Formation Of Phenol Research Articles

Hydroconversion of lignin-derived platform compound guaiacol to fuel additives and value-added chemicals over alumina-supported Ni catalysts

Hydroconversion of guaiacol (GUA) over γ-Al2O3 and phosphatized-γ-Al2O3 (γ-Al2O3(P)) supported Ni catalysts was initiated by Lewis-sites and active Ni sites. Conversion proceeded via transmethylation and hydrodemethylation/hydrodemethoxylation as major and minor pathways, respectively, resulting in mainly catechol and methylcatechols, and via series of consecutive hydrodehydroxylation (HDHY) and ring hydrogenation (HYD) reactions leading to partially and fully deoxygenated, saturated, and unsaturated products. High Ni-loading and high H2 pressure promoted the formation of cyclohexane and methyl-substituted cyclohexanes; however, above 300 °C the hydrogenation–dehydrogenation equilibrium favored the formation of benzene and methyl-substituted benzenes. Ni/γ-Al2O3(P) showed suppressed HYD/HDHY activity resulting in pronounced formation of catechol and/or phenol and their methyl-substituted derivatives. Surface phenolate species were substantiated as surface intermediates of hydrodeoxygenation. Phosphatizing reduced the concentration of both basic OH and Lewis acid (Al+) – Lewis base (O–) pair surface sites of the γ-Al2O3 support and, thereby, suppressed phenolate formation and hydrodeoxgenation.

Unveiling the distribution of free and bound phenolic acids, flavonoids, anthocyanins, and proanthocyanidins in pigmented and non-pigmented rice genotypes.

The total phenolic content, phenolic acid profile, anthocyanins, proanthocyanidins, flavonoids, and antioxidant capacity of the whole-grain and bran portion of sixteen distinct rice genotypes that correspond to three distinct pericarp bran colors-black, red, and non-pigmented (NP)-were examined. Ten free and bound phenolic acids, as well as two flavonoids, were analyzed using HPLC-PDA. The flavonoids included kaempferol and catechin hydrate, and the free phenolic acids included gallic acid, 2,5-dihydroxybenzoic acid, vanillic acid, syringic acid, p-coumaric acid, chlorogenic acid, trans-cinnamic acid, trans-ferulic acid, p-coumaric acid, and sinapic acid. Trans-ferulic acid (207.39 mg/kg), p-hydroxybenzoic acid (94.36 mg/kg), and p-coumaric acid (59.75 mg/kg) were the principal bound phenolic acids in pigmented rice genotypes, whereas in NP genotypes they were trans-ferulic acid (95.61 mg/kg) and p-hydroxybenzoic acid (58.32 mg/kg). The main free phenolic acid was syringic acid (120.43 mg/kg) in all genotypes. 2,5-dihydroxybenzoic acid was also detected in NP genotypes, mainly in the bound form (4.88 mg/kg). NP genotypes Basmati 386 and Punjab Basmati 7 also displayed high content of bran flavonoids (1001 and 1028 mg CE/100g). The bound form of phenolics had significant DPPH and ABTS + activity. This study found wide diversity in the phenolic acid profile, total phenolic constituents, and antioxidant activity in the bran and whole grain of pigmented and NP rice. The individual phenolic acids in free and bound forms in different fractions of the grain were found to exert their antioxidant activity differently. The results obtained will provide new opportunities to improve the nutritional quality of rice with enhanced levels of phytochemicals in the ongoing breeding programs. Black rice bran contains a high level of phytochemicals and thus has a potent pharmaceutical role. This information would enhance the use of whole-grain and bran of pigmented rice in food product development by food technologists. Further studies may be focused on clinical trials with respect to cancer and diabetes.

