Guaiacol Research Articles

Preparation and characterization of coconut shell liquid smoke and the properties of preserving tofu

Coconut shell waste can generate environmental problems if left without treatment, as it contains lignin, cellulose, and hemicellulose compounds, which pyrolyze to produce liquid smoke, charcoal, and tar. This study aims to prepare and characterize liquid smoke using several parameters, including the chemical content preserving tofu and the hedonic test of consumer preferences. The dried coconut shell (3000 g) was pyrolyzed at 300 °C for 5 h. Liquid smoke (grade 3) was purified by distillation (grade 2) and filtered with activated charcoal to produce grade 1 liquid smoke. The liquid smoke properties were characterized as yield, pH, phenol, and moisture, while the chemical components were identified by gas chromatography-mass spectroscopy (GC-MS). For the commercial and coconut shell liquid smoke (grade 1) used in this study, the application was aimed at preserving the tofu for three days. Panelists observed the aroma, the texture, and the appearance compared to the control. Ten panelists performed the hedonic test of fried preserved tofu. The organoleptic aspects included taste, texture, aroma, and color. The liquid smoke obtained from coconut shell pyrolysis was red-brown, with a yield of 52.75%, pH 0.5 (grade 3), pH 1.7 (grade 2), and pH 2.3, with a total phenol of 2.479 (grade 1). The GC-MS results exhibited three essential chemical compounds, namely phenol, methoxy phenol, and hydroxyphenyl phosphonic acid, influencing the preservation. The liquid smoke solution extended the shelf life of tofu, especially at a concentration of 1.5 (% v/v), so the water content decreased. The average panelist responded “good” on the hedonic test on all of the tofu treatments compared to the control.

Insights into reverse oxygen spillover effect induced via CeO2 modulation to enhance the stability of CuCoOx catalysts in hydrodeoxygenation of biomass derivatives

In hydrodeoxygenation (HDO) reactions, the evolution of the chemical states of active species in the catalyst caused by the spillover effects greatly influences their catalyst performance. Herein, the HDO of guaiacol (GUA) over CuCoOx and CuCoCeOx catalysts synthesized by co-precipitation method was systematically investigated. During the HDO reaction of GUA, acid sites (Co(II)) facilitated the C-O bond (demethylation via -OCH3) cleavage, which was the rate-determining step. A series of characterizations and experimental results revealed that introducing CeO2 into the CuCoOx catalyst could enable the catalyst to undergo reverse oxygen spillover in the hydrogenation environment, promoting the regeneration of CoO in the catalyst. Therefore, the deactivation of the CuCoOx catalyst due to hydrogen spillover and CoO reduction could be avoided, and the catalyst stability improved. The present study methodically investigated the spillover effects induced by Cu and CeO2 and provided the theoretical basis for the structural design of heterogeneous catalysts.

Phytochemical characterization and bioactivity assessment of Avicennia officinalis L. bark extracts

The study aimed at phytochemical profiling and evaluating the bioactive potentials of aqueous bark extracts of a mangrove plant Avicennia officinalis by in vitro and in silico techniques. The quantitative phytochemical study exhibited total phenol and total flavonoid content as 16.6 mg GAE/g and 82 mg QE/g respectively. The GC-MS study indicated presence of five major compounds viz. 2,6-dimethoxy phenol; 4-[(1E)-3-hydroxy-1-propenyl)- 2-methoxy phenol; 2,5-dimethoxybenzyl acetate; vitamin-E; stigmasterol. The in silico molecular docking of compounds 2,6-dimethoxy phenol; 2,5-dimethoxy benzene methanol acetate and stigmasterol indicated strong binding interactions, validating the antiradical, antidiabetic, anti-inflammatory and antibacterial activities. The extract exhibited DPPH, ABTS, α-glucosidase and protein denaturation inhibition activities with IC50 values of 112.78, 76.34, 257.4, 99.86 μg/mL respectively suggesting the antioxidant, antidiabetic and anti-inflammatory potential of the plant. The antiglycation study exhibited inhibition of fructosamine and congo red with 50.63% and 64.39% at 200 μg/mL concentration. The biofilm inhibitory concentration required to reduce biofilm coverage by 50% values for the extract was 625 μg/mL. The results provide a basis for new pharmacological avenues and further research of this plant.

