Fluorescent multichannel sensor array based on three carbon dots derived from Tibetan medicine waste for the quantification and discrimination of multiple heavy metal ions in water.

A fluorescent multichannel sensor array has been established based on three carbon dots derived from Tibetan medicine waste for rapid quantification and discrimination of six heavy metal ions. Due to the chelation between metal ions and carbon dots (CDs), this fluorescence "turn off" mode sensing array can quantify six metal ions as low as "µM" level. Moreover, the six heavy metal ions display varying quenching effects on these three CDs owing to diverse chelating abilities between each other, producing differential fluorescent signals for three sensing channels, which can be plotted as specific fingerprints and converted into intuitive identification profiles via principal component analysis (PCA) and hierarchical cluster analysis (HCA) technologies to accurately distinguish Cu2+, Fe3+, Mn2+, Ag+, Ce4+, and Ni2+ with the minimum differentiated concentration of 5 µM. Valuably, this sensing array unveils good sensitivity, exceptional selectivity, ideal stability, and excellent anti-interference ability for both mixed standards and actual samples. Our contribution provides a novel approach for simultaneous determination of multiple heavy metal ions in environmental samples, and it will inspire the development of other advanced optical sensing array for simultaneous quantification and discrimination of multiple targets.

Life in Suspension with Death: Biocultural Ontologies, Perceptual Cues, and Biomarkers for the Tibetan Tukdam Postmortem Meditative State.

This article presents two cases from a collaborative study among Tibetan monastic populations in India on the postdeath meditative state called tukdam (thugs dam). Entered by advanced Tibetan Buddhist practitioners through a variety of different practices, this state provides an ontological frame that is investigated by two distinct intellectual traditions-the Tibetan Buddhist and medical tradition on one hand and the Euroamerican biomedical and scientific tradition on the other-using their respective means of inquiry. Through the investigation, the traditions enact two paradigms of the body at the time of death alongside attendant conceptualizations of what constitutes life itself. This work examines when epistemologies of these two traditions might converge, under what ontological contexts, and through which correlated indicators of evidence. In doing so, this work explores how these two intellectual traditions might answer how the time course and characteristics of physiological changes during the postmortem period might exhibit variation across individuals. Centrally, this piece presents an epistemological inquiry delineating the types of valid evidence that constitute exceptional processes post-clinical death and their potential ontological implications.

Chemical fingerprint analysis and quality assessment of Tibetan medicine Triphala from different origins by high-performance liquid chromatography.

INTRODUCTION: Although the Tibetan medicine Triphala (THL) is widely used in many countries, insufficient progress has been made in quality control. OBJECTIVES: The present study aimed to propose a methodology for quality control of THL based on HPLC fingerprinting combined with an orthogonal array design. METHODS: Seven identified peaks were used as indicators to examine the effects of temperature, extraction time, and solid-liquid ratio on the dissolution of active ingredients in THL. Fingerprint analysis was performed on 20 batches of THL from four geographical areas (China, Laos, Thailand, and Vietnam). For further chemometric assessment, analysis techniques including similarity analysis, hierarchical clustering analysis, principal component analysis, and orthogonal partial least squares discrimination analysis (OPLS-DA) were used to classify the 20 batches of samples. RESULTS: Fingerprints were established and 19 common peaks were identified. The similarity of 20 batches of THL was more than 0.9 and the batches were divided into two clusters. Four differential components of THL were identified based on OPLS-DA, including chebulinic acid, chebulagic acid, and corilagin. The optimal extraction conditions were an extraction time of 30 min, a temperature of 90°C, and a solid-liquid ratio of 30 mL/g. CONCLUSION: HPLC fingerprinting combined with an orthogonal array design could be used for comprehensive evaluation and quality assessment of THL, providing a theoretical basis for further development and utilization of THL.

A Meroterpenoid from Tibetan Medicine Induces Lung Cancer Cells Apoptosis through ROS-Mediated Inactivation of the AKT Pathway.

