determine the effects of piperine on neuronal apoptosis in peri-infarcted cerebral cortices of rats with permanent middle cerebral artery occlusion (pMCAO) injury. Evaluation of the different behavioral components was conducted after pMCAO. 2, 3, 5-Triphenyltetrazolium chloride (TTC) was used to evaluate the area of cortical ischemia. Gross histopathological changes, as well as microscopic neuronal changes, were observed in brain tissue samples. The protein expression of Caspase-3, Caspase-9, Bax, Bcl-2, and Cytochrome C (Cyt-c) was analyzed using western blotting. The findings reveal that rats that received piperine treatment show markedly decreased neurological deficit, less ischemia-induced cellular damage, as well as smaller areas of cerebral infarction, with less severe macro and microcellular cerebral structural changes. Western blotting analysis reveals that piperine administration inhibits Bax, while enhancing Bcl-2 expression. The protein expression of Caspase-3, Caspase-9, and Cyt-c was also found to be significantly inhibited. We conclude that piperine may provide several beneficial neuroprotective effects that warrant further investigation.

Euxanthone Attenuates Aß1-42-Induced Oxidative Stress and Apoptosis by Triggering Autophagy.

Alzheimer's disease (AD) is the most common neurodegenerative disorder and is characterized by the deposition of ß-Amyloid (Aß) plaques which contribute to its pathology. The present study was aimed at exploring the protective effects of euxanthone against Aß-induced neurotoxicity both in vivo and in vitro. We found that euxanthone significantly attenuated Aß1-42-induced memory and spatial learning dysfunction and also significantly reversed Aß1-42-induced neuronal apoptosis and autophagy in the hippocampal region. Euxanthone also protected the neuroblastic PC12 cells against Aß1-42-induced oxidative stress and apoptosis by inducing autophagy. In conclusion, euxanthone exerts its neuroprotective effect against Aß1-42 by inducing autophagy, indicating its potential therapeutic role in AD.

Clinical significance of fucosylated GP73 in the differential diagnosis of hepatocellular carcinoma.

OBJECTIVE:: To investigate the clinical value of fucosylated GP73 (Fuc-GP73) levels for differential diagnosis of hepatocellular carcinoma from other liver diseases. METHODS:: Serum specimens were collected from 50 patients with hepatocellular carcinoma, 60 patients with other digestive system diseases (ODSD), and 40 normal controls. Lectin affinity chromatography column combining with the enzyme-linked immunosorbent assay (ELISA) using the ELISA index was utilized to measure the level of Fuc-GP73. By receiver operating characteristic (ROC) curve analysis its sensitivity and specificity were used to evaluate the diagnostic significance of Fuc-GP73 in hepatocellular carcinoma. RESULTS:: The median serum Fuc-GP73 level of hepatocellular carcinoma (20.4 µg/L) was much higher than that of ODSD patients (1.8 µg/L) and the normal controls group (0.3 µg/L), significantly ( P <0.01). There was no significant correlation between serum Fuc-GP73 level and sex, age, and tumor size in the hepatocellular carcinoma group ( P > 0.05); however, it was related to tumor, node, metastasis stage and lymph node metastasis ( P <0.05). The area under the ROC curve (AUC) of Fuc-GP73 to detect hepatocellular carcinoma alone was 0.885; with the prespecified specificity of 95%, the sensitivity and the cutoff value were 82% and 3.1 µg/L. In addition, the combined test of Fuc-GP73 with other biomarkers can improve the clinical diagnostic efficiency; the AUC can reach to 0.983; and with the prespecified specificity of 95% its sensitivity increased to 94%. CONCLUSION:: Fuc-GP73 can act as a superior glycobiomarker for the differential diagnosis of hepatocellular carcinoma; its combined detection with other biomarkers can improve diagnostic accuracy.

Severe Cerebral Falciparum Malaria with Dengue Coinfection: A Case Report.

