Identification and quantification of the anti-inflammatory constituents in Pian-Tze-Huang by liquid chromatography combined with quadrupole time-of-flight and triple quadrupole mass spectrometry

Pien Tze Huang Inhibits Proliferation of Colorectal Cancer Cells through Suppressing PNO1 Expression and Activating p53/p21 Signaling Pathway

OBJECTIVE

To explore the regulatory effect of Pien Tze Huang (PZH) on targeting partner of NOB1 (PNO1) and it's down-stream mediators in colorectal cancer (CRC) cells.

METHODS

Quantitative polymerase chain reaction was performed to determine mRNA levels of PNO1, TP53, and CDKN1A. Western blotting was performed to determine protein levels of PNO1, p53, and p21. HCT-8 cells were transduced with a lentivirus over-expressing PNO1. Colony formation assay was used to detect cell survival in PNO1 overexpression of HCT-8 cells after PZH treatment. Cell-cycle distribution, cell viability and cell apoptosis were performed to identify the effect of PNO1 overexpression on cell proliferation and apoptosis of HCT-8 cells after PZH treatment. Xenograft BALB/c nude mice bearing HCT116 cells transduced with sh-PNO1 or sh-Ctrl lentivirus were evaluated. Western blot assay was performed to detect PNO1, p53, p21 and PCNA expression in tumor sections. Terminal deoxynucleotidyl transferase dUTP nick end labling (TUNEL) assay was used to determine the apoptotic cells in tissues.

RESULTS

PZH treatment decreased cell viability, down-regulated PNO1 expression, and up-regulated p53 and p21 expressions in HCT-8 cells (P<0.05). PNO1 overexpression attenuated the effects of PZH treatment, including the expression of p53 and p21, cell growth, cell viability, cell cycle arrest and cell apoptosis in vitro (P<0.05). PNO1 knockdown eliminated the effects of PZH treatment on tumor growth, inhibiting cell proliferation inhibition and apoptosis induction in vivo (P<0.05). Similarly, PNO1 knockdown attenuated the effects of PZH treatment on the down-regulation of PNO1 and up-regulation of p53 and p21 in vivo (P<0.05).

CONCLUSION

The mechanism by which PZH induces its CRC anti-proliferative effect is at least in part by regulating the expression of PNO1 and its downstream targets p53 and p21.

Evaluation and mechanism study of Pien Tze Huang against EV-A71 infection

Hand, foot, and mouth disease (HFMD) caused by enterovirus A71 (EV-A71) infection, currently lacks specific preventive and therapeutic interventions. Here, we demonstrated that Pien Tze Huang (PZH) could dose-dependently inhibit EV-A71 replication at the cellular level, resulting in significant reductions in EV-A71 virus protein 1 (VP1) expression and viral yields in Vero and human rhabdomyosarcoma cells. More importantly, we confirmed that PZH could protect mice from EV-A71 infection for the first time, with Ribavirin serving as a positive control. PZH treatment reduced EV-A71 VP1 protein expression, viral yields in infected muscles, and improved muscle pathology. Additionally, we conducted a preliminary mechanism study using quantitative proteomics. The results suggested that the suppression of the PI3K/AKT/mTOR and NF-κB signaling pathways may contribute to the anti-EV-A71 activity of PZH. These findings provide strong evidence supporting the potential therapeutic application of PZH for EV-A71 infection management.

Research progress on the pharmacological effects and chemical constituents of Pien Tze Huang and its potential Q-markers

Pien Tze Huang (PTH) was documented as an imperial prescription composed of Notoginseng Radix, Calculus Bovis, Snake Gallbladder, and Musk. It is famous in China and Asian countries due to its excellent effects in heat clearing, detoxifying, swelling reduction, and pain relieving. Modern pharmacological studies demonstrate that PTH shows excellent effects against various inflammatory diseases, liver diseases, and cancers. This review summaries the pharmacological effects, clinical applications, and mainchemical components of PTH. More importantly, its potential quality markers (Q-markers) were then analyzed based on the "five principles" of Q-markers under the guidance of Traditional Chinese Medicine theory, including transfer and traceability, specificity, efficacy, compatibility, and measurability. As a result, ginsenosides Rb1, ginsenoside Rg1, ginsenoside Rd, ginsenoside Re, notoginsenoside R1, dencichine, bilirubin, biliverdin, taurocholic acid, and muscone are considered as the Q-markers of PTH. These findings will provide guidance and assistance for the construction of a quality control system for PTH.

