Vanillic Acid Nanocomposite: Synthesis, Characterization Analysis, Antimicrobial, and Anticancer Potentials.

Recently, nanoparticles have received considerable attention owing to their efficiency in overcoming the limitations of traditional chemotherapeutic drugs. In our study, we synthesized a vanillic acid nanocomposite using both chitosan and silver nanoparticles, tested its efficacy against lung cancer cells, and analyzed its antimicrobial effects. We used several characterization techniques such as ultraviolet-visible spectroscopy (UV-Vis), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDAX), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) to determine the stability, morphological characteristics, and properties of the biosynthesized vanillic acid nanocomposites. Furthermore, the vanillic acid nanocomposites were tested for their antimicrobial effects against Escherichia coli and Staphylococcus aureus, and Candida albicans. The data showed that the nanocomposite effectively inhibited microbes, but its efficacy was less than that of the individual silver and chitosan nanoparticles. Moreover, the vanillic acid nanocomposite exhibited anticancer effects by increasing the expression of pro-apoptotic proteins (BAX, Casp3, Casp7, cyt C, and p53) and decreasing the gene expression of Bcl-2. Overall, vanillic acid nanocomposites possess promising potential against microbes, exhibit anticancer effects, and can be effectively used for treating diseases such as cancers and infectious diseases.

Does vanillic acid affect fracture healing? An experimental study in a rat model of femur fracture.

BACKGROUND AND OBJECTIVES: We aimed to determine the effects of vanillic acid (VA) on fracture healing radiologically, histologically, immunohistochemically, and biomechanically using a rat femur open fracture injury model. METHODS: 32 male Wistar-Albino rats were used and divided into two groups: the study group (VA) and the control group. From the time they were operated on until they were sacrificed, the rats in the study group were given 100 mg/kg/day VA by oral gavage. After sacrification, the femurs were analyzed. RESULTS: It was observed that the Huo histological scoring was significantly higher in the VA group (p = 0.001), and the ratio of the amount of callus tissue compared to intact bone tissue was significantly higher. While no significant difference was observed in immunohistochemical H-scores in ColI antibody staining (p = 1.000), a borderline significant difference in favor of VA was observed in ColIII antibody staining (p = 0.078). In biomechanical analysis, failure load (N), total energy (J), maximum stress (MPa), and stiffness (N/mm) measurements were significantly higher in the VA group (p = 0.040, p = 0.021, p = 0.015, and p = 0.035, respectively). CONCLUSION: It has been observed that VA, with its antioxidative properties, increases fracture healing in rats, in which an open fracture model was created. We are hopeful that such an antioxidant, which is common in nature, will increase fracture healing. Since this study is the first to examine the effect of VA on fracture healing, further studies are needed.

Gastroprotective effect of vanillic acid against ethanol-induced gastric injury in rats: involvement of the NF-κB signalling and anti-apoptosis role.

BACKGROUND: Vanillic acid (VA; 4-hydroxy-3-methoxybenzoic acid) is a flavouring agent found in various natural sources such as olives, fruits, and green tea. While VA exhibits numerous pharmacological effects, its potential protective effects against gastric injury warrants further investigation. Therefore, the primary objective of this study is to elucidate investigate the gastroprotective properties of VA against ethanol-induced gastric injury. METHODS AND RESULTS: Rats were orally administered either saline or VA at different doses (50, 100, and 200 mg/kg/day), with omeprazole (20 mg/kg) serving as a positive control, for fourteen consecutive days before ethanol administration. Blood and gastric tissue samples were collected one hour after ethanol administration for biochemical, molecular, and histological analyses. Pre-treatment with VA before ulcer induction alleviated both macroscopic and microscopic damage. It also increased antioxidant glutathione levels and decreased malondialdehyde and myeloperoxidase activity, along with reducing inflammatory markers such as tumour necrosis factor (TNF)-α, interleukin (IL)-6, and nuclear factor kappa B (NF-κB). Additionally, VA pre-treatment reversed the elevation of Bax mRNA expression and gastric caspase-3 levels induced by gastric damage. It also mitigated the reduction in Bcl-2 mRNA expression. CONCLUSION: These findings suggest that VA exerts protective effects against ethanol-induced gastric injury in rats. It achieves this by augmenting gastric antioxidant capacity and mitigating oxidative, inflammatory, and apoptotic damage.

