Total Syntheses, Absolute Configurations, and Cytotoxicity Evaluation of Ugonstilbenes A, B, and C from the Rhizomes of Helminthostachys zeylanica.

This study describes the first and efficient syntheses of the naturally occurring ugonstilbenes A, B, and C. The stilbene skeleton was prepared using the Horner-Wadsworth-Emmons reaction. On the basis of their specific rotations, the absolute configurations of ugonstilbenes A and C were both determined to be R, while the absolute configuration of ugonstilbene B was determined as 4aS,9aR. The synthesized compounds showed cytotoxic activities against selected human cancer cell lines.

ß-Lapachone, an NQO1 activator, alleviates diabetic cardiomyopathy by regulating antioxidant ability and mitochondrial function.

BACKGROUND: Diabetic cardiomyopathy (DC) is one of the major lethal complications in patients with diabetes mellitus (DM); however, no specific strategy for preventing or treating DC has been identified. PURPOSE: This study aimed to investigate the effects of ß-lapachone (Lap), a natural compound that increases antioxidant activity in various tissues, on DC and explore the underlying mechanisms. STUDY DESIGN AND METHODS: As an in vivo model, C57BL/6 mice were fed with the high-fat diet (HF) for 10 weeks to induce type 2 DM. Mice were fed Lap with the HF or after 5 weeks of HF treatment to investigate the protective effects of Lap against DC. RESULTS: In the two in vivo models, Lap decreased heart weight, increased heart function, reduced oxidative stress, and elevated mitochondrial content under the HF. In the in vitro model, palmitic acid (PA) was used to mimic the effects of an HF on the differentiated-cardiomyoblast cell line H9c2. The results demonstrated that Lap reduced PA-induced ROS production by increasing the expression of antioxidant regulators and enzymes, inhibiting inflammation, increasing mitochondrial activity, and thus reducing cell damage. Via the use of specific inhibitors and siRNA, the protective effects of Lap were determined to be mediated mainly by NQO1, Sirt1 and mitochondrial activity. CONCLUSION: Heart damage in DM is usually caused by excessive oxidative stress. This study showed that Lap can protect the heart from DC by upregulating antioxidant ability and mitochondrial activity in cardiomyocytes. Lap has the potential to serve as a novel therapeutic agent for both the prevention and treatment of DC.

Mitochondrial activity is the key to the protective effect of ß-Lapachone, a NAD+ booster, in healthy cells against cisplatin cytotoxicity.

BACKGROUND: Cisplatin (CDDP) is a first-line chemotherapeutic drug for treating various cancers. However, CDDP also damages normal cells and causes many side effects. Recently, CDDP has been demonstrated to kill cancer cells by targeting mitochondria. Protecting mitochondria might be a potential therapeutic strategy for CDDP-induced side effects. ß-Lapachone (ß-lap), a recognized NAD+ booster, has been reported to regulate mitochondrial activity. However, it remains unclear whether maintaining mitochondrial activity is the key factor in the protective effects of ß-lap in CDDP-treated normal cells. PURPOSE: In this study, the protective effects of ß-lap on mitochondria against CDDP cytotoxicity in normal cells were evaluated. STUDY DESIGN: In vitro cell models were used in this study, including 3T3 fibroblasts, human dermal fibroblasts, MCF-7 breast cancer cells, and MDA-MB-231 breast cancer cells. METHODS: Cells were treated with CDDP and ß-lap, and cell survival, NAD+, mitochondrial activity, autophagy, and ATP production were measured. Various inhibitors and siRNAs were used to confirm the key signal underlying the protective effects of ß-lap. RESULTS: The results demonstrated that ß-lap significantly decreased CDDP cytotoxicity in normal fibroblasts. With various inhibitors and siRNAs, ß-lap reduced CDDP-induced damage to normal fibroblasts by maintaining mitochondrial activity and increasing autophagy through the NQO1/NAD+/SIRT1 axis. Most importantly, the protective effects of ß-lap in fibroblasts did not affect the therapeutic effects of CDDP in cancer cells. This study indicated that mitochondrial activity, energy production, and NQO1 levels might be crucial responses separating normal cells from cancer cells under exposure to CDDP and ß-lap. CONCLUSION: ß-lap could be a good synergistic drug for reducing the side effects of CDDP without affecting the anticancer drug effect.

Salvia miltiorrhiza Extract and Individual Synthesized Component Derivatives Induce Activating-Transcription-Factor-3-Mediated Anti-Obesity Effects and Attenuate Obesity-Induced Metabolic Disorder by Suppressing C/EBPα in High-Fat-Induced Obese Mice.

