Three new flavonoids from Penthorum chinense Pursh and their docking studies

Preparation of Alcohol Dehydrogenase-Zinc Phosphate Hybrid Nanoflowers through Biomimetic Mineralization and Its Application in the Inhibitor Screening

A biomimetic mineralization method was used in the facile and rapid preparation of nanoflowers for immobilizing alcohol dehydrogenase (ADH). The method mainly uses ADH as an organic component and zinc phosphate as an inorganic component to prepare flower-like ADH/Zn₃(PO₄)₂ organic-inorganic hybrid nanoflowers (HNFs) with the high specific surface area through a self-assembly process. The synthesis conditions of the ADH HNFs were optimized and its morphology was characterized. Under the optimum enzymatic reaction conditions, the Michaelis-Menten constant (K_m) of ADH HNFs (β-NAD⁺ as substrate) was measured to be 3.54 mM, and the half-maximal inhibitory concentration (IC₅₀) of the positive control ranitidine (0.2-0.8 mM) was determined to be 0.49 mM. Subsequently, the inhibitory activity of natural medicine Penthorum chinense Pursh and nine small-molecule compounds on ADH was evaluated using ADH HNFs. The inhibition percentage of the aqueous extract of P. chinense is 57.9%. The vanillic acid, protocatechuic acid, gallic acid, and naringenin have obvious inhibitory effects on ADH, and their percentages of inhibition are 55.1%, 68.3%, 61.9%, and 75.5%, respectively. Moreover, molecular docking analysis was applied to explore the binding modes and sites of the four most active small-molecule compounds to ADH. The results of this study can broaden the application of immobilized enzymes through biomimetic mineralization, and provide a reference for the discovery of ADH inhibitors from natural products.

An Updated Review on Efficiency of Penthorum chinense Pursh in Traditional Uses, Toxicology, and Clinical Trials

Traditional Chinese medicines (TCM) play an important role in the control and treatment of several animal diseases. Penthorum chinense Pursh (PCP) is a famous plant for its use in traditional medication practice and therapeutic effects in numerous pathological conditions. In China, PCP is utilized for both food and medication due to numerous bioactivities. PCP is widely administered in prevention and treatment of traumatic injury, edema, and liver diseases with functions of reducing swelling, support diuresis, blood stasis, and mitigation symptoms of excessive alcohol intake. Recently, PCP highlighted for research trials in various fields including pharmacology, pharmacognosy, cosmeceuticals, nutraceuticals, and pharmaceuticals due to medicinal significance with less toxicity and an effective ethnomedicine in veterinary practice. PCP contains diverse important ingredients such as flavonoids, organic acids, coumarins, lignans, polyphenols, and sterols that are important bioactive constituents of PCP exerting the therapeutic benefits and organ-protecting effects. In veterinary, PCP extract, compound, and phytochemicals/biomolecules significantly reversed the liver and kidney injuries, via antioxidation, oxidative stress, apoptosis, mitochondrial signaling pathways, and related genes. PCP water extract and compounds also proved in animal and humans' clinical trial for their hepatoprotective, antiaging, nephroprotective, anti-inflammatory, antidiabetic, antibacterial, antiapoptotic, immune regulation, and antioxidative stress pathways. This updated review spotlighted the current information on efficiency and application of PCP by compiling and reviewing recent publications on animal research. In addition, this review discussed the toxicology, traditional use, comparative, and clinical application of PCP in veterinary practices to authenticate and find out new perspectives on the research and development of this herbal medicine.

Isolation of oligostilbenes from Iris lactea Pall. var. chinensis (Fisch.) Koidz and their anti-inflammatory activities

Iris lactea Pall. var. chinensis (Fisch.) Koidz (Iris lactea) is an herbaceous perennial widely distributed in China, India, and South Korea. Iris lactea has been extensively used in traditional Chinese medicine. The present study isolated a new oligostilbene (compound 1), together with three known oligostilbenes (compounds 2, 3 and 4) from the seeds of Iris lactea. The structures of these compounds were elucidated by HRESIMS, NMR, and chemical analyses. The network-based pharmacologic analysis platform was used to predict the target proteins related to inflammation of isolated compounds. Furthermore, the isolated compounds were tested for their anti-inflammatory effects in LPS-stimulated RAW 264.7 cells. In this network, 138 candidate targets of compounds related to its therapeutic effect on inflammation were identified. In addition, compounds 1, 2, 3 and 4 significantly decreased NO content and the IL-6 levels as well as the expression of COX-2 in LPS-stimulated RAW 264.7 cells.

