Production of salicylic acid; a potent pharmaceutically active agent and its future prospects

Study on the acoustic emission frequency of salicylic acid crystal growth based on beam vibration

This study aims to investigate the relationship between the grain size of salicylic acid crystals and the frequency of acoustic emission signalsduring the crystallization of salicylic acid. During the crystallization process of salicylic acid, an acoustic emission system was utilized to monitor the emitted sound signals. Based on the beam vibration theory, a lateral vibration model of the crystals was constructed to study the correlation between acoustic emission signals and crystal grain size. This process occurs with one end of the crystal acting as a fixed end and the other as a free end. The study found that when the crystal grain size is between 100-300 µm, the characteristic frequency of the crystal is 115-344 kHz. Finite element analysis software was also employed to calculate the characteristic frequency of the crystal grain size, and the simulation results were highly consistent with the experimental data.

Chloroplast Functionality at the Interface of Growth, Defense, and Genetic Innovation: A Multi-Omics and Technological Perspective

Chloroplasts are important in plant growth, development, and defense mechanisms, making them central to addressing global agricultural challenges. This review explores the multi-faceted contributions of chloroplasts, including photosynthesis, hormone biosynthesis, and stress signaling, which orchestrate the trade-off between growth and defense. Advancements in chloroplast genomics, transcription, translation, and proteomics have deepened our understanding of their regulatory functions and interactions with nuclear-encoded proteins. Case studies have demonstrated the potential of chloroplast-targeted strategies, such as the expression of elongation factor EF-2 for heat tolerance and flavodiiron proteins for drought resilience, to enhance crop productivity and stress adaptation. Future research directions should focus on the need for integrating omics data with nanotechnology and synthetic biology to develop sustainable and resilient agricultural systems. This review uniquely integrates recent advancements in chloroplast genomics, transcriptional regulation, and synthetic biology to present a holistic perspective on optimizing plant growth and stress tolerance. We emphasize the role of chloroplast-driven trade-off in balancing growth and immunity, leveraging omics technologies and emerging biotechnological innovations. This comprehensive approach offers new insights into sustainable agricultural practices, making it a significant contribution to the field.

Sewage sludge valorization via phytohormones production: Parameter regulation and process evaluation

Sludge treatment is of great significance for environmental protection and sustainable development. Existing treatment technologies fall short in terms of carbon emissions, process efficiency, and resource recovery. This study focuses on alkaline hydrothermal treatment, proposing a short-cycle, low-energy, high-value management process for sludge valorization. Here, we investigate the impact of treatment duration, temperature, and solid content on the synthesis of high-value products and their effects on both solid and liquid phases. Based on the comprehensive results, 2 h, 160 °C, and 14 % solid content can be regarded as the optimized treatment condition. The resulting products, including phytohormones, humic substances, and essential nutrients (C, N, P and K), exhibit substantial potential for high-value agricultural utilization. In the unconcentrated solution, a single phytohormone can reach a concentration of 104 μg/L. Heavy metal content is well below standard limits, simultaneously achieving biological stability, and the volume can be reduced to 60 %. This process is 42.12 times more energy-efficient than conventional anaerobic digestion. This novel approach promotes waste resource recycling and sustainable urban management.

Controlled Release of Hydrophilic Drug from Hollow Nanodots

Here the challenge of limited encapsulation efficiency of ionizable hydrophilic molecules in silica materials is addressed. Two effective strategies are showcased that allow high encapsulation efficiency of salicylic acid, while simultaneously maintaining the morphology and particle size of silica nanocapsules. These promising approaches involve the formation and encapsulation of a prodrug or the complexation of the hydrophilic payload with a hydrophobic moiety to form a complex that is dissociated in acidic conditions. Well-defined core-shell silica nanocapsules with a diameter of 6 nm are obtained and exhibited an encapsulation efficiency of over 90%. High amounts of salicylic acid are released in acidic conditions from silica nanocapsules entrapping the prodrug or the complex, leading to pH-responsive characteristics. This work demonstrates promising strategies for the encapsulation and the controlled release of hydrophilic fertilizers, pesticides or drugs.

Intermediates of Hydrogen Peroxide-Assisted Photooxidation of Salicylic Acid: Their Degradation Rates and Ecotoxicological Assessment

Accelerated photooxidation of salicylic acid (SA) was performed using UV radiation and hydrogen peroxide. HPLC-MS analysis showed that the primary intermediates are 2,5-dihydroxybenzoic acid, 2,3-dihydroxybenzoic acid, pyrocatechol, and phenol. Deeper oxidation leads to low molecular weight aliphatic acids, such as maleic, fumaric, and glyoxylic. The photooxidation of the main intermediates was carried out in the same conditions. The degradation of SA and its main intermediates follows first-order reaction kinetics. In the case of UV irradiation alone, photodegradation of 2,5-dihydroxybenzoic acid is slightly faster (reaction rate constant is 0.007 min-1) compared to SA (0.0052 min-1). Other products degrade more slowly than SA. Hydrogen peroxide, in concentrations of 1.8-8.8 mM, accelerates the photodegradation of salicylic acid and intermediate products. An ecotoxicological evaluation of SA and the main products was performed using the EPI SuiteTM software. The overall persistence (POV) and long-range transport potential (LRTP) of all transformation products were assessed using OECD POV and the LRTP screening tool. Salicylic acid and its transformation products have low toxicity. Due to their high solubility, these contaminants can travel considerable distances in the aquatic environment. SA and phenol have LRTP values of 156-190 km. Other products can travel shorter distances (less than 100 km).

