Oxygen Scavenging Research Articles

OsPMS1 Mutation Enhances Salt Tolerance by Suppressing ROS Accumulation, Maintaining Na+/K+ Homeostasis, and Promoting ABA Biosynthesis.

World-wide, rice (Oryza sativa L.) is an important food source, and its production is often adversely affected by salinity. Therefore, to ensure stable rice yields for global food security, it is necessary to understand the salt tolerance mechanism of rice. The present study focused on the expression pattern of the rice mismatch repair gene post-meiotic segregation 1 (OsPMS1), studied the physiological properties and performed transcriptome analysis of ospms1 mutant seedlings in response to salt stress. Under normal conditions, the wild-type and ospms1 mutant seedlings showed no significant differences in growth and physiological indexes. However, after exposure to salt stress, compared with wild-type seedlings, the ospms1 mutant seedlings exhibited increased relative water content, relative chlorophyll content, superoxide dismutase (SOD) activity, K+ and abscisic acid (ABA) content, and decreased malondialdehyde (MDA) content, Na+ content, and Na+/K+ ratio, as well as decreased superoxide anion (O2-) and hydrogen peroxide (H2O2) accumulation. Gene ontology (GO) analysis of the differentially expressed genes (DEGs) of ospms1 mutant seedlings treated with 0 mM and 150 mM NaCl showed significant enrichment in biological and cytological processes, such as peroxidase activity and ribosomes. The Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathway analysis showed that the DEGs specifically enriched ascorbate and aldarate metabolism, flavone and flavonol biosynthesis, and glutathione metabolism pathways. Further quantitative real-time reverse transcription-PCR (qRT-PCR) analysis revealed significant changes in the transcription levels of genes related to abscisic acid signaling (OsbZIP23, OsSAPK6, OsNCED4, OsbZIP66), reactive oxygen scavenging (OsTZF1, OsDHAR1, SIT1), ion transport (OsHAK5), and osmoregulation (OsLEA3-2). Thus, the study's findings suggest that the ospms1 mutant tolerates salt stress at the seedling stage by inhibiting the accumulation of reactive oxygen species, maintaining Na+ and K+ homeostasis, and promoting ABA biosynthesis.

LDPE-Natural Rubber Composite Film as Active Packaging: A Paradigm Shift in Oxygen Scavengers.

Oxygen scavenging films, an emerging type of active packaging, play a crucial role in preserving the freshness and quality of food products. In this study, we proposed an extruded film made of low-density polyethylene (LDPE) with 5% natural rubber (NR) as the oxygen scavenging film. Characterization of the film revealed that its morphological and barrier properties remained intact, while the elongation attribute was enhanced. The obtained film was standardized for activation scavenging kinetics by varying the UV dose (time and distance). At the optimal UV dose, the film exhibited a total scavenging capacity of 61 cc/g. To assess the film's functionality, FTIR spectra were analyzed before and after exposure to oxygen, confirming the film's ability to scavenge oxygen based on observed peaks at 1718 and 3425 cm-1. Considering that bread and khoa (fatty food) are sensitive to oxygen, they were selected for testing the application of the oxygen scavenging film. Sensory analysis of bread samples, including appearance and mold formation, as well as microbial load studies, indicated that the shelf life of bread increased from 2-3 days (control) to 4-5 days when packed in the NR-based film and stored at 27 ± 2 °C. Similarly, when applied to khoa, the film extended its shelf life by 3 days compared to the control while maintaining sensory attributes and preserving nutritional value, such as fatty acids. In general, the developed oxygen scavenging film effectively prevents the detrimental effects of oxygen on food products, leading to an extension of their shelf life. This has significant implications for the food industry, as it helps mitigate the negative consequences of oxygen exposure and enhances the product shelf life.