Dihydroflavonoids as Bioactive Components of Penthorum chinense, a Miao Ethnomedicine, against NAFLD through Bile Acid Metabolism Pathway

Penthorum chinense Pursh. is a traditional herbal medicine of Miao, and its extracts (PCPE) have been used for treatment of liver diseases in the clinic including nonalcoholic fatty liver disease (NAFLD). However, the active components and pharmacological mechanisms of PCPE for treating NAFLD remain unclear. This study aimed to explore potential mechanisms of action through network pharmacology, molecular docking combined with experimental in vitro. A total of five dihydroflavonoids (1-5) with the same parent nucleus of pinocembrin (PCB) from PCPE, were selected as bioactive ingredients and 109 potential targets related to NAFLD were obtained from public databases and literature mining. The core targets related to the bile secretion signaling were selected based on PPI network and KEGG enrichment analysis for exploring the mechanism of PCPE against NAFLD. Molecular docking results showed good interaction between the core targets in bile secretion signaling pathway and the five compounds predicted to be bioactive. With the strong binding activity to retinoid X receptor-alpha (RXRA) and farnesoid X receptor (FXR) protein, pinocembrin-7-O-β-D-glucoside (PCBG, the highest content in PCPE) and its metabolite PCB, could significantly increase the expression of RXRA, FXR and bile salt export pump (BSEP) in L02 cells, and significantly decrease the expression of cholesterol 7α-hydroxylase (CYP7A1) at mRNA and protein levels. This study provided favorable evidence for mechanism of the main dihydroflavonoids of PCPE against NAFLD, and presented a paradigm for the study of ethnomedicine.

Nonselective Cell Necrosis Mediated by the Total Flavones of Penthorum Chinensis Pursh and Thonningianin-A in Human Hepatic and Hepatoma Cells

Penthorum chinensis Pursh (PCP), family Penthoraceae, has been used for hundreds of years in China. With the launch of PCP tablets, clinical applications focused on liver fibrosis and hepatocarcinoma. The purpose of this research was to explore the selectivity and toxicity of the active pharmacodynamic ingredients of PCP in vitro. The total flavones of PCP (TFPCE) and thonningianin-A (Th-A), a major flavone in TFPCE, were investigated on the cell death patterns in human hepatoma cells (HepG2) and human hepatic cells (LO2), followed by a concentration detection of LDH in the supernatants. Apoptosis and necrosis detection kits were used to validate the patterns of cell death caused by TFPCE and Th-A. Finally, the cytotoxicity of both TFPCE and Th-A were reproduced in the colorectal adenocarcinoma cells (NCI-H716). The results indicated that TFPCE inhibits the cell viability of HepG2 cells at a concentration lower than 25 μg/mL. Alternatively, the cell viability of LO2 cells dramatically decreased in the treatment of TFPCE at 25 μg/mL. The effects of Th-A on the cell viability of HepG2 cells and LO2 cells were consistent with TFPCE. LDH detection indicated that TFPCE and Th-A increased the LDH concentration of the supernatants in a dose-dependent way, indicating the pattern of cell necrosis. Fluorescence staining verified the necrosis cell death caused by TFPCE and Th-A. A dose-dependent tendency was obtained in NCI-H716 cells, indicating that the cell viability of NCI-H716 cells was significantly suppressed with the treatment of TFPCE and Th-A. Our results bring the potential toxicity of PCP to the forefront of public attention. Therefore, the clinical application of P chinensis is required to focus more on its cytotoxic effect.

Hepatoprotective Effect of the Penthorum Chinense Pursh Extract against the CCl4-Induced Acute Liver Injury via NF-κB and p38-MAPK PATHWAYS in Dogs

Acute liver injury (ALI), manifested by acute hepatocellular damages and necrosis, is a life-threatening clinical syndrome and Penthorum Chinense Pursh (PCP) is a well-known folk medicine practiced for liver-related diseases. This study aimed to investigate the ameliorative effects of PCP extract (PCPE) on carbon tetrachloride (CCl4) induced ALI in dogs via mitogen-activated protein kinase (MAPK) and Nuclear factor κB (NF-κB) signaling pathway. Healthy dogs were induced by CCl4 and treated with different dosage regimes of PCPE for 7 days. CCl4 produced acute liver injury and induced both oxidative stress and an inflammatory response in dogs. The PCPE significantly ameliorated and improved vacuolar inflammatory lesions in liver tissues during ALI, enhanced activity of superoxide dismutase, and restored glutathione peroxidase, further significantly reducing the indices of malondialdehyde and nitric oxide in serum. Inflammatory factors (IL-1β, IL-6, and TNF-α) were declined and anti-inflammatory factors (IL-10) were increased by the application of PCPE. PCPE treatment, down-regulated the MEKK4, MKK3, p38MAPK, MSK1, and NF-κB, and upregulated the IkB mRNA levels (p < 0.01) in ALI affected dogs. In conclusion, PCPE repaired acute liver injury by improving antioxidant enzymes and by reducing oxidation products. Furthermore, the PCPE inhibited the MAPK/NF-κB signaling pathway, which resulted in anti-inflammatory and antioxidant effects on ALI-induced dogs. In the future, PCPE could be a useful ethnomedicine in veterinary clinical practices for the treatment of liver injuries or failures.