Rational and Semirational Approaches for Engineering Salicylate Production in Escherichia coli

Salicylate plays a pivotal role as a pharmaceutical intermediate in drugs, such as aspirin and lamivudine. The low catalytic efficiency of key enzymes and the inherent toxicity of salicylates to cells pose significant challenges to large-scale microbial production. In this study, we introduced the salicylate synthase Irp9 into an l-phenylalanine-producing Escherichia coli, constructing the shortest salicylate biosynthetic pathway. Subsequent protein engineering increased the catalytic efficiency of Irp9 by 33.5%. Furthermore, by integrating adaptive evolution with transcriptome analysis, we elucidated the crucial mechanism of efflux proteins in salicylate tolerance. The elucidation of this mechanism guided us in the targeted modification of these transport proteins, achieving a reported maximum level of 3.72 g/L of salicylate in a shake flask. This study highlights the importance of efflux proteins for enhancing the productivity of microbial cell factories in salicylate production, which also holds potential for application in the green synthesis of other phenolic acids.

Air quality of health facilities in Spain

The present study examines indoor air pollution in health facilities, focusing on compounds from various sources, such as industrial products, healthcare activities and building materials. It assesses chemical and microbiological concentrations in two public hospitals, two public healthcare centres, and one public health laboratory in Spain. Measurements included indoor air quality, microbiological contaminants, ambient parameters and non-target analysis across ten different locations. Outdoor air quality was also assessed in the surroundings of the hospitals. The results showed that around 350 substances were tentatively identified at a high confidence level, with over 50 % of compounds classified as of high toxicological risk. Three indoor and 26 outdoor compounds were fully confirmed with standards. These confirmed substances were linked to medical, industrial and agricultural activities. Indoor Air Quality (IAQ) results revealed that CO, CO2, formaldehyde (HCHO), O3 and total volatile organic compounds (TVOCs) showed average values above the recommended guideline levels in at least one of the evaluated locations. Moreover, maximum concentrations detected for CO, HCHO, O3 and TVOCs in hospitals surpassed those previously reported in the literature. SARS-CoV-2 was detected in three air environments, corresponding to COVID-19 patient areas. Fungi and bacteria concentrations were acceptable in all assessed locations, identifying different fungi genera, such as Penicillium, Cladosporium, Aspergillus, Alternaria and Botrytis.

Anti-Oomycete Effect and Mechanism of Salicylic Acid on Phytophthora infestans

Pathogenic oomycetes infect a wide variety of organisms, including plants, animals, and humans, and cause massive economic losses in global agriculture, aquaculture, and human health. Salicylic acid (SA), an endogenous phytohormone, is regarded as an inducer of plant immunity. Here, the potato late blight pathogen Phytophthora infestans was used as a model system to uncover the inhibitory mechanisms of SA on pathogenic oomycetes. In this research, SA significantly inhibited the mycelial growth, sporulation, sporangium germination, and virulence of P. infestans. Inhibition was closely related to enhanced autophagy, suppression of translation initiation, and ribosomal biogenesis in P. infestans, as shown by multiomics analysis (transcriptomics, proteomics, and phosphorylated proteomics). Monodansylcadaverine (MDC) staining and Western blotting analysis showed that SA promoted autophagy in P. infestans by probably targeting the TOR signaling pathway. These observations suggest that SA has the potential to control late blight caused by P. infestans.

Antioxidant and DNA-Protective Potentials, Main Phenolic Compounds, and Microscopic Features of Koelreuteria paniculata Aerial Parts

Interest in plant extracts as a natural source of antioxidants has grown significantly in recent years. The tree species Koelreuteria paniculata deserves attention due to its wide distribution, good adaptability, and growth to the degree of invasiveness in a number of European countries. The purpose of the present study was to analyze flavonoids and phenolic acids of the ethanol extracts from aerial parts of K. paniculata and to screen their antioxidant and DNA-protective activity. HPLC profiling revealed the presence of five flavonoids, with rutin (4.23 mg/g DW), hesperidin (2.97 mg/g DW), and quercetin (2.66 mg/g DW) as the major ones in the leaves, and (−)-epicatechin (2.69 mg/g DW) in the flower buds. Among the nine phenolic acids identified, rosmarinic, p-coumaric, salicylic, vanillic, and gallic acids were the best represented. All the extracts tested showed in vitro antioxidant activity that was determined by DPPH, ABTS, FRAP, and CUPRAC assays. The highest activity was recorded in the flower parts (in the range from 1133 to 4308 mmol TE/g DW). The DNA-protective capacity of the flower and stem bark extracts from the in vitro nicking assay performed, as well as the main diagnostic microscopic features of the plant substances, are given for the first time. According to the results obtained, the aerial parts of K. paniculata could be valuable sources of natural antioxidants.

Enantiotropic inconstancy, crystalline solid solutions and co-crystal in the salicylic acid–anthranilic acid system

T–X phase diagram of salicylic acid–anthranilic acid with three crystalline solid solution phases and a co-crystal, resulting in variable enantiotropic transition temperature and a polymorphic co-existence domain.