Lavandulyl flavanones from Sophora flavescens protect mouse hippocampal cells against glutamate-induced neurotoxicity via the induction of heme oxygenase-1

Prenylated Flavonoids in Sophora flavescens: A Systematic Review of Their Phytochemistry and Pharmacology

Sophora flavescens has been widely used in traditional Chinese medicine for over 1700 years. This plant is known for its heat-clearing, damp-drying, insecticidal, and diuretic properties. Phytochemical research has identified prenylated flavonoids as a unique class of bioactive compounds in S. flavescens. Recent pharmacological studies reveal that the prenylated flavonoids from S. flavescens (PFS) exhibit potent antitumor, anti-inflammatory, and glycolipid metabolism-regulating activities, offering significant therapeutic benefits for various diseases. However, the pharmacokinetics and toxicological profiles of PFS have not been systematically studied. Despite the diverse biological effects of prenylated flavonoid compounds against similar diseases, their structure-activity relationship is not yet fully understood. This review aims to summarize the latest findings regarding the chemical composition, drug metabolism, pharmacological properties, toxicity, and structure-activity relationship of prenylated flavonoids from S. flavescens. It seeks to highlight their potential for clinical use and suggest directions for future related studies.

Systematic elucidation of the bioactive alkaloids and potential mechanism from Sophora flavescens for the treatment of eczema via network pharmacology

ETHNOPHARMACOLOGY RELEVANCE

Sophora flavescens is a frequently used traditional Chinese medicine (TCM) for the treatment of skin disorders, diarrhea, vaginal itching and inflammatory diseases. In particular, the root of S. flavescens combination with other herbs mainly treat eczema ailment in the clinical applications. However, a holistic network pharmacology approach to understanding the mechanism by which alkaloids in S. flavescens treat eczema has not been pursued.

AIM OF THE STUDY

To examine the network pharmacological potential effect of S. flavescens on eczema, we studied the alkaloids, performed protein targets prediction and investigated interacting signal pathways. Furthermore, animal experiment was carried out to evaluate its efficacy and real-time quantitative polymerase chain reactions (RT-qPCR) analysis was explored the mechanism of action.

MATERIALS AND METHODS

The detail information on alkaloids from S. flavescens were obtained from a handful of public databases on the basis of oral bioavailability (OB ≥ 30%) and drug-likeness (DL ≥ 0.18). Then, correlations between compounds and protein targets were linked using the STRING database, and targets associated with eczema were gathered by the GeneCards database. Human genes were identified and subjected to Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis and Gene Ontology (GO) functional enrichment analysis. Particularly, matrine, the crucial alkaloid from S. flavescens, was estimated using a 2,4-dinitrochlorobenzene (DNCB)-induced eczema Kunming (KM) mice model, administered (50 mg/kg and 10 mg/kg) to mice for 22 days. On the last day, the activities of serum tumor necrosis factor α (TNF-α), interleukin-4 (IL-4) and histopathologic examinations were determined. For further to elucidate the mechanisms, the mRNA levels of TNF-α, STAT3, TP53, AKT1, IL-6, JUN and EGFR in dorsal skin tissues were also tested.

RESULTS

Network analysis collected and identified 35 alkaloids from S. flavescens. Among them, in total 10 dominating alkaloids, including matrine, oxymatrine, sophoridine, sophocarpine, oxysophocarpine, allomatrine, sophoramine, anagyrine, cytisine and N-methylcytisine. And 71 related targets were provided of alkaloids for the treatment of eczema from S. flavescens. Furthermore, matrine dose-dependently (50 or 10 mg/kg, 22 days, apply to dorsal skin) remarkable decreased the serum levels of TNF-α and IL-4, and significantly alleviated the skin lesions. The effects of 50 mg/kg of matrine were almost identical to those of 200 mg/kg of the positive drug dexamethasone (DXM). The further RT-qPCR analyses could reveal that matrine down-regulate TNF-α, STAT3 and TP53 at transcriptional level in dorsal skin tissues.

CONCLUSION

Pharmacological network analysis can utilize to illuminate the pharmacodynamic substances and the potential molecular mechanism of S. flavescens for treating eczema. Matrine, as the crucial alkaloid from S. flavescens, could be a promising drug candidate for the treatment of eczema ailment.

