Current Organic Chemistry - Volume 21, Issue 4, 2017

Arjunolic acid (AA) is a triterpenoid saponin isolated mainly from Terminalia arjuna bark. Arjunolic acid is associated with the various important physiological functions viz. antioxidant, antimicrobial, cardioprotective, hepatoprotective, and plays important role in supramolecular chemistry, etc. Arjunolic acid exhibits important function in maintaining the level of various antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST), glutathione reductase (GR) and glutathione peroxidase (GPx), level of cellular metabolites, reduced glutathione (GSH), oxidized glutathione (GSSG) and thereby reduces the oxidative stress. Its protective effect on liver, pancreas and kidney has also been the key property of arjunolic acid. Hence, arjunolic acid has potential to treat various disorders and this review may provide valuable information about arjunolic acid.

Excessive and persistent formation of ROS (reactive oxygen species) is a key factor in the origin of cancer, cardiac problems, inflammatory diseases, multiple organ dysfunction, aging and neurogenerative diseases. These ROS are produced from exogenous sources (ionizing radiation, chemicals and contaminants) and endogenous sources (Enzymes like Xanthine Oxidase and Monoamine Oxidase) which further originate a number of diseases along with genetic mutation. Due to the persistent side effects of synthetic antioxidants, there is flow towards naturally driven antioxidants as a large number of dietary supplements possess antioxidant potential. Coumarins are naturally occurring benzopyrones found in a variety of natural plants and exhibit different pharmacological properties. Among these activities the antioxidant potential of coumarins has been extensively studied that has been reviewed in this paper.

This review surveys the literature published on the emerging biological properties of furanodienone. Furanodienone (FDN) (1) is a furanosesquiterpenoid belonging to the class of furanogermacranes. This class of secondary metabolites is usually not widespread as they are present only in Asteraceae, Apiaceae, Myrtaceae, Lauraceae, Zingiberaceae and Burseraceae. It is commonly isolated from several species of Curcuma and Commiphora. This compound was shown to have several interesting activities, e.g. anti-inflammatory, antimicrobial and anticancer activity. Several in vitro and in vivo studies showed that FDN is able to inhibit several proinflammatory enzymes, such as COX and LOX, it decreases NO generation and reduces the production of proinflammatory cytokines. Furthermore, it is able to inhibit cell proliferation in different cancer cell lines, through the induction of apoptosis. Tested against several microorganism, FDN showed an antibacterial activity against Gram (+) and Gram (-) bacteria, an antifungal activity against pathogenic and phytopathogenic fungi, and an antiprotozoal activity against Trypanosoma brucei.

Coumarins represent an important family of naturally occurring and/or synthetic oxygen-containing heterocycles, bearing a characteristic benzopyrone framework. These compounds are widely distributed both in human diet and therapeutics. Among other characteristics, several coumarin derivatives proved to have an interesting antioxidant profile. In the current review, an overview of the role of natural coumarins as important antioxidants is presented and discussed. The benefits of antioxidants to prevent chronic diseases is also discussed in the current review. The most common assays performed to evaluate the antioxidant capacity described in this review are related to different reactive oxygen species involved in the oxidative process. Several reaction mechanisms were studied to investigate the antioxidant profile of coumarins. Among them, hydrogen atom transfer (HAT) and single electron transfer transfer (SET), were highly cited. To make the organization of this overview as clear as possible, coumarin derivatives were dived in: simple coumarins; aliphatic, terpenoid and aromaticcontaining coumarins; ring-fused coumarins and ellagic acid derivatives.

Olive oil is one of the most common and important cooking oils is obtained from olive fruits. It is known as the main source of bioactive phenyl ethyl alcohol, hydroxytyrosol. Hydroxytyrosol and its derivatives representing half of the polyphenols occurring in olive oil and are responsible for the nutraceutical properties and pharmacological effects of olive oil. Hydroxytyrosol is easily absorbed and it has a good bioavailability. In addition, hydroxytyrosol has negligible adverse effects and therefore, much attention has been paid to this compound as one of the most important polyphenols. Up to now, several scientific reports demonstrated a wide range of pharmacological effects about hydroxytyrosol. Therefore, the present study aimed to critically review the available knowledge about health-promotion effects of hydroxytyrosol and its chemistry, bioavailability, pharmacokinetics and toxicity.