Hesperidin, vanillic acid, and sinapic acid attenuate atorvastatin-induced mitochondrial dysfunction via inhibition of mitochondrial swelling and maintenance of mitochondrial function in pancreas isolated mitochondria.

It has been reported that lipophilic statins such as atorvastatin can more readily penetrate into ß-cells and reach the mitochondria, resulting in mitochondrial dysfunction, oxidative stress, decrease in insulin release. Many studies have shown that natural products can protect mitochondrial dysfunction induced by drug in different tissue. We aimed to explore mitochondrial protection potency of hesperidin, vanillic acid, and sinapic acid as natural compounds against mitochondrial dysfunction induced by atorvastatin in pancreas isolated mitochondria. Mitochondria were isolated form rat pancreas and directly treated with toxic concentration of atorvastatin (500 µM) in presence of various concentrations hesperidin, vanillic acid, and sinapic acid (1, 10, and 100 µM) separately. Mitochondrial toxicity parameters such as the reactive oxygen species (ROS) formation, succinate dehydrogenases (SDH) activity, mitochondrial swelling, depletion of glutathione (GSH), mitochondrial membrane potential (MMP) collapse, and malondialdehyde (MDA) production were measured. Our findings demonstrated that atorvastatin directly induced mitochondrial toxicity at concentration of 500 µM and higher in pancreatic mitochondria. Except MDA, atorvastatin caused significantly reduction in SDH activity, mitochondrial swelling, ROS formation, depletion of GSH, and collapse of MMP. While, our data showed that all three protective compounds at low concentrations ameliorated atorvastatin-induced mitochondrial dysfunction with the increase of SDH activity, improvement of mitochondrial swelling, MMP collapse and mitochondrial GSH, and reduction of ROS formation. We can conclude that hesperidin, vanillic acid, and sinapic acid can directly reverse the toxic of atorvastatin in rat pancreas isolated mitochondria, which may be beneficial for protection against diabetogenic-induced mitochondrial dysfunction in pancreatic ß-cells.

The pulmonary protective potential of vanillic acid-loaded TPGS-liposomes: modulation of miR-217/MAPK/NF-κb signalling pathway.

The aim is to investigate the possible pulmonary protective effect of vanillic acid (VA) in liposome-TPGS nanoparticles, to overcome VA's poor bioavailability. VA was successfully extracted. Liposomes were prepared using thin film hydration. Central composite design was adopted for optimisation of liposomes to get the maximum entrapment efficiency (EE%) and the minimum mean diameter, where the liposomes were further modified with TPGS, and tested for PDI, zeta-potential, and in-vitro drug release. In-vivo study on mice with LPS-acute pulmonary toxicity was tested. TPGS-modified VA-liposomes showed EE% of 69.35 ± 1.23%, PS of 201.7 ± 3.23 nm, PDI of 0.19 ± 0.02, and zeta-potential of -32.2 ± 0.32 mv. A sustained drug release of the TPGS-modified VA-liposomes was observed compared to standard VA, and a pulmonary-protective effect through decreasing miR-217 expression with subsequent anti-inflammatory effect through suppression of MAPK and PI3K/NF-κB pathways was also demonstrated in the current study. TPGS-modified VA-liposomes showed an enhanced bioavailability and a sustained drug release with promising pulmonary protective effects against acute pulmonary injury diseases.

[Multi-index evaluation of different parts of Amomum villosum].