As a traditional Tibetan medicine in China, Meconopsis grandis Prain has been used to treat a variety of illnesses by local people for thousands of years. However, the active ingredients contained in Meconopsis grandis Prain and its pharmacodynamic mechanisms have scarcely been reported. We isolated a meroterpenoid named D1399 from Meconopsis grandis Prain endophytic fungi with strong antitumor activity. The structure analysis showed that D1399 is an alkaloid containing a 13-membered macrocyclic structure. The IC50 of D1399 for human lung cancer cells' viability ranged from 0.88 to 2.45 µM. Furthermore, we utilized TUNEL assay and western blotting to investigate the antitumor effectiveness of D1399. The results have shown that D1399 induced the apoptosis of lung cancer cells on the extrinsic and intrinsic pathways by boosting ROS generation and repressing AKT activity. In the mouse xenograft model, the average tumor weight with 30 mg·kg-1 D1399 treatment exhibited 73.19% inhibition compared with the untreated control, without affecting body weight loss. Above all, for the first time, our study provides a possible mechanism for the antitumor activity of D1399 in vitro and in vivo as a natural product from Tibetan medicine with Meconopsis grandis Prain, which may be a potentially promising antitumor drug candidate.

[Exploration and practice on construction of Tibetan medicine prescription information database and knowledge discovery].

This study aimed to explore the underlying framework and data characteristics of Tibetan prescription information. The information on Tibetan medicine prescriptions was collected based on 11 Tibetan medicine classics, such as Four Medical Canons(Si Bu Yi Dian). The optimal classification method was used to summarize the information structure of Tibetan medicine prescriptions and sort out the key problems and solutions in data collection, standardization, translation, and analysis. A total of 11 316 prescriptions were collected, involving 139 011 entries and 63 567 pieces of efficacy information of drugs in prescriptions. The information on Tibe-tan medicine prescriptions could be summarized into a "seven-in-one" framework of "serial number-source-name-composition-efficacy-appendix-remarks" and 18 expansion layers, which contained all information related to the inheritance, processing, origin, dosage, semantics, etc. of prescriptions. Based on the framework, this study proposed a "historical timeline" method for mining the origin of prescription inheritance, a "one body and five layers" method for formulating prescription drug specifications, a "link-split-link" method for constructing efficacy information, and an advanced algorithm suitable for the research of Tibetan prescription knowledge discovery. Tibetan medicine prescriptions have obvious characteristics and advantages under the guidance of the theories of "three factors", "five sources", and "Ro-nus-zhu-rjes" of Tibetan medicine. Based on the characteristics of Tibetan medicine prescriptions, this study proposed a multi-level and multi-attribute underlying data architecture, providing new methods and models for the construction of Tibetan medicine prescription information database and knowledge discovery and improving the consistency and interoperability of Tibetan medicine prescription information with standards at all levels, which is expected to realize the "ancient and modern connection-cleaning up the source-data sharing", so as to promote the informatization and modernization research path of Tibetan medicine prescriptions.

[Two new isoquinoline alkaloids from Corydalis hendersonii].

Corydalis hendersonii(CH) is a Tibetan folk medicine with the functions of clearing heat, detoxifying, cooling blood, checking diarrhea, and lowering blood pressure. It is often used to treat high altitude polycythemia, vasculitis, peptic ulcer, and diarrhea. Nine compounds were separated from the ethanol extract of CH by silica gel, ODS, Sephadex LH-20 chromatography and semi-preparative HPLC. Their structures were identified as hendersine H(1),hendersine I(2), dehydrocheilanthifoline(3), protopine(4), izmirine(5), 6,7-methylenedioxy-1(2H)-isoquinolinone(6), icariside D_2(7), ethyl 4-(ß-D-glucopyranosyloxy)-3-methoxybenzoate(8), 3-hydroxy-4-methoxybenzoic acid(9), respectively, by the spectroscopic data analysis and comparison with those in the literature. Among them, compounds 1 and 2 are new isoquinoline alkaloids, and compounds 7-9 are reported the first time for Corydalis. The hypoglycemic model of H9c2 cardiomyocytes and the inflammatory model of H9c2 cardiomyocytes induced by conditional supernatant were employed to determine the activities of the above compounds. The results showed that 20 µmol·L~(-1) compound 1 had a protective effect on H9c2 cardiomyocytes and 10 µmol·L~(-1) compounds 4 and 5 inhibited H9c2 cardiomyocyte inflammation induced by conditional supernatant.

