Exploring the World of Natural Sciences

Your Source for Nature-based Education and Exploration

A Hub for Exploring the Wonders of Nature

Natural Science Hub Search function

Type your keywords and we will find the results


  • Dimethylallyl tryptophan synthases (DMATSs) are aromatic prenyltransferases that catalyze the transfer of a prenyl moiety from a donor to an aromatic acceptor during the biosynthesis of microbial secondary metabolites. Due to their broad substrate scope, DMATSs are anticipated as biotechnological tools for producing bioactive prenylated aromatic compounds. Our study explored the substrate scope and product profile of a recombinant RePT, a novel DMATS from the thermophilic fungus Rasamsonia emersonii. Among a variety of aromatic substrates, RePT showed the highest substrate conversion for L-tryptophan and L-tyrosine (> 90%), yielding two mono-prenylated products in both cases. Nine phenolics from diverse phenolic subclasses were notably converted (> 10%), of which the stilbenes oxyresveratrol, piceatannol, pinostilbene, and resveratrol were the best acceptors (37-55% conversion). The position of prenylation was determined using NMR spectroscopy or annotated using MS fragmentation patterns, demonstrating that RePT mainly catalyzed mono-O-prenylation on the hydroxylated aromatic substrates. On L-tryptophan, a non-hydroxylated substrate, it preferentially catalyzed C7 prenylation with reverse N1 prenylation as a secondary reaction. Moreover, RePT also possessed substrate-dependent organic solvent tolerance in the presence of 20% (v/v) methanol or DMSO, where a significant conversion (> 90%) was maintained. Our study demonstrates the potential of RePT as a biocatalyst for the production of bioactive prenylated aromatic amino acids, stilbenes, and various phenolic compounds. KEY POINTS: • RePT catalyzes prenylation of diverse aromatic substrates. • RePT enables O-prenylation of phenolics, especially stilbenes. • The novel RePT remains active in 20% methanol or DMSO.

    Read More on PubMed
  • The aim of this study was to evaluate the anticancer effects of piceatannol, a natural stilbenoid, on human neuroblastoma cells. In order to accomplish this goal, we performed various cellular assays, including the XTT cell proliferation assay for cell viability, colony formation assay for colony formation capacity, FITC Annexin V and cell death detection kit for apoptosis, matrigel invasion assay for invasion capacity, intracellular reactive oxygen species (ROS) red dye for intracellular ROS levels, TMRM staining method for mitochondrial membrane potential (MMP), and the CYTO-ID autophagy detection kit for autophagy. Furthermore, we analyzed the expression levels of genes associated with apoptosis and autophagy using RT-qPCR. Based on our findings, piceatannol exhibited cytotoxic effects on neuroblastoma cells. Besides, treatment with piceatannol at both 50 and 100 μM concentrations for 72 h decreased colony formation, induced apoptosis and autophagy, inhibited cell invasion, decreased MMP, and increased ROS levels in SH-SY5Y cells. In addition, we observed significant upregulation in the expression levels of CASP8, BECLIN, ATG5, ATG7, and MAPILC3A genes between the two doses. These results suggest that piceatannol enhances autophagic activity and induces caspase-dependent apoptosis, indicating its potential as a therapeutic agent against neuroblastoma cells.

    Read More on PubMed
  • The pathophysiological understanding of dental caries explains that the primary factor responsible is linked to an imbalance in microbial composition within the oral cavity, stemming from both artificial and natural sources. Streptococcus mutans (S. mutans) is the most accountable and prevalent pathogen for caries development among the diverse pool. S. mutans, an acidogenic bacterium, lowers oral pH through the metabolic conversion of dietary sugar into organic acids, leading to enamel demineralization and dental caries. Numerous antibacterial interventions have been employed in the past to address this issue. However, adopting such an approach poses the risk of exacerbating concerns related to Antimicrobial Resistance (AMR) and long-term oral cytotoxicity. In response to this, a sustainable strategy is suggested, involving the utilization of L-Arginine (L-Arg) as a probiotic nutrient supplement for non-pathogenic microbes. It will help in creating a natural competitive environment against the pathogenic microbes responsible for initiating dental caries. The hypothesis involves utilizing a combination of a nutrient supplement and the repurposed drug Piceatannol, specifically for its anti-biofilm properties. This combination synergistically improves the effectiveness of the therapy by converting the complex microbial biofilm into a planktonic state.