A rare severe case of the coinfection of cerebral falciparum malaria and dengue is reported in this paper. The patient was a 50 yr old male in the north of China, who returned from Uganda not long ago and suffered unconsciousness after fever for 4 d before the falciparum malaria and dengue infection was diagnosed via blood smear microscopy, RT-PCR and serology, although the antimalarial and symptomatic treatment was carried out, ultimately the patients died of septic shock because of multiple organ dysfunctions. This case report showed such a coinfection was prone to cause severe acute consequence. The timely diagnosis and delicate treatment are crucial for prognosis of patients.

Discrimination of three Ephedra species and their geographical origins based on multi-element fingerprinting by inductively coupled plasma mass spectrometry.

Discrimination of species and geographical origins of traditional Chinese medicine (TCM) is essential to prevent adulteration and inferior problems. We studied Ephedra sinica Stapf, Ephedra intermedia Schrenk et C.A.Mey. and Ephedra przewalskii Bge. to investigate the relationship between inorganic element content and these three species and their geographical origins. 38 elemental fingerprints from six major Ephedra-producing regions, namely, Inner Mongolia, Ningxia, Gansu, Shanxi, Shaanxi, and Sinkiang, were determined to evaluate the importance of inorganic elements to three species and their geographical origins. The contents of 15 elements, namely, N, P, K, S, Ca, Mg, Fe, Mn, Na, Cl, Sr, Cu, Zn, B, and Mo, of Ephedra samples were measured using inductively coupled plasma mass spectroscopy. Elemental contents were used as chemical indicators to classify species and origins of Ephedra samples using a radar plot and multivariate data analysis, including hierarchical cluster analysis (HCA), principal component analysis (PCA), and discriminant analysis (DA). Ephedra samples from different species and geographical origins could be differentiated. This study showed that inorganic elemental fingerprint combined with multivariate statistical analysis is a promising tool for distinguishing three Ephedra species and their geographical origins, and this strategy might be an effective method for authenticity discrimination of TCM.

Protective effects of dehydrocostuslactone on rat hippocampal slice injury induced by oxygen­glucose deprivation/reoxygenation.

The present study aimed to investigate the protective effects of dehydrocostuslactone (DHL) against rat hippocampal slice injury caused by oxygen­glucose deprivation/reoxygenation (OGD/R). Rat hippocampal slice injury was induced by OGD/R in vitro, and the degree of injury was evaluated through a lactate dehydrogenase (LDH) assay and 2,3,5­triphenyltetrazolium chloride (TTC) staining. The protein expression levels of B­cell lymphoma-2 (Bcl­2), Bcl­2­associated X protein (Bax), cytochrome c (cyt­c), apoptotic protease activating factor 1 (apaf­1), caspase­9, caspase­7, caspase­3, sequestosome 1 (SQSTM1) and microtubule­associated protein 1 light chain 3 (LC3) were analyzed through western blot analysis. The results showed that 1, 5 and 10 µM DHL decreased the levels of LDH (P<0.05) and increased the A490 value of TTC (P<0.05). Furthermore, the expression of Bcl­2 was enhanced, and the protein expression levels of Bax, cyt­c, apaf­1, caspase­9, caspase­7, caspase­3, SQSTM1 and LC3 were significantly inhibited (P<0.05), compared with those in the OGD/R group. These results suggested that DHL elicited protective effects against hippocampal OGD/R injury, and its underlying mechanism may be associated with inhibiting apoptosis.

Rhein protects against cerebral ischemic­/reperfusion­induced oxidative stress and apoptosis in rats.

