Mini Reviews in Medicinal Chemistry - Volume 13, Issue 12, 2013

Triglycerides participate in key metabolic functions such as energy storage, thermal insulation and as deposit for essential and non-essential fatty acids that can be used as precursors for the synthesis of structural and functional phospholipids. The liver is a central organ in the regulation of triglyceride metabolism, and it participates in triglyceride synthesis, export, uptake and oxidation. The metabolic syndrome and associated diseases are among the main concerns of public health worldwide. One of the metabolic syndrome components is impaired triglyceride metabolism. Diseases associated with the metabolic syndrome promote the appearance of hepatic alterations e.g., non-alcoholic steatosis, steatohepatitis, fibrosis, cirrhosis and cancer. In this article, we review the molecular actions involved in impaired triglyceride metabolism and its association with hepatic diseases. We discuss mechanisms that reconcile the chronic inflammation and insulin resistance, and new concepts on the role of intestinal micro-flora permeability and proliferation in fatty liver etiology. We also describe the participation of oxidative stress in the progression of events leading from steatosis to steatohepatitis and fibrosis. Finally, we provide information regarding the mechanisms that link fatty acid accumulation during steatosis with changes in growth factors and cytokines that lead to the development of neoplastic cells. One of the main medical concerns vis-a-vis hepatic diseases is the lack of symptoms at the onset of the illness and, as result, its late diagnosis. The understandings of the molecular mechanisms that underlie hepatic diseases could help design strategies towards establishing markers for their accurate and timely diagnosis.

Human immunodeficiency virus-1 (HIV-1) infections cause global health problems. Indole derivatives have been considered as one of the promising HIV inhibitors. Recent inventions have focused on substituted indole and azaindole derivatives that possess unique antiviral activities against HIV-1. In this review, the evaluation of recent advances in substituted indole and azaindole derivatives for the treatment or prevention of HIV-1 and acquired immune deficiency syndrome (AIDS) has been focused. In this respect, compounds having drug and bio-active properties, including their synthesis and pharmacologic properties have been reported. In addition, anti-HIV properties of compounds, the structural features of inhibitors, the current progress in terms of therapeutic interventions and the leading groups in the field are discussed. Moreover, clinical and ADME (Absorption, Distribution, Metabolism, Elimination) properties of some clinically important compounds such as BMS-378806, L-737126 and IDX899 are reported.

Saponins are natural glycosides consisting of a triterpene or steroid aglycone with a range of pharmacological properties such as significant anti-tumor activity. In this article, we review our recent progress in the studies of the saponins possessing anticancer effects, especially anti-glioblastoma effects from twelve species of marine organisms and terrestrial plants. The anti-glioblastoma active saponins discovered by other researchers in recent decades are also reviewed and compared. Systematic extraction, isolation and structural elucidation on the saponin constituents from three species of starfishes, five species of sea cucumbers and four species of medicinal plants led to the identification of more than 129 saponins, among which 76 saponins are new compounds. Most of the new compounds were found to possess relatively rare structural features showing in vitro cytotoxicity against tumor cells, especially glioblastoma cells. Several saponins exhibited significant anti-glioblastoma effects in vivo by in situ administration (interstitial chemotherapy) and their haemolytic side effects were avoided in the tests. Multiple mechanisms of action, such as interfering with cell cycle progression, inducing apoptosis, promoting stabilization of microtubule, as well as several signal transduction pathways, were involved in their anticancer effects. The review provided valuable leads for pursuing new anti-glioblastoma drugs, and established a new viewpoint for further development of these marine and terrestrial organisms. The successful approach to administrate saponins in situ conquered the bottleneck in the development of saponins as new drugs— haemolytic effects. It means that saponins may be developed as potential chemotherapeutic agents in pursuing new antiglioblastoma drugs.

The synthesis of novel compound libraries along with screening is a rapid and effective approach for the discovery of potential chemical agents, and it becomes an important method in pharmaceutical chemistry research. 1,3,4- oxadiazole derivatives as the typical heterocyclic compounds, exhibit a broad spectrum of biological activities and vital leading compounds for the development of chemical drugs. Herein, we focus on the synthesis and screening of novel 1,3,4-oxadiazoles derivatives with antimicrobial, antitumor or antiviral activities during the past decade. In this review, we discussed the synthetic development of 1,3,4-oxadiazoles derivatives, and also the relevant bioactivity and their prospects as the potential chemical drugs.