To investigate the quality differences between the seeds and husks of Amomum villosum and explore the rationality of using the seeds without husks, this study determined the content of protocatechuic acid, vanillic acid, epicatechin, quercitrin, volatile oil, water extract, and ethanol extract. The 2,2-diphenyl-1-picrylhydrazyl(DPPH), 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS), and hydroxyl radical scavenging activities were determined to evaluate the antioxidant activities of seeds and husks. The quality differences between the seeds and husks were assessed through orthogonal partial least squares-discriminant analysis(OPLS-DA) and analytic hierarchy process(AHP) combined with the entropy weight method(EWM). Significant differences(P<0.05) were observed in all 10 indicators between the seeds and husks. The levels of epicatechin, quercetin, and volatile oil were higher in the seeds, whereas those of protocatechuic acid, vanillic acid, water extract, and ethanol extract were higher in the husks. The seeds showed stronger scavenging ability against DPPH and ABTS radicals, while the husks showed a stronger scavenging effect on hydroxyl radicals. OPLS-DA significantly discriminated between the seeds and husks. Furthermore, volatile oil, water extract, DPPH radical scavenging rate, quercitrin, ABTS radical scavenging rate, hydroxyl radical scavenging rate, and vanillic acid were selected as the main differential indicators by variable importance in projection(VIP). Comprehensive scores calculated by AHP combined with EWM indicated that the seeds were superior to husks in terms of overall quality. However, there are still some dominant components and a certain antioxidant effect in the husks. Therefore, it is suggested to using Amomi Fructus with a certain amount of husks or utilizing the husks for other purposes.

The Protective Effects of Vanillic Acid and Vanillic Acid-Coated Silver Nanoparticles (AgNPs) in Streptozotocin-Induced Diabetic Rats.

The production of nanoparticles enhances the bioactivity of biological molecules for drug delivery to diseased sites. This study explains how silver nanoparticle (AgNP) coating enhanced the protection effects of vanillic acid in male diabetic rats with streptozotocin- (STZ-) induced diabetes. Twenty-four rats were divided into four groups (n = 6) for this investigation. The first group (G1) is untreated, whereas diabetes was induced in the other three groups through STZ injection. Diabetic rats that were not getting therapy were included in the second group (G2, STZ-positive), whereas the other diabetic rats were divided into the third group (G3, vanillic acid-treated) and the fourth group (G4, vanillic acid-coated AgNPs treated). The treatment lasted four weeks. In G2, the induction of diabetes significantly (at P = 0.05) increased in serum glucose, glycated proteins, renal indices, interleukin-6 (IL-6), K+, immunoglobulins, and lipid peroxidation, while decreased Ca++, Na+, and other antioxidants in the kidney tissue homogenate. In addition, pathological altered signs were present in the pancreas and kidneys of diabetic rats. The renal and pancreatic tissues were effectively enhanced by vanillic acid or vanillic acid-coated AgNPs, bringing them very close to their prediabetic conditions. Vanillic acid-coated AgNPs offered a stronger defense against STZ-induced diabetes and lessened the effects of hyperglycemia compared to ordinary vanillic acid. Additionally, using vanillic acid coated with silver nanoparticles greatly increased the antioxidant and antidiabetic activity and reduced inflammation when compared to using vanillic acid alone.

Biological effects of vanillic acid, iso-vanillic acid, and orto-vanillic acid as environmental pollutants.