[Investigation and clarification of traditional measuring units of Tibetan medicine].

Quantity is the key factor to ensure the safety and effectiveness of medicines. It is very important to study and determine the traditional measuring units and their quantity values of Tibetan medicine. Based on the literature records of Tibetan medicine and combined with modern experimental verification and investigation research, this study determined the reference, name, and conversion rate of traditional measuring units of Tibetan medicine. Meanwhile, through large sample sampling and repeated quantification of refe-rence of basic units, its weight and volume were clarified. The modern SI volume and weight unit values corresponding to the traditional volume and weight units of Tibetan medicine were deduced, and the correctness, reliability, and practicability of these determination results were demonstrated. This study also put forward some specific suggestions and reference values for formulating the standards of measuring units of weight and volume of Tibetan medicine. It is of great significance in guiding the processing, production, and clinical treatment of Tibetan medicine, and promoting the standardization and standardized development of Tibetan medicine.

Lipskynoids A-G, New Acyclic Diterpenes from the Flowers of Carpesium lipskyi.

Seven new acyclic diterpenes, namely lipskynoids A-G (1-7), were isolated from the flowers of Carpesium lipskyi, a traditional Tibetan herbal medicine with anti-inflammatory and antipyretic-analgesic effects. These new compounds were elucidated by analysis of extensive spectroscopic data including ESI-MS, 1D, 2D NMR, and DP4+ analyses. Biological assays showed that 1-7 display significant inhibitory effects against the NO production in LPS-induced RAW264.7 cells with its IC50 values from 9.9 to 18.47 µM, however, no cytotoxicity effect was observed of these isolates against the growth of HePG2, PC3, DU145, and A549 cells.

[Therapeutic effects of alkaloids in Tibetan medicine Bangna (Aconiti Penduli et Aconiti Flavi Radix) on osteoarthritis rats and mechanisms].

This study aims to investigate the therapeutic effects of alkaloids in Tibetan medicine Bangna(Aconiti Penduli et Aconiti Flavi Radix) on osteoarthritis(OA) rats in vitro and in vivo and the underlying mechanisms. Chondrocytes were isolated from 2-3 week-old male SD rats and lipopolysaccharide(LPS) was used to induce OA in chondrocytes in vitro. Methyl thiazolyl tetrazolium(MTT) assay was used to investigate the toxicity of seven alkaloids(12-epi-napelline, songorine, benzoylaconine, aconitine, 3-acetylaconitine, mesaconitine, and benzoylmesaconine) to chondrocytes. Chondrocytes were classified into the control group, model group(induced by LPS 5 µg·mL~(-1) for 12 h), and administration groups(induced by LPS 5 µg·mL~(-1) for 12 h and incubated for 24 h). The protein expression of inflammatory factors cyclooxygenase-2(COX-2), inducible nitric oxide synthetase(iNOS), tumor necrosis factor-α(TNF-α), and interleukin-1ß(IL-1ß) in each group were detected by Western blot, and the protein expression of matrix metalloprotease-13(MMP-13), aggrecan, collagen Ⅱ, fibroblast growth factor 2(FGF2) by immunofluorescence staining. For the in vivo experiment, sodium iodoacetate was used to induce OA in rats, and the expression of MMP-13, TNF-α, and FGF2 in cartilage tissues of rats in each group was detected by immunohistochemistry. The results showed that the viability of chondrocytes could reach more than 90% under the treatment of the seven alkaloids in a certain dose range. Aconitine, 12-epi-napelline, songorine, 3-acetylaconitine, and mesaconitine could decrease the protein expression of inflammatory factors COX-2, iNOS, TNF-α and IL-1ß compared with the model group. Moreover, 12-epi-napelline, aconitine, and mesaconitine could down-regulate the expression of MMP-13 and up-regulate the expression of aggrecan and collagen Ⅱ. In addition, compared with the model group and other Bangna alkaloids, 12-epi-napelline significantly up-regulated the expression of FGF2. Therefore, 12-epi-napelline was selected for the animal experiment in vivo. Immunohistochemistry results showed that 12-epi-napelline could significantly reduce the expression of MMP-13 and TNF-α in cartilage tissues, and up-regulate the expression of FGF2 compared with the model group. In conclusion, among the seven Bangna alkaloids, 12-epi-napelline can promote the repair of OA in rats by down-regulating the expression of MMP-13 and TNF-α and up-regulating the expression of FGF2.