The dynamic changes in olive fruit phenolic metabolism and its contribution to the activation of quiescent Colletotrichum infection

Anthracnose, the most critical disease affecting olive fruits, is caused by Colletotrichum species. While developing olive fruits are immune to the pathogen regardless of the cultivar, the resistance level varies once the fruit ripens. The defense mechanisms responsible for this difference in resistance are not well understood. To explore this, we analyzed the phenolic metabolic pathways occurring in olive fruits and their susceptibility to the pathogen during ripening in two resistant cultivars (‘Empeltre’ and ‘Frantoio’) and two susceptible cultivars (‘Hojiblanca’ and ‘Picudo’). Overall, resistant cultivars induced the synthesis of aldehydic and demethylated forms of phenols, which highly inhibited fungal spore germination. In contrast, susceptible cultivars promoted the synthesis of hydroxytyrosol 4-O-glucoside during ripening, a compound with no antifungal effect. This study showed that the distinct phenolic profiles between resistant and susceptible cultivars play a key role in determining olive fruit resistance to Colletotrichum species.

Oxygen bond cleavage and its migration mechanisms during pyrolysis of naomaohu sub-bituminous coal

Investigating the oxygen bond cleavage and its migration mechanisms during the pyrolysis process of sub-bituminous coals is essential for their classification utilization. The present study employed a fixed-bed pyrolysis technique (temperature range: 350–600 °C) to explore the cleavage of oxygen-containing bonds and subsequent behavior of oxygen migration and transformation during the pyrolysis process of Naomaohu sub-bituminous coal (NSBC). X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy results reveal that the organic oxygen in NSBC predominantly exists as the form of C–O bonds, accounting for 22.81 wt% of the total composition, mainly encompassing hydroxyl, carbonyl, ester, and ether groups. The organic oxygen in the light tar is mainly in the form of phenols, reaching 1.71 wt%, of which methyl substituted phenols is predominant at a final pyrolysis temperature of 600 °C. This can be attributed to the presence of more aryl ether bonds and hydroxyl groups in NSBC, which are prone to cleavage at higher temperatures, resulting in the formation of phenoxyl radicals. Additionally, the higher temperature facilitates the weakening of hydrogen bonds between phenolic hydroxyl groups, thereby enhancing the yield of phenolic compounds. The ester compounds present a decreasing trend with increasing temperature, primarily associated with the cleavage temperature of ester linkers being 350 °C, suggesting that an increase in temperature favors the cleavage of ester bonds. In addition, the cleavage of C–O bonds begins to accelerate significantly during the pyrolysis temperature range of 450–500 °C, subsequently accounting for the pronounced proliferation of phenols within this specific thermal interval. The oxygen content in semi-coke decreased with the increase of temperature, from 85.27 wt% at 350 °C to 37.17 wt% at 600 °C, while the oxygen content in the pyrolysis gas increases from 11.63 wt% at 350 °C to 47.53 wt% at 600 °C, indicating that a significant migration of organic oxygen to the pyrolysis gas during the pyrolysis of NSBC. This study can deepen the understanding of the transformation mechanism of oxygen-containing structure in NSBC pyrolysis process, and provide a theoretical basis for high-grade utilization of low-rank coals.

Low temperature oxidation chemistry of n-butylbenzene in n-decane/n-butylbenzene mixture: Product characterization and kinetic modeling study

n-Alkanes and aromatics are two essential components in transportation fuels and have distinct oxidation reactivities. Due to products with different chemical functionalities generated in oxidation of n-alkanes and aromatics, the interaction kinetics may significantly affect the overall reactivity as well as product distributions. This work investigated the oxidation chemistry of the mixture of n-decane and n-butylbenzene, both of which are C10 hydrocarbons commonly used as jet fuel surrogate components. The experiments were conducted in a jet stirred reactor at pressure of 1 atm, the temperature range of 450–850 K, and the equivalence ratios of 0.5, 1.0 and 2.0. Key low temperature oxidation intermediates and radicals, including C10-cyclic ethers, C10-ketohydroperoxides, C10-ketodihydroperoxide, C10-diketohydroperoxide, benzyl hydroperoxide, methyl peroxy radical and methyl hydroperoxide, were detected by using synchrotron vacuum ultraviolet photoionization mass spectrometry. A detailed kinetic model was developed and validated against the speciation data in this work. Results reveal that the reactions of n-decane greatly enhance the low temperature oxidation reactivity of n-butylbenzene by efficiently producing reactive radicals, such as OH radicals. Besides, the reactions of n-butylbenzene play an inhibiting role in low temperature oxidation reactivity of n-decane. The measured intermediates, such as C10-cyclic ethers, C10-ketohydroperoxides and C10-ketodihydroperoxide, provide experimental evidence to validate the first, second and third O2-addition reactions, respectively. Due to the addition of n-decane, the evolution profiles of aromatic intermediates as a function of temperature are quite different from the cases of pure n-butylbenzene oxidation. For example, the formation of benzene, phenol and benzaldehyde at low temperatures is significantly enhanced, whose mole fractions present negative temperature coefficient behaviours. Finally, the reaction pathways of the binary fuel to produce C5C1 alkenes, alkynes, aldehydes, alcohols, acids and peroxides were analysed.