Vanillic acid (4-hydroxy-3-methoxybenzoic acid) (VA) is a natural benzoic acid derivative commonly found in herbs, rice, maize, and some fruits and vegetables. However, due to the wide use of VA in various industrial sectors, its presence in the environment might harm living organisms. This study evaluated the toxicity of VA and its isomers, iso-VA and orto-VA. Firstly, the antimicrobial effect of VA and its isomers iso-VA and orto-VA (in doses of 1000; 100, 10, 1; 0.1; 0.01 mg/L) against Escherichia coli, Sarcina spp., Enterobacter homaechei, Staphylococcus aureus and Candida albicans were identified. The toxic effect and protein degradation potential of VA and its isomers were determined using E. coli grpE:luxCDABE and lac:luxCDABE biosensor strains. However, the genotoxicity and oxidative stress generation were assessed with the E. coli recA:luxCDABE biosensor and E. coli strain. The results showed that VA, iso-VA, and orto-VA exhibited antimicrobial activity against all tested bacterial strains. However, VA's antimicrobial effect differed from iso-VA and orto-VA. Similar toxic, genotoxic, and oxidative stress-inducing effects were observed for VA and its isomers. Each compound exhibited toxicity, cellular protein degradation, and genotoxic activity against E. coli grpE:luxCDABE, E. coli lac:luxCDABE, and E. coli recA:luxCDABE strains. Analysis of reactive oxygen species (ROS) generation within E. coli cells highlighted oxidative stress as a contributing factor to the toxicity and genotoxicity of VA and its isomers. While the findings suggest potential applications of VA compounds as food preservatives, their presence in the environment raises concerns regarding the risks posed to living organisms due to their toxic and genotoxic characteristics.

Unleashing the potential of vanillic acid: A new twist on nature's recipe to fight inflammation and circumvent azole-resistant fungal infections.

Vanillic acid (VA) - a naturally occurring phenolic compound in plants - is not only used as a flavoring agent but also a prominent metabolite post tea consumption. VA and its associated compounds are believed to play a significant role in preventing diseases, underscoring the need for a systematic investigation. Herein, we report a 4-step synthesis employing the classical organic reactions, such as Willamson's alkylation, Fischer-Spier reaction, and Steglich esterification, complemented with a protection-deprotection strategy to prepare 46 VA derivatives across the five series (1a-1i, 2a-2i, 3, 3a-3i, 4a-4i, 5a-5i) in high yields. The synthesized compounds were investigated for their antifungal, anti-inflammatory, and toxic effects. Notably, compound 1a demonstrated remarkable ROS inhibition with an IC50 value of 5.1 ± 0.7 µg/mL, which is more than twice as effective as the standard ibuprofen drug. A subset of the synthesized derivatives (2b, 2c, 2e, 3b-3d, 4a-4c, 5a, and 5e) manifested their antifungal effect against drug-resistant Candida strains. Compound 5g, in particular, revealed synergism with the established antifungal drugs amphotericin B (AMB) and fluconazole (FLZ), doubling FLZ's potency against azole resistant Candida albican ATCC 36082. Furthermore, 5g improved the potency of these antifungals against FLZ-sensitive strains, including C. glabrata ATCC 2001 and C. parapsilosis ATCC 22019, as well as various multidrug-resistant (MDR) Candida strains, namely C. albicans ATCC 14053, C. albicans CL1, and C. krusei SH2L OM341600. Additionally, pharmacodynamics of compound 5g was examined using time-kill assay, and a benign safety profile was observed with no hemolytic activity in whole blood, and no cytotoxicity towards the normal BJ human cell line. The synergistic potential of 5g was further investigated through both experimental methods and docking simulations.These findings highlight the therapeutic potential of VA derivatives, particularly in addressing inflammation and circumventing FLZ resistance in Candida albicans.

Engineering the activity and thermostability of a carboxylic acid reductase in the conversion of vanillic acid to vanillin.

Vanillin is a valuable natural product that can be used as a fragrance and additive. Recent research in the biosynthesis of vanillin has brought attention to a key enzyme, carboxylic acid reductase (CAR), which catalyzes the reduction of vanillic acid to vanillin. Nevertheless, the biosynthesis of vanillin is hampered by the low activity and stability of CAR. As such, a rational design campaign was conducted on a well-documented carboxylic acid reductase from Segniliparus rugosus (SrCAR), using vanillic acid as the model substrate. After combined active site saturation and iterative site-specific mutagenesis, the best quadruple mutant N292H/K524S/A627L/E1121W (M3) was successfully obtained. In comparison to the wildtype SrCAR, M3 demonstrated a 4.2-fold increase in catalytic efficiency (kcat/Km), and its half-life (t1/2) was enhanced by 3.8 times up to 385.08 minutes at 40 °C. In silico docking and molecular dynamics simulation provided insights into the improved activity and stability. In the subsequent preparative-scale reaction with 100 mM (16.8 g L-1) vanillic acid, the whole cell catalysis utilizing M3 produced 10.15 g·L-1 of vanillin and 1.11 g·L-1 of vanillyl alcohol, respectively. This work demonstrates a dual improvement in the activity and thermal stability of SrCAR, thereby potentially facilitating the application of carboxylic acid reductase in the biosynthesis of vanillin.