ANRIL promotes the regulation of colorectal cancer on lymphatic endothelial cells via VEGF-C and is the key target for Pien Tze Huang to inhibit cancer metastasis

lncRNA ANRIL is an oncogene, however the role of ANRIL in the regulation of colorectal cancer on human lymphatic endothelial cells (HLECs) is remain elusive. Pien Tze Huang (PZH, PTH) a Tradition Chinese Medicine (TCM) as an adjunctive medication could inhibit the cancer metastasis, however the mechanism still uncovering. We used network pharmacology, subcutaneous and orthotopic transplanted colorectal tumors models to determine the effect of PZH on tumor metastasis. Differential expressions of ANRIL in colorectal cancer cells, and stimulating the regulation of cancer cells on HLECs by culturing HLECs with cancer cells' supernatants. Network pharmacology, transcriptomics, and rescue experiments were carried out to verify key targets of PZH. We found PZH interfered with 32.2% of disease genes and 76.7% of pathways, and inhibited the growth of colorectal tumors, liver metastasis, and the expression of ANRIL. The overexpression of ANRIL promoted the regulation of cancer cells on HLECs, leading to lymphangiogenesis, via upregulated VEGF-C secretion, and alleviated the effect of PZH on inhibiting the regulation of cancer cells on HLECs. Transcriptomic, network pharmacology and rescue experiments show that PI3K/AKT pathway is the most important pathway for PZH to affect tumor metastasis via ANRIL. In conclusion, PZH inhibits the regulation of colorectal cancer on HLECs to alleviate tumor lymphangiogenesis and metastasis by downregulating ANRIL dependent PI3K/AKT/VEGF-C pathway.

Pien Tze Huang attenuated acetaminophen-induced liver injury by autophagy mediated-NLRP3 inflammasome inhibition

ETHNOPHARMACOLOGICAL RELEVANCE

Pien Tze Huang is a classic traditional Chinese medicinal product, used for inflammatory diseases as stated in Chinese Pharmacopoeia. In particular, it is effective in treating liver diseases and pro-inflammatory conditions. Acetaminophen (APAP) is a widely used analgesic drug, but its over-dose is associated with acute liver failure where the clinical approved antidote treatment is limited. Inflammation has been considered as one of the therapeutic targets against APAP-induced liver injury.

AIM OF THE STUDY

We aimed to explore the therapeutic potential of Pien Tze Huang tablet (PTH) on protecting liver against APAP-induced liver injury through its strong anti-inflammatory pharmacological action.

MATERIALS AND METHODS

Wild-type C57BL/6 mice were given PTH (75, 150 and 300 mg/kg) by oral gavage 3 days before the APAP injection (400 mg/kg). The protective effect of PTH was assessed by aspartate aminotransferase (AST) and alanine transaminase (ALT) levels and pathological staining. The mechanisms underlying PTH's hepatoprotective effects were investigated in nucleotide-binding domain (NOD)-like receptor protein 3 (NLRP3) knock-out (NLRP3^-/-), over expression NLRP3 (oe-NLRP3) mice, and wild-type mice with the injection of autophagy inhibitor (3-methyladenine, 3-MA).

RESULTS

APAP-exposed mice resulted in evident liver injury which was evidenced by hepatic necrosis and elevated levels of AST and ALT in the wild-type C57BL/6 mice. PTH dose-dependently reduced ALT, AST and upregulated autophagy activity. In addition, PTH significantly reduced elevated levels of proinflammatory cytokines and NLRP3 inflammasome. The liver protective effect of PTH (300 mg/kg) was still obvious in the oe-NLRP3 mice, however, it became insignificant in the NLRP3^-/- mice. When PTH (300 mg/kg) was co-treated with 3-MA to the wild-type C57BL/6 mice, the NLRP3 inhibition were reversed when autophagy was blocked.