Kurarinone attenuates hydrogen peroxide-induced oxidative stress and apoptosis through activating the PI3K/Akt signaling by upregulating IGF1 expression in human ovarian granulosa cells

Dysregulated follicular development may lead to follicular atresia, and this is associated with oxidative stress in granulosa cells. Kurarinone is a natural compound possessing multiple activities, including antioxidative ability. However, the role of kurarinone in granulosa cell damage during follicular atresia remains unknown. Human ovarian granulosa KGN cells were treated with hydrogen peroxide (H₂ O₂ ) to induce cellular damage. Cytotoxicity was investigated by lactate dehydrogenase (LDH) release assay. Oxidative stress was evaluated by detection of reactive oxygen species (ROS) generation and oxidative biomarker levels. Cell apoptosis was evaluated by flow cytometry, a Cell Death Detection ELISA Kit, and a Caspase-3 Assay Kit. The downstream target and related signaling pathway were analyzed by western blotting. Kurarinone attenuated H₂ O₂ -induced LDH release in KGN cells. Kurarinone relieved H₂ O₂ -induced increase in ROS generation and malondialdehyde level as well as decrease in superoxide dismutase-1 activity and heme oxygenase 1 and NAD(P)H quinone dehydrogenase 1 mRNA levels. Kurarinone inhibited H₂ O₂ -induced apoptosis in KGN cells. Kurarinone targeted insulin-like growth factor 1 (IGF1) and upregulated IGF1 expression to activate the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling. IGF1 silencing attenuated the suppressive effects of kurarinone on H₂ O₂ -induced oxidative stress and apoptosis in KGN cells. In conclusion, kurarinone attenuates H₂ O₂ -induced oxidative stress and apoptosis in KGN cells through activating the PI3K/Akt signaling by upregulating IGF1 expression, indicating the therapeutic potential of kurarinone in follicular atresia.

Chemical diversity, biological activities and Traditional uses of and important Chinese herb Sophora

BACKGROUND

Sophora flavescens Aiton (SF), also known as Kushen (Chinese:), has been an important species in Chinese medicine since the Qin and Han dynasties. It is also recognized as a plant resource suitable for the globalization of Chinese medicine. Traditionally, it has been used in various ethnic medical systems in East Asia, especially in China, to kill insects and dispel dampness. Sophora flavescens is commonly used for clearing heat-clearing, killing worms, and diuretic. Nowdays, accumulating studies demonstrated its anticancer and cardioprotection.

OBJECTIVE OF THE REVIEW

This paper aims to systematically review information on the genus, pharmacological and toxicological significance, chemical composition and biological activity of Sophora flavescens. To promoting its development and application. To summarize recent findings regarding to the metabolism, pharmacological/toxicological effects of Sophora flavescens.

MATERIAL AND METHODS

Online academic databases (including PubMed, Google Scholar, Web of Science and CNKI) were searched using search terms of "Sophora flavescens Aiton", "Ku shen", "Pharmacology", "Active ingredient", "Toxicology" and combinations to include published studies of Sophora flavescens Aiton primarily from 1970-2021. Several critical previous studies beyond this period were also included and other related terms.

CONCLUSION

Sophora flavescens has a broad spectrum of biological activities associated with Sophora flavescens has been considered a valuable resource in both traditional and modern medicine. However, there is a lack of in-depth studies on the medicinal uses of Sophora flavescens. Moreover, further studies on single chemical components should be conducted based on the diversity of chemical structures, significant biological activities and clinical applications. The discovery of its bioactive molecules and multi-component interactions would be of great importance for the clinical application of Sophora flavescens spp. Detailed pharmacological and toxicological studies on the classic prescriptions of Sophora flavescens are also needed. It is more beneficial to the wide application of SF plant and facilitates the worldwide promotion of modern Chinese medicine. However, an increasing number of reports indicate that the administration of Sophora flavescens has serious adverse effects. Its main toxic effects are neurotoxicity and acute toxicity, which have caused widespread concern worldwide. In addition, the alkaloids of Sophora flavescens are distributed in the heart, liver, stomach and large intestine. They are excreted from the body through gluconeogenesis, which is the mode of action of certain therapeutic mechanisms of action such as anticancer. The detailed metabolic study of alkaloids and other components of Sophora flavescens in vivo needs to be further investigated. It is important to improve the pharmacological effects and reduce the toxicity of Sophora flavescens. For this purpose, structural modification of active components of Sophora flavescens or combination with other drugs is very essential.

