Antimicrobial and antibiofilm properties of selenium-chitosan-loaded salicylic acid nanoparticles for the removal of emerging contaminants from bacterial pathogens.

In this study salicylic acid loaded containing selenium nanoparticles was synthesized and called SA@CS-Se NPs. the chitosan was used as a natural stabilizer during the synthesis process. Fourier transforms infrared spectroscopy (FTIR), Powder X-ray diffraction (XRD), field emission electron microscopy (FESEM), and transmission electron microscopy (TEM) were used to describe the physicochemical characteristics of the SA@CS-Se NPs. The PXRD examination revealed that the grain size was around 31.9 nm. TEM and FESEM techniques showed the spherical shape of SA@CS-Se NPs. Additionally, the analysis of experiments showed that SA@CS-Se NPs have antibacterial properties against 4 ATCC bacteria; So that with concentrations of 75, 125, 150, and 100 µg/ml, it inhibited the biofilm formation of Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Staphylococcus aureus respectively. Also, at the concentration of 300 µg/ml, it removed 22.76, 23.2, 10.62, and 18.08% biofilm caused by E. coli, P. aeruginosa, B. subtilis, and S. aureus respectively. The synthesized SA@CS-Se NPs may find an application to reduce the unsafe influence of pathogenic microbes and, hence, eliminate microbial contamination.

Salicylic acid in plant immunity and beyond.

As the most widely used herbal medicine in human history and a major defence hormone in plants against a broad spectrum of pathogens and abiotic stresses, salicylic acid (SA) has attracted major research interest. With applications of modern technologies over the past 30 years, studies of the effects of SA on plant growth, development, and defence have revealed many new research frontiers and continue to deliver surprises. In this review, we provide an update on recent advances in our understanding of SA metabolism, perception, and signal transduction mechanisms in plant immunity. An overarching theme emerges that SA executes its many functions through intricate regulation at multiple steps: SA biosynthesis is regulated both locally and systemically, while its perception occurs through multiple cellular targets, including metabolic enzymes, redox regulators, transcription cofactors, and, most recently, an RNA-binding protein. Moreover, SA orchestrates a complex series of post-translational modifications of downstream signaling components and promotes the formation of biomolecular condensates that function as cellular signalling hubs. SA also impacts wider cellular functions through crosstalk with other plant hormones. Looking into the future, we propose new areas for exploration of SA functions, which will undoubtedly uncover more surprises for many years to come.

Biochemical Pathways of Salicylic Acid Derived from l-Phenylalanine in Plants with Different Basal SA Levels.

As a plant hormone, salicylic acid (SA) has diverse regulatory roles in plant growth and stress resistance. Although SA is widely found in plants, there is substantial variation in basal SA among species. Tea plant is an economically important crop containing high contents of SA whose synthesis pathway remains unidentified. The phenylalanine ammonia-lyase (PAL) pathway is responsible for basal SA synthesis in plants. In this study, isotopic tracing and enzymatic assay experiments were used to verify the SA synthesis pathway in tea plants and evaluate the variation in phenylalanine-derived SA formation among 11 plant species with different levels of SA. The results indicated that SA could be synthesized via PAL in tea plants and conversion efficiency from benzoic acid to SA might account for variation in basal SA among plant species. This research lays the foundation for an improved understanding of the molecular regulatory mechanism for SA biosynthesis.

Comparative analyses reveal a phenylalanine ammonia lyase dependent and salicylic acid mediated host resistance in Zingiber zerumbet against the necrotrophic soft rot pathogen Pythium myriotylum.