ANTIBACTERIAL EFFECTIVENESS TEST OF KECAPI LEAVES EXTRACTS (Sandoricum koetjape) AGAINST THE GROWTH OF Porphyromonas gingivalis

Background: Chronic periodontitis is a disease of the oral cavity that is influenced by the presence of plaque bacteria caused by Porphyromonas gingivalis which can cause chronic infection of the periodontal tissue. Kecapi leaf (Sandoricum koetjape) extract contains active compounds in the form of flavonoids, saponins, alkaloids, steroids, phenolics, and triterpenoids which function as antibacterial against the growth of Porphyromonas gingivalis. Kecapi leaf extract is used as an alternative to using herbal gluconate to prevent infection caused of Porphyromonas gingivalis. Purpose: To determine the antibacterial effectiveness of kecapi leaf extract against bacterial growth of Porphyromonas gingivalis. Methods: This study used a pure experimental research (true experimental) with post-test only with control design, consists of 7 treatment groups, including: concentrated kecapi leaf extract 5%, 10%, 15%, 25%, 50%, chlorhexidine gluconate 0.2% as positive control, and distilled water as negative control. It was repeated 7 times, the antibacterial effectiveness was assessed from Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) on BHIB and NA media by dilution method. Results: MIC on kecapi leaf extract at a concentration of 5% showed the smallest result of -0.147 and the MBC value at a concentration of 50% did not show the growth of bacterial colonies. Conclusion: Kecapi leaf extract with concentrations of 5%, 10%, 15%, 25%, 50%, and positive control was effective in inhibiting and killing bacterial growth of Porphyromonas gingivalis. Keywords: Antibacterial, Kecapi leaf extract, Porphyromonas gingivalis

Gas-phase oxidation of benzene using Cu-loaded MFI binderless zeolite compacts

Phenols are essential raw materials for various fields, and several studies have focused on their synthesis. The development of an efficient one-step synthetic method for the industrial production of phenols is highly important in terms of cost, energy, and environmental impact. In this study, we investigated the formation of phenols via the gas-phase oxidation of benzene using copper-loaded MFI zeolite compacts prepared via a binderless zeolite synthetic method. The catalytic activity of the zeolite in the gas-phase phenol one-step synthetic reaction was investigated, in addition to the effect of benzene diffusion in the molded zeolite and the reaction due to water vapor addition to the reaction gas. The results showed that the activity of the copper-loaded MFI zeolite compacts was almost equivalent to that of powdered copper-loaded MFI zeolites. An effect of diffusion was observed on the external boundary film diffusion where the linear velocity was low. However, no effect of diffusion or internal diffusion was observed in the area where the linear velocity was high. Furthermore, the addition of water vapor to the reaction gas suppressed the decrease in phenol formation activity due to the formation of coke on the catalyst surface.

