Discovery of the Highly Selective and Potent STAT3 Inhibitor for Pancreatic Cancer Treatment.

Signal transducer and activator of transcription 3 (STAT3) is an attractive cancer therapeutic target. Unfortunately, targeting STAT3 with small molecules has proven to be very challenging, and for full activation of STAT3, the cooperative phosphorylation of both tyrosine 705 (Tyr705) and serine 727 (Ser727) is needed. Further, a selective inhibitor of STAT3 dual phosphorylation has not been developed. Here, we identified a low nanomolar potency and highly selective small-molecule STAT3 inhibitor that simultaneously inhibits both STAT3 Tyr705 and Ser727 phosphorylation. YY002 potently inhibited STAT3-dependent tumor cell growth in vitro and achieved potent suppression of tumor growth and metastasis in vivo. More importantly, YY002 exhibited favorable pharmacokinetics, an acceptable safety profile, and superior antitumor efficacy compared to BBI608 (STAT3 inhibitor that has advanced into phase III trials). For the mechanism, YY002 is selectively bound to the STAT3 Src Homology 2 (SH2) domain over other STAT members, which strongly suppressed STAT3 nuclear and mitochondrial functions in STAT3-dependent cells. Collectively, this study suggests the potential of small-molecule STAT3 inhibitors as possible anticancer therapeutic agents.

Preparation of type 3 rice resistant starch using high-pressure homogenous coenzyme treatment and investigating its potential therapeutic effects on blood glucose and intestinal flora in db/db mice.

Resistant starch from rice was prepared using high-pressure homogenization and branched chain amylase treatment. The yield, starch external structure, thermal properties, and crystal structure of rice-resistant starch prepared in different ways were investigated. The results showed that the optimum homogenizing pressure was 90 MPa, the optimum digestion time was 4 h, the optimum concentration of branched-chain amylase was 50 U/g and the yield of resistant starch was 38.58 %. Scanning electron microscopy results showed a rougher surface and more complete debranching of the homogenized coenzyme rice-resistant starch granules. FT-IR and X-ray diffraction results showed that the homogenization treatment exhibited a spiral downward trend on rice starch relative crystallinity and a spiral upward trend on starch debranching and recrystallization. The 4-week dietary intervention in db/db type 2 diabetic mice showed that homogeneous coenzyme rice-resistant starch had a better glycemic modulating effect than normal debranched starch and had a tendency to interfere with the index of liver damage in T2DM mice. Additionally, homogeneous coenzyme rice-resistant starch proved more effective in improving intestinal flora disorders and enhancing the abundance of probiotics in T2DM mice.

Discovery of WD-890: A novel allosteric TYK2 inhibitor for the treatment of multiple autoimmune diseases.

Tyrosine kinase 2 (TYK2) as a member of Janus kinase (JAK) family, mainly mediates the signaling of type I interferons (IFN), interleukin-12 (IL-12) and interleukin-23 (IL-23), which has become an attractive target for treatment of immune and inflammatory diseases. However, the development of selective TYK2 inhibitors is challenging due to the high homology of the catalytic kinase domain among the JAK family members. Here, we report a novel and potent allosteric inhibitor, WD-890, which binds to the pseudokinase domain of TYK2 with high selectivity and inhibits its function. We accomplished a series of preclinical studies to demonstrate the therapeutic efficacy of WD-890 in four animal models: systemic lupus erythematosus (SLE), psoriasis, psoriatic arthritis (PsA), and inflammatory bowel disease (IBD). The pharmacokinetic and toxicology results further indicate that WD-890 has favorable absorption, distribution, metabolism, and excretion (ADME) properties and tolerable toxicity. In conclusion, our study shows that WD-890 could be a promising oral TYK2 inhibitor for future treatment of autoimmune diseases.

Targeting of STAT5 using the small molecule topotecan hydrochloride suppresses acute myeloid leukemia progression.

