Current Bioactive Compounds - Volume 7, Issue 4, 2011

Cysteine proteases are important therapeutic targets for numerous disease states including arthritis, osteoporosis, African sleeping sickness and Chagas disease. They have been shown to be viable drug targets for parasitic diseases through in vitro and animal model studies. This review examines the development of vinyl sulfone containing cysteine protease inhibitors. Peptidyl vinyl sulfones are superior inhibitors as they comprise the reactive vinyl sulfone warhead in addition to the peptide backbone, which has complementarity with the enzyme active site. The design, synthesis and activity of these protease inhibitors are discussed. Additionally, different methods for the preparation of vinyl sulfones are presented.

Probiotic agents are defined as live microorganisms, which confer a health benefit to the host when administered in adequate amounts. However, also molecules produced by both probiotic and non-probiotic bacteria and administered alone seem to provide beneficial effects similar to those obtained with live cells. These molecules can stimulate different signalling pathways by activating pattern recognition receptors and modulate different immune responses in the host. This review focuses on bacterial components, such as surface molecules and DNA, with beneficial immunomodulatory properties. Lipopolysaccharides from Gram-negative bacteria, lipoteichoic acid from Gram-positive bacteria and DNA of specific strains are the most effective molecules in modulating the host immune response, as they can modify the pattern of released cytokines. Bacterial components with beneficial properties could be an interesting substitute to traditional probiotics, as they could eliminate some of the risks associated with the consumption of live bacteria. Data presented in this review show that the concept of probiotic agent should change, as a large portion of the beneficial effects of probiotic bacteria does not depend on their viability and integrity. A more clear understanding of molecular mechanisms resulting in the health benefits provided by probiotics could be the basis for a more rational application of probiotics in functional foods or as supporting therapy for specific disorders.

Epidemiological studies have consistently shown that regular consumption of fruits and vegetables, as well as whole grains and fish oils, is strongly associated with reduced risk of developing chronic diseases, such as cancer and cardiovascular diseases. Over the years, numerous bioactive compounds have been identified that contribute to these beneficial health effects. In particular, carotenoids have been shown to exhibit potential antioxidant, anti-atherogenic and anticarcinogenic properties in several experimental studies. More recently, evidence is emerging that specific combinations of carotenoids with other bioactive food components may be far more effective in protecting against cancer and cardiovascular diseases than isolated compounds. The present review summarizes the in vitro and in vivo evidence for additive and synergistic interactions of carotenoids with various dietary bioactive food components, including vitamin E, vitamin C, phenolics, n-3 polyunsaturated fatty acids (PUFAs) and lipoic acid, in preventing oxidative stress, cancer and cardiovascular diseases. Our understanding of the molecular mechanisms underlying such synergistic effects, as well as the number of the studies, is still limited, but it appears that different combinations of complementary modes of actions may be an appropriate strategy for significantly reducing the risk of chronic diseases and to meet nutrient requirements for optimum health.

This review documents chemical structures and antifungal activities of 68 compounds isolated from 22 Piper species of the plant family Piperaceae. These compounds include amides, flavonoids, prenylated benzoic acid derivatives, lignans, phenylpropanoids, butenolides, and cyclopentenediones. Some of them may serve as leads for potential pharmaceutical or agricultural fungicide development.

Thirty secnidazole derivatives have been synthesized and evaluated for Helicobacter pylori (H. Pylori) urease inhibitory activities and anti-inflammatory activities. All of them were reported for the first time. Their chemical structures were characterized by 1H NMR, 13C NMR, MS, and elemental analysis. Compound 5a, 6c and 8c showed the most potent urease inhibitory activities and anti-inflammatory activities with IC50 values of 1.7 μM, 1.0 μM, 2.0 μM and inhibition of 62.60%, 59.54%, 71.76%, respectively. Docking simulation was performed to position compound 6c into the urease active site to determine the probable binding model. Compound 5a, 6c and 8c with potent inhibitory activity against H. pylori may be potential antibacterial agents.

Stevia rebaudiana (Bert.) Bertoni (Asteraceae) leaves are natural source of steviol glycosides, which are used commercially for sweetening and flavouring foods and beverage. The essential oil from the roots of S. rebaudiana was isolated by hydrodistillation and analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GCMS) techniques. A total of sixty components constituted 86.57% of the total oil composition were identified. Major components of this oil were α-longipinene (22.58%), α-isocomene (15.36%), modheph-2-ene (14.41%), (Z)-caryophyllene (6.18%), silphinene (6.08%) and α-amorphene (2.91%). This is a first report on S. rebaudiana root essential oil composition. It is concluded that S. rebaudiana roots, which are leftover in the field after harvesting aerial parts, can be used as a potent source of rarely occurring sesquiterpenes.