Upcycling of pine and sodium silicate composites through pyrolysis: Effects of pyrolysis temperature and sodium silicate content

In 3D-printing, sodium silicate (SS) can be used as an inorganic binder for wood-based composites due to its better rheological properties, high strength, and affordability. Investigating the recyclability of 3D-printed composites is necessary to understand the reusability of demolished additively manufactured construction waste. In this work, the bio-oil through pyrolysis was produced using pine and SS composites and further characterized to observe the effects of the pyrolysis temperatures and the proportion of SS in composites. Pine and SS composites with 0, 33.33, 50, and 66.67 % of the SS on a mass basis were prepared and cured to mimic the 3D-printed composites. Then, pyrolysis of cured composites was performed in a bench-scale fixed bed pyrolysis reactor at four temperatures (450–600 °C). From the pyrolysis of composites with 66 % SS at 600 ℃, a maximum condensed liquid yield of 68 % (wt.%, dry basis) was obtained. Further, it was observed that the selectivity towards hydrocarbons and alkyl phenols increased by increasing the proportion of SS in the composite, but methoxy phenols decreased, which enhanced bio-fuel production. A maximum hydroxyl concentration of 6.54 mmol g−1 was observed for the bio-oil from pyrolysis of SS-based composite at 600 ℃. This study shows the feasibility of upcycling the 3D-printed wood composites through pyrolysis to generate bio-oil that can be used for bio-based resin synthesis and bio-fuel applications.

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.

Selective production of phenolic monomer via catalytic depolymerization of lignin over cobalt-nickel-zirconium dioxide catalyst

The utilization of lignin, an abundant and renewable bio-aromatic source, is of significant importance. In this study, lignin oxidation was examined at different temperatures with zirconium oxide (ZrO2)-supported nickel (Ni), cobalt (Co) and bimetallic Ni-Co metal catalysts under different solvents and oxygen pressure. Non-catalytic oxidation reaction produced maximum bio-oil (35.3 wt%), while catalytic oxidation significantly increased the bio-oil yield. The bimetallic catalyst Ni-Co/ZrO2 produced the highest bio-oil yield (67.4 wt%) compared to the monometallic catalyst Ni/ZrO2 (59.3 wt%) and Co/ZrO2 (54.0 wt%). The selectively higher percentage of vanillin, 2-methoxy phenol, acetovanillone, acetosyringone and vanillic acid compounds are found in the catalytic bio-oil. Moreover, it has been observed that the bimetallic Co-Ni/ZrO2 produced a higher amount of vanillin (43.7% and 13.30 wt%) compound. These results demonstrate that the bimetallic Ni-Co/ZrO2 catalyst promotes the selective cleavage of the ether β-O-4 bond in lignin, leading to a higher yield of phenolic monomer compounds.

Chromatographic analysis of triple cough therapy; bromhexine, guaiafenesin and salbutamol and pharmaceutical impurity: in-silico toxicity profile of drug impurity

Bromhexine (BR), guaiafenesin (GUF) and salbutamol (SAL) are formulated as Ventocough syrup® (with and without sugar), labeled to contain propyl paraben and sodium benzoate as inactive ingredients. They are used to make coughing more productive and easier. A crucial element and a major issue in the pharmaceutical industry is the control of organic related impurities to obtain safe and effective treatment. Guaiacol (GUL) is reported to be GUF related impurity that was proved to be extremely toxic (toxic rating class 5), and its use should be banned. In this work, In-Silico study and ADMET estimation were conducted to predict GUL pharmacokinetic properties and its toxicity profile. Additionally, two chromatographic methods were conducted to analyze the studied components along with GUF impurity in the presence of the labeled dosage form excipients. The In-Silico study assured that GUL has oral rat acute toxicity and it is considered to be skin sensitizer. On the other hand, the developed TLC- densitometeric method depended on using a mobile phase mixture of hexane: methylene chloride: triethylamine (5.0:6.0:0.3, by volume) as a developing system. UV-Scanning was performed immediately at 275 nm for SAL, GUF and GUL, while scanning at 310 nm was used for scanning BR. Linearity was established in the ranges of 0.25–4.0, 0.25–4.0, 0.5–8.0 and 0.1–1.6 µg/band for BR, SAL, GUF and GUL, respectively. In the developed HPLC method, separation was performed on X-Bridge® C18 column (250 × 4.6 mm, 5 μm) using a solvent mixture of 0.05M disodium hydrogen phosphate pH 3 with aqueous phosphoric acid: methanol (containing 0.3%, v/v triethylamine) (40:60, v/v). Detection was done at 225 nm and separation was achieved within 10 min. Linearity was proved in the range of 2–50 µg/mL for the proposed drugs. Validation of the developed methods was done and all the calculated parameters were within the acceptable limits recommended by ICH guidelines. After that, methods were used to examine the potency of the selected marketed dosage forms and concentrations of all drugs were within the acceptable limits. Additionally, complete separation between the studied drugs and the additives were observed. The developed methods can be used during routine quality control analysis of the proposed drugs when the required issues concern on sensitivity, selectivity and analysis time.Graphical