Benzopyran derivatives are the potassium channel openers (KCOs) having antihypertensive, cardio-protective, myocardial protectors, powerful peripheral vasodilators and anti-ischemic activity. Their usage as anti-ischemic including angina, hypertension and diabetes is thought to be due to the stimulation of KATP channels which are contemplated to produce vasorelaxation and myocardial protection. It is observed that potassium channels are involved in mediating the cardio-protective effects of pre-conditioning in animal models and man. KCOs protect heart from an ischemic insult without contribution from vasodilatation. This review provides an overview of the characteristics of KCOs and their actions on subtypes used widely for the treatments of various diseases including hypertension, cardiac ischemia, arrhythmia, smooth muscle relaxation, diabetes, cardio-protective and anti-angiogenic activities.

Sophorolipids, a kind of glycolipids, regarded as the most promising bio-surfactant, are synthesized by a selected number of yeast species. Instead of offering, as an environmental friendly alternative to the petrochemical based surfactants, it also exhibits various bioactivities. Sophorolipids in particular are on the brink of being incorporated into several cosmetic application. The potential of this molecule is also screened in various industries like the cosmetics, pharmaceuticals, and other medical applications. In this review, our aim is to provide an overview and updates on basic and applied research on Sophorolipid especially in terms of cosmetics and medicinal uses.

Curcumin, a natural diaryl heptanoid continues to be used as an alternative medicinal agent in many parts of South East Asia for treatment of many ailments. It can be usually obtained from substituted aryl aldehydes and acetylacetone and this route enables synthesis of a diverse set of curcumin analogues. Numerous analogues have been synthesized and tested by several researchers to investigate their activity against known biological targets and to improve upon the pharmacological and ADME profile by modifying substitutions on aromatic rings, β-diketone moiety and two flanking double bonds conjugated to the β-diketone moiety. Successful synthesis of such derivatives with modifications has resulted in the development of potential anticancer candidates that target various stages in cancer cell growth and development. Based on the evidences in modifications of these three functional elements, we have attempted to summarize the structure activity relationship of molecules which can be further utilized by researchers in medicinal chemistry in exploring the structure of curcumin.

Malaria is one of the major health problems in developing countries. It kills 1-2 million people every year and also it affects financial status of many countries. Developed resistance to aminoquinoline (chloroquine), quinoline methanols (Quinine, Mefloquine) created troubles in malarial chemotherapy and signs of appearance of resistance to artemisinin based combination therapy (ACT) created emergency to develop novel antimalarial agents with high efficacy before spreading of resistance to ACT. From the ages natural products played an important role in antimalarial therapy, identification of natural products, semisynthetic and synthetic analogs with potent antiplasmodium activity is one of the best methods to develop novel antimalarial agents. In this review, we are presenting the antimalarial activity of natural β-carboline alkaloids and special interest on manzamine alkaloids and their structure activity relationship.

The present review article is related with the method of preparation, importance and medicinal application of indole and indazoles. The studies of heterocycles is an evergreen field in the branch of organic chemistry and always attract the attention of chemists working not only in the area of natural products but also in the synthetic chemistry. Moreover many useful drugs have emerged from the successful investigation carried out in this branch. The derivatives of indoles and indazoles exhibits antibacterial, anticancer, antionidants, anti-inflammatory, antidiabetic, antiviral, atniproliferative, antituberculosis, antispermetogenic activity, antipsychotic drugs etc.

During the course of the past two decades, our group has worked towards the development of increasingly potent inotropic agents by making structural modifications to compounds derived from 3,4-dihydro-2(1H)-quinolinone (DHQO) and related analogues. Herein, we describe the design and synthesis of a new series of DHQO derivatives and the subsequent evaluation of their positive inotropic activity towards left atrium stroke volume in isolated rabbit-heart preparations. Some of these derivatives presented favorable in vitro activities compared with the reference drug, milrinone, and compound 10a, in particular is currently being investigated as a preclinical drug candidate. This review also describes our progress towards the development of DHQO derivatives and related analogues with positive inotropic activities from 1999 to 2013.

In the last few decades, a lot of work has been done on heterocycles, especially the imidazole ring, to obtain a scaffold with potential pharmacological properties such as antibacterial, antifungal, anticancer, antiviral, antidiabetic and others, with lesser side effects. The search for new biologically active imidazoles continues to be an interesting area of investigation in medicinal chemistry. The present paper aims to bring together and discuss the wealth of information on antibacterial profile of imidazoles. So it can be employed for future development to obtain new potent drug molecules.