Acute myeloid leukemia (AML) is a common type of acute leukemia in adults and relapse is one of the main reasons for treatment failure. FLT3­ITD mutations are associated with poor prognosis, short disease­free progression survival and high relapse rates in patients with AML. STAT5 is activated by FLT3­ITD and drives the pathogenesis of AML. STAT5 activation is usually a hallmark of hematologic malignancies and occurs in ~70% of patients with AML. Moreover, STAT5 is a key molecule which regulates hematopoiesis, and its high expression is closely associated with drug resistance, thus direct targeting of STAT5 for AML is of great clinical value. The present study introduces a new small­molecule inhibitor that targets STAT5, presenting a promising approach for AML therapy. A high throughput fluorescence polarization (FP) screening system for STAT5 was designed and established, and used to screen an existing compound library to obtain the highly active small molecule inhibitor, topotecan hydrochloride. Topotecan hydrochloride was demonstrated to be an effective inhibitor of STAT5 by molecular docking prediction and cellular thermal shift assay. Topotecan hydrochloride bound to STAT5, inhibiting its dimerization, phosphorylation and transcription of specific target genes. The compound exhibits cellular activity at the nanomolar level and significantly inhibits the proliferation of human AML cell lines and FLT3­ITD+ AML cells. Furthermore, topotecan hydrochloride has the potential to exert an anti­tumor effect in vivo. Overall, topotecan hydrochloride offers a new opportunity for the treatment of AML and other hematologic malignancies by directly targeting STAT5.

Prediction of Cholecystokinin-Secretory Peptides Using Bidirectional Long Short-term Memory Model Based on Transfer Learning and Hierarchical Attention Network Mechanism.

Cholecystokinin (CCK) can make the human body feel full and has neurotrophic and anti-inflammatory effects. It is beneficial in treating obesity, Parkinson's disease, pancreatic cancer, and cholangiocarcinoma. Traditional biological experiments are costly and time-consuming when it comes to finding and identifying novel CCK-secretory peptides, and there is an urgent need to develop a new computational method to predict new CCK-secretory peptides. This study combines the transfer learning method with the SMILES enumeration data augmentation strategy to solve the data scarcity problem. It establishes a fusion model of the hierarchical attention network (HAN) and bidirectional long short-term memory (BiLSTM), which fully extracts peptide chain features to predict CCK-secretory peptides efficiently. The average accuracy of the proposed method in this study is 95.99%, with an AUC of 98.07%. The experimental results show that the proposed method is significantly superior to other comparative methods in accuracy and robustness. Therefore, this method is expected to be applied to the preliminary screening of CCK-secretory peptides.

In vitro gastrointestinal digestion of buckwheat (Fagopyrum esculentum Moench) protein: release and structural characteristics of novel bioactive peptides stimulating gut cholecystokinin secretion.

Satiety hormone cholecystokinin (CCK) plays a vital role in appetite inhibition. Its secretion is regulated by dietary components. The search for bioactive compounds that stimulate CCK secretion is currently an active area of research. The objective of this study was to evaluate the ability of buckwheat (Fagopyrum esculentum Moench) protein digest (BPD) to stimulate CCK secretion in vitro and in vivo and clarify the structural characteristics of peptides stimulating CCK secretion. BPD was prepared by an in vitro gastrointestinal digestion model. The relative molecular weight of BPD was <10 000 Da, and peptides with <3000 Da accounted for 70%. BPD was rich in essential amino acids Lys, Leu, and Val but lacked sulfur amino acids Met and Cys. It had a stimulatory effect on CCK secretion in vitro and in vivo. Chromatographic separation was performed to isolate peptide fractions involved in CCK secretion, and five novel CCK-releasing peptides including QFDLDD, PAFKEEHL, SFHFPI, IPPLFP, and RVTVQPDS were successfully identified. A sequence length range of 6-8 and marked hydrophobicity (18-28) were observed among the most CCK-releasing peptides. The present study demonstrated for the first time that BPD could stimulate CCK secretion and clarify the structural characteristics of bioactive peptides having CCK secretagogue activity in BPD.