In Vitro and In Silico Characterization of Kurarinone as a Dopamine D1A Receptor Antagonist and D2L and D4 Receptor Agonist

Alterations in the expression and/or activity of brain G-protein-coupled receptors (GPCRs) such as dopamine D₁R, D_2LR, D₃R, and D₄R, vasopressin V_1AR, and serotonin 5-HT_1AR are noted in various neurodegenerative diseases (NDDs). Since studies have indicated that flavonoids can target brain GPCRs and provide neuroprotection via inhibition of monoamine oxidases (hMAOs), our study explored the functional role of kurarinone, an abundant lavandulated flavonoid in Sophora flavescens, on dopamine receptor subtypes, V_1AR, 5-HT_1AR, and hMAOs. Radioligand binding assays revealed considerable binding of kurarinone on D₁R, D_2LR, and D₄R. Functional GPCR assays unfolded the compound's antagonist behavior on D₁R (IC₅₀ 42.1 ± 0.35 μM) and agonist effect on D_2LR and D₄R (EC₅₀ 22.4 ± 3.46 and 71.3 ± 4.94 μM, respectively). Kurarinone was found to inhibit hMAO isoenzymes in a modest and nonspecific manner. Molecular docking displayed low binding energies during the intermolecular interactions of kurarinone with the key residues of the deep orthosteric binding pocket and the extracellular loops of D₁R, D_2LR, and D₄R, validating substantial binding affinities to these prime targets. With appreciable D_2LR and D₄R agonism and D₁R antagonism, kurarinone might be a potential compound that can alleviate clinical symptoms of Parkinson's disease and other NDDs.

Two New Isoprenoid Flavonoids from Sophora flavescens with Antioxidant and Cytotoxic Activities

Sophora flavescens is a regularly used traditional Chinese medicine. In an attempt to discover adequate active agents, the isoprenoid flavonoids from S. flavescens were further investigated. In this work, two new compounds (1-2, kurarinol A-B) together with 26 known ones (3-28) were isolated and elucidated on the basis of extensive NMR, UV and MS analyses. Furthermore, the antioxidant activity of all constituents was assessed through ABTS, PTIO and DPPH methodologies and also were evaluated for cytotoxic activity by three tumor cell lines (HepG2, A549 and MCF7) and one human normal cell line (LO2 cells). As a result, a multitude of components revealed significant inhibitory activity. In particular, compound 1-2 (kurarinol A-B), two new flavanonols derivatives, exhibited the most potent ABTS inhibitory activity with IC50 of 1.21 µg/mL and 1.81 µg/mL, respectively. Meanwhile, the new compound 1 demonstrated remarkable cytotoxicity against three cancer cells lines with IC50 values ranging from 7.50-10.55 μM but showed little effect on the normal cell. The two new isoprenoid flavonoids could be promising antioxidant and anti-tumor nature agents.

Five-Decade Update on Chemopreventive and Other Pharmacological Potential of Kurarinone: a Natural Flavanone

