Papers by Keyword: Antioxidant

Abstract: Nowadays, thermoplastic starch-based biopolymers are an option to be developed into products for domestic use. However, thermoplastic starch (TPS) has poor antioxidant characteristic, which restricts its use in food packaging or films. To address this issue, the starch can be combined with a green and low-cost anti-oxidative agent, to create a new, reasonably priced TPS biocomposites. Anti-oxidative agent that derived from natural sources is the best option due to the non-toxicity, environmentally friendly and abundancy. In this study, the shear mixing and casting processes were employed to form biocomposite films made of TPS, red cabbage, and calcium carbonate with varying calcium carbonate loadings. Prior to the production of the biocomposite, the anthocyanins in the red cabbage was extracted for use as an antioxidant. The biocomposites' structures and morphology were examined using Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Diffraction (XRD). Antioxidant and biodegradability testing were performed to assess the suitability of the TPS biocomposites for biodegradable food packaging application. Results indicate that the antioxidant activity and biodegradability of the TPS improved with the addition of the red cabbage, either in powder form or liquid form. Furthermore, the red cabbage powder not only acts as antioxidant but also as filler together with CaCO₃ to improve the performance of the TPS biocomposite for food packaging application.

Abstract: Novel approaches to engineer nanoparticles with desired chemical characteristics open new opportunities to utilize such materials for assorted applications. In this context, various methods have been developed to prepare metal nanoparticles. In the present work, we report a single-step synthesis method to prepare silver nanoparticles by using Carbidopa which is useful in treating Parkinson's disease to increase the dopamine level of the brain. Here we used the Carbidopa drug as a capping agent. Nanoparticles were characterized by Uv-Visible spectroscopy, Particle size Analyzer (PSA), dynamic light scattering (DLS), Powder X-ray Diffractometry (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Transmission electron microscopy (TEM). Then amino acid detection study was performed with all 24 amino acids, which provides the successful data for sensing the amino acid L-dopa. These prepared nanoparticles were further applied for metal analyte studies which reveal that lead can be sensed successfully by using these nanoparticles. Nanoparticle also shows radical scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH).

Abstract: It is no doubt that plants are a vital centerpiece and contributed immensely in the health care industry. Besides, it has been found that the indigenous people in developing countries had long been using local traditional plants for the treatment of diseases. The traditional plants are highly valued for their bioactive compounds which exhibits high antioxidant activity and has the potential in bringing down the risk of diseases. Canarium odontophyllum, also called dabai is one of the underutilized traditional plants consumed by the indigenous people in Borneo Island. The objective of this research is to characterize the antioxidant activity, metal chelating activity, the hydroxyl radical scavenging activity and identifying the potential bioactive compounds of dabai. The antioxidant, metal chelating and hydroxyl radical scavenging activity of dabai extract was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, Fe²⁺ chelating assay and the hydroxyl radical scavenging assay and found that it yielded an inhibition of 2.31%, 4.89% and 13.06% respectively. Then, chracterization using FTIR revealed the presence of flavonoids, anthocyanins and phenols serving as the potential bioactive compounds for the antioxidant activities. The knowledge gained from the antioxidant capacities and properties of dabai extract are potentially useful for the application of traditional plant medicine as an alternative nutraceutical product in the modern medical industry.

Abstract: Monoclinic Ag₂S nanoparticles have been synthesized via a thermal decomposition of Ag(I) complex of N-methyl-N-phenyl dithiocarbamate (as a single source precursor) in oleylamine at 180 °C. The complex was characterized by spectroscopic techniques. The decomposition profile was studied using thermogravimetry analysis (TGA) coupled to differential scanning calorimetry (DSC), and the results obtained from these characterization techniques confirmed the formation of the silver dithiocarbamate complex. The Ag₂S nanoparticles was characterized using X-ray diffraction, energy dispersive X-ray spectrometer (EDS), transmission electron microscopy (TEM), UV-visible spectroscopy, and fourier transform infra-red (FTIR) spectroscopy. The XRD patterns of the silver sulphide nanoparticles confirmed acanthite phase, with the most prominent (-121) peak identified at 2θ value of 34.39^o_, while EDS analysis showed Ag:S ratio of 2:1, which agreed with the XRD result. FTIR spectrum revealed the presence of amine groups, thereby confirmed that the synthesized Ag₂S was capped by oleylamine. Finally, the antioxidant activity of the Ag₂S was determined by using 1, 1-diphenyl-2-picrylhydrazyl (DPPH) assay and it exhibited better antioxidant activities than silver nanoparticles.

Abstract: Oxidation is a natural part of the aerobic world. Usually oxidation is suppressed by adding various antioxidants. Although a huge amount of antioxidants is known, studies of more active antioxidants which could be used in smaller amounts are crucial. Previously we have demonstrated arylmethyl Meldrum`s acids as promising free radical scavengers. On the other hand various phenol type compounds represent one of the most diverse group of antioxidants. In this study, two types of antioxidants – 1,3-dicarbonyl and phenol – were combined in a single molecule to study the plausible synergistic effects. Vanillic acid was used as a phenolic antioxidant, and Meldrum’s acid was the 1,3-dicarbonyl type antioxidant. The target compound was synthesized in four steps, and its antiradical activity was assessed using the DPPH method. The antiradical activity of the synthesized antioxidant was higher than that of widely used BHT.

