One-pot synthesis of thioethers from indoles and p-quinone methides using thiourea as a sulfur source.

Thiourea is an inexpensive and user friendly sulfur reagent that acts as a sulfur source. A simple and efficient protocol has been developed to access thioethers by reacting indoles with p-quinone methides using thiourea as the sulfur source. In our experiments, the reaction apparently proceeded through an S-(3-indolyl)isothiuronium iodide intermediate and subsequent generation of indolethiol that attacked the 1,6 position of p-quinone methides to give desired thioethers in good to excellent yields.

Pyrazoline analogues: Design, synthesis, and evaluation of anti-osteoporosis activity.

A series of pyrazoline compounds were synthesised and their osteogenic potential was explored. Out of fifteen, six compounds (3a, 4ac, 5aaa, 7, 8ab and 4aa) showed significant osteoblast differentiation in the range of 1 pM -1 µM concentrations. Amongst all, compound 4aa was identified as most active molecule which showed effective mineralisation of osteoblast cells and up regulates the osteogenic marker gene such as Bmp-2, Runx-2 and Type-1col at both transcriptional and translational level. Besides exhibiting potential osteogenic activity, 4aa also possess significant anti-apoptotic activity at 1 pM &100 pM concentration and increases the osteoblast survival in serum deprived conditions.

Gedunin isolated from the mangrove plant Xylocarpus granatum exerts its anti-proliferative activity in ovarian cancer cells through G2/M-phase arrest and oxidative stress-mediated intrinsic apoptosis.

Gedunin is a natural tetranorterpenoid secondary metabolite found in plants of the Meliaceae family, which has been reported for its antiparasitic, antifungal and anticancer activities. Here, we describe the molecular mechanisms underlying the in vitro anti proliferative activity of gedunin (isolated from the mangrove plant Xylocarpus granatum) in human ovarian cancer cells. We observed that gedunin triggered severe ROS generation leading to DNA damage and cell cycle arrest in G2/M phase thus inhibiting cell proliferation. ROS upregulation also led to mitochondrial stress and membrane depolarization, which eventually resulted in mitochondria-mediated apoptosis following cytochrome C release, caspase 9, 3 activation, and PARP cleavage. Transmission electron microscopy of gedunin treated cells revealed sub-cellular features typical of apoptosis. Moreover, an upregulation in stress kinases like phospho-ERK 1/2, phospho-p38 and phospho-JNK was also observed in gedunin treated cells. Free radical scavenger N-Acetyl-L-Cysteine (NAC) reversed all these effects resulting in increased cell survival, abrogation of cell cycle arrest, rescue of mitochondrial membrane potential and suppression of apoptotic markers. Interestingly, gedunin is also an inhibitor of the evolutionarily conserved molecular chaperone Heat Shock Protein 90 (hsp90) responsible for maintaining cellular homeostasis. Targeting this chaperone could be an attractive strategy for developing cancer therapeutics since many oncogenic proteins are also client proteins of hsp90. Collectively, our findings provide insights into the molecular mechanism of action of gedunin, which may aid drug development efforts against ovarian cancer.

Ecliptal, a promising natural lead isolated from Eclipta alba modulates adipocyte function and ameliorates metabolic syndrome.

A swift increase has been observed in the number of individuals with metabolic syndrome worldwide. A number of natural compounds have been identified towards combating metabolic syndrome. Adding to this premise, here we report the pleiotropic activities of Ecliptal (EC); a natural compound isolated from the herb Eclipta alba. Administration of EC was shown to have prominent anti-adipogenic effects in 3T3-L1 and hMSC derived adipocytes. It was shown to activate Wnt-pathway and alter AKT signaling. Additionally, it caused cell cycle arrest and inhibited mitotic clonal expansion. EC treatment augmented mitochondrial biogenesis as well as function as estimated by expression of PGC1α, UCP-1, mitochondrial complexes and estimation of oxygen consumption rate. EC also reduced LPS-induced inflammation and tunicamycin induced ER stress. Further, EC enhanced insulin sensitivity by increasing AKT phosphorylation, inhibiting PKCα/ßII phosphorylation and reducing leptin/adiponectin ratio. Finally, EC administration in Syrian golden hamsters was shown to have potent anti-dyslipidemic effects. Cumulatively, encompassing pleiotropic activities of EC, it could prove to be a potential drug candidate against obesity, insulin resistance and related metabolic syndrome.