Toxicity of nitrophenolic pollutant 4-nitroguaiacol to terrestrial plants and comparison with its non-nitro analogue guaiacol (2-methoxyphenol)

Phenols, and especially their nitrated analogues, are ubiquitous pollutants and known carcinogens which have already been linked to forest decline. Although nitrophenols have been widely recognized as harmful to different aquatic and terrestrial organisms, we could not find any literature assessing their toxicity to terrestrial plants. Maize (monocot) and sunflower (dicot) were exposed to phenolic pollutants, guaiacol (GUA) and 4-nitroguaiacol (4NG), through a hydroponics system under controlled conditions in a growth chamber. Their acute physiological response was studied during a two-week root exposure to different concentrations of xenobiotics (0.1, 1.0, and 10 mM). The exposure visibly affected plant growth and the effect increased with increasing xenobiotic concentration. In general, 4NG affected plants more than GUA. Moreover, sunflower exhibited an adaptive response, especially to low and moderate GUA concentrations. The integrity of both plant species deteriorated during the exposure: biomass and photochemical pigment content were significantly reduced, which reflected in the poorer photochemical efficiency of photosystem II. Our results imply that 4NG is taken up by sunflower plants, where it could enter a lignin biosynthesis pathway.

Quality of Vanilla spp. from Madagascar: evolution of the compound fingerprints from the green beans to the vanilla pods’ preparation

Description of the subject. Vanilla is a spice whose name comes from the spanish word “vanilla”, meaning little black pods. It comes from a variety of orchids, more specifically the vanilla plant. Although vanilla is the second most expensive spice, next to saffron, it is still the most used in the food, cosmetics, beverage, and tobacco industries. The quality of vanilla pods depends on their preparation. Objectives. This work aims to quantitatively determine the rate of five aromatic quality marker compounds in five selected vanilla species cultivated in Madagascar and to understand the evolution of these compounds during the maturity and preparation of the pods. Method. High-Performance Liquid Chromatography (HPLC) analysis was undertaken on five Vanilla species, including Vanilla planifolia Andrews, V. pompona Schiede, V. tsy taitry, V. planifolia var. sterile and V. planifolia var. tsy vaky, to assess the concentration of the marker compounds, including vanillin (VAN), p-hydroxybenzoic acid (p-HBAc), vanillic acid (VAc), guaiacol (GUA), and p-hydroxybenzaldehyde (p-HB), in the selected pods during their stage of collection and preparation. Results. VAN (2.63-45.30 µg·ml-1 at 6 months old; 8.72-122.66 µg·ml-1 at 9 months old; 26.81-60.69 µg·ml-1 after the drying process and 13.35-105.03 µg·ml-1 after the conditioning process) was the major component followed by the p-HB (7.59 µg·ml-1 for V. pompona at 6 months old; 5.52-24.47 µg·ml-1 at 9 months old; 5.40-14.72 µg·ml-1 after the drying process and 4.69-24.84 µg·ml-1 after the conditioning process) in each vanilla species. Generally, VAN concentration increased from the 6th to the 9th month then decreased after the drying process and increased again after the conditioning process. Guaiacol was not detected in all species during the stages of collection and preparation. Conclusions. Vanilla planifolia or V. fragrance remains the vanilla with the highest concentration of the important marker compounds suggesting that it could have the best quality among those selected in this study making this species still the most traded in the international market.

Insights into Enhanced Peroxydisulfate Activation with B and Fe Co-Doped Biochar from Bark for the Rapid Degradation of Guaiacol.