COMPARISON OF THE PHENOLIC COMPOUNDS CONTENT AND COMPOSITION IN SYNECHOCYSTIS SP. AND DESERTIFILUM THARENSE

The content and composition of phenolic compounds in Synechocystis sp. PCC 6803 GT-L and Desertifilum tharense were studied for the first time. A spectrophotometric method was used to determine the phenolic compounds content, thin-layer chromatography and UV spectrometry to study their composition. A higher accumulation of these secondary metabolites was found in Synechocystis sp., which was almost twice as high as that in Desertifilum tharense. In both cases, the higher content of phenolic compounds was observed in the linear phase of cyanobacteria growth (3 days). Synechocystis sp. and Desertifilum tharense characterized by the formation of phenolics (4 and 7 compounds, respectively), which contain p-oxybenzoic or p-coumaric acids – the initial stages’metabolites of the phenolic compounds biogenesis.

Synthesis of hybrid azobenzene-chalcone dyes and studies on their photophysical properties: Molecular recognition of carbonate and phosphate ions using a novel turn-off fluorescent probe

The work presented here describes the synthesis and comparative physiochemical studies of hybrid compounds C-1 to 5 of azobenzene A-1 and chalcone B-1, which exhibited the characteristic of both. Further, electron-withdrawing and donating substituents analogues have also been synthesized. The hybrid compound is unique in nature because it contains the phenolic -OH, -N = N-, as well as α,β-unsaturated enone functional groups. The photophysical properties of hybrid C-1 behaved more or less like the azobenzene moieties and showed the same pattern of UV–vis absorption as with the change in the polarity of the solvent and the change in the pH of the medium. Thus, in the non-polar solvent or in the water medium, the phenol form dominates with its yellow colour and in polar solvents shows an intense red colour of keto form. They show a dramatic quenching of fluorescence emission in the polar solvent. Furthermore, after screening, C-1 was found to show selective sensing of the aqueous CO32− ion as well as minimally with PO43- and show a characteristic colour change in an organic solvent such as CH3CN. A few ions also changed colour in DMF, but that was due to the only shifting of the tautomerization equilibrium from keto to enol form. The UV–vis as well as fluorescent spectral studies, determination of the detection limits, and binding constants illustrated significant sensing of CO32− ions. A systematic study was performed to understand the binding interactions of the chemosensor by using Job's plot and time-dependent 1H NMR studies that supported the involvement of phenoloc -OH and β carbon of α,β-unsaturated system. The characteristic pattern of UV–vis and interaction mode was confirmed by DFT studies. The applicability of chemosensor C-1 was demonstrated by the development of a paper strip model to check the presence of CO32− ions in different kinds of water in society.

Role of tea polyphenols in enhancing the performance, sustainability, and catalytic cleaning capability of membrane separation for water-soluble pollutant removal

Tea polyphenols (TPs), like green tea polyphenol (GTP) and black tea polyphenol (BTP), with phenolic hydroxyl structures, form coordination and hydrogen bonds, making them effective for bridging inorganic catalysts and membranes. Here, TPs were employed as interface agents for the preparation of TPs-modified needle-clustered NiCo-layered double hydroxide/graphene oxide membranes (NiCo-LDH-TPs/GO). The incorporation of porous guest material, NiCo-LDH-TPs, facilitated water channel expansion, enhancing membrane permeability and resulting in the development of high-performance, sustainable catalytic cleaning membranes. The introduction of TPs through coordination weakened the surface electronegativity of NiCo-LDH, promoting a uniform mixed dispersion with GO and facilitating membrane self-assembly. NiCo-LDH-GTP/GO-5 and NiCo-LDH-BTP/GO-5 membranes demonstrated permeances of 85.98 and 90.76 L m−2 h−1 bar−1, respectively, with rejections of 98.73% and 99.54% for methylene blue (MB). Notably, the NiCo-LDH-BTP/GO-5 membrane maintained a high rejection of 97.11% even after 18 cycles in the catalytic cleaning process. Furthermore, the modification of GTP and BTP enhanced MB degradation through PMS activation, resulting in a 0.33% and 0.35% increase in the reaction rate constants of NiCo-LDH, respectively, while reducing metal ion spillover. These findings highlighted the potential of TPs in enhancing the efficiency and sustainability of catalytic cleaning GO membranes for water purification and separation processes.