Lupeol derivative mitigates Echis carinatus venom-induced tissue destruction by neutralizing venom toxins and protecting collagen and angiogenic receptors on inflammatory cells.

BACKGROUND: Echis carinatus bite is a serious threat in South-Asian countries including India, as it causes highest number of deaths and terrifying long-term tissue destruction at the bitten site. Although venom metalloproteinases and hyaluronidases are the suggested key players, studies on the effect of venom on polymorphonuclear cells, peripheral blood mononuclear cells and platelets, and their role in long-term tissue destruction are still in infancy. While, the effect of venom on collagen receptors, integrin α2ß1/GP VI/DDR1 and CX3CR1 chemokine receptor present on these cells is an untouched area. METHODS: Lupeol, lupeol acetate, its synthetic derivatives 2-8 were screened for inhibition of E. carinatus venom induced-hemorrhage in mouse model where compound 8 was found to be the most potent. Further, compound 8 efficiently neutralized venom induced hemorrhage, edema, dermonecrosis, myonecrosis, myotoxicity, pro-coagulant, oxidative stress, inflammatory cytokines and cleavage of collagen and CX3CR1 receptors on inflammatory cells in in vivo, in silico, ex vivo and in vitro studies. CONCLUSIONS: This study for the first time demonstrated the cleavage of collagen receptors and the receptor for angiogenesis and wound healing by the venom and its inhibition by compound 8, as these are important for firm adhesion of inflammatory cells at the damaged site to resolve inflammation and promote tissue repair. GENERAL SIGNIFICANCE: This study provides a lead in venom pharmacology, wherein, compound 8 could be a therapeutic agent for the better management of viper venom-induced long-term tissue destruction.

Dose-dependent effects of Asparagus adscendens root (AARR) extract on the anabolic, reproductive, and sexual behavioral activity in rats.

CONTEXT: Asparagus adscendens Roxb (Liliaceae) has a promising role in modulation of various disorders such as leucorrhea, diarrhea, dysentery, diabetes, senile pruritus, asthma, fatigue antifilarial, antifungal, spermatorrhea, and sexual debility/seminal weakness. OBJECTIVE: To investigate dose-dependent effects of Asparagus adscendens root (AARR) extract on anabolic, reproductive, and sexual behavioral activities with a view to emphasize the pharmacological basis. MATERIALS AND METHODS: Rats were divided into five groups: Group I (control), Groups II-IV (AARR treated, 100, 200, and 300 mg/kg body weight, respectively, orally for 30 d) and Group V (standard control treated with sildenafil citrate, 5 mg/kg body weight). On day 31, copulatory and potency tests were carried out and an autopsy was done to study the reproductive function, namely, organ weights, spermatogenesis, daily sperm production rate (DSP), and epididymal sperm counts (ESC). RESULTS: AARR extract (200 and 300 mg/kg doses) caused a significant increase in body (p < 0.02 and p < 0.001) and testes (p < 0.01 and p < 0.001, control versus treated) weights. Reproductive activity showed significant a increase in testicular tubular diameter (p < 0.005-0.001), the number of round/elongated spermatids (p < 0.02-0.001), DSP, and ESC (p < 0.05-0.001). The sexual behavioral parameters including mounting/intromission frequency (13.0 ± 0.32/11.8 ± 0.37 and 18.2 ± 2.12/14.8 ± 1.15 versus 11.2 ± 0.66/8.2 ± 1.16), ejaculation latency (187.4 ± 1.91 and 191.4 ± 1.72 versus 180.0 ± 3.47), and penile erections (13.5 ± 0.3 and 14.5 ± 0.5 versus 8.5 ± 0.2) showed a significant increase at 200 and 300 mg/kg doses (ED50 300 mg/kg), but less than a standard control. In contrast, 100 mg/kg dose caused an increase (p < 0.005) in mounting latency only. CONCLUSION: These results indicate increased anabolic, reproductive, and sexual activities by AARR treatment. Thus, the data provide scientific rationale for its traditional use as an aphrodisiac or for sexual disorders.