[Research progress on precious Tibetan medicine formula in prevention and treatment of central nervous system diseases].

Precious Tibetan medicine formula is a characteristic type of medicine commonly used in the clinical treatment of central nervous system diseases. Through the summary of modern research on the precious Tibetan medicine formulas such as Ratnasampil, Ershiwuwei Zhenzhu Pills, Ershiwewei Shanhu Pills, and Ruyi Zhenbao Pills, it is found that they have obvious advantages in the treatment of stroke, Alzheimer's disease, epilepsy, angioneurotic headache, and vascular dementia. Modern pharmacological studies have shown that the mechanisms of precious Tibetan medicine formulas in improving central nervous system diseases are that they promote microcirculation of brain tissue, regulate the permeability of the blood-brain barrier, alleviate inflammation, relieve oxidative stress damage, and inhibit nerve cell apoptosis. This review summarizes the clinical and pharmacological studies on precious Tibetan medicine formulas in prevention and treatment of central nervous system diseases, aiming to provide a reference for future in-depth research and innovative discovery of Tibetan medicine against central nervous diseases.

[Analysis of the principles of Tibetan medicine processing].

Tibetan medicine processing ensures the safety of clinical application of Tibetan medicine. It is of great significance to analyze the principles of Tibetan medicine processing in the development, inheritance, and innovation of Tibetan medicine. However, due to the late start of modern Tibetan medicine research and the disciplinary division, the current research on Tibetan medicine processing focuses on the exploration and collation of traditional techniques and the analysis of the processing mechanism of Tibetan medicine through chemical and pharmacological research, but its principles and traditional theories have been rarely reported. In view of this, after analyzing the concept, essence, theories, purposes, and functions of Tibetan medicine processing through the integration of Tibetan medicine, Tibetan pharmacology, and clinical research of Tibetan medicine, this study proposed that the essence of Tibetan medicine processing was to change the "five sources" composition of medicinal materials through physical, chemical, and biological means, or the comprehensive means, and the theoretical principle of Tibetan medicine processing was to change or transform the positive and adverse effects or the obvious and recessive effects by altering the "five sources" composition of the drug to maximize the positive effect and minimize the adverse effect and the damage to the body, thereby achieving the purposes of toxicity reduction, efficacy enhancement, and drug property harmonization represented by sharpening, softening, nourishing, and reasonable compatibility. This study is expected to provide references for the construction of the theoretical system of Tibetan medicine processing, the inheritance of processing techniques, and innovative research.

[Mechanism of Tibetan medicine Ershiwuwei Songshi Pills against liver injury induced by acetaminophen in mice based on Keap1/Nrf2 and TLR4/NF-κB p65 signaling pathways].