Abstract: Reduced glutathione (GSH) is incorporated in polymeric wound dressings to prevent oxidative stress-induced cellular damage and the development of chronic wounds. The present study investigates the influence of polyvinyl alcohol (PVA), polyethylene oxide (PEO), and PVA/PEO blend polymeric solutions on the stability of GSH during the preparations or storage. The stability was studied in three concentrations which were 3%, 5% and 8%, after sometimes between 0 to 7 days. The level of GSH achieved the highest electron donor activity at day 7 in 8% PVA/PEO (95.42%) and 8% PVA (94.27%) solutions, whereas GSH activity decreased when incorporated with PEO solutions. Such a decrease in the GSH activity due to PEO being less water-resistant and hydrolytic degradation susceptibility could expose the GSH to an aqueous environment and lead to the loss of GSH activity. In conclusion, a higher concentration of polymer and less-water resistant polymers can shield the GSH from an aqueous environment and maintain its stability in the polymer solutions used in wound dressing applications.

Abstract: Synthesis and antioxidant assay of 4-phenoxyquinoline derivative namely, (E)-7-chloro-4-(2-methoxy-4-(prop-1-en-1-yl)phenoxy)quinoline, from clove leaf oil have been conducted. This compound can be prepared from eugenol (isolated from clove leaf oil) in either two-step or one-pot synthesis. In two-step synthesis, eugenol was subjected to base-catalyzed-isomerization to give isoeugenol, which in turn underwent aromatic nucleophilic aromatic nucleophilic substitution with 4,7-dichloroquinoline to generate (E)-7-chloro-4-(2-methoxy-4-(prop-1-en-1-yl)phenoxy)quinoline in 57% total yields. By combining these two reactions, the 4-phenoxyquinoline derivative can be furnished in one-pot fashion in 63%. The results showed that the synthesized 4-phenoxyquinoline derivative, however, did not show strong antioxidant activity.

Abstract: Bimetallic nanoparticles (BMNPs) of silver and gold are synthesized by eco- friendly green chemical procedure using leaf extract of Cocculus hirsutus. Under the experimental condition most individual silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) are spherical whereas silver-gold bimetallic nanoparticles (Ag-Au BMNPs) found cloudy and lost their individual shape. Ag-Au BMNPs formed by the co-reduction of Au(III) and Ag(I) ions in aqueous leaves extract solution where the extract act as both reducing and capping agent. NPs were characterized with the help of UV-Vis absorption spectroscopy, high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) analysis. UV-Vis spectroscopy exhibit surface plasmon absorption maxima at 435 and 540 nm for AgNPs and AuNPs respectively whereas surface plasmon resonance (SPR) maxima for Au-Ag bimetallic appeared in between the peaks corresponding to pure silver and gold at the same reaction conditions. X-ray diffraction analysis confirmed that crystalline nanoparticles (NPs) are face centered cubic structure. The synthesized bimetallic nanocomposites show stronger scavenging ability, around 67% and 75% on hydroxyl radical and superoxide radicals at the concentration of 400 µg/ml respectively, compared to the mono metallic AgNPs and AuNPs, indicating stronger antioxidant properties of Ag-Au BMNPs.

Abstract: Boesenbergia rotunda (B. rotunda) extract-loaded hydrogel patches were fabricated to be an antibacterial dressing. The biological properties such as antioxidant properties, bacterial protection activity, and the effect on normal human fibroblast (NHF) viability were assessed compared with blank hydrogel patches. The antioxidant activity of B. rotunda extract-loaded hydrogel patches was 75.00 ± 0.79 % (at 4-h treatment time), whereas the blank hydrogel patch had low antioxidant activity. The extract-loaded patches exhibited antioxidant activity approximately 16.5 times higher than that of the blank patches. In addition, the qualitative antibacterial activity of the patches was studied by agar disc diffusion. The inhibition zone of the extract-loaded hydrogel discs against Staphylococcus aureus (S. aureus) was 7.33 ± 0.58 mm, whereas the inhibition zone of the discs against Escherichia coli (E. coli) could not be observed. Moreover, the quantitative antibacterial activity showed an inhibition effect of the extract-loaded hydrogels against both types of bacteria. After incubation for 24 h, the extract-loaded hydrogel patches inhibited the growth of S. aureus and E. coli at the percentage of 49.76 ± 3.82 and 20.13 ± 2.75%, respectively. The results from the infiltration test showed that the extract-loaded hydrogel patches could prevent bacteria contamination. In addition, no toxicity to NHF cells had been observed. Therefore, the B. rotunda extract-loaded hydrogel patches could be a candidate material as an antibacterial wound dressing.

Abstract: Nanotechnology is receiving an intense attention these days due to its potential application in various fields including cosmeceutical and pharmaceutical. Nanoparticles encapsulating natural extract are usually characterised for their particle size and polydispersity index but zeta potential is hardly discussed. The zeta potential is the measurement that shows the aggregation behaviour, reactivity and toxicology. In this study, nanoparticle encapsulating Cymbopogon sp. have been formulated to develop a cosmeceutical product. The antioxidant properties from aqueous extract of Cymbopogon sp. was encapsulated with chitosan/alginate biopolymeric nanoparticles. Central Composite Design (CCD) of Response Surface Methodology (RSM) was employed to investigate and optimise the effects of independent variables such as pH of SA, concentration of non-ionic surfactant concentration of CaCl₂ and pH of chitosan on zeta potential and encapsulation efficiency (EE). Following the model, the optimum condition for zeta potential was selected as 6.2 of sodium alginate pH, 0.12% of non-ionic surfactant concentration, 0.05 concentration of CaCl₂ and 5.6 of chitosan pH with negative zeta potential of 18.3mV. The zeta potential obtained experimentally was close to its predicted value which is-18.09mV. The model provides a basis on the optimisation of the zeta potential on chitosan/alginate nanoparticle encapsulating Cymbopogon sp. extracts.