Chebulinic acid alleviates LPS-induced inflammatory bone loss by targeting the crosstalk between reactive oxygen species/NFκB signaling in osteoblast cells.

Chebulinic acid (CA), a plant ellagitannin derived from Triphala, is reported to exhibit both anti-inflammatory & anti-oxidant activity apart from anti-tumour property. However, its role in inflammatory bone loss conditions was unexplored. We hypothesized that CA may prevent the bone loss under inflammatory conditions induced by lipopolysaccharide (LPS) in 10-week-old male C57BL/6J mice. Micro-CT analysis and histomorphometric evaluations were carried out where it was found that CA significantly improved the bone micro-architectures by enhancing trabecular connectivity and strength of the bone. CA also increased the bone regeneration as examined by calcein labelling and ex-vivo mineralisation along with maintaining the bone serum markers. Further, CA ameliorated the reduction in osteoblast cell differentiation, proliferation and viability after LPS stimulation. DCFDA and Mitosox staining revealed that CA presented remarkable protective effects against LPS treatment by attenuating oxidative stress, both at cellular & mitochondrial levels. In addition, CA significantly decreased the production of pro-inflammatory cytokines, and down-regulated the phosphorylation of NFκB and IκBα, indicating that CA could attenuate the inflammatory impairment to primary osteoblast cells by suppressing the NFkB signalling pathway. Taken together, the protective role of CA against LPS-induced bone loss & inhibitory effect on total ROS levels hold promise as a potential novel therapeutic strategy for the inflammatory diseases in bones.

Glucose uptake stimulatory effect of 4-hydroxypipecolic acid by increased GLUT 4 translocation in skeletal muscle cells.

Peganum harmala Linn, commonly known as 'harmal' belonging to the family Zygophyllaceae, is one of the most important medicinal plants of India. In continuation of our drug development program on Indian medicinal plants we discovered antihyperglycemic activity in 4-hydroxypipecolic acid (4-HPA), isolated from the seed of P. harmala. Effect of 4-HPA on glucose uptake and glucose transporter-4 (GLUT-4) translocation was investigated in L6 skeletal muscle cell lines. Treatment with 4-HPA stimulated both glucose uptake and GLUT4 translocation from intracellular to cell surface in skeletal muscle cells in a concentration-dependent manner, which might be leading to antihyperglycemic effect.

Synthesis of novel N-(2-hydroxy-2-p-tolylethyl)-amide and N-(2-oxo-2-p-tolylethyl)-amide derivatives and their antidyslipidemic and antioxidant activity.

In continuation of our drug discovery program on metabolic diseases, we identified an alkaloidal amide, that is, Aegeline (V) from the plant Aegle marmelos leaves as a dual acting agent (antihyperlipidemic and antihyperglycemic). We therefore synthesized a series of alkaloidal amides [N-(2-hydroxy-2-p-tolylethyl)-amides and N-(2-oxo-2-p-tolylethyl)-amide derivatives] related to Aegeline and screened for their in vivo antihyperlipidemic activity in Triton induced hyperlipidemia model. The synthetic compounds 4, 17 and 20 showed equipotent activity to the natural product, that is, Aegeline (V). These compounds also showed strong antioxidant activity, which support their antihyperlipidemic activity. Compound 12 showed better antihyperlipidemic and antioxidant profile than the natural product V.