Optical properties, surface composition and desorption of Stainless Steel (316L) studied from ambient temperature to 1000 K in vacuum

Stainless steels are widely used as structural materials due to their excellent corrosion resistance and fabricability. In some applications, in nuclear fusion reactors for instance, these materials may be exposed to harsh conditions, including high heat flux and ion bombardment in a vacuum environment, which can significantly affect their surface properties and composition. In this work, we investigate the temperature-dependent evolution of the surface composition and optical properties (reflectivity, emissivity) of stainless steel 316L. X-ray photoelectron spectroscopy analyses, temperature programmed desorption and reflectivity measurements in the visible/near-infrared range were performed on polished samples from ambient temperature to 1000 K. It was found that around 750 K, the initial Fe/Cr surface abundance of 90/10 changes to 35/55 following the onset of Cr and CrO desorption at 575 K, with Cr scavenging oxygen initially bound to Fe. In addition, Mn segregated at the surface and oxidized, while small amounts of metallic Ni segregated. Despite these modifications in surface composition, no significant change in reflectivity up to 900 K was observed. These results provide insight into the behavior of stainless steel under extreme conditions which is relevant for understanding its performance and durability in high-temperature applications.

Sedation Therapy in Intensive Care Units: Harnessing the Power of Antioxidants to Combat Oxidative Stress.

In critically ill patients requiring intensive care, increased oxidative stress plays an important role in pathogenesis. Sedatives are widely used for sedation in many of these patients. Some sedatives are known antioxidants. However, no studies have evaluated the direct scavenging activity of various sedative agents on different free radicals. This study aimed to determine whether common sedatives (propofol, thiopental, and dexmedetomidine (DEX)) have direct free radical scavenging activity against various free radicals using in vitro electron spin resonance. Superoxide, hydroxyl radical, singlet oxygen, and nitric oxide (NO) direct scavenging activities were measured. All sedatives scavenged different types of free radicals. DEX, a new sedative, also scavenged hydroxyl radicals. Thiopental scavenged all types of free radicals, including NO, whereas propofol did not scavenge superoxide radicals. In this retrospective analysis, we observed changes in oxidative antioxidant markers following the administration of thiopental in patients with severe head trauma. We identified the direct radical-scavenging activity of various sedatives used in clinical settings. Furthermore, we reported a representative case of traumatic brain injury wherein thiopental administration dramatically affected oxidative-stress-related biomarkers. This study suggests that, in the future, sedatives containing thiopental may be redeveloped as an antioxidant therapy through further clinical research.

Novel 3-hydroxyphenol-based moisture activated oxygen scavenger for active packaging

A novel non-metallic oxygen scavenging system consisting of 3-hydroxyphenol (resorcinol-RC) and potassium carbonate (PC) was developed and activated with the help of moisture. Different proportions, such as control, RC/PC 1:0.25, RC/PC 1:0.5, and RC/PC 1:1 (%w/w), were prepared to determine the optimal quantities of active compounds. Their oxygen scavenging capacities and rates were measured over 48–264 hr at different storage temperatures (5, 25, and 45 ℃) and humidity (11%, 75%, and 99% RH). Assessments of oxygen scavenging capacities indicated that an optimum formulation of resorcinol and potassium carbonate was achieved at RC/PC 1:1 (%w/w). Further, colorimetry and infrared spectroscopy were carried out prior to and following oxygen scavenging and observed a visible color change from whitish to red with a brownish tinge. The developed system for scavenging oxygen displayed a capability of 290 mL O2/g and 366 mL O2/g at 5⁰C (75% RH and 99% RH, respectively) and 1716 mL O2/g. at 25⁰C and 11% RH, the remaining demonstrated 2090 mL O2/g at 25⁰C (75% RH and 99% RH), and all three humidities at 45 ⁰C in 48 h. The rate constant values were observed to be increased by 2.66 times and 4.43 times when temperatures increased from 5 ℃− 25 ℃ 5 ℃− 45 ℃, respectively. Hence, results demonstrated that a 3-hydroxyphenol-based moisture-activated oxygen scavenging system could efficiently replace commercially available metallic oxygen scavengers.