Little is known about the molecular basis of host defense in resistant wild species Zingiber zerumbet (L.) Smith against the soil-borne, necrotrophic oomycete pathogen Pythium myriotylum Drechsler, which causes the devastating soft rot disease in the spice crop ginger (Zingiber officinale Roscoe). We investigated the pattern of host defense between Z. zerumbet and ginger in response to P. myriotylum inoculation. Analysis of gene expression microarray data revealed enrichment of phenylpropanoid biosynthetic genes, particularly lignin biosynthesis genes, in pathogen-inoculated Z. zerumbet compared to ginger. RT-qPCR analysis showed the robust activation of phenylpropanoid biosynthesis genes in Z. zerumbet, including the core genes PAL, C4H, 4CL, and the monolignol biosynthesis and polymerization genes such as CCR, CAD, C3H, CCoAOMT, F5H, COMT, and LAC. Additionally, Z. zerumbet exhibited the accumulation of the phenolic acids including p-coumaric acid, sinapic acid, and ferulic acid that are characteristic of the cell walls of commelinoid monocots like Zingiberaceae and are involved in cell wall strengthening by cross linking with lignin. Z. zerumbet also had higher total lignin and total phenolics content compared to pathogen-inoculated ginger. Phloroglucinol staining revealed the enhanced fortification of cell walls in Z. zerumbet, specifically in xylem vessels and surrounding cells. The trypan blue staining indicated inhibition of pathogen growth in Z. zerumbet at the first leaf whorl, while ginger showed complete colonization of the pith within 36 h post inoculation (hpi). Accumulation of salicylic acid (SA) and induction of SA regulator NPR1 and the signaling marker PR1 were observed in Z. zerumbet. Silencing of PAL in Z. zerumbet through VIGS suppressed downstream genes, leading to reduced phenylpropanoid accumulation and SA level, resulting in the susceptibility of plants to P. myriotylum. These findings highlight the essential role of PAL-dependent mechanisms in resistance against P. myriotylum in Z. zerumbet. Moreover, our results suggest an unconventional role for SA in mediating host resistance against a necrotroph. Targeting the phenylpropanoid pathway could be a promising strategy for the effective management of P. myriotylum in ginger.

Are antibiotics still relevant in acne? A review of the therapeutic conundrum.

Antibiotics have constituted the mainstay of acne therapy despite acne being classified as an inflammatory disorder. The indiscriminate usage of antibiotics over the years has thus fueled the issue of antimicrobial resistance. Cutibacterium acnes (C. acnes) can acquire resistance due to chromosomal mutation or genetic acquisition. C. acnes can transfer resistance to other resident flora, complicating the management of skin and soft tissue infections. It can also transfer resistant strains to other body sites and to immunocompromised and elderly patients thus putting them at risk of serious infections. Recent studies have highlighted the physiologic role of C. acnes in maintaining the normal homeostasis of the skin microbiome. The role of Malassezia in causation of acne has piqued interest in recent times. The efficacy of antibiotics in acne is attributed to their para-antibiotic, anti-inflammatory action rather than antimicrobial action. Thus, usage of low-dose antibiotics and alternatives to antibiotics has been advocated. Some alternative therapies showing efficacy in acne are probiotics, oral zinc, precision therapy using succinic acid, bacteriophages, and anti-biofilm therapy like myrtacin, topical azelaic acid, and salicylic acid. Using isotretinoin in early stages of acne can reduce the incidence of scarring and alleviate the need for antibiotics. Thus, a gradual shift from antibiotics to alternative therapies in acne is the need of the hour.

Synthesis of salicylic acid from wintergreen oil by green chemistry overcomes its cytotoxicity in keratinocyte cells and teratogenicity in zebrafish embryos.