Dietary Lactobacillus acidophilus and Mannan-Oligosaccharides Alter the Lipid Metabolism and Health Indices in Broiler Chickens.

The effects of dietary Lactobacillus acidophilus (LBA) and mannan-oligosaccharide (MOS) supplementation on lipid metabolism and consequent lipid profile and health indices in broiler chicken were investigated in this study. Supplementation of 0.2% MOS along with either 106 or 107 LBA/g feed in broiler chicken downregulated hepatic expression of genes involved in lipogenesis, and upregulated expression of lipolytic genes. It caused decline of lipogenesis and increase of lipid oxidation which resulted in lower carcass fat content. None of the genes studied influenced fatty acid profile of chicken meat except the expression of stearoyl CoA (Δ9) desaturase-1 (SCD-1) whose upregulation increased monounsaturated fatty acid (MUFA) content at the cost of saturated fatty acid (SFA) content. The lipid metabolism indices of chicken meat such as ∆9 desaturase index (DI) increased in birds supplemented with 0.2% MOS along with either 106 or 107 CFU LBA/g feed, whereas no effect was observed on ∆5 + ∆6 DI. The supplementation of 0.2% MOS along with either 106 or 107 CFU LBA/g feed in birds improved the health indices of chicken meat due to upregulation of SCD-1 expression. The supplementation of 0.2% MOS along with either 106 or 107 CFU LBA/g feed in broiler chicken produced hypocholesterolemic and hypolipidemic effects with improved serum cardio-protective indices.

An unprecedented biogenetic-type chemical synthesis of 1(15-->11) abeotaxanes from normal taxanes.

A one-pot chemical process using BF(3).Et(2)O for the synthesis of a new class of 1(15-->11) abeotaxanes from normal taxanes has been developed. The chemical structures of rearranged 1(15-->11) abeotaxane were established by extensive 2D NMR spectroscopic data.

Diastereomeric Mixture of Calophyllic and Isocalophyllic Acid Ameliorates Scopolamine-Induced Memory Impairment in Mice: Involvement of Antioxidant Defense and Cholinergic Systems.

Dementia of Alzheimer disease type (AD) and type 2 diabetes mellitus (T2D) are two most common diseases of aging which has reached epidemic proportions. Moreover, there is a shared mechanism of pathogenesis between metabolic disorders and AD. Hence, the need for discivery of effective prevention and treatment strategies. Diastereomeric mixture of calophyllic acid and isocalophyllic acid (ISO) has been shown to stimulate glucose uptake through GLUT4- translocation. In this study, an attempt was made to investigate the effect of ISO on scopolamine-induced memory deficit in mice. ISO (5, 25 or 50 mg/kg, p.o.) or vehicle (10 ml/kg, p.o.) was administered for 3 consecutive days. One hour post-treatment on day 3, scopolamine (3 mg/kg, i.p.) was given before the animals were subjected to Y-maze, open field, novel object recognition (NOR) or Morris water maze (MWM; 5 consecutive days) paradigms. The mice were sacrificed 45 min after MWM test on day 8. The hippocampus and prefrontal cortex were rapidly isolated on ice for assay of biochemical markers of oxidative stress and acetylcholinesterase activity. Scopolamine reduced the percentage alternation behaviour in the Y-maze and discrimination index in NOR tests with no significant change in escape latency time in MWM task suggestive of deficit in learning and memory. However, the pretreatment of mice with ISO produced a dose-dependent improvement in learning and memory. Moreover, ISO administration attenuated scopolamine-induced increase in malondialdehyde/nitrite generation and acetylcholinesterase activity and deficit in antioxidant enzyme activity in the hippocampus and prefrontal cortex. Findings from this study showed that the diastereomeric mixture of calophyllic acid and isocalophyllic acid possesses anti-amnesic effect through enhancement of antioxidant defense and cholinergic signaling pathway.