Pharmacological studies indicate that Salvia miltiorrhiza extract (SME) can improve cardiac and blood vessel function. However, there is limited knowledge regarding the effects (exerted through epigenetic regulation) of SME and newly derived single compounds, with the exception of tanshinone IIA and IB, on obesity-induced metabolic disorders. In this study, we administered SME or dimethyl sulfoxide (DMSO) as controls to male C57BL/J6 mice after they were fed a high-fat diet (HFD) for 4 weeks. SME treatment significantly reduced body weight, fasting plasma glucose, triglyceride levels, insulin resistance, and adipogenesis/lipogenesis gene expression in treated mice compared with controls. Transcriptome array analysis revealed that the expression of numerous transcriptional factors, including activating transcription factor 3 (ATF3) and C/EBPα homologous protein (CHOP), was significantly higher in the SME group. ST32db, a novel synthetic derivative similar in structure to compounds from S. miltiorrhiza extract, ameliorates obesity and obesity-induced metabolic syndrome in HFD-fed wild-type mice but not ATF3-/- mice. ST32db treatment of 3T3-L1 adipocytes suppresses lipogenesis/adipogenesis through the ATF3 pathway to directly inhibit C/EBPα expression and indirectly inhibit the CHOP pathway. Overall, ST32db, a single compound modified from S. miltiorrhiza extract, has anti-obesity effects through ATF3-mediated C/EBPα downregulation and the CHOP pathway. Thus, SME and ST32db may reduce obesity and diabetes in mice, indicating the potential of both SME and ST32db as therapeutic drugs for the treatment of obesity-induced metabolic syndrome.

Characterizing the structure-activity relationships of natural products, tanshinones, reveals their mode of action in inhibiting spleen tyrosine kinase.

The cytosolic non-receptor protein kinase, spleen tyrosine kinase (SYK), is an attractive drug target in autoimmune, inflammatory disorder, and cancers indications. Here, we employed pharmacophore-based drug screening combined with biochemical assay and molecular dynamics (MD) simulations to identify and characterize inhibitors targeting SYK. The built pharmacophore model, phar-TanI, successfully identified tanshinone (TanI (IC50 = 1.72 µM)) and its analogs (TanIIA (IC50 = 3.2 µM), ST32da (IC50 = 46 µM), and ST32db (IC50 = 51 µM)) which apparently attenuated the activities of SYK in vitro. Additionally, the MD simulations followed by Ligplot analyses revealed that TanI and TanIIA interfered SYK activity through binding deeply into the active site. Besides, TanI and TanIIA mainly interact with residues L377, A400, V433, M448, M450, A451, E452, L453, G454, P455, and L501, which are functional hotspots for structure-based inhibitor optimization against SYK. The structure-activity relationships (SAR) study of the identified SYK inhibitors demonstrated that the pharmacophore model, phar-TanI is reliable and precise in screening inhibitors against SYK. This study disclosed the structure-function relationships of tanshinones from Traditional Chinese Medicine (Danshen), revealing their binding site and mode of action in inhibiting SYK and provides applicability in developing new therapeutic agents.

Adipocyte browning and resistance to obesity in mice is induced by expression of ATF3.

Billions of people have obesity-related metabolic syndromes such as diabetes and hyperlipidemia. Promoting the browning of white adipose tissue has been suggested as a potential strategy, but a drug still needs to be identified. Here, genetic deletion of activating transcription factor 3 (ATF3-/- ) in mice under a high-fat diet (HFD) resulted in obesity and insulin resistance, which was abrogated by virus-mediated ATF3 restoration. ST32da, a synthetic ATF3 inducer isolated from Salvia miltiorrhiza, promoted ATF3 expression to downregulate adipokine genes and induce adipocyte browning by suppressing the carbohydrate-responsive element-binding protein-stearoyl-CoA desaturase-1 axis. Furthermore, ST32da increased white adipose tissue browning and reduced lipogenesis in HFD-induced obese mice. The anti-obesity efficacy of oral ST32da administration was similar to that of the clinical drug orlistat. Our study identified the ATF3 inducer ST32da as a promising therapeutic drug for treating diet-induced obesity and related metabolic disorders.

Discovery of Potent Cysteine-Containing Dipeptide Inhibitors against Tyrosinase: A Comprehensive Investigation of 20 × 20 Dipeptides in Inhibiting Dopachrome Formation.

Tyrosinase is an essential copper-containing enzyme required for melanin synthesis. The overproduction and abnormal accumulation of melanin cause hyperpigmentation and neurodegenerative diseases. Thus, tyrosinase is promising for use in medicine and cosmetics. Our previous study identified a natural product, A5, resembling the structure of the dipeptide WY and apparently inhibiting tyrosinase. Here, we comprehensively estimated the inhibitory capability of 20 × 20 dipeptides against mushroom tyrosinase. We found that cysteine-containing dipeptides, directly blocking the active site of tyrosinase, are highly potent in inhibition; in particular, N-terminal cysteine-containing dipeptides markedly outperform the C-terminal-containing ones. The cysteine-containing dipeptides, CE, CS, CY, and CW, show comparative bioactivities, and tyrosine-containing dipeptides are substrate-like inhibitors. The dipeptide PD attenuates 16.5% melanin content without any significant cytotoxicity. This study reveals the functional role of cysteine residue positional preference and the selectivity of specific amino acids in cysteine-containing dipeptides against tyrosinase, aiding in developing skin-whitening products.