Salicylic acid topical is used to treat variety of skin conditions. However, salicylic acid in these products is generated through industrial synthesis and has been shown to negatively impact fetal development and cause congenital abnormalities. We hypothesized that teratogenic effects reported in salicylic acid can be prevented by naturally synthesizing salicylic acid from wintergreen oil using green chemistry method. For this purpose, we investigated the effects of natural salicylic acid (NSA) synthesized from wintergreen oil using green chemistry and synthetic salicylic acid (SSA) on keratinocyte cell (HaCaT) proliferation and zebrafish embryo development. NSA structures were analyzed by 1H NMR, 13C NMR, and GC/MS methods. Percentage inhibition against HaCaT cell was determined by MTS assay. xCelligence system was used for cellular activities. Zebrafish embryos were exposed to NSA and SSA for 72 h post-fertilization. Lipid peroxidation, nitric oxide, sialic acid, glutathione-S-transferase, catalase, and superoxide dismutase were evaluated using biochemical methods. Expressions of nqO1, gfap, bdnf, vtg, egr, cyp1a, and igf2 were determined by RT-PCR as developmental indicators. MTS and RT-cell analysis showed increased cell viability by NSA, whereas SSA decreased cell viability. NSA beneficially affected zebrafish embryo development while SSA exerted deleterious effects through oxidant-antioxidant status, inflammation, and development. Results of our study showed for the first time that synthesis of salicylic acid from wintergreen oil by green chemistry overcomes its cytotoxicity in keratinocyte cells and teratogenicity in zebrafish embryos. This finding is important for drug research on safe topical applications during pregnancy, when preventing exposure to drug and chemical-derived teratogens is vital.

Topical Silymarin Cream as a Novel Therapy Versus Salicylic Acid Peels in Acne Vulgaris: A Split-Face Clinical Trial.

BACKGROUND: Acne vulgaris is a common dermatological condition that greatly impacts patients' self-confidence. Ongoing research is conducted to explore new treatment modalities. Silymarin owns special characteristics that qualify it as a possible treatment for acne vulgaris. OBJECTIVE: We evaluated the efficacy and safety of silymarin cream as a new therapeutic option against salicylic acid peels in the treatment of mild to moderate acne vulgaris. METHODS: A split-face, comparative, Quasi-experimental clinical trial included 30 patients with acne vulgaris. Salicylic acid 30% peels were applied as an office procedure to one half of the face every 2 weeks for 3 months. Topical silymarin 1.4% cream was prescribed as a home treatment, twice daily, to the other half of the face for 3 months. The results were evaluated using the Global Acne Grading System (GAGS), photographic evaluation, and patient self-assessment scale. The adverse effects during treatment were recorded. The sample size was calculated by Stata/IC 16.1. RESULTS: After treatment, a significant reduction of GAGS was noted on both sides of the face, with an insignificant difference between both treatments. The comparative photographic evaluation and patient self-assessment scale were also insignificant. Hyperpigmentation was recorded in 2 cases on the salicylic acid-treated side. No side effects for silymarin cream were observed. CONCLUSION: Topical silymarin cream 1.4% showed comparable results to Salicylic acid 30% peels. It can be considered a promising safe treatment modality for mild to moderate acne vulgaris.

2,4-Dihydroxybenzoic Acid, a Novel SA Derivative, Controls Plant Immunity via UGT95B17-Mediated Glucosylation: A Case Study in Camellia Sinensis.

The plant hormone salicylic acid (SA) plays critical roles in plant innate immunity. Several SA derivatives and associated modification are identified, whereas the range and modes of action of SA-related metabolites remain elusive. Here, the study discovered 2,4-dihydroxybenzoic acid (2,4-DHBA) and its glycosylated form as native SA derivatives in plants whose accumulation is largely induced by SA application and Ps. camelliae-sinensis (Pcs) infection. CsSH1, a 4/5-hydroxylase, catalyzes the hydroxylation of SA to 2,4-DHBA, and UDP-glucosyltransferase UGT95B17 catalyzes the formation of 2,4-DHBA glucoside. Down-regulation reduced the accumulation of 2,4-DHBA glucosides and enhanced the sensitivity of tea plants to Pcs. Conversely, overexpression of UGT95B17 increased plant disease resistance. The exogenous application of 2,4-DHBA and 2,5-DHBA, as well as the accumulation of DHBA and plant resistance comparison, indicate that 2,4-DHBA functions as a potentially bioactive molecule and is stored mainly as a glucose conjugate in tea plants, differs from the mechanism described in Arabidopsis. When 2,4-DHBA is applied exogenously, UGT95B17-silenced tea plants accumulated more 2,4-DHBA than SA and showed induced resistance to Pcs infection. These results indicate that 2,4-DHBA glucosylation positively regulates disease resistance and highlight the role of 2,4-DHBA as potentially bioactive molecule in the establishment of basal resistance in tea plants.