A boron and iron co-doped biochar (B-Fe/biochar) from Masson pine bark was fabricated and used to activate peroxydisulfate (PDS) for the degradation of guaiacol (GL). The roles of the dopants and the contribution of the radical and non-radical oxidations were investigated. The results showed that the doping of boron and iron significantly improved the catalytic activity of the biochar catalyst with a GL removal efficiency of 98.30% within 30 min. The degradation of the GL mainly occurred through the generation of hydroxyl radicals (·OHs) and electron transfer on the biochar surface, and a non-radical degradation pathway dominated by direct electron transfer was proposed. Recycling the B-Fe/biochar showed low metal leaching from the catalyst and satisfactory long-term stability and reusability, providing potential insights into the use of metal and non-metal co-doped biochar catalysts for PDS activation.

Evaluation of a dye-decolorizing peroxidase from Comamonas serinivorans for lignin valorization potentials

Although dye-decolourising peroxidases (DyPs) are well-known for lignin degradation, a comprehensive understanding of their mechanism remains unclear. Therefore, studying the mechanism of lignin degradation by DyPs is necessary for industrial applications and enzyme engineering. In this study, a dye-decolourising peroxidase (CsDyP) gene from C. serinivorans was heterologously expressed and studied for its lignin degradation potential. Molecular docking analysis predicted the binding of 2, 2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), veratryl alcohol (VA), 2, 6-dimethylphenol (2, 6- DMP), guaiacol (GUA), and lignin to the substrate-binding pocket of CsDyP. Evaluation of the enzymatic properties showed that CsDyP requires pH 4.0 and 30 °C for optimal activity and has a high affinity for ABTS. In addition, CsDyP is stable over a wide range of temperatures and pH and can tolerate 5.0 mM organic solvents. Low NaCl concentrations promoted CsDyP activity. Further, CsDyP significantly reduced the chemical oxygen demand decolourised alkali lignin (AL) and milled wood lignin (MWL). CsDyP targets the β-O-4, CO, and CC bonds linking lignin's G, S, and H units to depolymerize and produce aromatic compounds. Overall, this study delivers valuable insights into the lignin degradation mechanism of CsDyP, which can benefit its industrial applications and lignin valorization.

Proton coupled electron transfer in tri-molecular system involving 7-Methylbenzo [a] pyrene and different phenol–base pairs: A case study for determining hydrogen bonding equilibrium constant

Photo induced proton-coupled electron transfer (PCET) reactions comprehend the concerted transfer of an electron from donor to acceptor and a proton along the hydrogen bonded axis in same time scale. Photo-oxidations of hydrogen-bonded phenols by excited-state polyarene are utilized to extract concerted proton−electron transfer reactions rate and hydrogen bonding equilibrium constant. Experiments have examined fluorescence quenching of 7-Methyl benzo[a]pyrene (7-MeB[a]P) in all possible ways in solution phase by phenol-bases pairs (hydrogen bonded adducts) for two phenols, 4-Methoxy phenol (4-MeO PhOH) and 2,6- Dimethoxy phenol (2,6-DiMeo PhOH), and different pyridine derivatives, such as simple Pyridine (Py), 2,4-Dimethylpyridine (DMPy), 2,4,6-Trimethylpyridine (TMPy), 4-(N,N-Dimethylaminopyridine) (DMAPy), along with 1-Methylimidazole (IM). Detection of 7-MeB[a]P anion in femtosecond transient absorption studies and positive kinetic isotope effect confirm the fluorescence quenching of 7-MeB[a]P is due to PCET reaction where photo-oxidations of phenols proceed by intermolecular proton movement of phenolic proton to the base along the hydrogen bond axis concerted with electron transfer to the photo excited 7-MeB[a]P. The systematic fluorescence quenching experiments of 7-MeB[a]P by hydrogen bonded adducts are performed in two different ways: Case-1, variation of base concentration for fixed and dilute solution of 7-MeB[a]P and phenol mixture and Case-2, changing phenol concentration for fixed and dilute solution of 7-MeB[a]P and base. These two data sets are thus well described by non-linear Stern-Volmer type relation, providing a strong validation for the use of these approaches for determining hydrogen bonding equilibrium constants (KHB) along with rate constant (kQB) for PCET reaction. The estimated KHB values are fairly consistence to that observed in typical spectrophotometric method following Mataga-Tsuno relation. Thus, this is a very clear demonstration that the PCET reactions can be used to determine KHB in favourable cases where ground state hydrogen bonding is the essential and necessary condition for PCET reaction to occur.