CONCLUSION

PTH exerted a beneficial effect in protecting liver against APAP-induced liver injury. The underlying molecular mechanism was associated with the NLRP3 inflammasome inhibition which was likely driven by the upregulated autophagy activity. Our study underpins the traditional use of PTH in protecting liver through its anti-inflammatory action.

Pien-tze-huang promotes wound healing in streptozotocin-induced diabetes models associated with improving oxidative stress via the Nrf2/ARE pathway

Diabetic foot ulcers are a serious complication of diabetes, with high mortality and a lack of effective clinical treatment, which leads to a considerable financial burden. Pien-Tze-Huang (PZH) is a Chinese traditional medicine with a long history that has been found to be an effective and convenient treatment for inflammatory diseases such as skin abscesses and ulcers. In this study, we assessed the effects of PZH on diabetic wounds and the underlying mechanisms. The wounds were established on the backs of streptozotocin-induced type 1 diabetic rats and type 2 diabetic mouse models. We found that PZH treatment used locally or by gavage significantly promoted wound healing, accelerated re-epithelialization and vasculature in the wound tissue, upregulated the expression of the growth factors VEGF-A, PDGF, and EGF, and activated the Nrf2/ARE pathway in the wound tissue. In vitro assays showed that PZH improved the proliferation, migration and angiogenic function of human umbilical vein endothelial cells (HUVECs) cultured in palmitic acid, reduced the expression of the apoptotic proteins p53, Bax, and cleaved-caspase3, and activated Nrf2/ARE signaling; however, these protective effects were abrogated after Nrf2 was knocked down by specific siRNA. In addition, the levels of the serum inflammatory cytokines IL-1β, TNF-α, and IL-6 were reduced after PZH gavage treatment. In conclusion, the positive role of PZH in diabetic wound healing might be related to the activation of the Nrf2/ARE pathway to regulate the level of oxidative stress in vivo and increase the expression of growth factors to improve angiogenesis.

Pien-Tze-Huang attenuates neuroinflammation in cerebral ischaemia-reperfusion injury in rats through the TLR4/NF-κB/MAPK pathway

CONTEXT

Pien-Tze-Huang (PTH) is traditionally applied to treat various inflammation-related diseases including stroke. However, literature regarding the anti-inflammatory effects and possible mechanisms of PTH in ischaemic stroke is unavailable.

OBJECTIVE

This study investigates the anti-inflammatory effects and its underlying mechanism of PTH on ischaemic stroke.

MATERIALS AND METHODS

Cerebral ischaemia-reperfusion injury was induced through 2 h middle cerebral artery occlusion (MCAO) followed by 24 h reperfusion in male Sprague-Dawley (SD) rats receiving oral pre-treatment with PTH (180 mg/kg) for 4 days. TLR4 antagonist TAK-242 (3 mg/kg) was injected intraperitoneally at 1.5 h after MCAO. MRI, HE staining, qRT-PCR, western blot, and immunofluorescence methods were employed.

RESULTS

PTH treatment markedly reduced cerebral infarct volume (by 51%), improved neurological function (by 33%), and ameliorated brain histopathological damage in MCAO rats. It also reduced the levels of four inflammatory mediators including IL-1β (by 70%), IL-6 (by 78%), TNF-α (by 60%) and MCP-1 (by 58%); inhibited microglia and astrocyte activation; and decreased protein expression of iNOS and COX-2 in injured brains. Moreover, PTH down-regulated the protein expressions of TLR4, MyD88, and TRAF6; reduced the expression and nuclear translocation of NF-κB; and lowered the protein expressions of p-ERK1/2, p-JNK, and p-p38. Similar effects were observed in MCAO rats with TAK-242 treatment. However, combined administration of PTH and TAK-242 did not significantly reinforce the anti-inflammatory effects of PTH.