Vanillic acid restores homeostasis of intestinal epithelium in colitis through inhibiting CA9/STIM1-mediated ferroptosis.

The damage of integrated epithelial epithelium is a key pathogenic factor and closely associated with the recurrence of ulcerative colitis (UC). Here, we reported that vanillic acid (VA) exerted potent therapeutic effects on DSS-induced colitis by restoring intestinal epithelium homeostasis via the inhibition of ferroptosis. By the CETSA assay and DARTS assay, we identified carbonic anhydrase IX (CAIX, CA9) as the direct target of VA. The binding of VA to CA9 causes insulin-induced gene-2 (INSIG2) to interact with stromal interaction molecule 1 (STIM1), rather than SREBP cleavage-activating protein (SCAP), leading to the translocation of SCAP-SREBP1 from the endoplasmic reticulum (ER) to the Golgi apparatus for cleavage into mature SREBP1. The activation of SREBP1 induced by VA then significantly facilitated the transcription of stearoyl-CoA desaturase 1 (SCD1) to exert an inhibitory effect on ferroptosis. By inhibiting the excessive death of intestinal epithelial cells caused by ferroptosis, VA effectively preserved the integrity of intestinal barrier and prevented the progression of unresolved inflammation. In conclusion, our study demonstrated that VA could alleviate colitis by restoring intestinal epithelium homeostasis through CA9/STIM1-mediated inhibition of ferroptosis, providing a promising therapeutic candidate for UC.

Biotransformation of maize bran-derived ferulic acid to vanillin using an adapted strain of Amycolatopsis sp. ATCC 39116.

Maize bran, an agro-processing waste residue, is a good source of ferulic acid that can be further valorized for vanillin production. However, extraction of ferulic acid from natural sources has been challenging due to low concentrations and intensive extraction procedures. In the present work, ferulic acid streams (purities ranging from 5% to 75%) extracted from maize bran using thermochemical methods were evaluated for biotransformation to vanillin, employing Amycolatopsis sp. as a whole-cell biocatalyst. Initial adaptation studies were critical in improving ferulic acid assimilation and its conversion to vanillin by 65% and 56%, respectively by the fourth adaptation cycle. The effect of cell's physiological states and vanillic acid supplementation on vanillin production was studied using standard ferulic acid as a substrate in an effort to achieve further improvement in vanillin yield. In the presence of vanillic acid, 18 h cultured cells using 2 g/L of standard and isolated ferulic acid produced vanillin concentrations of up to 0.71 and 0.48 g/L, respectively. Furthermore, intermediates involved in the ferulic acid catabolic pathway and their interrelations were studied using GC-MS analysis. Results indicated that two different routes were involved in the catabolism of standard ferulic acid, and similar metabolic routes were observed for an isolated ferulic acid stream. These findings effectively evaluated isolated ferulic acid for sustainable vanillin production while reducing agro-industrial waste pollution.

Metabolic Engineering of Pseudomonas putida KT2440 for De Novo Biosynthesis of Vanillic Acid.