ZY-444 inhibits the growth and metastasis of prostate cancer by targeting TNFAIP3 through TNF signaling pathway.

Prostate cancer is one of the most lethal malignancies, and androgen deprivation therapy remains the mainstay of treatment for prostate cancer patients. Although androgen deprivation can initially come to remission, the disease often develops into castration-resistant prostate cancer (CRPC), which is still dependent on androgen receptor (AR) signaling and is related to a poor prognosis. Some success against CRPC has been achieved by drugs that target AR signaling, but secondary resistance uninterrupted emerges, and new therapies are urgently needed. In this study, we identified a potent small molecule compound, ZY-444, that suppressed PCa cells proliferation and metastasis, and inhibited tumor growth both in subcutaneous. Transcriptome sequencing analysis showed that TNFAIP3 was significantly elevated in prostate cancer cells after ZY-444 treatment. Further studies through overexpression of TNFAIP3 confirmed that TNFAIP3, as a direct target gene of ZY-444, contributes to the functions of ZY-444. In addition, we demonstrated the effects of TNFAIP3 on prostate cancer cell apoptosis, migration and proliferation to elucidate the mechanism of ZY-444. We found that TNFAIP3 inhibited the TNF signaling pathway, which could inhibit cell migration and proliferation and contribute to apoptosis. Overall, these findings highlighted TNFAIP3 as a tumor suppressor gene in the regulation of the progression and metastatic potential of prostate cancer and that targeting TNFAIP3 by ZY-444 might be a promising strategy for prostate cancer treatment.

Different multi-scale structural features of oat resistant starch prepared by ultrasound combined enzymatic hydrolysis affect its digestive properties.

In this research, oat resistant starch (ORS) was prepared by autoclaving-retrogradation cycle (ORS-A), enzymatic hydrolysis (ORS-B), and ultrasound combined enzymatic hydrolysis (ORS-C). Differences in their structural features, physicochemical properties and digestive properties were studied. Results of particle size distribution, XRD, DSC, FTIR, SEM and in vitro digestion showed that ORS-C was a B + C-crystal, and ORS-C had a larger particle size, the smallest span value, the highest relative crystallinity, the most ordered and stable double helix structure, the roughest surface shape and strongest digestion resistance compared to ORS-A and ORS-B. Correlation analysis revealed that the digestion resistance of ORS-C was strongly positively correlated with RS content, amylose content, relative crystallinity and absorption peak intensity ratio of 1047/1022 cm-1 (R1047/1022), and weakly positively correlated with average particle size. These results provided theoretical support for the application of ORS-C with strong digestion resistance prepared by ultrasound combined enzymatic hydrolysis in the low GI food application.

Health benefits of saponins and its mechanisms: perspectives from absorption, metabolism, and interaction with gut.

Saponins, consisting of sapogenins as their aglycones and carbohydrate chains, are widely found in plants and some marine organisms. Due to the complexity of the structure of saponins, involving different types of sapogenins and sugar moieties, investigation of their absorption and metabolism is limited, which further hinders the explanation of their bioactivities. Large molecular weight and complex structures limit the direct absorption of saponins rendering their low bioavailability. As such, their major modes of action may be due to interaction with the gastrointestinal environment, such as enzymes and nutrients, and interaction with the gut microbiota. Many studies have reported the interaction between saponins and gut microbiota, that is, the effects of saponins on changing the composition of gut microbiota, and gut microbiota playing an indispensable role in the biotransformation of saponins into sapogenins. However, the metabolic routes of saponins by gut microbiota and their mutual interactions are still sparse. Thus, this review summarizes the chemistry, absorption, and metabolic pathways of saponins, as well as their interactions with gut microbiota and impacts on gut health, to better understand how saponins exert their health-promoting functions.

α-ionone promotes keratinocyte functions and accelerates epidermal barrier recovery.