DISCUSSION AND CONCLUSION

PTH improved cerebral ischaemia-reperfusion injury by inhibiting neuroinflammation partly via the TLR4/NF-κB/MAPK signalling pathway, which will help guide its clinical application.

Binary Eluent Based Vortex-Assisted Matrix Solid-Phase Dispersion for the Extraction and Determination of Multicomponent from Musk by Gas Chromatography-Mass Spectrometry

A green, flexible, and effective strategy was proposed to quantify four target compounds (muscone, ethyl palmitate, ethyl oleate, and ethylparaben) from musk by binary eluent based vortex-assisted matrix solid-phase dispersion (MSPD) extraction coupled with GC/MS. Single-factor tests and orthogonal design were employed to optimize the MSPD parameters. In addition, the binary eluent system, methanol, and ethyl acetate 3 : 7 (v/v) were used to extract the target analytes. Finally, C ₁₈ was applied as the easily available dispersant and the sample powder was ground for 2 min. Thereafter, the mixture was rapidly extracted with the binary eluents under whirling for 3 min. Eventually, the analysis of the samples was completed within 12 min by GC/MS. All correlation coefficients (r) of four targets were more than 0.9991. The recoveries of all target compounds ranged from 92.8% to 101% while their RSDs were less than 6.94%. There was no significant matrix interference for the analysis. Thus, the combination of vortex-assisted MSPD with GC/MS was considered as a novel, rapid, and environmentally friendly quantitative approach for musk samples.

Pien-Tze-Huang, a Chinese patent formula, attenuates NLRP3 inflammasome-related neuroinflammation by enhancing autophagy via the AMPK/mTOR/ULK1 signaling pathway

NLRP3 inflammasome is a key mediator in ischemic stroke-induced neuroinflammation and subsequent brain injury. Our previous study demonstrated the potent activity of Pien-Tze-Huang (PTH), a well-known Chinese patent formula, in reducing mitochondria-mediated neuronal apoptosis in cerebral ischemia/reperfusion impaired rats. This study aims to elucidate the mechanistic action of PTH related to neuroinflammation in LPS-induced BV2 microglial cells and cerebral ischemia/reperfusion impaired rats. BV2 cells were stimulated with LPS for 12 h and treated with PTH with various concentrations. Modulation by PTH of relevant genes (IL-6, IL-1β, IL-18, TNF-α, COX-2 and iNOS mRNA) and proteins (NLRP3 inflammasome, autophagy and AMPK/mTOR/ULK signaling) was analyzed by real-time PCR and western blot, respectively. Similar analyses were conducted in middle cerebral artery occlusion rat model including neurological deficit, infarct volume, microglial activation, and key genes and proteins in modulating autophagy and NLRP3. Our results showed that PTH significantly inhibited the production of key proinflammatory mediators and protein expressions of NLRP3 and caspase-1 p20 in LPS induced BV2 cells. It also enhanced the autophagy response by modulating the key autophagy proteins via AMPK/mTOR/ULK related pathway. The reduced inflammatory responses and NLRP3 expressions by PTH were partially blocked by the autophagy inhibitor (3-MA) and AMPK blocker (compound C). In rats, PTH significantly reduced infarct size, suppressed microglial activation, and improved neuron deficit. It also promoted autophagy and reduced NLRP3 activity. Our study demonstrated that PTH inhibited NLRP3 inflammasome-mediated neuroinflammation, which was associated with enhanced autophagy via AMPK/mTOR/ULK1 pathway in vitro and in vivo.