Cardioprotective effect of 2-methoxy phenol derivatives against oxidative stress-induced vascular complications: An integrated in vitro, in silico, and in vivo investigation

BackgroundOxidative stress and inflammation play crucial roles in macro/microvascular complications. Phenolic compounds and their derivatives show promise as therapeutic agents for diseases like cancer, metabolic disorders, and cardiovascular diseases. With their antioxidant and anti-inflammatory properties, these compounds hold potential for mitigating vascular complications and improving overall health. MethodologyThis study aimed to assess the therapeutic potential of five 2-methoxy phenol derivatives (T2, T5, T6, T7, and T8) as antioxidants, anti-inflammatory agents, and vasorelaxants using in vitro, in silico, and in vivo approaches. ResultsAmong all, T2 exhibited substantial antioxidant potential against 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radicals with IC50 (27.97 µg/mL), nitric oxide (NO) radicals (IC50 = 34.36 µg/mL), hydroxyl (OH) radicals (IC50 = 34.83 µg/mL) and Iron chelation (IC50 = 24.32 µg/mL). Molecular docking analysis confirms that all derivatives, particularly T2, exhibit favorable binding energies with the target proteins, ACE (−7.7 Kcal/mol), ECE-1 (−7.9 Kcal/mol), and COX-1 (−7.8 Kcal/mol). All of the compounds demonstrated satisfactory physicochemical and pharmacokinetic characteristics, and showed minimal to no toxicity during in silico, in vitro, and in vivo assessments. In isolated aortic rings from Sprague Dawley rats, pre-contracted with high K+ (80 mM), T2 induced vasorelaxation in dose dependent manner and shifted calcium response curves to the right as compared to verapamil. T2 also showed substantial platelet aggregation inhibition in a dose dependent manner with IC50 21.29 µM. All derivatives except T7 exhibited significant conservation of endogenous antioxidants i.e. catalase (CAT), peroxidase (POD), superoxide dismutase (SOD) and reduced glutathione (GSH) and significantly suppressed serum levels of inflammatory markers i.e. nitric oxide (NO), peroxides (TBARS), interleukin-6 (IL-6) and cyclooxygenase-2 (COX-2). ConclusionThe study concludes that T2 has significant antioxidant potential and vasorelaxant effects with adequate pharmacokinetics, making it a promising lead compound for further molecular investigation in cardiovascular disorders.

Chemical constituents and antioxidant activity of Britton's wild petunia (Ruellia brittoniana) flower

Abstract. Sianturi GLR, Trisnawati EW, Koketsu M, Suryanti V. 2023. Chemical constituents and antioxidant activity of Britton's wild petunia (Ruellia brittoniana) flower. Biodiversitas 24: 3665-3672. Britton's wild petunia orkencana ungu (Ruellia brittoniana), which has purple flowers, is widely used as a decorative plant. Isolation and structure determination of the antioxidant compound of R. brittoniana flower were carried out. Extraction was carried out by maceration, and compound isolation was conducted by column chromatography. Structure elucidation was accomplished by FTIR, NMR, and MS Spectrometry. Apigenin (4',5,7-trihydroxyflavone) was isolated from the B1 fraction using chloroform: methanol (10: 1) eluent. Fraction A1, obtained from elution by chloroform: methanol (10: 0), consisted of 24 compounds. Two compounds were identified as 1-hexadecanol and 1-phenyl ethanone, which have antioxidant properties of fraction A1. Fraction B2 was eluted by chloroform: methanol (10:1), consisting of 20 compounds. A compound was identified as 2-methoxy phenol, contributingto the antioxidant properties of fraction B2. The total phenolic content of R. brittoniana flower extract was 1.033 mg GAE/g, and its total anthocyanin content was 16.97%. Fractions A1 and B2 possessed strong antioxidant activities due to their phenolic compounds. Apigenin has three -OH groups in the 4’, 5, and 7 positions; only the -OH group at the 4’ position contributes to its antioxidant activity. Therefore, apigenin has moderate antioxidant activity by DPPH assay. The modification structure of apigenin needs further study to enhance its antioxidant activity. This research shows that R. brittoniana flower can be a source of apigenin, also known to have anticancer properties.

