Ru(II)-catalyzed synthesis of poly-substituted furans via intermolecular oxidative annulation reaction of ethyl 3-oxo-3-phenylpropanoates with aryl alkynes/heteroaryl alkynes.

The oxidative annulation reaction of ethyl 3-oxo-3-phenylpropanoates with internal alkynes proceeds efficiently in the presence of a Ru(II)-catalyst, a copper oxidant and an additive such as AgSbF6 to give poly-substituted furans, which offers a novel method for the selective construction of poly-substituted furans. The reaction has wider substrate scope with simple starting materials, and the desired tetrasubstituted furans were prepared in good to excellent yields.

Design, synthesis, and evaluation of benzofuran-based chromenochalcones for antihyperglycemic and antidyslipidemic activities.

A series of benzofuran-based chromenochalcones (16-35) were synthesized and evaluated for in vitro and in vivo antidiabetic activities in L-6 skeletal muscle cells and streptozotocin (STZ)-induced diabetic rat models, respectively, and further in vivo dyslipidemia activity of the compounds was evaluated in a Triton-induced hyperlipidemic hamster model. Among them, compounds 16, 18, 21, 22, 24, 31, and 35 showed significant glucose uptake stimulatory effects in skeletal muscle cells and were further evaluated for in vivo efficacy. Compounds 21, 22, and 24 showed a significant reduction in blood glucose levels in STZ-induced diabetic rats. Compounds 16, 20, 21, 24, 28, 29, 34, 35, and 36 were found active in antidyslipidemic studies. Furthermore, compound 24 effectively improved the postprandial and fasting blood glucose levels, oral glucose tolerance, serum lipid profile, serum insulin level, and the HOMA-index of db/db mice, following 15 days of successive treatment.

Synthesis of highly substituted isoquinolines/isoquinolones by ruthenium (II)-catalyzed reaction of benzyl/α-methyl benzyl/benzoyl isocyanates with diaryl alkynes.

An efficient and novel method has been developed for the synthesis of highly substituted isoquinolines/isoquinolones by Ru(II)-catalyzed intermolecular oxidative annulation of benzyl/benzoyl isocyanates with diaryl alkynes in the presence of Cs2CO3 as base and Cu(OTf)2 as an oxidant at 120 °C for 1 h.

Phenanthrenoid Coelogin Isolated from Coelogyne cristata Exerts Osteoprotective Effect Through MAPK-Mitogen-Activated Protein Kinase Signaling Pathway.

Osteoporosis is a major health problem in postmenopausal women globally. This study determined the mechanism through which coelogin stimulates osteoblastogenesis and its osteoprotective and bone regenerating potential. Coelogin effect on primary calvarial osteoblast cells was determined by measuring alkaline phosphatase activity, mineralization, osteoblast survival, and apoptosis and protein expression studies. The osteoprotective effect of coelogin was also evaluated on osteopenic adult female Swiss mice. At autopsy, bones were collected for dynamic and histomorphometry studies. Serum samples were also collected for assessment of serum parameters. Coelogin treatment led to increased osteoblast proliferation, survival, differentiation, and mineralization in osteoblast cells. Coelogin supplementation to Ovx mice promoted new bone formation, prevented Ovx-induced deterioration of bone microarchitecture, and enhanced bone regeneration. In addition, signaling studies revealed that coelogin treatment activates the ER-Erk and Akt-dependent signaling pathways which stimulate the osteoblastogenesis in osteoblast cells.

Synthesis of Unprotected and Highly Substituted Indoles by the Ruthenium(II)-Catalyzed Reaction of Phenyl Isocyanates with Diaryl/Diheteroaryl Alkynes/Ethyl-3-phenyl Propiolates.

A one-pot transformation has been developed for the synthesis of unprotected and highly substituted indoles by an in situ installed carbamide-directed Ru(II)-catalyzed intermolecular oxidative annulation of phenyl isocyanates with diaryl/diheteroaryl alkynes/ethyl phenyl propiolates in the presence of Cu(OAc)2·H2O as an oxidant and AgSbF6 as an additive at 120 °C within 3 h.

In Vitro: Cytotoxicity, Apoptosis and Ameliorative Potential of Lawsonia inermis Extract in Human Lung, Colon and Liver Cancer Cell Line.