The present study investigated the mechanism of the Tibetan medicine Ershiwuwei Songshi Pills(ESP) against the liver injury induced by acetaminophen(APAP) in mice based on the kelch-like ECH-associated protein 1(Keap1)/nuclear transcription factor E2 related factor 2(Nrf2) and Toll-like receptor 4(TLR4)/nuclear factor-kappa B(NF-κB) p65 signaling pathways. Kunming mice were randomly divided into a blank control group, a model group, an N-acetyl-L-cysteine(NAC) group, and high-(400 mg·kg~(-1)), medium-(200 mg·kg~(-1)), and low-dose(100 mg·kg~(-1)) ESP groups. After 14 days of continuous administration, except for those in the control group, the mice were intraperitoneally injected with 200 mg·kg~(-1) APAP. After 12 h, the serum and liver tissues of mice were collected. Hematoxylin-eosin(HE) staining was performed on pathological sections of the liver, and the levels of aspartate aminotransferase(AST) and alanine aminotransferase(ALT) in the serum and the levels of glutathione(GSH), malondialdehyde(MDA), superoxide dismutase(SOD), catalase(CAT), myeloperoxidase(MPO), and total antioxidant capacity(T-AOC) in liver tissue homogenate were detected to observe and analyze the protective effect of ESP on APAP-induced liver injury in mice. The serum levels of tumor necrosis factor-alpha(TNF-α), interleukin-1 beta(IL-1ß), and interleukin-6(IL-6) were determined by enzyme-linked immunosorbent assay(ELISA). The protein expression of Nrf2, Keap1, TLR4, and NF-κB p65 in the liver was determined by Western blot. Quantitative real-time was used to determine the mRNA expression of glutamate-cysteine ligase catalytic subunit(GCLC), glutamate-cysteine ligase regulatory subunit(GCLM), heme oxygenase-1(HO-1), and NAD(P)H dehydrogenase quinone 1(NQO-1) in the liver to explore the mechanism of ESP in improving APAP-induced liver damage in mice. As revealed by results, compared with the model group, the ESP groups showed improved liver pathological damage, decreased ALT and AST levels in the serum and MDA and MPO content in the liver, increased GSH, SOD, CAT, and T-AOC in the liver, reduced TNF-α and IL-6 levels in the serum, down-regulated expression of Keap1 in the liver cytoplasm and NF-κB p65 in the liver nucleus, up-regulated expression of Nrf2 in the liver nucleus, insignificant change in TLR4 expression, and elevated relative mRNA expression levels of antioxidant genes GCLC, GCLM, HO-1, and NQO-1. ESP can reduce the oxidative damage and inflammation caused by APAP, and the mechanism may be related to the Keap1/Nrf2 signaling pathway and the signal transduction factors on the TLR4/NF-κB p65 pathway.

[Mechanism of Tibetan medicine Pterocephalus hookeri extract in treatment of rheumatoid arthritis based on serum metabonomics].

Ultra-high performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry(UPLC-Q-TOF/MS) was used to investigate the effect of Pterocephalus hookeri on serum metabolism of adjuvant arthritis(AA) model rats induced by complete Freund's adjuvant. After the AA model was properly induced, the serum of rats was collected 30 days after treatment. UPLC-Q-TOF-MS chromatograms were collected and analyzed by principal component analysis(PCA) and orthogonal partial least squares discriminant analysis(OPLS-DA). The results revealed that compared with the control group, the model group showed increased content of 12 biomarkers in the serum(P<0.05) and reduced content of the other nine biomarkers(P<0.05). P. hookeri extract could recover the above-mentioned 19 biomarkers to a certain range. Pathway enrichment showed that these markers mainly involved eight metabolic pathways, including valine, leucine, and isoleucine degradation, arachidonic acid metabolism, arginine and proline metabolism, glycerol phospholipid metabolism, primary bile acid biosynthesis, bile acid biosynthesis, tryptophan metabolism, and unsaturated fatty acid biosynthesis. The findings of this study demonstrate that P. hookeri extract can regulate metabolic disorders and promote the regression of metabolic phenotype to the normal level to exert the therapeutic effect on AA rats. This study is expected to provide a certain scientific basis for the biological research on the treatment of rheumatoid arthritis by P. hookeri.