In the present article we present an update on the role of chemoprevention and other pharmacological activities reported on kurarinone, a natural flavanone (from 1970 to 2021). To the best of our knowledge this is the first and exhaustive review of kurarinone. The literature was obtained from different search engine platforms including PubMed. Kurarinone possesses anticancer potential against cervical, lung (non-small and small), hepatic, esophageal, breast, gastric, cervical, and prostate cancer cells. In vivo anticancer potential of kurarinone has been extensively studied in lungs (non-small and small) using experimental xenograft models. In in vitro anticancer studies, kurarinone showed IC₅₀ in the range of 2–62 µM while in vivo efficacy was studied in the range of 20–500 mg/kg body weight of the experimental organism. The phytochemical showed higher selectivity toward cancer cells in comparison to respective normal cells. kurarinone inhibits cell cycle progression in G2/M and Sub-G1 phase in a cancer-specific context. It induces apoptosis in cancer cells by modulating molecular players involved in apoptosis/anti-apoptotic processes such as NF-κB, caspase 3/8/9/12, Bcl2, Bcl-XL, etc. The phytochemical inhibits metastasis in cancer cells by modulating the protein expression of Vimentin, N-cadherin, E-cadherin, MMP2, MMP3, and MMP9. It produces a cytostatic effect by modulating p21, p27, Cyclin D1, and Cyclin A proteins in cancer cells. Kurarinone possesses stress-mediated anticancer activity and modulates STAT3 and Akt pathways. Besides, the literature showed that kurarinone possesses anti-inflammatory, anti-drug resistance, anti-microbial (fungal, yeast, bacteria, and Coronavirus), channel and transporter modulation, neuroprotection, and estrogenic activities as well as tyrosinase/diacylglycerol acyltransferase/glucosidase/aldose reductase/human carboxylesterases 2 inhibitory potential. Kurarinone also showed therapeutic potential in the clinical study. Further, we also discussed the isolation, bioavailability, metabolism, and toxicity of Kurarinone in experimental models.

Kurarinone Attenuates Collagen-Induced Arthritis in Mice by Inhibiting Th1/Th17 Cell Responses and Oxidative Stress

Kurarinone is a flavanone, extracted from Sophora flavescens Aiton, with multiple biological effects. Here, we determine the therapeutic potential of kurarinone and elucidate the interplay between kurarinone and the autoimmune disease rheumatoid arthritis (RA). Arthritis was recapitulated by induction of bovine collagen II (CII) in DBA/1 mice as a collagen-induced arthritis (CIA) model. After the establishment of the CIA, kurarinone was given orally from day 21 to 42 (100 mg/kg/day) followed by determination of the severity based on a symptom scoring scale and with histopathology. Levels of cytokines, anti-CII antibodies, and the proliferation and lineages of T cells from the draining lymph nodes were measured using ELISA and flow cytometry, respectively. The expressional changes, including STAT1, STAT3, Nrf2, KEAP-1, and heme oxygenase-1 (HO-1) changes in the paw tissues, were evaluated by Western blot assay. Oxidative stress featured with malondiadehyde (MDA) and hydrogen peroxide (H₂O₂) activities in paw tissues were also evaluated. Results showed that kurarinone treatment reduced arthritis severity of CIA mice, as well as their levels of proinflammatory cytokines, TNF-α, IL-6, IFN-γ, and IL-17A, in the serum and paw tissues. T cell proliferation was also reduced by kurarinone even under the stimulation of CII and anti-CD3 antibody. In addition, kurarinone reduced STAT1 and STAT3 phosphorylation and the proportions of Th1 and Th17 cells in lymph nodes. Moreover, kurarinone suppressed the production of MDA and H₂O_2. All while promoting enzymatic activities of key antioxidant enzymes, SOD and GSH-Px. In the paw tissues, upregulation of Nrf-2 and HO-1, and downregulation of KEAP-1 were observed. Overall, kurarinone showed an anti-inflammatory effect by inhibiting Th1 and Th17 cell differentiation and an antioxidant effect exerted in part through activating the Nrf-2/KEAP-1 pathway. These beneficial effects in CIA mice contributed to the amelioration of their arthritis, indicating that kurarinone might be an adjunct treatment option for rheumatoid arthritis.

Natural Antioxidant and Anti-Inflammatory Compounds in Foodstuff or Medicinal Herbs Inducing Heme Oxygenase-1 Expression

Heme oxygenase-1 (HO-1) is an inducible antioxidant enzyme that catalyzes heme group degradation. Decreased level of HO-1 is correlated with disease progression, and HO-1 induction suppresses development of metabolic and neurological disorders. Natural compounds with antioxidant activities have emerged as a rich source of HO-1 inducers with marginal toxicity. Here we discuss the therapeutic role of HO-1 in obesity, hypertension, atherosclerosis, Parkinson's disease and hepatic fibrosis, and present important signaling pathway components that lead to HO-1 expression. We provide an updated, comprehensive list of natural HO-1 inducers in foodstuff and medicinal herbs categorized by their chemical structures. Based on the continued research in HO-1 signaling pathways and rapid development of their natural inducers, HO-1 may serve as a preventive and therapeutic target for metabolic and neurological disorders.