Cancer has emerged as a major public health issue in developed as well as in developing countries. Plant-derived molecules are widely being used in the treatment of cancer due to their minimum side effects. Lawsonia inermis (Henna) is one of the medicinal plants containing many therapeutic properties. In the present study, bioactive components of L. inermis extract were analyzed by LCMS/MS method and validated. Lawsone (3.5%) is primarily responsible for cytotoxic and anti-cancerous activities. These properties were studied on human lung carcinoma (A549), colorectal cancer (DLD1) and Hepatocellular carcinoma (HepG2) cancer cell lines. The activities were assessed by MTT assay, evaluation of apoptosis by measuring the production of Reactive Oxygen Species (ROS) and mitochondrial membrane potential of the cancer cell lines. Moreover, apoptosis in the respective cancer cell lines was also determined by chromatin condensation and DNA fragmentation using Hoechst 33528 and propidium iodide (PI) staining. The preliminary in vitro result of MTT showed that the henna extract induces cytotoxic properties against A549, DLD1, HepG2 with IC50values 490, 480 and 610 µg/ml respectively (more than 40% growth inhibition). In addition, the extract induced a concentration-dependent rise in ROS production which was 84, 102, and 110% in HepG2, DLD1 AND A549 respectively at 300 µg/ml, whereas at 400 µg/ml concentration it was 86, 102, and 106% in respective cell lines while decreasing mitochondrial membrane potential was more than 20% in the investigated cell lines. The extract also provoked changes associated with apoptosis and the data indicate that the ROS production leads to a diminution in mitochondrial membrane potential and this correlated with the extract cytotoxicity.

Determination of Bioactive Compounds of Fenugreek (Trigonella foenum-graecum) Seeds Using LC-MS Techniques.

Trigonella foenum-graecum (fenugreek), a legume has been used as spice throughout the world to enhance the sensory quality of foods, is considered to have a high nutraceutical value. The antidiabetic actions of Trigonella seeds have been speculated due to the presence of steroid saponins, alkaloids, and fiber content. Five bioactive compounds, namely, trigonelline, isoorientin, orientin, vitexin, and isovitexin, were detected and quantified by HPLC system. Further rapid detection of bioactive compounds was achieved using high-performance liquid chromatography hybrid electrospray quadrupole time-of-flight mass spectrometric (HPLC-ESI-QTOF-MS/MS) method. Twenty-five compounds were tentatively identified based on their retention time and measured accurate mass. The fragmentation patterns of known compounds were utilized to elucidate their structures. Six of these identified compounds, that is, 4-hydroxyisoleucine, trigonelline, isoorientin, isovitexin, pinitol, and sarsasapogenin, were simultaneously quantified by UHPLC-ESI-MS/MS method under the multiple reactions monitoring (MRM) mode using ultrahigh-performance liquid chromatography hybrid electrospray triple quadrupole linear ion trap mass spectrometer. The analytical method was validated and successfully applied for simultaneous determination of compounds in Fenugreek seeds, which indicated the suitability of the validated method for its quality control.

Biological evaluation of novel curcumin-pyrazole-mannich derivative active against drug-resistant Mycobacterium tuberculosis.

AIM: Our objective was to identify a more potent curcumin derivative with specific activity against Mycobacterium tuberculosis. MATERIALS & METHODS: A total of 21 curcumin derivatives were synthesized and detailed bio-evaluation was carried out including determination of static/cidality, synergy with front-line antituberculosis drugs and determination of efficacy in the murine model of M. tuberculosis infection. RESULTS: We identified CPMD-6d dihydrochloride exhibiting concentration-dependent bactericidal activity against M. tuberculosis (MIC 2 µg/ml), even against drug-resistant strains. In addition, it synergizes with front-line antituberculosis drugs as well as significantly reduces bacterial load in mice lungs and spleen at 25 mg/kg as compared with ethambutol at 100 mg/kg. CONCLUSION: Taken together, CPMD-6d dihydrochloride exhibits all properties to be positioned as a novel molecule of interest for treatment of tuberculosis. Graphical abstract: [Formula: see text].

Curcumin-3,4-Dichloro Phenyl Pyrazole (CDPP) overcomes curcumin's low bioavailability, inhibits adipogenesis and ameliorates dyslipidemia by activating reverse cholesterol transport.

BACKGROUND: Adipocyte dysfunction, obesity and associated metabolic disorders are of prime healthcare concern worldwide. Among available medications, natural products and inspired molecules hold 40% space in clinically prescribed medicines. In queue, this study overcomes the drawback of curcumin's low bioavailability with potent anti-adipogenic and anti-dyslipidemic activity. METHODS: To evaluate the role of CDPP on adipocyte differentiation, 3T3-L1 adipocytes were used as an in-vitro model. Flow cytometry was performed for cell cycle analysis. Syrian golden hamsters were used to study pharmacokinetic profile and dyslipidemic activity exhibited by CDPP. RESULT: CDPP was found to be a potent inhibitor of adipogenesis in-vitro. It blocked mitotic clonal expansion by causing cell cycle arrest. CDPP showed marked improvement in gastrointestinal stability and bioavailability in-vivo as compared to curcumin. Administration of CDPP (100mg/kg) significantly improved HFD induced dyslipidemic profile in hamsters and activated reverse cholesterol transport machinery. CONCLUSION: CDPP could be used as a potential drug candidate against adipogenesis and dyslipidemia with enhanced gastrointestinal stability and bioavailability.