[Chemome profiling of Pien-Tze-Huang by online pressurized liquid extraction-ultra-high performance liquid chromatography-ion trap-time-of-flight mass spectrometry]

Pien-Tze-Huang is one of the most famous traditional Chinese medicine prescriptions and consists of several precious medicinal materials, such as Notoginseng Radix et Rhizoma, Bovis Calculus, Snake Gall, and Moschus. However, its formula has not been completely revealed. It is mainly applied for the treatment of acute and chronic viral hepatitis, carbuncle, and boils caused by blood stasis, unknown swelling, bruises, and various inflammation disorders. The chemical composition of Pien-Tze-Huang is extremely complicated. Thus far, extensive attention has been paid to the principal chemical families in Pien-Tze-Huang, such as ginsenosides, bile acids, and muscone derivatives. Comprehensive chemical profiling, although of immense importance for systematic quality control, has not been achieved. Therefore, we configured a platform, namely online pressurized liquid extraction-ultra-high-performance liquid chromatography-ion trap-time-of-flight mass spectrometry (online PLE-UHPLC-IT-TOF-MS), to characterize the chemical profile of Pien-Tze-Huang in detail as well as to conduct source attribution, aiming to clarify the chemome of Pien-Tze-Huang and to provide a reliable method for quality assessment. A sub-microgram amount of Pien-Tze-Huang powder (0.3 mg) was placed in a hollow guard column, which was subsequently filled with clear silica gel. Filter membranes were used to seal the extraction vessel. The vessel was then placed in an adapted guard column holder and maintained in a thermal column oven (70 ℃). Metal tubing was used to connect the outlet of the guard column holder to the mass spectrometer. The extraction phase was maintained for 3 min by employing 0.1%(v/v) formic acid aqueous solution as the extraction solvent with a flow rate of 0.2 mL/min. Moreover, a six-port two-position electronic valve was introduced to automatically switch the system from extraction to elution phases. Within the elution phase, 0.1%(v/v) formic acid aqueous solution and acetonitrile composed the mobile phase, and the extracts were eluted with a gradient program. Because of the elevated temperature and pressure, the physical and chemical properties of water, especially polarity and solubility, were modified. Therefore, warm water could be an eligible green solvent to achieve wide polarity-spanned extraction. In addition, IT-TOF-MS was employed to acquire tandem mass spectrometry information. The mass fragmentation pathways of saponins and bile acids were carefully studied. Finally, according to authentic compounds, mass fragmentation pathways, reference information in the literature, and accessible databanks, a total of 73 signals were observed from Pien-Tze-Huang, of which 71 components were tentatively identified and assigned. Among them, 36 were from Notoginseng Radix et Rhizoma, 15 from Snake Gall, and 9 from Bovis Calculus, while the occurrences of the other 11 components were synergistically contributed by both Bovis Calculus and Snake Gall, through retrieving the in-house chemical database that was built by considering all accessible chemical information from Notoginseng Radix et Rhizoma, Bovis Calculus, Snake Gall, and Moschus. The other two compounds were assigned as unknown compounds. However, none of the components were assigned to Moschus because they mainly contained hydrophobic compounds, such as cycloketones, cholesterol, and sterols, among others, and it was difficult to detect them with the current measurement program. The extraction efficiency of online PLE was assessed by comparing it with the efficiency obtained from ultrasonication at the same time. According to base peak ion current chromatograms (BPCs) and mass spectrometry information, the efficiency of online PLE was greater than that of ultrasonic extraction, even through direct analysis. Online PLE-UHPLC-IT-TOF-MS is not only a tool fit for the concept of green analytical chemistry, but also a reliable analytical pipeline for the direct characterisation of other complicated matrixes. Above all, this study clarified the chemome of Pien-Tze-Huang and provided meaningful information for the quality control of this famous TCM prescription.

Pien Tze Huang (PZH) as a Multifunction Medicinal Agent in Traditional Chinese Medicine (TCM): a review on cellular, molecular and physiological mechanisms

RELEVANCE

Pien Tze Huang (PZH) is a well-known Traditional Chinese Medicine (TCM), characterized by a multitude of pharmacological effects, such as hepatoprotection and inhibition of inflammation and cell proliferative conditions. Many of these effects have been validated at the cellular, molecular and physiological levels but, to date, most of these findings have not been comprehensively disclosed.

OBJECTIVES

This review aims to provide a critical summary of recent studies focusing on PZH and its multiple pharmacological effects. As a result, we further discuss some novel perspectives related to PZH's mechanisms of action and a holistic view of its therapeutic activities.