Pterocephanoside A, a new iridoid from a traditional Tibetan medicine, Pterocephalus hookeri.

This work obtained and identified pterocephanoside A (1), one new iridoid glucoside derivative with rare structure of three iridoid glycosides linked to cyclopenta[c]pyran-3(1H)-one, and 10 known iridoids (2-11) from Pterocephalus hookeri through silica gel column chromatography and semi-preparative HPLC. The structure of the new compound was confirmed by 1D and 2D NMR and HRMS data analysis. Compounds 1 and 2 were isolated from this plant for the first time. The iridoids mostly possessed seco-iridoid subtype and iridoid subtype skeletons from P. hookeri. Compounds 1, 3, 4, and 6-11 showed weak anti-inflammatory activity.

Human Methylmercury Exposure and Potential Impacts in Central Tibet: Food and Traditional Tibetan Medicine.

Methylmercury presents potent neurotoxicity to humans. Fish consumption is the leading source of human exposure to methylmercury worldwide. However, the exposure source in Tibet remains poorly understood because of the scarcity of observational data on most Tibetan foods, although high mercury levels were recently detected in some traditional Tibetan medicines. Here, the results of field investigations show that the joint consumption of traditional Tibetan medicines (TTMs), fish, and rice constitutes a primary exposure pathway to methylmercury in Tibetans and that the probable daily intake of methylmercury is close to that for many coastal regions. People who are young and high-income may have higher methylmercury exposure levels mainly because of economic development and cultural exchanges among regions. Our analysis indicates that a large proportion of the Tibetan population are likely to face a high methylmercury exposure risk and that mercury-susceptible populations in Tibet should be attentive to consuming TTMs with fish.

[General screening principles and inheritance paths of classic prescriptions in Tibetan medicine].

Due to the profound theoretical rationale, perfect diagnosis and treatment system, and characteristic medicinal resources, Tibetan medicine has been passed down to the present day as one of the four traditional medicine systems all over the world. With the development of modern society and the change in people's concept of seeking medical services, Tibetan medicine has gradually attracted wide attention by virtue of its natural, green and safe diagnosis and treatment characteristics, which enables it to be vigo-rously developed and inherited. There are numerous ancient books on Tibetan medicine, covering a large number of ancient prescriptions, which has laid a solid foundation for later scholars to thoroughly investigate the diagnosis and treatment rules in Tibetan medicine and apply them to modern clinical practice. Screening the classic prescriptions that meet modern clinical needs from those numerous ancient books is a new direction in the inheritance and development of Tibetan medicine. On the basis of historical origin and current application status of ancient prescriptions in Tibetan medicine, this paper preliminarily elaborated the definition of classic prescriptions of Tibetan medicine and their general screening principles and precautions, and also discussed the modern inheritance paths of classic prescriptions in Tibetan medicine from basic research, post-marketing evaluation, and the development of novel preparations. Considering the shortcomings in the present study, the key technical issues mentioned need to be more deeply explored and analyzed in future studies.

[Analysis of varieties and standards of Saxifragaceae medicinal plants used in Tibetan medicine].

On the basis of literatures and standards relating to Tibetan medicine, the varieties, origin, standards and efficacy of Saxifragaceae plant used in Tibetan medicine were summarized. According to the findings, 75 species(including varieties) in 8 genera of Saxifragaceae plants, involving 21 varieties, are used in Tibetan medicine. Among them, 9 commonly used varieties, namely Songdi, Sedi, Yajima, Aoledansaierbao, Jiansidawu, Saiguo, Katuer, Sangdi, Maoqinghong, are recorded in Chinese Pharmacopoeia, Ministry Standards for Tibetan Medicine, Tibetan Medicine Standards and other local standards, accounting for 42.9% of the total number of varieties. Tibetan names, Tibetan translation of Chinese names, as well as original plant of Tibetan medicine varieties are quite different in relevant Tibetan medicine standards and literatures, which resulted in common phenomena of synonym and homonym. The standards of most varieties only involve characters, and microscopic, physical and chemical identification, with low quality standards. Based on the results of the analysis, this paper suggests strengthening surveys on herbal textual research, resources and current utilization of Saxifragaceae plants used in Tibetan medicine, summarizing the varieties, establishing improved quality standards, and perfor-ming a comparative study on therapeutic material basis and biological activity of different original plants, in order to promote rational use of these medicinal plant resources, and ensuring the accuracy, safety, and effectiveness of clinical medication.