Background: As a common fragrance ingredient, α-ionone is widely used in cosmetics, perfume, and hygiene products. Nevertheless, little information is available for its biological activities on the skin. In this study, we investigated the effect of α-ionone on keratinocyte functions associated with skin barrier repair and further evaluated its skin barrier recovery capacity to explore its therapeutic potential for the treatment of skin barrier disruption. Methods: The effect of α-ionone on the keratinocyte functions including cell proliferation, migration, and production of hyaluronic acid (HA) and human ß-defensin-2 (HBD-2) were examined in vitro using human immortalized keratinocytes (HaCaT cells) as experimental model. The barrier recovery effects of topical hydrogels containing 0.1% or 1% α-ionone were tested on the volar forearm of 31 healthy volunteers by measuring transepidermal water loss (TEWL) and stratum corneum (SC) hydration following barrier disruption induced by repeated tape-stripping. The statistical significance was evaluated by one-way analysis of variance (ANOVA) followed by a Dunnett's post-hoc test. Results: α-ionone promoted HaCaT cell proliferation (P<0.01) dose-dependently in the 10 to 50 µM range. Meanwhile, it also increased the intracellular cyclic adenosine monophosphate (cAMP) levels (P<0.05). Furthermore, HaCaT cells treated with α-ionone (10, 25, 50 µM) showed enhanced cell migration (P<0.05), up-regulated gene expression of hyaluronic acid synthases 2 (HAS2) (P<0.05), HAS3 (P<0.01), and HBD-2 (P<0.05), and enhanced production of HA (P<0.01) and HBD-2 (P<0.05) in the culture supernatant. These beneficial actions of α-ionone were abrogated by cAMP inhibitor, suggesting that its effects are cAMP-mediated in HaCaT cells. In vivo study showed that topical application of α-ionone-containing hydrogels accelerated the epidermal barrier recovery of human skin after barrier disruption by tape stripping. Treatment with hydrogel containing 1% α-ionone resulted in a significant increase of above 15% in the barrier recovery rate at day 7 post-treatment when compared to the vehicle control (P<0.01). Conclusions: These results demonstrated the role of α-ionone in the improvement of keratinocyte functions and the epidermal barrier recovery. These findings suggest possible therapeutic application of α-ionone in the treatment of skin barrier disruption.

Targeting metabolic vulnerability in mitochondria conquers MEK inhibitor resistance in KRAS-mutant lung cancer.

MEK is a canonical effector of mutant KRAS; however, MEK inhibitors fail to yield satisfactory clinical outcomes in KRAS-mutant cancers. Here, we identified mitochondrial oxidative phosphorylation (OXPHOS) induction as a profound metabolic alteration to confer KRAS-mutant non-small cell lung cancer (NSCLC) resistance to the clinical MEK inhibitor trametinib. Metabolic flux analysis demonstrated that pyruvate metabolism and fatty acid oxidation were markedly enhanced and coordinately powered the OXPHOS system in resistant cells after trametinib treatment, satisfying their energy demand and protecting them from apoptosis. As molecular events in this process, the pyruvate dehydrogenase complex (PDHc) and carnitine palmitoyl transferase IA (CPTIA), two rate-limiting enzymes that control the metabolic flux of pyruvate and palmitic acid to mitochondrial respiration were activated through phosphorylation and transcriptional regulation. Importantly, the co-administration of trametinib and IACS-010759, a clinical mitochondrial complex I inhibitor that blocks OXPHOS, significantly impeded tumor growth and prolonged mouse survival. Overall, our findings reveal that MEK inhibitor therapy creates a metabolic vulnerability in the mitochondria and further develop an effective combinatorial strategy to circumvent MEK inhibitors resistance in KRAS-driven NSCLC.

Selectively Targeting STAT3 Using a Small Molecule Inhibitor is a Potential Therapeutic Strategy for Pancreatic Cancer.