METHODS

A systematic review was performed focusing on PZH studies originated from original scientific resources. The scientific literature retrieved for this work was obtained from International repositories including NCBI/PubMed, Web of Science, Science Direct and China National Knowledge Infrastructure (CNKI) databases.

RESULTS

The major active componentes and their potential functions, including hepatoprotective and neuroprotective effects, as well as anti-cancer and anti-inflammatory activities, were summarized and categorized accordingly. As indicated, most of the pharmacological effects were validated in vitro and in vivo. The identification of complex bioactive components in PZH may provide the basis for further therapeutic initiatives.

CONCLUSION

Here we have collectively discussed the recent evidences covering most, if not all, pharmacological effects driven by PZH. This review provides novel perspectives on understanding the modes of action and the holistic view of TCM. The rational development of future clinical trials will certainly provide evidence-based medical evidences that will also confirm the therapeutic advantages of PZH, based on the current information available.

Therapeutic Potential of Pien-Tze-Huang: A Review on Its Chemical Composition, Pharmacology, and Clinical Application

Pien-Tze-Huang (PTH) is a famous and commonly used traditional Chinese medicine formula in China. It was first formulated by a royal physician of the Ming Dynasty (around 1555 AD). Recently, PTH has attracted attention worldwide due to its beneficial effects against various diseases, especially cancer. This paper systematically reviewed the up-to-date information on its chemical composition, pharmacology, and clinical application. A range of chemical compounds, mainly ginsenosides and bile acids, have been identified and quantified from PTH. Pharmacological studies indicated that PTH has beneficial effects against various cancers, hepatopathy, and ischemic stroke. Furthermore, PTH has been used clinically to treat various diseases in China, such as colorectal cancer, liver cancer, and hepatitis. In summary, PTH is a potential agent with extensive therapeutic effects for the treatment of various diseases. However, the lack of information on the side effects and toxicity of PTH is a non-negligible issue, which needs to be seriously studied in the future.

Comprehensive characterization of multiple components and metabolites of Xiaojin Capsule based on ultra high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry

Xiaojin Capsule, a classic traditional Chinese medicine formula, has been used to treat mammary cancer, thyroid nodules, and hyperplasia of the mammary glands. However, its systematic chemical information remained unclear, which hindered the interpretation of the pharmacology and the mechanism of action of this drug. In this research, an ultra high performance liquid chromatography coupled with a quadrupole time-of-flight mass spectrometry method was developed to identify the complicated components and metabolites of Xiaojin Capsule. Two acquisition modes, including the MS^Energy mode and fast data directed acquisition mode, were utilized for chemical profiling. As a result, 156 compounds were unambiguously or tentatively identified by comparing their retention times and mass spectrometry data with those of reference standards or literature. After the oral administration of Xiaojin Capsule, 53 constituents, including 24 prototype compounds and 29 metabolites, were detected in rat plasma. The obtained results were beneficial for a better understanding of the therapeutic basis of Xiaojin Capsule. A high-resolution and efficient separation method was firstly established for systematically characterizing the compounds of Xiaojin Capsule and the associated metabolites in vivo, which could be helpful for quality control and pharmacokinetic studies of this medicine.

Pien-Tze-Huang protects cerebral ischemic injury by inhibiting neuronal apoptosis in acute ischemic stroke rats

ETHNOPHARMACOLOGICAL RELEVANCE

Pien-Tze-Huang (PZH) is a famous formula of traditional Chinese medicine used to treating stroke. However, the protective effect of PZH and its mechanisms in acute ischemic stroke remain to be explored.

AIM OF THE STUDY

To investigate the protective effect of PZH on neuronal apoptosis in acute cerebral ischemic injury rats and explore its underlying mechanisms.

MATERIALS AND METHODS

The effects of PZH were studied in acute ischemic stroke rats induced by transient middle cerebral artery occlusion, and the mitochondria-mediated apoptotic proteins including cytochrome C (Cyt C), Bax, Bcl-xl, P53, caspase-3, and caspase-9 as well as AKT and glycogen synthase kinase-3 beta (GSK-3β) were assessed.