Exogenous salicylic acid induces defense responses in tea plants against Toxoptera aurantii (Hemiptera: Aphididae).

Toxoptera aurantii is one of the most destructive pests, threatening the yield and quality of tea plantations. The salicylic acid (SA)-mediated signaling pathway is vital for the induction of plant defense responses; however, its role in tea plant resistance to T. aurantii remains unclear. Thus, this study used and electrical penetration graph and monitoring of population dynamics to evaluate the effects of exogenous SA application on T. aurantii feeding behavior and population growth in tea seedlings. Moreover, the effects of SA treatment on the activities of defense-related enzymes were analyzed. Probe counts and the duration of xylem sap ingestion were significantly higher in SA-treated plants than those in the control group. The total duration of passive phloem ingestion was significantly decreased in 0.5 mmol/l SA-treated plants, and the application of 0.5, 1, and 4 mmol/l SA significantly inhibited T. aurantii population growth. In addition, the activities of polyphenol oxidase, peroxidase, and superoxide dismutase were significantly increased in the 0.5 mmol/l SA-treated plants. Overall, this study demonstrates the capacity of exogenous SA to activate defense responses against T. aurantii. These results have crucial implications for understanding the mechanisms of enhanced resistance, thereby providing a sustainable approach for managing T. aurantii.

Plantar warts successfully treated with bee venom: A case report.

BACKGROUND: Plantar warts, or verruca plantaris, are common cutaneous lesions of the plantar surface caused by the human papilloma virus (HPV) infection. Current treatments include salicylic acid, cryotherapy, bleomycin, and immunotherapy; however, they have limitations of low-cure rates or side effects. Plantar warts treated with bee venom (BV) have not been reported. Here we present a case of a patient who showed complete remission of multiple plantar warts after BV treatment. CASE PRESENTATION: A 13-year-old boy experienced total of 16 plantar warts and visited department of dermatology of Korean Medicine. BV was injected into wart sites. Warts were completely removed at the end of the 8-week treatment with no adverse event recorded. There was improvement during the follow-up after 4 weeks. CONCLUSION: This is the first case of plantar warts that improved with BV injection. This study suggests that BV may be a therapeutic option for individuals who cannot receive cryotherapy due to pain during and after treatment or who have refractory or relapsed warts.

Comparison of nocturnal and diurnal metabolomes of rose flowers and leaves.

INTRODUCTION: Roses are one of the most essential ornamental flowers and are commonly used in perfumery, cosmetics, and food. They are rich in bioactive compounds, which are of interest for therapeutic effects. OBJECTIVES: The objective of this study was to understand the kinds of changes that occur between the nocturnal and diurnal metabolism of rose and to suggest hypotheses. METHODS: Reversed-phase ultrahigh-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry or triple quadrupole mass spectrometry (TQ MS/MS) was used for nontargeted metabolomics and hormonal profiling respectively. For metabolite annotation, accurate mass spectra were compared with those in databases. RESULTS: The hormonal profile of flowers showed an increase in jasmonate at night, while that of leaves indicated an increase in the salicylic acid pathway. Nontargeted analyses of the flower revealed a switch in the plant's defense mechanisms from glycosylated metabolites during the day to acid metabolites at night. In leaves, a significant decrease in flavonoids was observed at night in favor of acid metabolism to maintain a level of protection. Moreover, it might be possible to place back some of the annotated molecules on the shikimate pathway. CONCLUSION: The influence of day and night on the metabolome of rose flowers and leaves has been clearly demonstrated. The hormonal modulations occurring during the night and at day are consistent with the plant circadian cycle. A proposed management of the sesquiterpenoid and triterpenoid biosynthetic pathway may explain these changes in the flower. In leaves, the metabolic differences may reflect night-time regulation in favor of the salicylic acid pathway.

[Chemical constituents from whole herb of Hedyotis scandens].