The present study aimed to investigate the protective effects of rhein on cerebral ischemic/reperfusion (I/R) injury in rats. The present study focused on the effect of rhein on oxidative stress and apoptotic factors, which are considered to serve an important role in the onset of I/R injury. Sprague­Dawley rats were subjected to middle cerebral artery occlusion. Neurological functional scores (NFSs) were evaluated according to the Zea Longa's score criteria and the area of brain infarct was determined by triphenyltetrazolium chloride staining. The morphology of the nerve cells in the cortex was observed following hematoxylin and eosin staining. In addition, levels of oxidative stress were assessed by measuring the levels of superoxide dismutase (SOD), glutathione­peroxidase (GSH­Px), catalase (CAT) and malondialdehyde (MDA). Levels of B­cell lymphoma-2 (Bcl­2), apoptosis regulator Bax (BAX), caspase-9, caspase­3 and cleaved caspase­3 expression were analyzed using western blot analysis. Levels of caspase­9 and caspase­3 mRNA expression were obtained using reverse transcription­quantitative polymerase chain reaction. The results revealed that treatment with 50 or 100 mg/kg rhein significantly improved the NFS and markedly attenuated the area of infarction. Rhein also significantly reduced the content of MDA and significantly increased SOD, GSH­Px and CAT activity. Western blot analysis indicated that rhein significantly decreased the expression of BAX and enhanced the expression of Bcl­2. Compared with the I/R group, levels of caspase­9, caspase­3 and cleaved caspase­3 protein expression were significantly decreased in the rhein treatment groups. Additionally, rhein treatment significantly reduced levels of caspase­9 and caspase­3 mRNA expression. These results suggest that rhein exhibits protective effects during cerebral I/R injury and its underlying mechanism of action may involve the inhibition of oxidative stress and apoptosis.

Thermo-Economic Optimization of an Idealized Solar Tower Power Plant Combined with MED System.

Based on the reversible heat engine model, theoretical analysis is carried out for economic performance of a solar tower power plant (STPP) combined with multi-effect desalination (MED). Taking total revenue of the output power and the fresh water yield per unit investment cost as the economic objective function, the most economical working condition of the system is given by analyzing the influence of the system investment composition, the receiver operating temperature, the concentration ratio, the efficiency of the endoreversible heat engine, and the relative water price on the economic parameters of the system. The variation curves of the economic objective function are given out when the main parameter is changed. The results show that the ratio of water price to electricity price, or relative price index, has a significant impact on system economy. When the water price is relatively low, with the effect numbers of the desalination system increasing, and the economic efficiency of the overall system worsens. Only when the price of fresh water rises to a certain value does it make sense to increase the effect. Additionally, the threshold of the fresh water price to the electricity price ratio is 0.22. Under the conditions of the current price index and the heliostat (or reflector), the cost ratio and the system economy can be maximized by selecting the optimum receiver temperature, the endoreversible heat engine efficiency, and the optimum concentration ratio. Given the receiver surface temperature and the endoreversible heat engine efficiency, increasing the system concentration ratio of the heliostat will be in favor of the system economy.

UPLC Quantitative Analysis of Multi-Components by Single Marker and Quality Evaluation of Polygala tenuifolia Wild. Extracts.

The quality control of Polygala tenuifolia Wild. is a major challenge in its clinical application. In this paper, a new strategy for the quality evaluation of P. tenuifolia extracts was verified through reverse-phase ultra-performance liquid chromatography (UPLC). The quantitative analysis of multi-components by a single marker (QAMS) was conducted with 3,6'-disinapoyl sucrose as an internal reference substance. Eight components (i.e., sibiricose A5, sibiricose A6, glomeratose A, tenuifoliside A, tenuifoliside B, tenuifoliside C, sibiricaxanthone B, and polygalaxanthone III) were determined based on the relative correction factors. The concentrations of these components were also determined by applying a conventional external standard method. The cosine value confirmed the consistency of the two methods (cosine ratio value >0.999920). Hierarchical cluster analysis, radar plots, and discriminant analysis were performed to classify 23 batches of P. tenuifolia extracts from Shanxi, Hebei, and Shaanxi in China. Results revealed that QAMS combined with radar plots and multivariate data analysis could accurately measure and clearly distinguish the different quality samples of P. tenuifolia. Hence, QAMS is a feasible and promising method for the quality control of P. tenuifolia.

