BIOACTIVITIES OF THE THAI MEDICINAL AND EDIBLE PLANTS C. CAJAN, M. CITRIFOLIA AND O. AMERICANUM

Objective: Inflammation and oxidative stress are closely related and play a role in various diseases. If an infectious component plays a role, an antibacterial effect is of advantage. Thus, natural remedies which combine different bioactivities have a broader range of application.Methods: Here we elucidate the anti-inflammatory, antioxidant and antibacterial effects of three edible and traditionally used Thai plants including leaves of Cajanus cajan, Morinda citrifolia and Ocimum americanum.Results: The extracts exerted significant anti-inflammatory activity in lipopolysaccharide (LPS)-stimulated macrophages. C. cajan extract shows a broad spectrum of antibacterial activity against Gram positive and negative, aerobic and anaerobic bacteria, whereas M. citrifolia and O. americanum possess antibacterial activity only against anaerobic bacteria. Extracts of all three plants showed significant antioxidant effects.Conclusion: The three plants are potential herbal remedies or supplements for functional food for the treatment and prevention of inflammation, oxidative imbalance, and bacterial infections or associated diseases.Â

ANTI-INFLAMMATORY, ANTIBACTERIAL, AND ANTIOXIDANT ACTIVITIES OF THAI MEDICINAL PLANTS

Objective: Acacia farnesiana (L.) Willd, Senna alata (L.) Roxb., Sesbania grandiflora (L.) Pers., Syzygium cumini (L.) Skeels and Tabernaemontana divaricate (L.) R. Br. ex Roem. & Schult. are used in Thai traditional remedies to treat various disorders ranging from fever and pain to inflammation or microbial infections. However, there is a lack of scientific data on some of the biological activities. Methods: The present study was designed to compare the antibacterial, antioxidant, and anti-inflammatory effects of the five plants. Ethanolic extracts of A. farnesiana, S. alata, S. grandiflora, S. cumini, T. divaricata were firstly compared for antioxidant activity using free radical scavenging of 2,2-diphenyl-1-picrylhydrazyl and ferric reducing antioxidant power tests. Antibacterial activity indicated by minimum bactericidal concentration (MBC) was determined using broth and agar dilution tests against aerobic and anaerobic pathogenic bacterial strains. The anti-inflammatory activity was evaluated in vitro using a lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage model.Results: All the tested extracts exerted antioxidant, antibacterial and anti-inflammatory effects. S. cumini and S. grandiflora extracts showed the highest free radical scavenging activities. S. cumini extract showed the highest activity against Staphylococcus aureus, S. epidermidis, and Corynebacterium diphtheriae. All extracts exerted anti-inflammatory activity as indicated by a reduction of interleukin (IL)-6 secretion and/or tumor necrosis factor (TNF)-α production.Conclusion: Taken together, these findings suggest that the tested plants can be developed as effective herbal remedies for the treatment and prevention of inflammation or associated diseases as well as against bacterial infections.Â

Examining the ribonuclease H primer grip of HIV-1 reverse transcriptase by charge neutralization of RNA/DNA hybrids

The crystal structure of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) bound to an RNA/DNA hybrid reveals an extensive network of contacts with the phosphate backbone of the DNA strand ∼4–9 bp downstream from the ribonuclease H (RNase H) catalytic center. Collectively designated as ‘the RNase H primer grip’, this motif contains a phosphate binding pocket analogous to the human and Bacillus halodurans RNases H. The notion that the RNase H primer grip mediates the trajectory of RNA/DNA hybrids accessing the RNase H active site suggests that locally neutralizing the phosphate backbone may be exploited to manipulate nucleic acid flexibility. To examine this, we introduced single and tandem methylphosphonate substitutions through the region of the DNA primer contacted by the RNase H primer grip and into the RNase H catalytic center. The ability of mutant hybrids to support RNase H and DNA polymerase activity was thereafter examined. In addition, site-specific chemical footprinting was used to evaluate movement of the DNA polymerase and RNase H domains. We show here that minor alteration to the RNase H primer can have a dramatic effect on enzyme positioning, and discuss these findings in light of recent crystallography of human RNase H containing an RNA/DNA hybrid

Energetics of base flipping at a DNA mismatch site confined at the latch constriction of α-hemolysin

Unique, two-state modulating current signatures are observed when a cytosine-cytosine mismatch pair is confined at the 2.4 nm latch constriction of the [small alpha]-hemolysin ([small alpha]HL) nanopore. We have previously speculated that the modulation is due to base flipping at the mismatch site. Base flipping is a biologically significant mechanism in which a single base is rotated out of the DNA helical stack by 180[degree]. It is the mechanism by which enzymes are able to access bases for repair operations without disturbing the global structure of the helix. Here, temperature dependent ion channel recordings of individual double-stranded DNA duplexes inside [small alpha]-HL are used to derive thermodynamic ([capital Delta]H, [capital Delta]S) and kinetic (Ea) parameters for base flipping of a cytosine at an unstable cytosine-cytosine mismatch site. The measured activation energy for flipping a cytosine located at the latch of [small alpha]HL out of the helix (18 +/- 1 kcal mol-1) is comparable to that previously reported for base flipping at mismatch sites from NMR measurements and potential mean force calculations. We propose that the [small alpha]HL nanopore is a useful tool for measuring conformational changes in dsDNA at the single molecule level