Plant growth-promoting rhizobacteria Bacillus velezensis JB0319 promotes lettuce growth under salt stress by modulating plant physiology and changing the rhizosphere bacterial community

Salt stress inhibits plant growth, which is an important factor that restricts crop yield. Plant growth-promoting rhizobacteria (PGPR) promote plant growth, but their effect on lettuce under salt stress has not been reported. In this study, the salt-tolerant growth-promoting bacteria Bacillus velezensis JB0319 in the plant rhizosphere was screened and used as microbial inoculum in a pot experiment to explore the effects of B. Velezensis JB0319 on growth, reactive oxygen scavenging, osmotic adjustment, and the rhizosphere bacterial community of lettuce planted in soils with different NaCl concentrations (0, 50, 100, 150 mM). B. Velezensis JB0319 inoculation significantly promoted the shoot height, root length and shoot biomass of lettuce, increased the activity of SOD, POD, decreased the accumulation of MDA in lettuce, and increased the accumulation of osmotic regulation substance SS, Pro. Most importantly, Inoculation B. Velezensis changed bacterial community structure in the rhizosphere of lettuce. The LDA analysis showed that B. Velezensis inoculation helped lettuce enrich more nitrogen-fixing bacteria. These results showed that B. Velezensis inoculation could alleviate the inhibitory effect of salt stress on lettuce and promote lettuce growth. This study provides a theoretical basis for plant growth-promoting rhizobacteria to alleviate salt stress in the future.

Research Progress on Skin Aging and Active Ingredients.

With the advancement of living standards in modern society and the emergence of an aging population, an increasing number of people are becoming interested in the topic of aging and anti-aging. An important feature of aging is skin aging, and women are particularly concerned about skin aging. In the field of cosmetics, the market share of anti-aging products is increasing year by year. This article reviews the research and development progress of skin aging and related active compounds both domestically and internationally in recent years. The results show that, in terms of the research on skin aging, the popular theories mainly include free radicals and oxidative stress theory, inflammation theory, photoaging theory, and nonenzymatic glycosyl chemistry theory. In terms of research on the active ingredients with anti-aging activities in the skin, there are numerous reports on related products in clinical studies on human subjects, animal experiments, and experimental studies on cell cultures, with a variety of types. Most of the compounds against skin aging are sourced from natural products and their action mechanisms are mainly related to scavenging oxygen free radicals and enhancing antioxidant defenses. This review provides important references for the future research of skin aging and the development of related products. Although there is a great progress in skin aging including related active ingredients, ideal compounds or products are still lacking and need to be further validated. New mechanisms of skin aging, new active ingredients sourced from natural and artificial products, and new pharmaceutical forms including further clinical validations should be further investigated in the future.

Holistic effect of operating conditions and purification methods on the pollution characteristics of washing water and biodiesel quality

This study aimed to optimize the experimental conditions in terms of converting waste cooking oil to biodiesel and minimizing contaminants in the washing water. The statistical interactions of the experimental conditions such as alcohol:oil ratio, catalyst ratio, temperature and reaction time on the biodiesel and the washing water quality were determined. Aqueous and dry washing methods were carried out and optimum alcohol:oil and catalyst ratios were obtained as 30 % (molar ratio 3:1) and 1 %, respectively, for both methods. Kinematic viscosity, density and pH of the biodiesel and chemical oxygen demand (COD), phosphate (PO4), total nitrogen (TN), conductivity, pH, absorbance values, metals and long-chain fatty acid composition of the washing water were measured. It was concluded that COD and fatty acid concentrations of the washing water have significantly decreased to 10,015 mg/L and 7 mg/L, respectively, at the optimum conditions. Long-chain fatty acid composition in the wastewater was determined to be related with the experimental conditions and the quality of produced biodiesel. It was observed that types and concentrations of the fatty acids increased in the waste washing water of biodiesel at low alcohol and catalyst ratios. As an important contribution to the literature, fatty acids passing from biodiesel into wastewater were determined by gas chromatography and their relation to COD was analyzed. Besides linear correlation was found between fatty acids and COD. The increase of metals in waste washing water thought to be as a result of frying process in the metallic containers.