Brassicaphenanthrene A from Brassica rapa protects HT22 neuronal cells through the regulation of Nrf2‑mediated heme oxygenase‑1 expression

Brain cell damage that results from oxidative toxicity contributes to neuronal degeneration. The transcription factor nuclear factor‑E2‑related factor 2 (Nrf2) regulates the expression of heme oxygenase (HO)‑1 and glutathione (GSH), and serves a key role in the pathogenesis of neurological diseases. Brassica rapa is a turnip that is unique to Ganghwa County, and is used mainly for making kimchi, a traditional Korean food. In the current study, brassicaphenanthrene A (BrPA) from B. rapa was demonstrated to exhibit protective effects against neurotoxicity induced by glutamate via Nrf2‑mediated HO‑1 expression. Similarly, BrPA increased the expression of cellular glutathione and glutamine‑cysteine ligase genes. Furthermore, BrPA caused the nuclear translocation of Nrf2 and increased antioxidant response element (ARE) promoter activity. Nrf2 also mediated HO‑1 induction by BrPA through the PI3K/Akt and JNK regulatory pathways. The results of the present study indicated the neuroprotective effect of BrPA, a natural food component from B. rapa.

Sophora Tomentosa Extract Prevents MPTP-Induced Parkinsonism in C57BL/6 Mice Via the Inhibition of GSK-3β Phosphorylation and Oxidative Stress

Sophora species are used as dietary medicines in aging-associated symptoms. Sophora tomentosa L. (ST) is a native medicinal plant in Southeast Asia; however, there is no pharmacological literature about ST extract. The present study evaluates the antioxidant phytoconstituent contents and radical scavenging capacities of ST extract. The further investigation was to clarify the neuroprotective mechanism of ST extract against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinsonism by assaying the activities of the dopaminergic system and antioxidant defenses, glycogen synthase kinase 3β (GSK3-β) phosphorylation, and α-synuclein levels in C57BL/6 mice. The results show that ST extract alleviated the motor deficits in MPTP-induced Parkinsonism with four behavioral tests, including a rearing locomotor, catalepsy test, balance beam walking test, and pole test. ST extract reversed the number of tyrosine hydroxylase (TH)-positive neurons in substantia nigra (SN) that had decreased by MPTP. ST extract also restored the decreased levels of dopamine and the expression of tyrosine hydroxylase (TH) in the striatum. Furthermore, ST extract restored the levels of glutathione (GSH) and the activities of antioxidant enzymes, and decreased the elevated levels of malondialdehyde (MDA) in mouse striatum. ST extract also decreased α-synuclein overexpression and GSK-3β phosphorylation in mouse striatum. In vitro, ST extract exerted higher 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging capacities through its higher phenolic contents, especially protocatechuic acid and epicatechin. These results suggest that ST extract has the potential to counteract MPTP-induced motor deficit. The neuroprotective mechanism of ST extract against MPTP-induced Parkinsonism might be related to decreasing GSK-3β phosphorylation and restoring the activities of striatal antioxidant defenses to restore the nigrostriatal dopaminergic function and decrease α-synuclein accumulation.

The rational search for PDE10A inhibitors from Sophora flavescens roots using pharmacophore‑ and docking‑based virtual screening

Phosphodiesterase 10A (PDE10A) has been confirmed to be an important target for the treatment of central nervous system (CNS) disorders. The purpose of the present study was to identify PDE10A inhibitors from herbs used in traditional Chinese medicine. Pharmacophore and molecular docking techniques were used to virtually screen the chemical molecule database of Sophora flavescens, a well‑known Chinese herb that has been used for improving mental health and regulating the CNS. The pharmacophore model generated recognized the common functional groups of known PDE10A inhibitors. In addition, molecular docking was used to calculate the binding affinity of ligand‑PDE10A interactions and to investigate the possible binding pattern. Virtual screening based on the pharmacophore model and molecular docking was performed to identify potential PDE10A inhibitors from S. flavescens. The results demonstrated that nine hits from S. flavescens were potential PDE10A inhibitors, and their biological activity was further validated using literature mining. A total of two compounds were reported to inhibit cyclic adenosine monophosphate phosphodiesterase, and one protected against glutamate‑induced oxidative stress in the CNS. The remaining six compounds require further bioactivity validation. The results of the present study demonstrated that this method was a time‑ and cost‑saving strategy for the identification of bioactive compounds from traditional Chinese medicine.