Chitosan is the N-deacetylated derivative of chitin which is second most available natural polymer after cellulose. Chitosan is associated with various important biological effects such as anticancer, wound healing, antimicrobial, antioxidant, as excipients in various formulations including control release drug delivery products etc. However chitosan as such is poorly soluble in water and other common solvents which may restrict its commercial application and the problem of solubility may be resolved to some extent by the use of different synthesized derivatives of chitosan. Further, the vast application of chitosan and its derivatives has fostered the researchers to find more new and improved derivatives having newer applications in various fields of science.

One of the biggest challenges in the modern medicine and the food industry is to provide chemical agents that, incorporated in the foods, could have some pharmacological properties, but mainly that can protect and preserve our health from oxidative stress, and could be used in clinical treatments against some chronic diseases with minor side effects. In this sense, aporphine alkaloids have been the group of nitrogen compounds more studied in nature, incorporated in many foods and with a wide therapeutic application. Examples such as (-)- boldine (12), (-)-liridinine (15), (+)-lirinidine (16) and glaucine (24) have been studied for their interesting antioxidant activity and, in case of 24, synthetic modifications have managed to generate derivatives that exhibit more efficient antioxidant activity. Therefore, clinical treatment against oxidative stress-related diseases, such as Parkinson´s disease, anticancer, antinociceptive, therapeutic applications among other mentioned in this review, gives the possibility of using these aporphine alkaloids of low cytotoxicity as an excellent alternative in the development of new therapeutic patterns using the duplicity; biologically active ingredient-antioxidant.

Quercetin is a natural polyphenolic flavonoid, mainly present as quercetin glycosides. It is found in a wide variety of fruits, vegetables, wines and teas. Quercetin has shown a variety of biologic activities including antioxidant, anti-carcinogenic, anti-inflammatory, cardioprotective and a susceptibility reduction to viral infection. It is well established that regular and moderate exercise results in a low-moderate reactive oxygen species increase, with a role as cellular signals able to induce an adaptive response. On the contrary, intense and exhaustive exercise is associated with oxidative stress and inflammation. Quercetin is currently under study regarding the field of the physical activity as an ergogenic supplementation because of its potential antioxidant and antiinflammatory effects. In the present review, the potential use of quercetin as antioxidant aid against exerciseinduced oxidative stress and inflammation is discussed. The recent knowledge of the potential antioxidant and anti-inflammatory role of dietary quercetin in exercise is also summarized.

Since the early 1990s, a meaningful number of reports have been published supporting the idea that wines, especially reds, encompass a series of bioactive compounds, mainly phenolic compounds, which could bring health benefits if consumed with moderation. Beyond any other alcoholic beverage, the beneficial health effect of moderate wine consumption became noteworthy after the “French Paradox” was avowed. Besides similar intake patterns of saturated fatty acids, CVD incident rates were much lower in France than in the rest of Europe; a situation that was attributed to a type of diet that involves the consumption of large amounts of vegetables, fruits, olive oil, and red wine (“the Mediterranean diet”). Based on the above, this drink is a key component of the Mediterranean diet, associated with a lower incidence of cardiovascular diseases, some forms of cancer, and other disorders related with oxidative stress. In this paper, we review and discuss the main benefits attributed to its moderate consumption, examine the phenolics composition, the chemical characteristics of its major antioxidant components, and their relationship with its biological activity. We also summarize the main methodologies used for their identification and quantification, and the measurements of antioxidant activity.

Silica supported functionalized ionic liquid CuCl3-IL-SiO2 has been prepared and characterized by FTIR, scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD), thermogravimetry (TG) and differential scanning calorimetry (DSC) analysis. A series of arylamines and aryl ethers were obtained by Ullmann C-N and C-O coupling of aryl halides with amines and phenols catalyzed by this ionic liquid. The reactions were carried out with aryl halide (10 mmol), amine or phenol (10 mmol), CuCl3-IL-SiO2 (1.5 mol %), K2CO3 (11 mmol), and CH3CN (20 mL) at reflux conditions. This atom economical protocol affords the target products in good to high yields. The properties of the heterogeneous catalytic system were studied by tuning various reaction parameters including amount of the catalyst, influences of solvents and bases. The catalyst exhibited high efficiency in the Ullmann coupling reactions along with good recycle performance. The salient features of the present protocol are mild reaction conditions, shorter reaction time, easy recoverability and steady reuse.