Thermoplastic agar blended PBAT films with enhanced oxygen scavenging activity

The morphology and properties of biodegradable packaging comprising thermoplastic agar and poly (butylene adipate-co-terephthalate) (PBAT) blends (20/80 and 40/60 ratios) produced via cast extrusion were characterized. These polymers were blended with gallic acid (GA) and determined for oxygen scavenging activity. Increasing agar content formed non-homogeneous PBAT matrices with dispersed clumps, while GA facilitated the unfolding of agar molecules and reduced the number of clumps. GA interacted with agar and PBAT by modifying the CO and C–H stretching vibrations, causing polymer blend plasticization and decreasing the mechanical relaxation temperature. Addition of agar and GA modified the crystallinity, morphology, and barrier properties of PBAT. Compounding GA into the polymer matrices effectively enhanced oxygen scavenging, while oxygen absorption rates increased with increasing relative humidity (RH) from 50% to 100%. Rates and maximum scavenging capacity depended on GA contents and humidity at 50% RH, while higher humidity showed insignificant effects of GA contents, suggesting additional roles of polymer structures involving oxygen diffusion through the matrices. Blending thermoplastic agar at 20% in PBAT films produced biobased sustainable food packaging and effectively enhanced oxygen scavenging active functions.

Cryptotanshinone-Doped Photothermal Synergistic MXene@PDA Nanosheets with Antibacterial and Anti-Inflammatory Properties for Wound Healing.

Humans are threatened by bacteria and other microorganisms, resulting in countless pathogen-related infections and illnesses. Accumulation of reactive oxygen species (ROS) in infected wounds activates strong inflammatory responses. The overuse of antibiotics has led to increasing bacterial resistance. Therefore, effective ROS scavenging and bactericidal capacity are essential and the advanced development of collaborative therapeutic techniques to combat bacterial infections is needed. Here, this work developes an MXene@polydopamine-cryptotanshinone (MXene@PDA-CPT) antibacterial nanosystem with excellent reactive oxygen and nitrogen species scavenging ability, which effectively inactivates drug-resistant bacteria and biofilms, thereby promoting wound healing. In this system, the adhesion of polydopamine nanoparticles to MXene produced a photothermal synergistic effect and free radical scavenging activity, presenting a promising antibacterial and anti-inflammatory strategy. This nanosystem causes fatal damage to bacterial membranes. The loading of cryptotanshinone further expanded the advantages of the system, causing a stronger bacterial killing effect and inflammation mitigatory effect with desired biosafety and biocompatibility. In addition, combining nanomaterials and active ingredients of traditional Chinese medicine, this work provides a new rationale for the future development of wound dressings, which contributes to eliminating bacterial resistance, delaying disease deterioration, and alleviating the pain of patients.

Corrosion Study of the Injection Equipments in Water in Al-Ahdeb Wells ‐Iraq

Water injection equipments such as pipelines, which are used in the second recovery of oil in the Al-Ahdeb wells, suffer from the corrosion in water during maintaining vacuum deoxygenated tower that used to decrease concentration of the dissolved oxygen gas in the water from 6.2-9.1 ppm to o.5 ppm. This study involved calculation the corrosion rates of the internal surfaces of the pipelines either during operation of the vacuum unit or when the tower out of operation. Finally, find the solution by one of the following suggestions. In the first suggestion removal of the dissolved O2 from water is achieved by increasing the dosage of the oxygen scavenger (sodium sulphite). The second suggestion involves removing the dissolved O2 from water by bubbling the oxygenated water with nitrogen gas. The study showed that the corrosion rates of various inside diameter pipelines are between 0.13 mm/yr and 1.5 mm/yr during operation of the vacuum tower and between 3.2 mm/yr and 18.5 mm/yr when the tower out of the operation. While the results showed that the corrosion rate of the pipelines when the tower out of operation reached to the acceptable value of 0.1 mm/y when the dissolved oxygen in the injected water removed by increasing the dosage of the sodium sulphite (Na2SO3) to 48-72 ppm. The results also explained that corrosion rates of the pipelines reached to 0.5 mm/y when the dissolved oxygen removed by bubbling the water with nitrogen gas.