Volatile profiles and aroma-active components of Northern Thai fermented soybean (thua nao) produced from controlled and uncontrolled fermentations

Thua nao is a fermented soybean product that is widely consumed, especially in the northern part of Thailand. Thua nao can be used as a condiment to enhance the aroma and flavor of foods. In general, commercial thua nao is traditionally made by indigenous microbial, especially Bacillus spp. fermentation under ambient conditions, leading to inconsistencies in product aroma quality. To solve this problem, inoculation of selected microorganisms can help control thua nao consistency. The objective of this research was to characterize and compare volatile aroma-active compounds in three samples, including thua nao made by commercial Bacillus subtilis inoculation fermented under controlled conditions (YSB) and two thua nao products made by indigenous fermentation in commercial production sites in Lumpoon (LPN) and Chiang-Mai (CMI) provinces, Thailand. It was found that 2-methyl butanoic acid, phenylethyl alcohol, benzaldehyde, 2,5-dimethylpyrazine, 2,6-dimethylpyrazine and 2-methoxy phenol were dominant compounds in the YSB samples. These compounds contributed to fermented/sour, floral, almond-like and nutty aromas, which were related to positive attributes perceived by consumers. In contrast, several aldehydes and ketones related to off-aroma as oxidized, fatty, green, and earthy attributes derived from lipid oxidations were dominantly detected in samples from uncontrolled fermentations (LPN and CMI). From the study, it can be implied that inoculation of B. subtilis in thua nao fermentation could enhance aroma compounds with positive attributes and thus improve the organoleptic property of the product. These findings could benefit fermented soybean manufacturers to improve their aroma quality and to control products’ consistency by controlling fermentation conditions.

Selective Hydrodeoxygenation of Lignin‐Derived Vanillin via Hetero‐Structured High‐Entropy Alloy/Oxide Catalysts

The chemoselective hydrodeoxygenation of natural lignocellulosic materials plays a crucial role in converting biomass into value‐added chemicals. Yet their complex molecular structures often require multiple active sites synergy for effective activation and achieving high chemoselectivity. Herein, it is reported that a high‐entropy alloy (HEA) on high‐entropy oxide (HEO) hetero‐structured catalyst for highly active, chemoselective, and robust vanillin hydrodeoxygenation. The heterogenous HEA/HEO catalysts were prepared by thermal reduction of senary HEOs (NiZnCuFeAlZrOx), where exsolvable metals (e.g., Ni, Zn, Cu) in situ emerged and formed randomly dispersed HEA nanoparticles anchoring on the HEO matrix. This catalyst exhibits excellent catalytic performance: 100% conversion of vanillin and 95% selectivity toward high‐value 2‐methyl‐4 methoxy phenol at low temperature of 120 °C, which were attributed to the synergistic effect among HEO matrix (with abundant oxygen vacancies), anchored HEA nanoparticles (having excellent hydrogenolysis capability), and their intimate hetero‐interfaces (showing strong electron transferring effect). Therefore, our work reported the successful construction of HEA/HEO heterogeneous catalysts and their superior multifunctionality in biomass conversion, which could shed light on catalyst design for many important reactions that are complex and require multifunctional active sites.

Phytochemicals in the treatment of inflammation-associated diseases: the journey from preclinical trials to clinical practice.

Advances in biomedical research have demonstrated that inflammation and its related diseases are the greatest threat to public health. Inflammatory action is the pathological response of the body towards the external stimuli such as infections, environmental factors, and autoimmune conditions to reduce tissue damage and improve patient comfort. However, when detrimental signal-transduction pathways are activated and inflammatory mediators are released over an extended period of time, the inflammatory process continues and a mild but persistent pro-inflammatory state may develop. Numerous degenerative disorders and chronic health issues including arthritis, diabetes, obesity, cancer, and cardiovascular diseases, among others, are associated with the emergence of a low-grade inflammatory state. Though, anti-inflammatory steroidal, as well as non-steroidal drugs, are extensively used against different inflammatory conditions, they show undesirable side effects upon long-term exposure, at times, leading to life-threatening consequences. Thus, drugs targeting chronic inflammation need to be developed to achieve better therapeutic management without or with a fewer side effects. Plants have been well known for their medicinal use for thousands of years due to their pharmacologically active phytochemicals belonging to diverse chemical classes with a number of these demonstrating potent anti-inflammatory activity. Some typical examples include colchicine (alkaloid), escin (triterpenoid saponin), capsaicin (methoxy phenol), bicyclol (lignan), borneol (monoterpene), and quercetin (flavonoid). These phytochemicals often act via regulating molecular mechanisms that synergize the anti-inflammatory pathways such as increased production of anti-inflammatory cytokines or interfere with the inflammatory pathways such as to reduce the production of pro-inflammatory cytokines and other modulators to improve the underlying pathological condition. This review describes the anti-inflammatory properties of a number of biologically active compounds derived from medicinal plants, and their mechanisms of pharmacological intervention to alleviate inflammation-associated diseases. The emphasis is given to information on anti-inflammatory phytochemicals that have been evaluated at the preclinical and clinical levels. Recent trends and gaps in the development of phytochemical-based anti-inflammatory drugs have also been included.