Current status and future prospects of biomarkers in the diagnosis of hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) has one of the highest death rates of any cancer in the world, and its incidence is increasing worldwide. Early-stage diagnosis of HCC is thus crucial for medical treatment. Detection of tumor biomarkers is one of the main methods for the early diagnosis of HCC. At present, α-fetoprotein (AFP) is the most practical serum biomarker for HCC diagnosis. However, the diagnostic accuracy of HCC with serum AFP exhibits both sensitivity and specificity far below satisfaction, especially with small sizes of HCC. As a result, the discovery of new biomarkers and/or their combination to enhance both the sensitivity and specificity for laboratory diagnosis of HCC is a crucial goal. With the development of new technology and advances in research, a number of new and specific biomarkers of HCC have been discovered. These biomarkers and their applications for the diagnosis, treatment monitoring and prognosis prediction of HCC, are reviewed in this article.

Discrimination of geographical origin of cultivated Polygala tenuifolia based on multi-element fingerprinting by inductively coupled plasma mass spectrometry.

Inorganic elements are important components of medicinal herbs, and provide valuable experimental evidence for the quality evaluation and control of traditional Chinese medicine (TCM). In this study, to investigate the relationship between the inorganic elemental fingerprint and geographical origin identification of cultivated Polygala tenuifolia, 41 elemental fingerprints of P. tenuifolia from four major polygala-producing regions (Shanxi, Hebei, Henan, and Shaanxi) were evaluated to determine the importance of inorganic elements to cultivated P. tenuifolia. A total of 15 elemental (B, Ca, Cl, Cu, Fe, K, Mg, Mn, Na, N, Mo, S, Sr, P, and Zn) concentrations of cultivated P. tenuifolia were measured using inductively coupled plasma mass spectroscopy (ICP-MS). The element composition samples were classified by radar plot, elemental fingerprint, and multivariate data analyses, such as hierarchical cluster analysis (HCA), principle component analysis (PCA), and discriminant analysis (DA). This study shows that radar plots and multivariate data analysis can satisfactorily distinguish the geographical origin of cultivated P. tenuifolia. Furthermore, PCA results revealed that N, Cu, K, Mo, Sr, Ca, and Zn are the characteristic elements of cultivated P. tenuifolia. Therefore, multi-element fingerprinting coupled with multivariate statistical techniques can be considered an effective tool to discriminate geographical origin of cultivated P. tenuifolia.

Microemulsions based on paeonol-menthol eutectic mixture for enhanced transdermal delivery: formulation development and in vitro evaluation.

In this work, microemulsion-based gels were prepared for transdermal delivery of paeonol. Microemulsions containing eutectic mixtures of paeonol and menthol were developed. The obtained microemulsions were evaluated for particle size, viscosity and physical stability. The selected microemulsions were incorporated into Carbopol gels. Drug crystallization behavior during a short-term storage was compared and in vitro permeation and deposition study were conducted on mouse skin. Results showed that the eutectic liquids of paeonol and menthol at all ratio (6:4, 5:5 and 4:6) could form microemulsions but with significantly different physical characteristics. As the ratio of paeonol increased, the prepared microemulsions exhibited larger droplet size, higher viscosity and quicker crystal growth. Microemulsion containing paeonol and menthol at a ratio of 4:6 possessed the smallest size of 27 nm. Accordingly, the related gel showed better physical stability during 10 days of storage, as well as the highest percent of drug deposition (111.8 µg/cm2) and steady-state flux (0.3 µg/cm2 h). These results suggested that the microemulsion formulation is a preferable approach for enhanced skin permeation, and the microemulsion based on drug-menthol eutectic mixture might be used as a potential transdermal delivery system for better therapeutic efficacy.