Oxidases as Oxygen Scavengers in Hypoxic Conditions: A Kinetic Model.

A simple kinetic model allowed for the description of the observed decay of the oxygen content in hypoxic aqueous samples with and without headspace, in the presence of glucose oxidase (Glucox) or laccase and their substrates (glucose for Glucox and ABTS for Laccase). The experimental tests involved both the direct measurement of the oxygen content with a fluorescence-based probe and the indirect stopped-flow spectroscopic detection of colored compounds generated from suitable chromogenic reagents. The complete depletion of dissolved oxygen occurred in the no-headspace samples, whereas some residual oxygen remained in a steady state in the samples with headspace. Simple pseudo-first-order kinetics was adequate to describe the behavior of the system, as long as oxygen was the rate-limiting compound, i.e., in the presence of excess substrates. The values of the kinetic constants drawn from best-fit routines of the data from both experimental approaches were quite comparable. The oxygen residues in the samples with headspace seemed related to the low solubility of O2 in the aqueous phase, especially if compared with the large amount of oxygen in the headspace. The extent of such residue decreased by increasing the concentration of the enzyme. The kinetic model proposed in this paper can be of help in assembling suitable sensors to be used for food safety and quality control.

Antioxidant and Antibacterial Activities of the Tropical Red Alga Eucheuma spinosum: In Silico Study

Recently, numerous studies have focused on characterizing the biochemical activities of new natural marine resources as functional foods. Eucheuma spinosum J. Agardh., family Solieraceae, is a potential functional food that is widely used as a natural food source and contains bioactive components. This study aims to identify the bioactivity, drug-likeness, and pharmacokinetics of 3-(3-methoxyphenyl) propanal isolated from E. spinosum, and to discover the molecular interactions between the ligand, 3-(3-methoxyphenyl) propanal, and various antioxidant and antibacterial receptors. The bioactivity of 3-(3-methoxyphenyl) propanal was analyzed using computational Prediction of Activity Spectra for Substance (PASS) analysis. The drug-likeness was examined based on Lipinski's rule and other parameters. The pharmacokinetics of 3-(3-methoxyphenyl) propanal were predicted, and the molecular interactions between the receptors governing the antioxidant and antibacterial activity and 3-(3-methoxyphenyl) propanal were determined using the molecular docking method and molecular dynamics simulation. Based on the PASS analysis, 3-(3-methoxyphenyl) propanal was predicted to inhibit JAK2 expression, which contributes to apoptosis, with a probability of a molecule to be active (Pa) values of 0.733 and 0.508. Additionally, 3-(3-methoxyphenyl) propanal is an oxygen scavenger (Pa 0.408) and antimutagenic (Pa 0.419). Based on the drug-likeness and pharmacokinetic analyses, 3-(3-methoxyphenyl) propanal meets the requirements for an oral drug. Molecular docking revealed that binding affinity of 3-(3-methoxyphenyl) propanal for superoxide dismutase, tyrosinase, glutathione peroxidase, UDP-N-acetylmuramate, and penicillin-binding protein was −5.5, −6.1, −4.2, −6.2, and −4.9 kcal mol −1, respectively. Moreover, according to molecular dynamics simulation, propanal 3-(3-methoxyphenyl) propanal has stronger interaction with tyrosinase than the positive control. Based on PASS analysis and molecular docking results, 3-(3-methoxyphenyl) propanal exhibited promising potential as an antioxidant.

Development of an active packaging with an oxygen scavenger and moisture adsorbent for fresh lulo (Solanum quitoense)

Development of an active packaging with an oxygen scavenger and moisture adsorbent for fresh lulo (Solanum quitoense)

Effects of packaging and temperature abuse on the quality of red pepper (Capsicum annuum L.) powder.