Reaction kinetics, pyrolytic behavior and product characterization of dewatered solids from spent fermentation coir wastes using a fixed batch reactor

Solid residues after pretreatment and hydrolysis of coir pith and Bit fiber waste was dewatered, dried and pyrolyzed at 300, 350, and 400 °C using a fixed bed batch pyrolyzer. The products were characterized using ultimate analysis, FTIR and GCMS. Bit fiber yielded more bio-oil (26.3 %), rich in 4-Methoxy phenol (60.94 %) and a Higher Heating Value of 27.06 MJ kg−1. Coir pith bio-oil with Higher Heating Value of 27.16 MJ kg−1, was rich in 2-Methoxy Phenol, which are principal lignin degradation products. Non condensable gases included mixture of methane, carbon dioxide and isomers of butene. Activation energy for thermal decomposition was studied using Coats and Redfern model from thermogravimetric data at heating rates of 10 and 15 k min−1, which showed two major phases of decomposition. Activation energy was higher for devolatilization phase of bit fiber waste (132 kJ/ mol) owing to higher percentage of lignin than in coir pith waste (Ea = 114 kJ/ mol).

The pH dependence of photochemical reactions between methoxyphenols with Fe(III)-oxalates

The changes in optical properties and chemical compositions of four methoxyphenols, including guaiacol (GU), vanillin (VA), 4-nitroguaiacol (NGU) and 5-nitrovanillin (NVA) were investigated during the photochemical reaction with Fe(III)-oxalates. The reaction pathways of methoxyphenols with Fe(III)-oxalates were varied with solution pH. Four methoxyphenols were significantly decomposed by ·OH produced from Fe(III)-oxalates under irradiation at a solution pH of 3, followed by the formation of phenols, ketones and ethers. The degradation rate of methoxyphenols was closely correlated to electron-withdrawing groups on the benzene ring, such as NO2 and CHO groups. Under the neutral condition, the absorbance of methoxyphenols varied or remained unchanged, depending on the pKa values of methoxyphenols. The changes in the light absorption of VA and NGU solutions were contributed to the deprotonation of OH group in the presence of dissolved O2.

Characterization of proteinaceous and other organic materials in historical stringed musical instruments by off-line analytical pyrolysis with silylation

Historical stringed musical instruments such as violins, violas, and violoncellos are a unique class of cultural heritage objects. The production of these precious musical instruments reached its peak of prosperity in the 16–18th century in a northern Italy city, Cremona, represented by the great Masters of violin-making art. The multi-layered coating system and the pre-treatments applied to the surfaces of wood substrates are assumed to be related to the special sounds and esthetics of these antique instruments. However, due to the absence of written historical records, their construction and finishing methods are still a mystery. For this purpose, chemical analyses are useful to recover historical recipes by providing information about the material composition, methods of manufacture, and past restoration and maintenance procedures. Pyrolysis gas chromatography-mass spectrometry provided useful information on material composition by using specific markers, but protein determination remains an open analytical problem. A comprehensive study on various proteinaceous materials was undertaken to evaluate the performance of off-line pyrolysis combined with solid-phase microextraction with and without on-fiber silylation. The molecular markers were selected for each method. The methods were applied to historic instrument samples from Jacob Steiner, Luigi Baioni, Andrea Guarneri, Francesco Ruggeri, Lorenzo Storioni instruments and a violin from Pietà of Venice. For the first time, the presence of proteinaceous materials was found by analytical pyrolysis in Stainer, Guarneri, Ruggeri, Storioni and probably Pietà of Venice. Different combinations of the markers were observed in each specimen, with pyrocoll, diketopiperazines or silylated 3-hydroxypyridine the most common. Besides collagen, markers indicative of wood components (methoxy phenols, anhydrosugars), gums (anhydrosugars), and resins (dehydroabietic acid, larixyl acetate) provided a complete picture of the organic materials in stringed instruments obtainable by a single analysis of a micro-sample.