Review Artikel: Tanaman Gaharu (Aquilaria malaccensis L.) sebagai Antioksidan

Indonesia is renowned for the variety of its plant life. Although poorly managed, Indonesia is a mega-biodiversity nation with a wealth of medicinal plants and significant development potential. Owned natural resources have benefited people's everyday lives in addition to being used as food and traditional medicine. Gaharu is a type of biodiversity that has the potential to be used in traditional medicine. Aquilaria agaloccha Rox, a member of the Thymeliaceae family, is the source of gaharu, however it can also be found in plants from the Leguminoceae and Euphorbiaceae families. The general populace believes that gaharu leaves can decrease blood pressure and act as an antioxidant. The Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) technique is the research methodology utilized in literature review articles. Publish or Perish, (2010-2023), is the text that was utilized. Gaharu (Aquilaria malaccensis L.) is a plant that may create secondary metabolites in the form of phenols, terpenoids, flavonoids, glycosides, tannins, and steroids/triterpenoids, all of which are potent antioxidants, according to the findings of a literature study.

A mitochondria-targeted colorimetric and NIR ratiometric fluorescent probe for biothiols with large Stokes shift based on thiol-chromene click reaction.

In this study, a carbazole-based mitochondria-targeted colorimetric and NIR ratiometric fluorescent probe 1 for biothiols based on the thiol-chromene click reaction was subtly designed and synthesized. Upon interaction with biothiols (Cys, Hcy and GSH), the absorption of 1 shifted from 496 nm to 388 nm, while its fluorescence spectrum shifted from 650 nm to 530 nm. These transformations were accompanied by a visible color change from pink to colorless under visible light and from red to green when observed under a 365 nm UV lamp, which can be attributed to the click reaction of biothiols with the α,β-unsaturated ketone of the chromene moiety, subsequent pyran ring-opening and phenol formation as well as 1,6-elimination of a p-hydroxybenzyl moiety yielding 2. These advancements in 1 have allowed us to ratiometrically detect biothiols with high sensitivity (LODs of 97 nM, 94 nM and 93 nM for Cys, GSH and Hcy, respectively), a large Stokes shift (154 nm) and excellent selectivity. In addition, 1 can target mitochondria and image the fluctuation of intracellular biothiols through fluorescence ratiometry. Furthermore, the novel design strategy of modifying chromene to the N atom of quinoline was proposed for the first time.

The formation of sulfur metabolites during in vitro gastrointestinal digestion of fish, white meat and red meat is affected by the addition of fructo-oligosaccharides.

The formation of sulfur metabolites during large intestinal fermentation of red meat may affect intestinal health. In this study, four muscle sources with varying heme-Fe content (beef, pork, chicken and salmon), with or without fructo-oligosaccharides (FOS), were exposed to an in vitro gastrointestinal digestion and fermentation model, after which the formation of sulfur metabolites, protein fermentation metabolites, and short (SCFA) and branched (BCFA) chain fatty acids was assessed. When FOS were present during muscle fermentation, levels of SCFA (+54%) and H2S (+36%) increased, whereas levels of CS2 (-37%), ammonia (-60%) and indole (-30%) decreased, and the formation of dimethyl sulfides and phenol was suppressed. Red meat fermentation was not accompanied by higher H2S formation, but beef ferments tended to contain 33 to 49% higher CS2 levels compared to the ferments of other muscle sources. In conclusion, there is a greater effect on sulfur fermentation by the addition of FOS to the meats, than the intrinsic heme-Fe content of meat.

Fe(III)-catalyzed p-selective C-H bond chalcogenation of phenols.

An efficient, eco-friendly, and scalable protocol has been introduced for the p-selective C-X (X = Se/S) bond formation of phenols employing earth-abundant, less-toxic Fe(III)-catalysts and the green solvent ethanol without using any directing template, stabilizing ligands, oxidants, or additives. The key attraction lies in the impressive p-selectivity with moderate to good yields, wide functional group compatibility under mild aerobic reaction conditions, and the synthetic modification of the products towards value-added molecules.

Recent applications of coinage metal nanoparticles passivated with salicylaldehyde and salicylaldehyde-based Schiff bases.