Determination of sophoraflavanone G and kurarinone in rat plasma by UHPLC-MS/MS and its application to a pharmacokinetic study

This study aimed to develop and validate a simple and sensitive ultra high performance liquid chromatography tandem mass spectrometry method for the simultaneous determination of sophoraflavanone G and kurarinone in rat plasma by using rutin as the internal standard. Then, the developed method was applied to investigate the pharmacokinetics of sophoraflavanone G and kurarinone in rats after dosing the flavonoid extract from Sophora flavescens. Plasma samples were processed using a liquid-liquid extraction procedure with ethyl acetate. The analysis was performed on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring with an electrospray ionization source in negative ionization mode. Quantitative ion transitions of m/z 423.2→161.2, 437.2→161.1, and 609.3→300.3 were monitored for sophoraflavanone G, kurarinone, and rutin, respectively. The calibration curves of the two analytes exhibited good linearity (r² >0.9923) over the range of 0.1-200 ng/mL for sophoraflavanone G and 0.1-1000 ng/mL for kurarinone. Relative standard deviations were less than 13.2% for the intra- and inter-day precisions and no more than 12.6% for the recovery, showing good precision and satisfactory accuracy of the developed method. The validated method was successfully applied to the pharmacokinetic study of sophoraflavanone G and kurarinone after a single intravenous (25 mg/kg) and oral (500 mg/kg) administration of the flavonoid extract from S. flavescens, and the absolute bioavailability for sophoraflavanone G and kurarinone was about 36 and 17%, respectively.

Sophoraflavanone G Induces Apoptosis in Human Leukemia Cells and Blocks MAPK Activation

Sophoraflavanone G (SG) was isolated from Sophora flavescens. Previously, we have found that SG is able to suppress the inflammatory response in lipopolysaccharide-stimulated RAW 264.7 macrophages. This study aimed to evaluate the effects of SG on apoptosis, and explore its molecular mechanism in human leukemia HL-60 cells. HL-60 cells were treated with various concentrations of SG (3–30 [Formula: see text]M). The viability of the HL-60 cells was assessed using the MTT method, and the nuclear condensation indicative of apoptosis was observed by DAPI fluorescence staining. In addition, apoptotic signal proteins were examined using Western blotting. The results showed that apoptosis, including DNA fragmentation and nuclear condensation, increased significantly in SG-treated HL-60 cells. SG activated caspase-3 and caspase-9, and downregulated Bcl-2 and Bcl-xL. SG also upregulated Bax and released cytochrome c from the mitochondria into the cytoplasm, enabling apoptosis via the mitochondrially-mediated “intrinsic” pathway. Additionally, SG was able to cleave poly (ADP-ribose) polymerase 1 and activate mitogen-activated protein kinase (MAPK) pathways. These results suggest that SG might increase the effect of apoptosis on HL-60 cells through caspase-3 activation, mitochondrial-mediated pathways, and the MAPK pathway.

Cudarflavone B provides neuroprotection against glutamate-induced mouse hippocampal HT22 cell damage through the Nrf2 and PI3K/Akt signaling pathways

Oxidative cell damage contributes to neuronal degeneration in many central nervous system (CNS) diseases such as Alzheimer's disease, Parkinson's disease, and ischemia. Nrf2 signaling-mediated heme oxygenase (HO)-1 expression acts against oxidants that are thought to play a key role in the pathogenesis of neuronal diseases. Cudraflavone B is a prenylated flavone isolated from C. tricuspidata which has shown anti-proliferative activity, mouse brain monoamine oxidase (MAO) inhibitory effects, apoptotic actions in human gastric carcinoma cells and mouse melanoma cells, and hepatoprotective activity. In this study, cudraflavone B showed neuroprotective effects and reactive oxygen species (ROS) inhibition against glutamate-induced neurotoxicity by inducing the expression of HO-1 in mouse hippocampal HT22 cells. Furthermore, cudraflavone B caused the nuclear accumulation of nuclear factor-E2-related factor 2 (Nrf2) and increased the promoter activity of antioxidant response elements (ARE) in mouse hippocampal HT22 cells. In addition, we found that the Nrf2-midiated HO-1 expression by cudraflavone B is involved in the cell protective response and ROS reductions, and cudraflavone B-induced expression of HO-1 was mediated through the phosphatidylinositol 3-kinase (PI3K)/Akt pathway in HT22 cells. Our results demonstrated the potential application of naturally occurring cudraflavone B as a therapeutic agent from neurodegenerative disease.