Identification of stress degradation products of iloperidone using liquid chromatography coupled with an Orbitrap mass spectrometer.

RATIONALE: Iloperidone (ILOP) is an atypical antipsychotic drug used for the treatment of schizophrenia and related psychotic disorders. Comprehensive stress testing of the ILOP drug was carried out as per ICH guidelines to understand its degradation profile. The presence of degradation products in a drug affects not only the quality, but also the safety and efficacy of drug formulation. Thus, it is essential to develop an efficient analytical method which can be useful for the separation, identification and characterization of all possible degradation products of ILOP. METHODS: ILOP was subjected to various stress conditions such as acidic, basic, neutral hydrolysis, oxidation, photolysis and thermal conditions; and the resulting degradation products were investigated using LC-PDA-HRMS and MS/MS. An efficient and simple ultra-high-performance liquid chromatography (UHPLC) method has been developed on Acquity UPLC® BEH C18 column (2.1 × 100mm, 1.7 µm) using a gradient elution of heptafluorobutyric acid (0.1% HFBA) and acetonitrile as mobile phase. RESULTS: ILOP was found to degrade under acidic and basic hydrolysis and oxidative stress conditions, whereas it was stable under neutral hydrolysis, thermal and photolytic conditions. A total of seven degradation products (DP1 to DP7) were identified and characterized by LC/MS/MS in positive ion mode with accurate mass measurements. The hydrolytic degradation under acidic and basic conditions produced two DPs (DP1 and DP2) and four DPs (DP4 to DP7), respectively, whereas DP3 was formed under oxidative conditions. In silico toxicity predictions showed higher probability values for DP4, DP6 and DP7, which indicates these DPs have the potential to mutate DNA. CONCLUSIONS: ILOP was found to be labile under hydrolytic and oxidative conditions. The structures of the degradation products were rationalized by appropriate mechanisms. The proposed method can be effectively used for the determination and detection of ILOP and its degradation products.

In vitro anti-hyperglycemic activity of 4-hydroxyisoleucine derivatives.

The nonproteinogenic amino acid, 4-hydroxyisoleucine (1) has been isolated in large quantities from the fenugreek (T. foenum-graecum) seeds. Few novel derivatives (3-11 and 13-18) were prepared from the naturally occurring 4-hydroxyisoleucine (1) and screened for their in vitro glucose uptake stimulatory effect in L-6 skeletal muscle cells. The derivatives 6, 7, 8, 10 and 11 exhibited better glucose uptake stimulatory activity than parent compound, 4-hydroxyisoleucine at 5 and 10µM concentrations and compounds 7 and 11 enhanced translocation of insulin sensitive glucose transporters-4 in skeletal muscle cells.

4-Hydroxyisoleucine improves insulin resistance by promoting mitochondrial biogenesis and act through AMPK and Akt dependent pathway.

4-Hydroxyisoleucine (4-HIL) is an unusual amino acid isolated from fenugreek seeds (Trigonella foenum graecum L). Various studies have shown that it acts as an antidiabetic agent yet its mechanism of action is not clear. We therefore investigated the effect 4-HIL on the high fructose diet fed streptozotocin induced diabetic rats and L6 myotubes. 4-HIL (50 mg/kg) has improved blood lipid profile, glucose tolerance and insulin sensitivity in a diabetic rat model. It has increased the glucose uptake in L6 myotubes in AMPK-dependent manner and upregulated the expression of genes (PGC-1α, PGC-1ß, CPT 1 and CPT 2), which have role in mitochondrial biogenesis and energy metabolism in the liver, skeletal muscles as well as in L6 myotubes. Interestingly, it also increased the AMPK and Akt expression along with their phosphorylated forms in the liver and muscle tissues of treated animals. Altogether we concluded that 4-HIL acts to improve insulin resistance by promoting mitochondrial biogenesis in high fructose diet fed STZ induced diabetic rats.

Synthesis and biological evaluation of chalcones as potential antileishmanial agents.

Antileishmanial activities of thirty-five synthetic chalcones have been examined. Among them, ten compounds (4, 6, 16, 22, 23, 24, 25, 29, 35 and 37) exhibited potent in vitro activity (IC50 range from 1.70 to 8 µM) against extracellular promastigotes and intracellular amastigotes form of Leishmania donovani. Two promising compounds 22 and 37 were tested in vivo in L. donovani/hamster model. Chalcone 37 showed 83.32% parasite inhibition at a dose of 50 mg/kg for 10 days whereas, 75.89% parasite inhibition at 100 mg/kg dose for 5 days by intraperitoneal route at day 7 post-treatment.