Preparation and evaluation of azithromycin binary solid dispersions using various polyethylene glycols for the improvement of the drug solubility and dissolution rate

ABSTRACT Azithromycin is a water-insoluble drug, with a very low bioavailability. In order to increase the solubility and dissolution rate, and consequently increase the bioavailability of poorly-soluble drugs (such as azithromycin), various techniques can be applied. One of such techniques is "solid dispersion". This technique is frequently used to improve the dissolution rate of poorly water-soluble compounds. Owing to its low solubility and dissolution rate, azithromycin does not have a suitable bioavailability. Therefore, the main purpose of this investigation was to increase the solubility and dissolution rate of azithromycin by preparing its solid dispersion, using different Polyethylene glycols (PEG). Preparations of solid dispersions and physical mixtures of azithromycin were made using PEG 4000, 6000, 8000, 12000 and 20000 in various ratios, based on the solvent evaporation method. From the studied drug release profile, it was discovered that the dissolution rate of the physical mixture, as the well as the solid dispersions, were higher than those of the drug alone. There was no chemical incompatibility between the drug and polymer from the observed Infrared (IR) spectra. Drug-polymer interactions were also investigated using Differential Scanning Calorimetry (DSC), Powder X-Ray Diffraction (PXRD) and Scanning Election Microscopy (SEM). In conclusion, the dissolution rate and solubility of azithromycin were found to improve significantly, using hydrophilic carriers, especially PEG 6000

Bioactive Compounds of Rambutan (Nephelium lappaceum L.)

Rambutan, a widely popular tropical fruit encompasses rich amount of bioactive compounds. All parts of this plant (leaves, bark, root, fruits, fruit skin, pulp and seeds) finds traditional usage, and are linked with high therapeutic values. Rambutan fruits parts like that of peel, pulp and seeds have been scientifically investigated in-depth and is reported to encompass high amounts of bioactive compounds (such as polyphenol, flavonoid, alkaloid, essential mineral, dietary fiber). These compounds contribute towards antioxidant, antimicrobial, anticancer, antidiabetic and anti-obesity activities. However, literature pertaining towards potential industrial applications (food, cosmetics, pharmaceutical) of rambutan fruits are limited. In the present chapter, it is intended to document some of the interesting research themes published on rambutan fruits, and identify the existing gaps to open up arena for future research work.This chapter theme is based on our ongoing project—VALORTECH, which has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 810630

Revolutions from above: worker training as trasformismo in South Korea

While making very substantial changes to the population's working conditions, government strategies to foster economic development in South Korea have historically attempted to keep worker involvement, in terms of influence on the process, to a bare minimum. Applying the Gramscian concept of passive revolution, this article analyses governance mechanisms and production relations over a history of authoritarianism and up to the contemporary period of democratic reform. Trasformismo, which is a strategy of limited concessions, has been provided via vocational training for workers. Despite this attempt at inclusion, it is concluded that workers have not enjoyed full participation in negotiation for their welfare at any time in Korean history

Neural Network Development in Late Adolescents during Observation of Risk-Taking Action

Emotional maturity and social awareness are important for adolescents, particularly college students beginning to face the challenges and risks of the adult world. However, there has been relatively little research into personality maturation and psychological development during late adolescence and the neural changes underlying this development. We investigated the correlation between psychological properties (neuroticism, extraversion, anxiety, and depression) and age among late adolescents (n = 25, from 18 years and 1 month to 22 years and 8 months). The results revealed that late adolescents became less neurotic, less anxious, less depressive and more extraverted as they aged. Participants then observed video clips depicting hand movements with and without a risk of harm (risk-taking or safe actions) during functional magnetic resonance imaging (fMRI). The results revealed that risk-taking actions elicited significantly stronger activation in the bilateral inferior parietal lobule, temporal visual regions (superior/middle temporal areas), and parieto-occipital visual areas (cuneus, middle occipital gyri, precuneus). We found positive correlations of age and extraversion with neural activation in the insula, middle temporal gyrus, lingual gyrus, and precuneus. We also found a negative correlation of age and anxiety with activation in the angular gyrus, precentral gyrus, and red nucleus/substantia nigra. Moreover, we found that insula activation mediated the relationship between age and extraversion. Overall, our results indicate that late adolescents become less anxious and more extraverted with age, a process involving functional neural changes in brain networks related to social cognition and emotional processing. The possible neural mechanisms of psychological and social maturation during late adolescence are discussed