Kurarinone regulates immune responses through regulation of the JAK/STAT and TCR-mediated signaling pathways

Sophora flavescens is a medicinal herb that contains flavonoids and quinolizidine alkaloids and has a wide range of biological activities due to its anti-inflammatory, anti-bacterial and anti-cancer properties. We isolated a series of flavonoids from the roots of Sophora flavescens and examined their ability to inhibit immune responses. Among the flavonoids, kurarinone exhibited the strongest inhibitory effect on immune responses. Kurarinone suppressed the differentiation of CD4(+) T cells by inhibiting the expression and production of T-cell lineage-specific master regulators and cytokines. Our results also demonstrated that kurarinone directly suppressed the cytokine-induced Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling and T-cell receptor (TCR) pathways. In two established animal models of chronic inflammatory skin disease, one in which psoriasis-like skin disease was induced by an interleukin 23 (IL-23) injection into mouse ears and another in which 2,4,6-trinitrochlorobenzene (TNCB) application on the abdomens of mice was used to induce contact dermatitis, kurarinone repressed disease development by inhibiting the expression of pro-inflammatory mediators, including cytokines, chemokines and enzyme in murine ear skin. This study provides new evidence that kurarinone may ameliorate chronic inflammatory skin diseases through the suppression of pathogenic CD4(+) T-cell differentiation and the overall immune response.

A possible novel anti-inflammatory mechanism for the pharmacological prolyl hydroxylase inhibitor 3,4-dihydroxybenzoate: implications for use as a therapeutic for Parkinson's disease

Parkinson's disease (PD) is an age-related neurodegenerative disorder characterized in part by the preferential loss of nigrostriatal dopaminergic neurons. Although the precise etiology of PD is unknown, accumulating evidence suggests that PD involves microglial activation that exerts neurotoxic effects through production of proinflammatory cytokines and increased oxidative and nitrosative stress. Thus, controlling microglial activation has been suggested as a therapeutic target for combating PD. Previously we demonstrated that pharmacological inhibition of a class of enzymes known as prolyl hydroxylases via 3,4-dihydroxybenzoate administration protected against MPTP-induced neurotoxicity, however the exact mechanisms involved were not elucidated. Here we show that this may be due to DHB's ability to inhibit microglial activation. DHB significantly attenuated LPS-mediated induction of nitric oxide synthase and pro-inflammatory cytokines in murine BV2 microglial cells in vitro in conjunction with reduced ROS production and activation of NFκB and MAPK pathways possibly due to up-regulation of HO-1 levels. HO-1 inhibition partially abrogates LPS-mediated NFκB activity and subsequent NO induction. In vivo, DHB pre-treatment suppresses microglial activation elicited by MPTP treatment. Our results suggest that DHB's neuroprotective properties could be due to its ability to dampen induction of microglial activation via induction of HO-1.

Selective Inhibition of Prenylated Flavonoids from Sophora flavescens against BACE1 and Cholinesterases