This study aimed to investigate the chemical constituents in the water extract of the whole herb of Hedyotis scandens by silica gel, ODS, and MCI column chromatographies together with preparative high-performance liquid chromatography(HPLC). The structures of isolated constituents were identified by NMR, HR-ESI-MS, etc. Thirteen compounds were isolated and identified as methyl 4-benzoyloxy-3-methoxybenzeneacetate(1), 4-benzoyloxy-3-methoxybenzeneacetic acid(2), 3-(4-hydroxy-3-methoxyphenyl)-propanoic acid(3), salicylic acid(4), 3-hydroxy-4-methoxypyridine(5), syringic acid(6), hydroxycinnamic acid(7),(R)-6-methyl-4,6-bis(4-methylpent-3-enyl)cyclohexa-1,3-dienecarbaldehyde(8), 1,2-bis(4-hydroxy-3-methoxyphenyl)-1,3-propanediol(9), 1H-indole-3-carboxaldehyde(10), isoscopoletin(11), syringaresinol(12), and pinoresinol(13). Among them, compounds 1 and 2 were new phenolic acid compounds, compounds 3-5, 8-11, and 13 were isolated from this genus for the first time, and compounds 6, 7, and 12 were obtained from H. scandens for the first time. The activity test showed that compounds 1 and 10 had a certain inhibitory effect on Mycobacterium smegmatis, with MIC_(50) values of 58.5 and 33.3 µg·mL~(-1), respectively.

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.

Deciphering morphological and biochemical responses of Salvia leriifolia to seed cold plasma treatment, priming, and foliar spraying with nano-salicylic acid.

The pretreatment of seeds with cold plasma (CP) (0 and 100 w for 240 s), and salicylic acid priming (SA) (0 and 2 mM normal and nano form), and foliar spraying of SA at the six-leaf stage (0 and 2 mM normal and nano form) of Salvia leriifolia plants in field condition was studied. Compared to the control plants of S. leriifolia, the results showed that CP + both forms of SA priming + nano-SA spraying increased plant height, leaf length, plant dry weight, total phenol, and the activities of phenylalanine ammonia-lyase (PAL) and tyrosine ammonia-lyase (TAL) enzymes. The chlorophyll a and b contents in all treated plants remained either unchanged or decreased when compared to the control. The highest PAL activity was obtained in CP-free + hydro-priming + nano-SA foliar spraying. The highest content of caffeic acid was achieved in CP + SA priming + SA foliar spraying in the leaf. The maximum contents of rosmarinic and salvianolic acid were obtained in the control plants. In conclusion, CP and nano-SA can increase PAL and TAL activity and total phenol accumulation in S. leriifolia plants, but not rosmarinic and salvianolic acid contents. Other phenolic compound enzymes and their production require further study.

Effect of foliar application of salicylic acid and mycorrhiza on quantitative and qualitative traits of maize.

An experiment was performed to investigate the effect of mycorrhizal symbiosis and foliar application of salicylic acid on quantitative and qualitative traits of maize during 2018 and 2019 in the research farm of Islamic Azad University, Chalous Branch. Split plot in a randomized complete block design with three replications was used. Experimental factors included mycorrhiza species of (G. mosseae), (G. geosporum) and (G. intraradices) at two levels (no consumption and consumption of mycorrhiza) and salicylic acid at two levels (no consumption and consumption of 1 mµ of salicylic acid). Results of interaction effects of mycorrhiza and salicylic acid on the measured traits revealed that the maximum 1000-grain weight, grain yield, biological yield, phosphorus, potassium, nitrogen percentage and yield of maize grain protein were observed in G. mosseae treatment under foliar application of salicylic acid. Foliar application of salicylic acid increases the root length and provides the necessary conditions for increasing water and nutrient uptake alongwith increase in photosynthesis and thus allocates more photosynthetic substance for development of reproductive organs. Hence, it increases maize grain weight and accordingly grain yield. In general, the results revealed that mycorrhiza and foliar application of salicylic acid increase growth indicators, yield and yield components. It also improved the quality traits of the maize plant. Based on results, the interaction effect of G. mosseae treatment and foliar application of salicylic acid yielded better results than other treatments. Mycorrhiza increases the number of grain in the ear, the number of rows in the ear, increases the plant's ability to absorb phosphorus, and the increase of mycorrhiza along with salicylic acid shows the maximum grain yield in maize. Finally, it can be concluded that the use of mycorrhiza and salicylic acid can be effective in increasing grain in the plant.