Salicylaldehyde (SD) and its derivatives are effective precursors for generating coinage metal (gold, silver, and copper) nanoparticles (NPs). These NPs have a variety of potential environmental applications, such as in water purification and sensing, and those arising from their antibacterial activity. The use of SD and its derivatives for synthesizing coinage NPs is attractive due to several factors. First, SD is a relatively inexpensive and readily available starting material. Second, the synthetic procedures are typically simple and can be carried out under mild conditions. Finally, the resulting NPs can be tailored to have specific properties, such as size, shape, and surface functionality, by varying the reaction conditions. In an alkaline solution, the phenolate form of SD was converted to its quinone form, while ionic coinage metal salts were converted to zero-valent nanoparticles. The capping in situ produced quinone of coinage metal nanoparticles generated metal-enhanced fluorescence under suitable experimental conditions. The formation of iminic bonds during the formation of Schiff bases altered the properties (especially metal-enhanced fluorescence) and applications.

Co-pyrolysis of thermoplastic polyurethane with paulownia wood: Synergistic effects on product properties and kinetics

Co-pyrolysis of plastics and biomass offers an effective approach for waste disposal. In this study, the synergistic effects during the co-pyrolysis of thermoplastic polyurethane (TPU) and paulownia wood (PAW) were investigated in terms of pyrolysis kinetics and product properties using tube furnace, TG-FTIR and GC/MS. The results revealed that co-pyrolysis promoted the material pyrolysis and facilitated the pyrolysis process taking place at low temperatures. By adopting the Kissinger-Akahira-Sunose (KAS), Flynn-Wall-Ozawa (FWO) and Starink methods, the average activation energies of pure TPU, PAW, and TPU/PAW blends with a 1:1 mass ratio were determined to be 139 kJ/mol, 288 kJ/mol, and 126 kJ/mol. It is indicated that co-pyrolysis significantly reduced the activation energies and enhanced reactivity. Tube furnace experiments demonstrated that TPU/PAW blend with 1:1 mass ratio exhibited the highest synergism. The TPU melt acted as a physical barrier, leading to increased production of char and oil, and lower production of volatile gas. In the pyrolysis oil, the synergistic effect effectively hindered a formation of alcohol phenols. In the meanwhile, the synergistic effect also boosted generations of aliphatic compounds and ketones, increasing the heat value use of pyrolysis oil. Furthermore, a reaction pathway and mechanism of co-pyrolysis of TPU and PAW was proposed. The active molecules and free radicals generated by the pyrolysis of PAW promote the hydrogen transfer cyclization of polyester polyols decomposed by TPU, and the hydrogen free radicals released by TPU promote the depolymerization and activation of PAW. Moreover, the catalytic effect of alkali metal elements in PAW promotes the synergistic effect. The results of the study provide a basis for the co-pyrolysis of waste plastics and biomass to achieve high value utilization of waste.

Controlling C−OAryl Hydrogenolysis vs Aryl Hydrogenation in Lignin Model Depolymerization Using Ni‐, Rh‐ or Ni/Rh‐based Silica Catalysts

AbstractThis paper focuses on the hydrogenolysis of 2‐phenoxy‐1‐phenylethanone, modelling a pre‐oxidized form of lignin using five catalysts of similar metal content, prepared by impregnation of Ni(II), Rh(III) and both metals onto Aerosil‐380 in the presence of NH3, followed by a reduction step. The materials were characterized in the dried as‐synthesized state and after consecutive reductive and oxidative treatments, showing the great dispersion of the metal (oxide nanoparticles with sizes<2 nm). Working with 1 mol % of the reduced metal (500 °C) per substrate at 180 °C with isopropanol as H‐donor, the most active catalyst, but also the least selective towards phenol, was initially found to be the Ni‐based one. Under similar conditions, the lower capacity of the Rh‐based catalyst to induce H transfer from isopropanol favoured phenol formation but resulted in much slower C−OAr cleavage. Despite a very high dispersion of the two metals in the bimetallic catalysts, no synergy was found, suggesting that Ni would be segregated at the surface. Finally, the best phenol productivity could be reached by reducing the Ni‐based catalyst at 650 °C, which led to a more efficient cleavage of C−OAr bonds. In this way, it was possible to produce 8 times more phenol per hour.