PURPOSE: Pancreatic cancer is the worst prognosis among all human cancers, and novel effective treatments are urgently needed. Signal transducer and activator of transcription 3 (STAT3) has been demonstrated as a promising target for pancreatic cancer. Meanwhile, selectively targeted STAT3 with small molecule remains been challenging. EXPERIMENTAL DESIGN: To specifically identify STAT3 inhibitors, more than 1.3 million compounds were screened by structure-based virtual screening and confirmed with the direct binding assay. The amino acid residues that WB436B bound to were verified by induced-fit molecular docking simulation, RosettaLigand computations, and site-directed mutagenesis. On-target effects of WB436B were examined by microscale thermophoresis, surface plasmon resonance, in vitro kinase assay, RNA sequencing, and selective cell growth inhibition assessment. In vivo studies were performed in four animal models to evaluate effects of WB436B on tumor growth and metastasis. Kaplan-Meier analyses were used to assess survival. RESULTS: WB436B selectively bound to STAT3 over other STAT families protein, and in vitro antitumor activities were improved by 10 to 1,000 fold than the representative STAT3 inhibitors. WB436B selectively inhibits STAT3-Tyr705 phosphorylation, STAT3 target gene expression, and the viability of STAT3-dependent pancreatic cancer cells. WB436B significantly suppresses tumor growth and metastasis in vivo and prolongs survival of tumor-bearing mice. Mechanistic studies showed that WB436B have unique binding sites located in STAT3 Src homology 2 domain. CONCLUSIONS: Our work presents the first-in-class selective STAT3 inhibitor WB436B as a potential therapeutic candidate for the treatment of pancreatic cancer.

Investigation of cytochrome P450 inhibitory properties of deoxyshikonin, a bioactive compound from Lithospermum erythrorhizon Sieb. et Zucc.

Deoxyshikonin, a natural naphthoquinone compound extracted from Lithospermum erythrorhizon Sieb. et Zucc (Boraginaceae), has a wide range of pharmacological activities, including anti-tumor, anti-bacterial and wound healing effects. However, the inhibitory effect of deoxyshikonin on cytochrome P450 (CYP) remains unclear. This study investigated the potential inhibitory effects of deoxyshikonin on CYP1A2, 2B1/6, 2C9/11, 2D1/6, 2E1 and 3A2/4 enzymes in human and rat liver microsomes (HLMs and RLMs) by the cocktail approach in vitro. The single-point inactivation experiment showed that deoxyshikonin presented no time-dependent inhibition on CYP activities in HLMs and RLMs. Enzyme inhibition kinetics indicated that in HLMs, deoxyshikonin was not only a competitive inhibitor of CYP1A2 and 2E1, but also a mixed inhibitor of CYP2B6, 2C9, 2D6 and 3A4, with Ki of 2.21, 1.78, 1.68, 0.20, 4.08 and 0.44 µM, respectively. In RLMs, deoxyshikonin not only competitively inhibited CYP2B1 and 2E1, but also exhibited mixed inhibition on CYP1A2, 2C11, 2D1 and 3A2, with Ki values of no more than 18.66 µM. In conclusion, due to the low Ki values of deoxythiokonin on CYP enzymes in HLMs, this may lead to drug-drug interactions (DDI) and potential toxicity.

[Regulation of inflammatory bowel disease by amino acids].

Inflammatory bowel disease (IBD) is a chronic, recurrent inflammatory disease of the gastrointestinal tract that includes Crohn's disease and ulcerative colitis. IBD patients are numerous and a complete cure is difficult to achieve. Due to impaired digestive function, food is not easily absorbed and malnutrition often occurs in patients. Nutritional therapy is often used to overcome nutritional deficiency and change the inflammatory state in the clinic. Amino acids are adjuvant therapeutic candidates that may help maintain intestinal integrity in patients with IBD. It maypromote the treatment of IBD through reducing the level of inflammation, oxidative stress, and intestinal cell death. Recent studies in animals have demonstrated the potential of using amino acids for treating IBD. The supply and metabolism of amino acids may be a promising adjuvant therapy. This review summarized the immunomodulatory effects of specific amino acids such as glutamine, arginine, and glycine, with the aim to provide new ideas for the treatment of IBD.