Panax notoginseng transcription factor WRKY15 modulates resistance to Fusarium solani by up-regulating osmotin-like protein expression and inducing JA/SA signaling pathways.

BACKGROUND: Panax notoginseng (Burk) F. H. Chen is a valuable traditional Chinese medicinal plant, but its commercial production is seriously affected by root rot caused by some pathogenic fungi, including Fusarium solani. Nevertheless, the genetic breeding for disease resistance of P. notoginseng remains limited. The WRKY transcription factors have been revealed to play important roles in plant defense responses, which might provide an inspiration for resistance improvement in P. notoginseng. RESULTS: In this study, the regulatory mechanism of transcription factor PnWRKY15 on P. notoginseng resistance to F. solani infection was revealed. The suppressed expression of PnWRKY15 via RNA interference increased the sensitivity of P. notoginseng to F. solani and decreased the expression levels of some defense-related genes, including PnOLP1, which encodes an osmotin-like protein that confers resistance to F. solani. Ectopic expression of PnWRKY15 in the model plant tobacco significantly enhanced the resistance to F. solani. Moreover, the transcriptome sequencing analysis discovered that some pathogenesis-related genes were expressed at higher levels in the PnWRKY15-overexpressing tobacco than that in the wild-type tobacco. In addition, the jasmonic acid (JA) and salicylic acid (SA) signaling pathways were evidently induced by PnWRKY15-overexpression, that was evidenced by that the JA and SA contents were significantly higher in the PnWRKY15-overexpressing tobacco than that in the wild-type. Furthermore, PnWRKY15, which was localized in the nucleus, can trans-activate and up-regulate PnOLP1 expression according to the EMSA, yeast one-hybrid and co-expression assays. CONCLUSIONS: PnWRKY15 contributes to P. notoginseng resistance to F. solani by up-regulating the expression of resistance-related gene PnOLP1 and activating JA/SA signaling pathways. These findings will help to further elucidate the transcriptional regulatory mechanism associated with the P. notoginseng defense response to F. solani.

Construction of tea tree oil/salicylic acid/palygorskite hybrids for advanced antibacterial and anti-inflammatory performance.

This study describes the construction of a tailor-made clay-based hybrid with advanced dermocompatibility, antibacterial and anti-inflammatory performance by incorporating tunable ratios of tea tree oil (TTO) and salicylic acid (SA) into the naturally occurring porous structure of palygorskite (Pal). Among the three TTO/SA/Pal (TSP) systems constructed, TSP-1 with a TTO : SA ratio of 1 : 3 demonstrated the lowest 3T3 NRU predicted acute oral toxicity and dermal HaCaT cytotoxicity as well as the most pronounced antibacterial activity with a selective inhibitory action against the pathogens (E. coli, P. acnes and S. aureus) over the beneficial (S. epdermidis) species inhabiting on the human skin. Also noticeable is that exposure of these skin commensal bacteria to TSP-1 prevented the antimicrobial resistance evolution compared to the conventional antibiotic ciprofloxacin. Mechanistic investigation of its antibacterial modes of action revealed a synergy between the TTO and SA loadings on the Pal supports in reactive oxygen production, causing oxidative damage to bacterial cell membranes and increased leakage of intracellular compounds. Additionally, TSP-1 significantly decreased the proinflammatory cytokines of IL-1ß, IL-6, IL-8, and TNF-α in a bacterial lipopolysaccharide-stimulated differentiated THP-1 macrophage model, showing the potential to inhibit inflammatory responses in bacterial infections. Overall, this is the first report exploring the potential of constructing clay-based organic-inorganic hybrids as alternatives to antibiotics to combat bacterial resistance with advanced compatibility and anti-inflammatory benefits that are desired for the development of topically applied biopharmaceuticals.