Decomposition of lignin and carbohydrates in a rewetted peatland: a comparative analysis of surface water and anaerobic soil layers

The rewetting of long-term drained peatlands leads to the development of eutrophic shallow lakes, gradually inhabited by reed communities. These shallow lakes are characterized by significant nutrient and methane emissions. To comprehend the fate of organic compounds from decaying Phragmites australis litter in water and anaerobic soil layers, we conducted a 1.6-year decomposition experiment. The experiment employed bulk and lignin-derived phenol analysis, as well as Fourier-transform infrared spectroscopy. As anticipated, the highest level of decomposition was observed in the surface water body of the shallow lake, while the non-rooted degraded peat exhibited the lowest decay. The bulk mass loss of plant litter decreased with depth from 55 to 27% across the four decomposition environments. Analysis using infrared spectroscopy indicated that the decrease in mass loss was primarily driven by the breakdown of carbohydrates, which constitute a significant portion of plant litter. Interestingly, litter in the rooted degraded peat layer exhibited the highest degree of lignin decay. Furthermore, the study revealed a preferential loss of vanillin phenols and an accumulation of p-hydroxyl phenols. These findings suggest that the increased methane emissions in rewetted fens may be partially attributed to the demethoxylation of vanillin phenols and the subsequent formation of p-hydroxyl phenols. In conclusion, this study provides valuable insights into anaerobic lignin decomposition of plant litter and sheds light on potential mechanisms underlying elevated methane emissions in rewetted peatlands. Furthermore, the study’s findings hold significant implications for both carbon cycling and sequestration within these ecosystems, thereby stimulating further research into the microbial community and its extended effects.

Comparison of different drying technologies for walnut (Juglans regia L.) pellicles: Changes from phenolic composition, antioxidant activity to potential application

The analysis of the phenolic profile in the walnut pellicle (WP) and its exploitability can help to promote the valorization of the industrial waste from walnut production. Three forms of 33 monomeric phenols in WPs were quantified based on our previously established LC-MS/MS method. The levels of protocatechuic acid and 4-hydroxybenzoic acid in the WPs were the highest, exceeding 400 μg/g. Antioxidant tests revealed that all three phenolic forms of WPs were effective antioxidants (IC50: 2.12–35.05 µg/mL). The findings also revealed that drying temperature had a substantial type-dependent effect on phenolics and their antioxidant ability in WPs. KEGG enrichment analysis found that drying method has the greatest impact on WPs phenols in six metabolic pathways. Besides, 11 active substances in WPs were identified by a compound-targeted activity screening approach, indicating that WPs could be used as a natural antioxidant source in the development of medical and nutraceutical products.

POTENSI EKSTRAK DAUN BINAHONG TERHADAP PERTUMBUHAN Salmonella sp.

This study aims to determine the potential of binahong leaf extract (Anredera cordifolia) against Salmonella sp. This study used 5 treatments consisting of P(-) Blank Disk as negative control, P(+) chlorampenicol Disk as positive control, P1 binahong leaf extract concentration 60%, P2 binahong leaf extract concentration 80%, P3 binahong leaf extract concentration 100 %. The results of this study indicated that binahong leaf extract at concentrations of 60%, 80% and 100% had the potential to reduce the growth of Salmonella sp, due to the presence of quite a lot of antibacterial levels in binahong leaf extract. The antibacterial levels of binahong leaf extract include (1) Tannins (positive) (2) Saponins (moderately positive) (3) Falvonoids (weakly positive) (4) Steroids (weakly positive) (5) Alkaloids (positive) (6) Phenolics ( weak positive). Antibacterial content in the form of saponins, falvonoids, alkaloids, phenolics and tannins which are the causes of Binahong leaf extract being able to inhibit the growth of Salmonella sp on Muller Hinton Agar (MHA) media.