Synthesis of new N-acryl-1-amino-2-phenylethanol and N-acyl-1-amino-3-aryloxypropanols and evaluation of their antihyperlipidemic, LDL-oxidation and antioxidant activity.

As a part of our drug discovery program, we identified an alkaloidal amide i.e. Aegeline (V) isolated from the leaves of Aegle marmelos as a dual acting agent (antihyperlipidemic and antihyperglycemic). In continuation of this program, we synthesized new N-acyl-1-amino-2-alcohols (N-acrylated-1-amino-2-phenylethanol and N-acylated-1-amino-3-aryloxypropanols) via Ritter reaction and screened for their in-vivo antihyperlipdemic activity in Triton induced hyperlipidemia model, LDL-oxidation and antioxidant activity. Compounds 3, 11 and 13 showed good antihyperlipidemic activity, LDL-oxidation as well as antioxidant activity and comparable activity with marketed antidyslipidemic drug.

Synthesis, structure-activity relationships, and biological studies of chromenochalcones as potential antileishmanial agents.

Antileishmanial activities of a library of synthetic chalcone analogues have been examined. Among them, five compounds (11, 14, 16, 17, 22, and 24) exhibited better activity than the marketed drug miltefosine in in vitro studies against the intracellular amastigotes form of Leishmania donovani. Three promising compounds, 16, 17, and 22, were tested in a L. donovani/hamster model. Oral administration of chalcone 16, at a concentration of 100 mg/kg of body weight per day for 5 consecutive days, resulted in >84% parasite inhibition at day 7 post-treatment and it retained the activity until day 28. The molecular and immunological studies revealed that compound 16 has a dual nature to act as a direct parasite killing agent and as a host immunostimulant. Pharmacokinetics and serum albumin binding studies also suggest that compound 16 has the potential to be a candidate for the treatment of the nonhealing form of leishmaniasis.

Synthesis of novel anticancer iridoid derivatives and their cell cycle arrest and caspase dependent apoptosis.

Nyctanthes arbortristis Linn (Oleaceae) is widely distributed in sub-Himalayan regions and southwards to Godavari, India commonly known as Harsingar and Night Jasmine. In continuation of our drug discovery programme on Indian medicinal plants, we isolated arbortristoside-A (1) and 7-O-trans-cinnamoyl 6ß-hydroxyloganin (2) from the seeds of N. Arbortristis, which exhibited moderate in vitro anticancer activity. Chemical transformation of 2 led to significant improvement in the activity in derivative 8 and 15 against HepG2 (human hepatocellular carcinoma), MCF-7 (breast adenocarcinoma) cell lines. The compounds 8 and 15 were also capable of cell cycle arrest and caspase dependent apoptosis in HepG2 cell lines. These iridoid derivatives hold promise for developing safer alternatives to the marketed drugs.

Synthesis of new andrographolide derivatives and evaluation of their antidyslipidemic, LDL-oxidation and antioxidant activity.

Andrographis paniculata, native to Taiwan, Mainland China and India, is a medicinal herb, which possesses various biological activities including anti-atherosclerosis. Andrographolide (1) has been identified as one of the active constituents against atherosclerosis. In continuation of our drug discovery program we synthesized few novel derivatives of 1 to improve their antidyslipidemic, LDL-oxidation and antioxidant activity. The tosylated derivative 7 has been turned out to be more potent than the parent compound and comparable activity with marketed antidyslipidemic drugs.

Synthesis and insight into the structure-activity relationships of chalcones as antimalarial agents.

Licochalcone A (I), isolated from the roots of Chinese licorice, is the most promising antimalarial compound reported so far. In continuation of our drug discovery program, we isolated two similar chalcones, medicagenin (II) and munchiwarin (III), from Crotalaria medicagenia , which exhibited antimalarial activity against Plasmodium falciparum . A library of 88 chalcones were synthesized and evaluated for their in vitro antimalarial activity. Among these, 67, 68, 74, 77, and 78 exhibited good in vitro antimalarial activity against P. falciparum strains 3D7 and K1 with low cytotoxicity. These chalcones also showed reduction in parasitemia and increased survival time of Swiss mice infected with Plasmodium yoelii (strain N-67). Pharmacokinetic studies indicated that low oral bioavailability due to poor ADME properties. Molecular docking studies revealed the binding orientation of these inhibitors in active sites of falcipain-2 (FP-2) enzyme. Compounds 67, 68, and 78 showed modest inhibitory activity against the major hemoglobin degrading cysteine protease FP-2.