Antioxidant activity and inhibition of α-glucosidase by hydroxyl-functionalized 2-arylbenzo[b]furans.

This study synthesized a series of hydroxyl-functionalized 2-arylbenzo[b]furans based on the structure of tournefolic acid A and evaluated them for antioxidant and α-glucosidase inhibitory activities. Compounds 5a, 5e, and 5n showed remarkable inhibition of α-glucosidase (IC50 values of 1.9-3.0 µM), and they appear to be even more potent than quercetin. A kinetic binding study indicated that compounds 5a and 5n used a mechanism of mixed-competition to inhibit α-glucosidase. This study also revealed that compounds 5a and 5n bind to either the α-glucosidase or α-glucosidase-4-NPGP complex. Using the crystal structure of the Saccharomyces cerevisiae α-glucosidase, the molecular docking study has predicted the binding of compounds 5a and 5n to the active site of α-glucosidase through both hydrophobic and hydrogen interactions. A DPPH radical scavenging assay further showed that most hydroxyl-functionalized 2-arylbenzo[b]furans possess antioxidant activity. The exception was compound 5p, which has only one hydroxyl group on the 2-phenyl ring of 2-arylbenzo[b]furan. Our results indicate that hydroxyl-functionalized 2-arylbenzo[b]furans possess both antidiabetic as well as antioxidant properties.

Ring-oxidative biotransformation and drug interactions of propofol in the livers of rats.

Propofol, an intravenous anesthetic agent, is widely used for inducing and maintaining anesthesia during surgical procedures and for sedating intensive care unit patients. In the clinic, rapid elimination is one of the major advantages of propofol. Meanwhile, the biotransformation and drug interactions of propofol in rat livers are still little known. In this study, we evaluated the ring-oxidative metabolism of propofol in phenobarbital-treated rat livers and possible drug interactions. Administration of phenobarbital to male Wistar rats significantly increased levels of hepatic cytochrome P450 (CYP) 2B1/2 and microsomal pentoxyresorufin O-dealkylase (PROD) activity. Analyses by high-performance liquid chromatography and liquid chromatography mass spectroscopy revealed that propofol was metabolized by phenobarbital-treated rat liver microsomes into 4-hydroxypropofol. In comparison, PROD activity and 4-hydroxy-propofol production from propofol metabolism were suppressed by orphenodrine, an inhibitor of CYP2B1/2, and a polyclonal antibody against rat CYP2B1/2 protein. Furthermore, exposure of rats to propofol did not affect the basal or phenobarbital-enhanced levels of hepatic CYP2B1/2 protein. Meanwhile, propofol decreased the dealkylation of pentoxyresorufin by phenobarbital-treated rat liver microsomes in a concentration-dependent manner. Taken together, this study shows that rat hepatic CYP2B1/2 plays a critical role in the ring-oxidative metabolism of propofol into 4-hydroxypropofol, and this anesthetic agent can inhibit CYP2B1/2 activity without affecting protein synthesis.

Neobavaisoflavone stimulates osteogenesis via p38-mediated up-regulation of transcription factors and osteoid genes expression in MC3T3-E1 cells.

Neobavaisoflavone (NBIF) is an isoflavone isolated from Psoralea corylifolia L, a plant claimed to have osteogenic activity and used to treat bone fractures, osteomalacia and osteoporosis. The present results showed that NBIF concentration-dependently promoted osteogenesis in MC3T3-E1cells, demonstrated by notable enhancement of alkaline phosphatase (ALP) activity, increase of bone-specific matrix proteins expression including type I collagen (Col-I), osteocalcin (OCN) and bone sialoprotein (BSP), and formation of bone nodules. However, cell proliferation in the presence of NBIF was not affected. Results also demonstrated that NBIF up-regulated the expression of runt-related transcription factor 2 (Runx2) and Osterix (Osx), the bone-specific transcription factors participating in regulation of bone marker genes expression. Application of p38 inhibitor SB203580 repressed not only NBIF-induced activation of ALP, the expression of Col-I, OCN and BSP, but also the matrix proteins mineralization. Western blot analysis further revealed that NBIF increased the phosphorylated level of p38 concentration-dependently. Additionally, inhibition of p38 abolished the stimulatory effect of NBIF on the expression of Runx2 and Osx. Taken together, the osteogenic activity of NBIF might probably act through activation of p38-dependent signaling pathway to up-regulate the mRNA levels of Runx2 and Osx then stimulate bone matrix proteins expression. The beneficial effect of NBIF on mineralization demonstrated that NBIF represented as an active component existed in P. corylifolia and might be a potential anabolic agent to treat bone loss-associated diseases.