Storage stability of pepper (Capsicum annuum L.) powder packaged using 2 different film pouches of Ny/PE and PET/Al/PE inserted with moisture absorbent and oxygen scavenger was investigated during storage at 25°C for 5months and at 40°C for 14days. The moisture content of red pepper powder did not change significantly in PET/Al/PE packaging but decreased significantly in Ny/PE packaging after the abuse of storage temperature. The color of red pepper powder was quite stable in all packaging treatments. Other quality characteristics of all packaged pepper powder, including microbial cell count, capsaicinoids, ascorbic acid, and free sugar content, were also maintained near their initial levels with no appreciable changes during storage. Red pepper powder with a moisture content of 13-14% and packaged with a film with high gas-barrier properties can be stored for more than 5months even if there is an unexpected temperature abuse during storage.

Biocompatible green technology principles for the fabrication of food packaging material with noteworthy mechanical and antimicrobial properties-- A sustainable developmental goal towards the effective, safe food preservation strategy

Biocompatible, eco-friendly, highly economical packaging methods should be needed as conventional packaging is known to cause undesirable effects. As food packaging is the major determining factor of food safety, the selection or methods of packaging materials plays a pioneering role. With this scope, modern food technology seeks unique sustainable approaches for the fabrication of package materials with notable desired properties. The principles, features, and fabrication methodology of modern food packaging are briefly covered in this review. We extensively revealed improved packaging (nanocoating, nanolaminates, and nano clay), active packaging (antimicrobial, oxygen scavenging, and UV barrier packaging), and intelligent/smart packaging (O2 indicator, CO2 indicator, Time Temperature Indicator, freshness indicator, and pH indicator). In particular, we described the role of nanomaterials in the fabrication of packaging material. Methods for the evaluation of mechanical, barrier properties, and anti-microbial assays have been featured. The present studies suggest the possible utilization of materials in the fabrication of food packaging for the production, utilization, and distribution of safe foods without affecting nutritional values.

Understanding the Risk of CBN Degradation - A Novel use for OxySorbTM & CannaFreshTM Oxygen Absorbers in Cannabis Storage

As cannabis (Cannabis sativa) legalization continues to sweep the globe, more and more people are enjoying the benefits of this muchloved plant. However, with increased use comes greater responsibility - especially when it comes to proper storage. CBN (cannabinol; C21H26O2) formation from the degradation of THC is of major concern[1]. Over time, however, CBN can begin to degrade when exposed to light or oxygen [2]. In fact, law enforcement agencies use the ratio of THC to CBN to estimate the age, and time stored of Cannabis when it has been sold illegally [3]. Cannabinoids in cannabis degrade into simpler compounds that are much less potent than their original form. Degraded terpenes will lead to a decrease in strong flavour and smell, as well as an overall decrease in potency [4], especially the psychoactive THC Δ9- tetrahydrocannabinol (THC). Tetrahydrocannabinol (THC) or C21H30O2 usually refers to the Delta-9-THC isomer with the chemical name (−)-trans-Δ9-tetrahydrocannabinol and is a terpenoid. CBD like the “Yin” or the THC “Yang”, complements the “high” with muscle relaxant, and anti-inflammatory properties [5]. As such, it is important for medicinal cannabis manufacturers and suppliers to ensure there is an oxygen-free environment to reduce potential THC degradation to CBN. One such innovation is the patented [6], OxySorbTM [7] & CannaFreshTM oxygen absorbers and desiccant systems. Wholesale Group International Pty. Ltd. (Australia) is the owner of both trademarks which are currently being trialed with a leading Global Cannabis researcher and manufacturer and the author of this discussion paper. Oxygen absorbers have been shown to be safe and an effective way to preserve food and plant material as per the study by Cichello [8]. Patent is shown in Table 1.