Vanillic acid (VA), as a plant-derived phenolic acid compound, has widespread applications and good market prospects. However, the traditional production process cannot meet market demand. In this study, Pseudomonas putida KT2440 was used for de novo biosynthesis of VA. Multiple metabolic engineering strategies were applied to construct these P. putida-based cell factories, including the introduction of a Hs-OMTopt, engineering the cofactor S-adenosylmethionine supply pathway through the overexpression of metX and metH, reforming solubility of Hs-OMTopt, increasing a second copy of Hs-OMTopt, and the optimization of the fermentation medium. The resulting strain, XCS17, de novo biosynthesized 5.4 g/L VA from glucose in a fed-batch fermentation system; this is the highest VA production titer reported up to recently. This study showed that P. putida KT2440 is a robust platform for achieving the effective production of phenolic acids.

The metabolite vanillic acid regulates Acinetobacter baumannii surface attachment.

The nosocomial bacterium Acinetobacter baumannii is protected from antibiotic treatment by acquiring antibiotic resistances and by forming biofilms. Cell attachment, one of the first steps in biofilm formation, is normally induced by environmental metabolites. We hypothesized that vanillic acid (VA), the oxidized form of vanillin and a widely available metabolite, may play a role in A. baumannii cell attachment. We first discovered that A. baumannii actively breaks down VA through the evolutionarily conserved vanABKP genes. These genes are under the control of the repressor VanR, which we show binds directly to VanR binding sites within the vanABKP genes bidirectional promoter. VA in turn counteracts VanR inhibition. We identified a VanR binding site and searched for it throughout the genome, especially in pili encoding promoter genes. We found a VanR binding site in the pilus encoding csu operon promoter and showed that VanR binds specifically to it. As expected, a strain lacking VanR overproduces Csu pili and makes robust biofilms. Our study uncovers the role that VA plays in facilitating the attachment of A. baumannii cells to surfaces, a crucial step in biofilm formation. These findings provide valuable insights into a previously obscure catabolic pathway with significant clinical implications.

Aflatoxin Decontamination in Maize Steep Liquor Obtained from Bioethanol Production Using Laccases from Species within the Basidiomycota Phylum.

Maize (Zea mays L.) is an important crop in Argentina. Aspergillus section Flavi can infect this crop at the pre-harvest stage, and the harvested grains can be contaminated with aflatoxins (AFs). During the production of bioethanol from maize, AF levels can increase up to three times in the final co-products, known as, dry and wet distiller's grain with solubles (DDGS and WDGS), intended for animal feed. Fungal enzymes like laccases can be a useful tool for reducing AF contamination in the co-products obtained from this process. The aim of the present study was to evaluate the ability of laccase enzymes included in enzymatic extracts (EE) produced by different species in the Basidiomycota phylum to reduce AF (AFB1 and AFB2) accumulation under the conditions of in vitro assays. Four laccase activities (5, 10, 15, and 20 U/mL) exerted by nine isolates were evaluated in the absence and presence of vanillic acid (VA), serving as a laccase redox mediator for the degradation of total AFs. The enzymatic stability in maize steep liquor (MSL) was confirmed after a 60 h incubation period. The most effective EE in terms of reducing AF content in the buffer was selected for an additional assay carried out under the same conditions using maize steep liquor obtained after the saccharification stage during the bioethanol production process. The highest degradation percentages were observed at 20 U/mL of laccase enzymatic activity and 1 mM of VA, corresponding to 26% for AFB1 and 26.6% for AFB2. The present study provides valuable data for the development of an efficient tool based on fungal laccases for preventing AF accumulation in the co-products of bioethanol produced from maize used for animal feed.

Underlying mechanisms behind the neuroprotective effect of vanillic acid against diabetes-associated cognitive decline: An in vivo study in a rat model.