Synthesis of novel triterpenoid (lupeol) derivatives and their in vivo antihyperglycemic and antidyslipidemic activity.

The triterpenoid, lupeol (1) has been isolated from the leaves extract of Aegle marmelos. Few novel derivatives (2-13) were synthesized from the naturally occurring lupeol (1) and screened for their antihyperglycemic activity (2-11) and antidyslipidemic activity (2-4 and 12-13). The derivative 4 lowered the blood glucose levels by 18.2% and 25.0% at 5h and 24h, respectively, in sucrose challenged streptozotocin induced diabetic rats (STZ-S) model at the dose of 100mg/kg body weight. The compound 4 also significantly lowered 40% (P <0.001) in triglycerides, 30% (P <0.05) in glycerol, 24% (P <0.05) in cholesterol quantity and also improved the HDL-cholesterol by 5% in dyslipidemic hamster model at the dose of 50mg/kg b.wt.

Peganine hydrochloride dihydrate an orally active antileishmanial agent.

Protozoic infections caused by genus Leishmania pose an enormous public health threat in developing countries, compounded by the toxicity and resistance to current therapies. Under the aegis of our ongoing program on drug discovery and development on antileishmanial agents from plants, we carried out bioassay guided fractionation on Peganum harmala seeds which resulted in the isolation of 1 as an antileishmanial agent. 2D-NMR spectral data and single crystal X-ray crystallography data indicated 1 as peganine hydrochloride in dihydrated form. The compound 1 exhibited in-vitro activity against both extracellular promastigotes as well as intracellular amastigotes residing within murine macrophages in Leishmania donovani. Furthermore, 1 also exhibited in-vivo activity, 79.6 (+/-8.07)% against established VL in hamsters at a dose of 100mg/kgb.wt.

Antileishmanial activity mediated by apoptosis and structure-based target study of peganine hydrochloride dihydrate: an approach for rational drug design.

OBJECTIVES: The aim of this study was to resolve the putative pathway responsible for death induced by peganine hydrochloride dihydrate isolated from Peganum harmala seeds at cellular, structural and molecular level in Leishmania donovani, a causative agent of fatal visceral leishmaniasis. METHODS: The mode of action was assessed using various biochemical approaches including phosphatidylserine exposure, estimation of mitochondrial transmembrane potential and in situ dUTP nick end labelling staining of nicked DNA in the parasite. Molecular modelling and molecular dynamics studies were conducted with DNA topoisomerase I to identify the target of peganine hydrochloride dihydrate mediating apoptosis. Further, DNA topoisomerase I inhibition by peganine hydrochloride dihydrate was also assessed using an L. donovani topoisomerase I relaxation assay. RESULTS: Peganine hydrochloride dihydrate, besides being safe, was found to induce apoptosis in both the stages of L. donovani via loss of mitochondrial transmembrane potential. Molecular docking studies suggest that a binding interaction with DNA topoisomerase I of L. donovani (binding energy of -79 kcal/mol) forms a stable complex, indicating a possible role in apoptosis. The compound also inhibits L. donovani topoisomerase I. CONCLUSIONS: The compound induces apoptosis in L. donovani and inhibits DNA topoisomerase I.

13C NMR spectroscopy of D and B, D-ring seco-limonoids of Meliaceae family.

The modified limonoids isolated from the Meliaceae are too complex or obtained in too small quantities to determine their structures by chemical and spectroscopic means, including 1H NMR. One method of dealing with such problem is direct crystallographic analysis, without or having a heavy atom, which requires an able crystallographic collaborator. The determination of the structure Utilin is one example. The analysis of the 13C NMR spectral data for different compounds has been very useful for the identification of the various skeletal types of limonoids and also for the determination of the substitution pattern. Owing to the great utilities that these data could help the scientific community, who are working in the area of limonoids, we here describe the application of NMR spectroscopy in the structure elucidation of D and B, D-ring seco-limonoids and a collection of 177 compound's 13C NMR spectral data.