Synthesis and pharmacological validation of fluorescent diarylsulfonylurea analogues as NLRP3 inhibitors and imaging probes.

The NOD-like receptor family pyrin domain-containing protein 3 (NLRP3) is a key cytosolic pattern recognition receptor that senses diverse pathogen- and host-originated threat signals. Aberrant activation of NLRP3 inflammasomes is closely associated with the pathogenesis of various complex inflammatory diseases. Nevertheless, the detailed regulation mechanism of NLRP3 inflammasome and its pathogenic roles in the inflammation progression remain to be fully elucidated. Fluorescent imaging with small molecule probe can provide valuable visualization information on the expression, occupancy and bio-distribution of target protein. Herein, we reported a series of diarylsulfonylurea NLRP3 fluorescent inhibitors bearing an amino benzodiazole fluorophore. Compared to the previously reported NLRP3 fluorescent probes, these inhibitors are more structurally concise and membrane permeable due to no additionally appended fluorophore via a linker. Among this series, compound 13a exhibited the most potent cellular NLRP3 inhibitory effect with an IC50 value of 49 nM, and significantly suppressed LPS/Nigericin-induced secretion of active caspase-1 and mature IL-1ß in a dose-dependent manner to block the activation of NLRP3 inflammasome. Meanwhile, this new probe exhibited promising fluorescent properties for specifically detecting and imaging the LPS-induced or constitutively expressed NLRP3 proteins in RAW264.7 cells. Collectively, probe 13a is a potent NLRP3 fluorescent inhibitor with cellular NLRP3 imaging ability, which is useful for NLRP3 inhibitor screening and related mechanism study.

A novel small-molecule activator of unfolded protein response suppresses castration-resistant prostate cancer growth.

Androgen receptor-targeted therapy improves survival in castration-resistant prostate cancer (CRPC). However, almost all patients with CRPC eventually develop secondary resistance to these drugs. Therefore, alternative therapeutic approaches for incurable metastatic CRPC are urgently needed. Unfolded protein response (UPR) is regarded as a cytoprotective mechanism that removes misfolded proteins in rapidly proliferating tumor cells. However, acute activation of the UPR directly leads to tumor cell death. This study has shown that WJ-644A, a novel small molecule activator of UPR, potently inhibited the proliferation of prostate cancer cells and caused tumor regression with a good safety profile in multiple animal models. Mechanistically, we have identified that WJ-644A induced cell methuosis and autophagy upon UPR activation. Our study not only identifies the UPR as an actionable target for CRPC treatment, but also establishes WJ-644A as a novel UPR activator that has potential therapeutic value for CRPC.

An orally available small molecule BCL6 inhibitor effectively suppresses diffuse large B cell lymphoma cells growth in vitro and in vivo.

The transcription factor B cell lymphoma 6 (BCL6) is an oncogenic driver of diffuse large B cell lymphoma (DLBCL) and mediates lymphomagenesis through transcriptional repression of its target genes by recruiting corepressors to its N-terminal broad-complex/tramtrack/bric-a-brac (BTB) domain. Blocking the protein-protein interactions of BCL6 and its corepressors has been proposed as an effective approach for the treatment of DLBCL. However, BCL6 inhibitors with excellent drug-like properties are rare. Hence, the development of BCL6 inhibitors is worth pursuing. We screened our internal chemical library by luciferase reporter assay and Homogenous Time Resolved Fluorescence (HTRF) assay and a small molecule compound named WK500B was identified. WK500B engaged BCL6 inside cells, blocked BCL6 repression complexes, reactivated BCL6 target genes, killed DLBCL cells and caused apoptosis as well as cell cycle arrest. In animal models, WK500B inhibited germinal center (GC) formation and DLBCL tumour growth without toxic and side effects. Moreover, WK500B displayed strong efficacy and favourable pharmacokinetics and presented superior druggability. Therefore, WK500B is a promising candidate that could be developed as an effective orally available therapeutic agent for DLBCL.