RESULTS

Four days of PZH treatment (180 mg/kg) could significantly reduce cerebral infarct volume, improve neurological deficit, attenuate inflammatory response, and inhibit neuronal apoptosis in acute ischemic stroke rats. Moreover, PZH treatment significantly decreased cytosolic Cyt C, Bax, P53, cleaved caspase-3, and cleaved caspase-9 levels, but elevated mitochondrial Cyt C and Bcl-xl levels. PZH treatment also increased phosphorylation of AKT and GSK-3β.

CONCLUSION

PZH potently protects the brain from cerebral ischemia/reperfusion injury in vivo, and inhibiting mitochondria-mediated neuronal apoptosis as well as attenuating inflammatory responses may be involved in this effect. This study provides experimental basis of PZH in treating acute cerebral ischemic stroke, which would provide some novel insights for its prevention and treatment of ischemic stroke.

Molecular mechanism of activation of human musk receptors OR5AN1 and OR1A1 by (R)-muscone and diverse other musk-smelling compounds

Understanding olfaction at the molecular level is challenging due to the lack of crystallographic models of odorant receptors (ORs). To better understand the molecular mechanism of OR activation, we focused on chiral (R)-muscone and other musk-smelling odorants due to their great importance and widespread use in perfumery and traditional medicine, as well as environmental concerns associated with bioaccumulation of musks with estrogenic/antiestrogenic properties. We experimentally and computationally examined the activation of human receptors OR5AN1 and OR1A1, recently identified as specifically responding to musk compounds. OR5AN1 responds at nanomolar concentrations to musk ketone and robustly to macrocyclic sulfoxides and fluorine-substituted macrocyclic ketones; OR1A1 responds only to nitromusks. Structural models of OR5AN1 and OR1A1 based on quantum mechanics/molecular mechanics (QM/MM) hybrid methods were validated through direct comparisons with activation profiles from site-directed mutagenesis experiments and analysis of binding energies for 35 musk-related odorants. The experimentally found chiral selectivity of OR5AN1 to (R)- over (S)-muscone was also computationally confirmed for muscone and fluorinated (R)-muscone analogs. Structural models show that OR5AN1, highly responsive to nitromusks over macrocyclic musks, stabilizes odorants by hydrogen bonding to Tyr260 of transmembrane α-helix 6 and hydrophobic interactions with surrounding aromatic residues Phe105, Phe194, and Phe207. The binding of OR1A1 to nitromusks is stabilized by hydrogen bonding to Tyr258 along with hydrophobic interactions with surrounding aromatic residues Tyr251 and Phe206. Hydrophobic/nonpolar and hydrogen bonding interactions contribute, respectively, 77% and 13% to the odorant binding affinities, as shown by an atom-based quantitative structure-activity relationship model.

Simultaneous quantification six active compounds in rat plasma by UPLC-MS/MS and its application to a pharmacokinetic study of Pien-Tze-Huang

Pien-Tze-Huang (PZH) is a popular traditional Chinese medicine (TCM) formula in China, but its pharmacokinetics has not been investigated yet. To better study the pharmacokinetic behaviors of PZH, an optimal ultra-performance liquid chromatography with triple quadrupole mass spectrometry (UPLC-MS/MS) method was developed for rapid quantification of six compounds (notoginsenoside R1, ginsenosides Re, Rg1, Rb1, Rd, and muscone) in rat plasma after oral administration of PZH. All analytes were extracted by protein precipitation with acetonitrile and separated on a Waters Acquity Cortecs C18 column within 3.9min, and detected by multiple-reaction monitoring in positive ion mode. This proposed method exhibited good linearity (r≥0.9932) with a lower quantification limits of 0.558-1.566ng/mL for all analytes. The intra- and inter-day precisions were within 8.24%, and the accuracy was within -10.05 to 9.87% for each analyte. The extraction recovery for each analyte ranged from 80.02 to 96.12%. This UPLC-MS/MS method was successfully applied to the pharmacokinetic study for PZH in rats.