The Status quo and way forwards on the development of Tibetan medicine and the pharmacological research of tibetan materia Medica.

Tibetan medicine (TM), the second largest traditional Chinese medicine system in China, boasts a long history and an integrated theoretical system. It abounds with classical medical works constituing a unique corpus of Tibetan materia medica (TMM). China has now conceived a modern education system of TM, and Tibetan medical hospitals at different levels have been set up. Many enterprises are granted the privileges to produce preparations of TM in compliance with Good Manufacturing Practices (GMP) regulations. However, there still exist unsolved issuess in TMM research as to the mechanism of action and the active constituents of TMM which are now been tackled through pharmacology and modern science and technology. Up till now, the mechanism of action and the active constituents of 141 medicines as well as 230 preparations of TM have been preliminarily revealed. This paper reviews in detail the development of TM and the status quo of TM's pharmacological research, in hope of serving a reference value for the promotion of the modernization of TM and understanding of TM among the medical scholars.

Magnetic molecularly imprinted specific solid-phase extraction for determination of dihydroquercetin from Larix griffithiana using HPLC.

The naturally occurring quercetin flavonoid, dihydroquercetin, is widely distributed in plant tissues and has a variety of biological activities. Herein, a magnetic molecularly imprinted solid-phase extraction was tailor made for selective determination of dihydroquercetin in Larix griffithiana using high-performance liquid chromatography. Amino-functionalized core-shell magnetic nanoparticles were prepared and characterized using scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometry, and infrared spectroscopy. The polymer had an average diameter of 250 ± 2.56 nm and exhibited good stability and adsorption for template molecule, which is enriched by hydrogen bonding interaction. Multiple factors for extraction, including loading, washing, elution solvents, and extraction time, were optimized. The limit of detection was 1.23 µg/g. The precision determined at various concentration of dihydroquercetin was less than 4% and the mean recovery was between 74.64 and 101.80%. It has therefore been shown that this protocol can be used as an alternative extraction to quantify dihydroquercetin in L. griffithiana and purify quercetin flavonoid from other complex matrices.

Preparative separation of isoquinoline alkaloids from Corydalis impatiens using middle chromatogram isolated gel column coupled with positively charged reversed-phase liquid chromatography.

Positively charged reversed-phase liquid chromatography was employed for the efficient preparative separation of isoquinoline alkaloids from Corydalis impatiens. Ten commercially available columns were compared for isoquinoline alkaloids analysis. While tailing, overloading, lower resolution, and buffer salts limited the application in purification of isoquinoline compounds of many of these columns, one positively charged reversed-phase C18 column (XCharge C18) overcame these drawbacks, allowing for favorable separation resolution, even when loading isoquinoline compounds on a larger, preparative scale. The general separation process is as follows. First, isoquinoline alkaloids are enriched with Corydalis impatiens extract via a middle chromatogram isolated gel column. After column selection, separation is performed on an XCharge C18 analytical column, from which two evident chromatographic peaks are readily obtained. Finally, two isoquinoline alkaloids (protopine and corydamine) are selectively purified on the XCharge C18 preparative column. These results demonstrate that a middle chromatogram isolated gel column coupled with positively charged reversed-phase liquid chromatography is effective for the preparative separation of isoquinoline alkaloids from Corydalis impatiens.