Single-Cell Analysis Reveals EP4 as a Target for Restoring T-Cell Infiltration and Sensitizing Prostate Cancer to Immunotherapy.

PURPOSE: Immunotherapies targeting immune checkpoint molecules have shown promising treatment for a subset of cancers; however, many "cold" tumors, such as prostate cancer, remain unresponsive. We aimed to identify a potential targetable marker relevant to prostate cancer and develop novel immunotherapy. EXPERIMENTAL DESIGN: Analysis of transcriptomic profiles at single-cell resolution was performed in clinical patients' samples, along with integrated analysis of multiple RNA-sequencing datasets. The antitumor activity of YY001, a novel EP4 antagonist, combined with anti-programmed cell death protein 1 (PD-1) antibody was evaluated both in vitro and in vivo. RESULTS: We identified EP4 (PTGER4) as expressed in epithelial cells and various immune cells and involved in modulating the prostate cancer immune microenvironment. YY001, a novel EP4 antagonist, inhibited the differentiation, maturation, and immunosuppressive function of myeloid-derived suppressor cells (MDSC) while enhancing the proliferation and anticancer functions of T cells. Furthermore, it reversed the infiltration levels of MDSCs and T cells in the tumor microenvironment by overturning the chemokine profile of tumor cells in vitro and in vivo. The combined immunotherapy demonstrated a robust antitumor immune response as indicated by the robust accumulation and activation of CD8+ cytotoxic T cells, with a significantly decreased MDSC ratio and reduced MDSC immunosuppression function. CONCLUSIONS: Our study identified EP4 as a specific target for prostate cancer immunotherapy and demonstrated that YY001 inhibited the growth of prostate tumors by regulating the immune microenvironment and strongly synergized with anti-PD-1 antibodies to convert completely unresponsive prostate cancers into responsive cancers, resulting in marked tumor regression, long-term survival, and lasting immunologic memory.

Risk assessment of the inhibition of hydroxygenkwanin on human and rat cytochrome P450 by cocktail method.

Hydroxygenkwanin (HGK), a natural flavonoid extracted from the buds of Daphne genkwa Sieb.et Zucc. (Thymelaeaceae), possesses a wide range of pharmacological activities, including anti-inflammatory, antibacterial and anticancer. However, the inhibitory effect of HGK on cytochrome P450 (CYP) remains unclear. This study investigated the potential inhibitory effects of HGK on CYP1A2, 2B1/6, 2C9/11, 2D1/6, 2E1 and 3A2/4 enzymes in human and rat liver microsomes (HLMs and RLMs) by the cocktail approach. HGK exhibited no time-dependent inhibition of CYP activities in HLMs and RLMs. Enzyme inhibition kinetics indicated that HGK was not only a competitive inhibitor of human CYP1A2 and 2C9, but also competitively inhibited rat CYP1A2 and 2C11 activities, with Ki value at 0.84 ± 0.03, 8.09 ± 0.44, 2.68 ± 0.32 and 8.35 ± 0.31 µM, respectively. Further studies showed that the inhibitory effect of HGK on CYP enzymes was weaker than that of diosmetin, which may be related to the substitution of hydroxyl and methoxy in the A and B rings of the flavone skeleton. Therefore, the low Ki values of HGK for CYP1A2 and 2C may lead to potential drug-drug interactions and toxicity.

Two new sesquiterpenoid lactone derivatives from Lindera aggregata.

Two new sesquiterpenoid lactone derivatives, linderin A (1) and linderin B (2) comprising a sesquiterpenoid lactone and a methyl geranylhomogentisate moiety together with six known compounds were isolated from the roots of Lindera aggregata. Their chemical structures were elucidated using extensive spectroscopic analysis including 1 D, 2 D NMR, and HR-ESI-MS data and compared with previously reported data. The absolute configurations of 1 and 2 were assigned based on the electronic circular dichroism calculation. Compound 2 showed moderate anticoagulant activity.