Influence of an innovative, biodegradable active packaging on the quality of sunflower oil and “pesto” sauce during storage

The aim of this research was to produce an innovative, biodegradable multilayer active packaging solution, with excellent oxygen barrier properties, to extend shelf- life of oily foods. In fact, one of the main drawbacks of biodegradable films is the low barrier they offer against external agents that can thus easily accelerate the foods degradation during shelf-life. In this study, a multilayer material obtained by the adhesion of two polylactic acid (PLA) films with cold plasma application, in place of synthetic adhesives, was realized. Moreover, cold plasma treatment was employed to immobilize the oxygen scavenger agent (ascorbic acid), chosen for the activation of the packaging material. Preliminary studies on activated PLA pouches filled with sunflower oil, used as model system, were performed. Model systems were stored at 35 °C to accelerate oil oxidation phenomenon and analysed for PV and colour during 64 days of storage. After that, different samples of “Genovese pesto”, were tested as real food, stored at 25 and 45 °C and analysed for PV, water activity, rheological parameters and microbiological loads during 41 days of storage. Obtained results showed the greater ability of the new active packaging to decrease the oxidation kinetics of “pesto”, mainly when stored at 25 °C. Moreover, all samples packed in the activated biodegradable pouches (both sunflower oils stored at 35 °C and pesto stored at 25 °C) showed better and more stable quality characteristics, in terms of colorimetric, microbiological and textural parameters when compared with the respective control samples. Overall obtained results highlighted the potentiality of the new biodegradable material, activated with the oxygen scavenger, to be applied successfully in food industry, to extend food products shelf-life and/or maintain high quality levels during storage.

Impact of extraction method on alkaloid content and antioxidant activity of Matricaria pubescens

Matricaria pubescens is a medicinal plant much appreciated by the people of the Saharan regions and widely used to treat many diseases. The present study was devoted to evaluate the effect of extraction technique, pH and nature of solvent on alkaloid content and antioxidant activity of M. pubescens. Alkaloid extraction was carried out by applying two techniques, maceration extraction and Soxhlet extraction, using several solvents at different pH (alkaline chloroform, acid methanol, neutral methanol and neutral ethanol). In the present study, the antioxidant activity of the alkaloid extracts of M. pubescens was evaluated using ferric reducing power, molybdate reducing power, DPPH radical scavenging activity, ABTS radical scavenging activity, β-carotene bleaching assay, hydroxyl radical scavenging activity (assessed by deoxyribose assay and HOSC assay) and oxygen radical absorbance capacity (ORAC). The obtained results show that the extraction rates obtained and the antioxidant activities of alkaloid extracts were affected by the extraction technique, pH and the solvent used. The highest extraction rates were obtained with the ethanolic neutral (Soxhlet) and methanolic acidified (maceration) extracts. The alkaloid extracts of M. pubescens exerted a reducing activity of ferric and molybdate ions. They also showed significant radical scavenger activity against DPPH, ABTS, hydroxyl, and peroxyl radicals. This significant wealth of alkaloids and these various antioxidant activities could justify the traditional use of M. pubescens.

Synthesis of Some Distinct Curcumin-Based Pyrano [2,3-D] Pyrimidines with Barbituric Acid, Cinnamaldehyde, and Benzaldehyde

Curcumin is a powerful radical oxygen scavenger. The modification of of curcumin’s α, β-unsaturated 1,3-diketone moiety can be carried out to improve its physicochemical stability and functionality. This research aimed to conduct a modification of curcumin structure and to study the antioxidant activity of the modified curcumin-based compound. The modified curcumin made from a combination of benzaldehyde and cinnamaldehyde, using barbituric acid and combination of citric acid as catalyst and ethanol as solvent. The combination of ethanol solvent and 20 mmol% citric acid catalyst produce the highest yield of curcumin product which has a yield of 99.3581±0.2873% and was chosen as the best combination for the next modification using different β-diketone compounds. In the following stage, the mixture was reacted with either benzaldehyde or cinnamaldehyde. Yield, TLC, and antioxidant activity parameters were assessed for all modified products and were accompanied by their characterization using UV-Vis spectrophotometry. This study showed that curcumin cinnamaldehyde had a yield of 47.4831±2.7032%, a maximum wavelength of 416 nm, and antioxidant activity of IC50 18.2130±2.8766 mg/L with a molecular mass of 594 m/z. Keywords: antioxidant activity, benzaldehyde, cinnamaldehyde, curcumin, dimedone, modification