Natural Products Targeting Liver X Receptors or Farnesoid X Receptor

Nuclear receptors (NRs) are a superfamily of transcription factors induced by ligands and also function as integrators of hormonal and nutritional signals. Among NRs, the liver X receptors (LXRs) and farnesoid X receptor (FXR) have been of significance as targets for the treatment of metabolic syndrome-related diseases. In recent years, natural products targeting LXRs and FXR have received remarkable interests as a valuable source of novel ligands encompassing diverse chemical structures and bioactive properties. This review aims to survey natural products, originating from terrestrial plants and microorganisms, marine organisms, and marine-derived microorganisms, which could influence LXRs and FXR. In the recent two decades (2000-2020), 261 natural products were discovered from natural resources such as LXRs/FXR modulators, 109 agonists and 38 antagonists targeting LXRs, and 72 agonists and 55 antagonists targeting FXR. The docking evaluation of desired natural products targeted LXRs/FXR is finally discussed. This comprehensive overview will provide a reference for future study of novel LXRs and FXR agonists and antagonists to target human diseases, and attract an increasing number of professional scholars majoring in pharmacy and biology with more in-depth discussion.

Identification of neolignans with PCSK9 downregulatory and LDLR upregulatory activities from Penthorum chinense and the potential in cholesterol uptake by transcriptional regulation of LDLR via SREBP2

ETHNOPHARMACOLOGICAL RELEVANCE

Penthorum chinense has been used in East Asia for the treatment of cholecystitis, infectious hepatitis, jaundice and to treat liver problems. Recent evidences provided the potential for the clinical use of P. chinense in the treatment of metabolic disease.

AIM OF THE STUDY

Based on the traditional use and recent evidences, we investigated the effects of constituents from P. chinense with modulation on proprotein convertase subtilisin/kexin type 9 (PCSK9) and low-density lipoprotein receptor (LDLR) expression, and the effect of the most active substance on cholesterol uptake, and genes relevant to lipid metabolism.

MATERIALS AND METHODS

The isolation of compounds from the BuOH-soluble extract of 80% methanol extract of P. chinense was conducted using chromatographic methods and the structures were established by interpreting spectroscopic data. Quantitative real time-PCR, and Western blot analysis were performed to monitor the regulatory activity on PCSK9 and LDLR expression. PCSK9-LDLR binding interaction was also tested. The cholesterol uptake in hepatocyte was measured using 1,1-dioctadecyl-3,3,3,3-tetramethylindocarbocyanine perchlorate (DiI)-labeled LDL cholesterol. Additionally, gene network analysis of LDLR and responses of its target proteins were carried out to discover genes germane to the effect of active compound on HepG2 cells. Moreover, we performed protein-protein interaction analysis via String and constructed the compound target network using Cytoscape.

RESULTS

Two new neolignans and 37 known compounds were characterized from P. chinense. Of the isolated compounds, (7'E,8S)-2',4,8-trihydroxy-3-methoxy-2,4'-epoxy-8,5'-neolign-7'-en-7-one (3), penthorin A (4) and methyl gallate (25) were found to suppress PCSK9 mRNA expression with IC₅₀ values of 5.13, 15.56 and 11.66 μM, respectively. However, all the isolated compounds were found to be inactive in PCSK9-LDLR interaction assay. Additionally, a dibenzoxepine-type lignan analog, (7'E,8S)-2',4,8-trihydroxy-3-methoxy-2,4'-epoxy-8,5'-neolign-7'-en-7-one (3) demonstrated to upregulate LDLR mRNA and protein expression via transcriptional factor sterol regulatory element-binding protein 2 (SREBP2). Furthermore, (7'E,8S)-2',4,8-trihydroxy-3-methoxy-2,4'-epoxy-8,5'-neolign-7'-en-7-one (3) increase the LDL-cholesterol uptake in DiI-LDL assay.

CONCLUSION

(7'E,8S)-2',4,8-trihydroxy-3-methoxy-2,4'-epoxy-8,5'-neolign-7'-en-7-one (3) seemed to increase potentially cholesterol uptake via the downregulation of PCSK9 and the activation of LDLR in hepatocytes. Moreover, SREBP2 was found to play an important role in regulation of PCSK9 and LDLR by (7'E,8S)-2',4,8-trihydroxy-3-methoxy-2,4'-epoxy-8,5'-neolign-7'-en-7-one.

A novel flavonoid with antioxidant activity from Patrinia villosa (Thunb.) Juss

Patrinia villosa (Thunb.) Juss (P. villosa), a perennial herb, is widely used as a medicinal plant in Chinese folk. This study aims to isolate and identify the chemical constituents from P. villosa and evaluate their antioxidant activity. Normal silica column chromatography, ODS silica column chromatography, Sephadex LH-20 column chromatography and semi-preparative HPLC methods were used to obtain a new compound named 3-n-pentadecyl-4'-methoxyluteolin (1) and two known compounds including luteolin-7-O-β-D-glucuronide methyl ester (2) and apigenin-7-O-β-D-glucuronide methyl ester (3). The antioxidant activity of these compounds was determined by DPPH and ABTS methods and the IC50 values were calculated. The IC50 values of ABTS scavenging activity of 1, 2 and 3 were 12.99 ± 0.09 μM, 7.13 ± 0.07 μM and 5.15 ± 0.08 μM, respectively, and the IC50 values of DPPH scavenging activity of 1, 2 and 3 were 51.86 ± 0.41 μM, 23.95 ± 0.71 μM and 25.06 ± 0.65 μM, respectively. All the compounds exhibited good antioxidant activities in vitro.