It was previously reported that certain lavandulylated flavanones from Sophora flavescens are β-site APP cleaving enzyme 1 (BACE1) inhibitors; however, based upon their levels within the extract, their inhibitory effects should be higher than expected. Moreover, chalcones and flavonols were reported to exert higher bioactivities than flavanones. These findings have led to a further search for other possible constituents potentially contributing to the strong inhibitory activity of the S. flavescens extract. In this study, BACE1 activities were significantly inhibited by 8-lavandulylkaempferol (IC50 7.29 μM), kuraridinol (IC50 7.10 μM), kuraridin (IC50 6.03 μM), and kushenol C (IC50 5.45 μM) from the ethyl acetate fraction, along with desmethylanhydroicaritin (IC50 1.86 μM), xanthohumol (IC50 7.19 μM), and leachianone G (IC50 8.56 μM) from the dichloromethane fraction of the extract. The results indicate that the prenyl group, rather than the lavandulyl group, and the flavonols and chalcones, rather than flavanones, might make predominant contributions to BACE1 inhibition. In particular, 8-lavandulylkaempferol exhibited significant inhibitory effects with IC50 values of 7.10 and 8.11 μM for butyrylcholinesterase and acetylcholinesterase, respectively, when compared to its counterpart, desmethylanhydroicaritin. This indicates that the lavandulyl group might play a predominant role in both cholinesterase inhibitions. This is the first study indicating that prenylated flavonoids exert varying degrees of inhibition primarily through their skeleton (flavonols, chalcones, flavanones), as well as their lipophilic chain length (prenyl and lavandulyl groups). Therefore, S. flavescens and its prenylated flavonoids, possessing low molecular weights and lipophilic moieties may be potent preventive and therapeutic candidates for Alzheimer's disease.

(2S)-2′-methoxykurarinone from Sophora flavescens suppresses cutaneous T cell-attracting chemokine/CCL27 expression induced by interleukin-ß/tumor necrosis factor-α via heme oxygenase-1 in human keratinocytes

One of the CC chemokines, cutaneous T cell-attracting chemokine (CTACK/CCL27), is a skin-specific CC chemokine that is produced constitutively by keratinocytes and is highly up-regulated in inflammatory skin conditions such as atopic dermatitis and contact dermatitis. (2S)-2′-Methoxykurarinone (MOK) from Sophora flavescens has been demonstrated to have antioxidant effects. Heme oxygenase (HO)-1 has recently emerged as an important cytoprotective enzyme against oxidative stress and inflammatory responses in many cell types. This study aimed to define whether and how MOK regulates skin specific CTACK/CCL27 chemokine production in human HaCaT keratinocytes. The level of CTACK/CCL27 and HO-1 expression was measured by reverse transcription-polymerase chain reaction, and signaling was evaluated by western blot analysis. CTACK/CCL27 production was determined by enzyme-linked immunosorbent assay. Pretreatment with MOK suppressed tumor necrosis factor-α (TNF-α)- and interleukin (IL)-1ß-induced CTACK/CCL27 production in human HaCaT keratinocytes. MOK inhibited TNF-α- and IL-1ß-induced nuclear factor κB (NF-κB) activation. Interestingly, pretreatment with MOK significantly suppressed TNF-α- and IL-1ß-induced CTACK/CCL27 production through the induction of HO-1. This suppression was completely abolished by HO-1 small interfering RNA. Furthermore, carbon monoxide, but not other end products of HO-1 activity, also suppressed TNF-α- and IL-1ß-induced CTACK/CCL27 production. These results demonstrate that MOK attenuates TNF-α- and IL-1ß-induced production of CTACK/CCL27 in human HaCaT keratinocytes by inhibiting NF-κB activation and induction of HO-1.

Neuroprotective effects of constituents of the root bark of Dictamnus dasycarpus in mouse hippocampal cells

Glutamate-induced oxidative injury causes neuronal degeneration related to many central nervous system diseases, such as Parkinson's disease, Alzheimer's disease, epilepsy and ischemia. The bioassay-guided fractionation of the EtOH extract of the root bark of Dictamnus dasycarpus Trucz. provided one neuroprotective limonoid, obacunone, together with a degraded limonoid, fraxinellone and two alkaloids, dictamine and haplopine. At concentrations of 100-150 microM, obacunone showed the potent neuroprotective effects on glutamateinduced neurotoxicity and induced the expression of heme oxygenase (HO)-1 in the mouse hippocampal HT22 cells. In addition, we found that obacunone increased p38 MAPK phosphorylation and induced HO-1 expression via p38 MAPK pathway. These results suggest that obacunone isolated from the root bark of D. dasycarpus increases cellular resistance to glutamate-induced oxidative injury in mouse hippocampal HT22 cells, presumably through the p38 MAPK pathway-dependent HO-1 expression. These results suggest that obacunone could be the effective candidates for the treatment of ROS-related neurological diseases.