Hippocampal synaptic dysfunction, oxidative stress, neuroinflammation, and neuronal loss play critical roles in the pathophysiology of diabetes-associated cognitive decline (DACD). The study aimed to investigate the effects of vanillic acid (VA), a phenolic compound, against DACD and explore the potential underlying mechanisms. Following confirmation of diabetes, rats were treated with VA (50 mg/kg/day; P.O.) or insulin (6 IU/rat/day; S.C.) for 8 consecutive weeks. The cognitive performance of the rats was evaluated using passive-avoidance and water-maze tasks. Long-term potentiation (LTP) was induced at hippocampal dentate gyrus (DG) synapses in response to high-frequency stimulation (HFS) applied to the perforant pathway (PP) to evaluate synaptic plasticity. Oxidative stress factors, inflammatory markers, and histological changes were evaluated in the rat hippocampus. This study showed that streptozotocin (STZ)-induced diabetes caused cognitive decline that was associated with inhibition of LTP induction, suppression of enzymatic antioxidant activities, enhanced lipid peroxidation, elevated levels of inflammatory proteins, and neuronal loss. Interestingly, chronic treatment with VA alleviated blood glucose levels, improved cognitive decline, ameliorated LTP impairment, modulated oxidative-antioxidative status, inhibited inflammatory response, and prevented neuronal loss in diabetic rats at a level comparable to insulin therapy. The results suggest that the antihyperglycemic, antioxidative, anti-inflammatory, and neuroplastic properties of VA may be the mechanisms behind its neuroprotective effect against DACD.

Basidiomycota strains as whole-cell biocatalysts for the synthesis of high-value natural benzaldehydes.

Substituted benzaldehydes are the most commonly used natural-occurring flavours in the world. The consumer's preference for 'natural or organic' aromas has increased the request for flavours possessing the 'natural' status. The resulting shortage of aromatic aldehydes of extractive origin, such as vanillin, veratraldehyde and piperonal, can be offset by developing a new biotechnological synthesis method. Here, we report a study on the microbiological reduction of five natural benzoic acid derivatives, namely p-anisic, vanillic, veratric, piperonylic and eudesmic acids, to produce the corresponding fragrant aldehydes. We found that different Basidiomycota strains can efficiently perform this transformation, with good chemical selectivity and tolerance to the toxicity of substrates and products. Besides confirming the carboxylic acid reductase activity of the already studied fungi Pycnoporus cinnabarinus, we discovered that other species such as Pleurotus eryngii, Pleurotus sapidus and Laetiporus sulphureus as well as the non-ligninolytic fungi Lepista nuda are valuable microorganisms for the synthesis of anisaldehyde, vanillin, veratraldehyde, piperonal and 3,4,5-trimethoxybenzaldehyde from the corresponding acids. According to our findings, we propose a reliable process for the preparation of the above-mentioned aldehydes, in natural form. KEY POINTS: • Fragrant benzaldehydes were obtained by biotransformation. • Basidiomycota strains reduced substituted benzoic acid to the corresponding aldehydes. • Anisaldehyde, vanillin, veratraldehyde, piperonal and 3,4,5-trimethoxybenzaldehyde were prepared in natural form.

Unveiling the effect of molecular weight of vanillic acid grafted chitosan hydrogel films on physical, antioxidant, and antimicrobial properties for application in food packaging.

Till now, a wide range of chitosan (CHS)-based food packaging films have been developed. Yet, the role of molecular weight (MW), which is an important physical property of CHS, in determining the physicochemical and biochemical properties of vanillic acid (VA)-grafted CHS hydrogel films synthesized using CHS with different MWs has not been investigated until now. Three kinds of CHS including low, medium, and high MWs were grafted separately with VA through a carbodiimide mediated coupling reaction. No significant difference in water resistance properties was observed with increasing MW of CHS, in contrast to obvious decrease in light transmittance and opacity. The VA-g-CHS hydrogel films exhibited significantly improved light blocking capacity. A significant improvement in antioxidant (~6-fold) and antimicrobial (~1.2-fold) activity was observed after grafting with VA. In contrast, the free radical scavenging and antimicrobial activity decreased with increasing MW of CHS. Most importantly, VA-g-CHS hydrogel films could maintain the freshness of cherry tomatoes for up to 10 days at ~25 °C. However, no significant difference was observed depending on the MW value of CHS. This pioneering work is of great importance in guiding the selection of MW of CHS biomacromolecule to design hydrogel films with desired physicochemical and biochemical properties.