Preliminary studies on the hypoglycemic effect of Peganum harmala L. Seeds ethanol extract on normal and streptozotocin induced diabetic rats.

Peganum harmala L. (Zygophyllaceae) is a traditional medicine used for the treatment of variety of human ailments, including antidepression, hallucination, antileishmaniasis etc. We report for first time the hypoglycemic activity of the ethanolic extract of this plant at two dose levels of 150 and 250mg/kg bw in sucrose challenged normal as well as in rats with streptozotocin induced diabetes. The oral administration of ethanolic extract causes maximum fall of blood glucose level to 22.9% (p<0.05) and 29.4% (p<0.01) respectively with the two doses in normal and 30.3% (p<0.01) and 48.4% (p<0.001) in diabetic rats. The standard drug metformin treated group showed 28.0% (p<0.01) and 45.5% (p<0.001) respectively in normal and diabetic rats. The above results show that the ethanolic extract of P. harmala is as effective as metformin in reducing the blood glucose levels of normoglycemic and streptozotocin-induced diabetic rats.

Total synthesis of munchiwarin, a triprenylated chalcone from Crotalaria medicagenia.

An efficient method is developed for the synthesis of the modified triprenylated chalcone, munchiwarin (1), isolated from the roots of Crotalaria medicagenia. The synthesis of 1 utilizes a Claisen-Schmidt condensation between 2,4-dihydroxy-3,5-C-diprenyl acetophenone and 4-methoxy benzaldehyde in the presence of Ba(OH)2 to yield the unusual chalcone 5 that contains a nine-membered ether ring. Further prenylation of 5 with 1-bromo-3-methylbut-2-ene and its subsequent demethylation with BBr3 gave munchiwarin (1).

Allium sativum constituents: effect on free radical generation from rat neutrophils.

Reactive oxygen species formation or respiratory burst by the neutrophils helps to remove the invaded pathogens and thus constitute a major defense against pathogenic microorganisms. Production of these radicals by activated neutrophils at the site of inflammation however inflicts damage to the host tissue. Modulation of the neutrophil respiratory burst is therefore important in determining the balance between immune defense and host tissue injury during inflammatory conditions. Garlic extracts and various compounds isolated from garlic have been found to possess various activities, however no report is available on their effect on neutrophil free radical generation. The present study was therefore undertaken to evaluate the effect of garlic aqueous extract, alcoholic extract and various fractions on the free radical generation from neutrophils. Among the tested fractions, chloroform fraction of garlic seems to be very potent in attenuating the free radical generation from rat neutrophils, which could be beneficial in the inflammation associated pathological conditions.

Ethyl acetate fraction of Eclipta alba: a potential phytopharmaceutical targeting adipocyte differentiation.

Natural products have always fascinated mankind for their miraculous properties. Eclipta alba (E. alba), a medicinal herb has long been used in traditional medicine for curing several pathologies. It has been shown to have anti-diabetic effect as well as hepato-protective activity. Here, in order to address metabolic derangements, the study was designed to evaluate the efficacy of E. alba and its fractions in adipogenesis inhibition and dyslipidemia. Of the crude extract and fractions screened, ethyl acetate fraction of E. alba inhibited adipocyte differentiation in 3T3-L1 pre-adipocytes and hMSC derived adipocytes. It inhibited mitotic clonal expansion and caused cell cycle arrest in G1 and S phase as suggested by western blot analysis and flow cytometry. It was also shown to have lipolytic effects. Oral administration of ethyl acetate fraction of E. alba to hamsters unveiled its anti-adipogenic as well as anti-dyslipidemic activity in-vivo. Mass spectrometry analysis of ethyl acetate fraction confirmed the presence of several bioactive components, projecting it as an effective phytopharmaceutical agent. In conclusion, ethyl acetate fraction of E. alba possesses potent anti-adipogenic as well as anti-dyslipidemic activity and could be projected as an herbal formulation towards obesity.