Optimizing elicitation strategy of salicylic acid for flavonoid and phenolic production of fed-batch cultured Oplopanax elatus adventitious roots.

Oplopanax elatus is a valuable medicinal plant, but its plant resource is lacking. Adventitious root (AR) culture of O. elatus is an effective way for the production of plant materials. Salicylic acid (SA) exerts enhancement effect on metabolite synthesis in some plant cell/organ culture systems. To clarify the elicitation effect of SA on fed-batch cultured O. elatus ARs, this study investigated the effects of SA concentration, and elicitation time and duration. Results showed that flavonoid and phenolic contents, and antioxidant enzyme activity obviously increased when the fed-batch cultured ARs were treated with 100 µM SA for 4 days starting on day 35. Under this elicitation condition, total flavonoid and phenolic contents reached 387 rutin mg/g DW and 128 gallic acid mg/g DW, respectively, which were significantly (p < 0.05) higher than those in the SA-untreated control. In addition, DPPH scavenging and ABTS+ scavenging rates, and Fe2+ chelating rate also greatly increased after SA treatment, and their EC50 values were 0.0117, 0.61, and 3.34 mg/L, respectively, indicating the high antioxidant activity. The findings of the present study revealed that SA could be used as an elicitor to improve the flavonoid and phenolic production in fed-batch O. elatus AR culture.

Possible implementation of salicylate anions in lead detoxification.

The water-soluble coordination polymer of formula {[Pb(Sal)2(H2O)]n} (SaLead), was obtained from the reaction between Pb(NO3)2 and the potassium salt of salicylic acid (SalH), an anti-inflammatory drug, which is also use as food preservation, in cosmetics etc. The compound was characterized by melting point, Attenuated Total Reflectance-Fourier Transform Infra-Red (ATR-FTIR) spectroscopy and X-ray diffraction crystallography (XRD) in solid state and in solution by Ultra Violet (UV) and 1H NMR spectroscopies. The binding affinity of SalK to Pb(II) ions towards SaLead was determined in order to examine its possible implementation in lead detoxification. The in vitro non-toxic behaviour of SalK and its complex SaLead was evaluated against normal human fetal lung fibroblast cells (MRC-5). The corresponding IC50 values are 260 ± 13 and > 1600 µM respectively. The non-genotoxic in vitro activity of SaLead was confirmed with the micronucleus (MN) assay, while its in vivo non-toxicity behaviour was evaluated with Allium cepa and Artemia salina assays.

Polyfluorinated salicylic acid analogs do not interfere with siderophore biosynthesis.

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb) is a leading cause of infectious disease mortality. The salicylic acid derived small molecule siderophores known as mycobactins are essential in vivo for iron acquisition of Mtb where iron is restricted in the host. Herein, we synthesize and explore the mechanism of action of polyfluorinated salicylic acid derivates, which were previously reported to possess potent antimycobacterial activity. We hypothesized fluorinated salicylic acid derivates may inhibit mycobactin biosynthesis through initial bioactivation and conversion to downstream metabolites that block late steps in assembly of the mycobactins. Enzymatic studies demonstrated that some of the fluorinated salicylic acid derivatives compounds were readily activated by the bifunctional adenylating enzyme MbtA, responsible for incorporation of salicylic acid into the mycobactin biosynthetic pathway; however, they did not inhibit mycobactin biosynthesis as confirmed by LS-MS/MS using an authentic synthetic mycobactin standard. Further mechanistic analysis of the most active derivative (Sal-4) using an MbtA-overexpressing Mtb strain as well as complementation studies with iron and salicylic acid revealed Sal-4 cannot be antagonized by overexpression of MbtA or through supplementation with iron or salicylic acid. Taken together, our results indicate the observed antimycobacterial activity of polyfluorinated salicylic acid derivative is independent of mycobactin biosynthesis.