    Read More on PubMed
  • Inhibition of the ATP synthase increases sensitivity of Escherichia coli carrying mcr-1 to polymyxin B.

    Bacterial infections caused by multidrug-resistant (MDR) gram-negative strains carrying the mobile colistin resistance gene mcr-1 are serious threats to world public health due to the lack of effective treatments. Inhibition of the ATP synthase makes bacteria such as Staphylococcus aureus and Klebsiella pneumoniae more sensitive to polymyxin. This provides new strategies for treating infections caused by polymyxins-resistant bacteria carrying mcr-1. Six mcr-1-positive strains were isolated from clinical samples, and all were identified as Escherichia coli. Here we investigated several ATP synthase inhibitors, N,N'-dicyclohexylcarbodiimide (DCCD), resveratrol, and piceatannol, for their antibacterial effects against the mcr-1-positive strains combined with polymyxin B (POL). Checkerboard assay, time-kill assay, biofilm inhibition and eradication assay indicated the significant synergistic effect of ATP synthase inhibitors/POL combination in vitro. Meanwhile, mouse infection model experiment was also performed, showing a 5 log reduction of the pathogen after treatment with the resveratrol/POL combination. Moreover, adding adenosine disodium triphosphate (NaATP) could inhibit the antibacterial effect of the ATP synthase inhibitors/POL combination. In conclusion, our study confirmed that inhibition of ATP production could increase the susceptibility of bacteria carrying mcr-1 to polymyxins. This provides a new strategy against polymyxins-resistant bacteria infection.

    Read More on PubMed
  • Dermal fibroblasts play a crucial role in skin structure and function by producing hyaluronic acid. Piceatannol (PIC), a polyphenol abundant in passion fruit seeds, has been reported to activate sirtuin 1 (SIRT1). Clinical trials have demonstrated that PIC intake improves skin moisture and maintains skin elasticity, yet the underlying mechanism remains unclear. This study aimed to investigate the effects of PIC on hyaluronic acid biosynthesis and the involvement of SIRT1 in this process. Human dermal fibroblast Hs68 cells were stimulated with PIC, and the expression levels of and , key enzymes in hyaluronic acid biosynthesis, as well as expression, were assessed using quantitative real-time PCR. Additionally, the role of in the hyaluronic acid biosynthesis pathway during PIC stimulation was examined using a SIRT1 inhibitor. The results demonstrated that PIC increased expression while decreasing expression in human dermal fibroblasts. Furthermore, PIC enhanced expression, and pre-treatment with a SIRT1 inhibitor mitigated PIC-induced upregulation of , suggesting that PIC promotes hyaluronic acid synthesis by inducing . These findings suggest that PIC could serve as a beneficial food ingredient, enhancing skin structure and function by promoting hyaluronic acid biosynthesis via induction.

    Read More on PubMed
  • In this study, chlorogenic acid (CA), piceatannol (PIC), epigallocatechin-3-gallate (EGCG) and ferulic acid (FA) was selected to explore the influence of polyphenol on the structural properties of wheat germ albumin (WGA) and wheat germ globulin (WGG). The emulsifying properties of the emulsions prepared by WGA-EGCG complex were also evaluated. The results indicated that all polyphenols could significantly enhance the antioxidant capacity of WGA and WGG. In particular, EGCG increased the ratio of random coil in WGA and WGG, resulting in protein unfolding and shifting from an order to disorder structure. In addition, lipid oxidation and protein oxidation of the soybean oil emulsion was significantly slowed down by WGA-EGCG. The stability of the emulsions under various environmental stress and the storage time was significantly improved by WGA-EGCG. These findings can provide a reference for expanding the application of wheat germ protein in food industry.

    Read More on PubMed
  • The objective of this study was to assess the pharmacological activity and therapeutic mechanism of Dahuang Mudan Decotion (DHMDD) for colorectal cancer using ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS), network pharmacology and in vitro experiments.

    Read More on PubMed
  • The reactivity of 4-[()-2-(3,5-dihydroxyphenyl)ethenyl]benzene-1,2-diol (piceatannol) toward electrochemically generated superoxide radical anion (O ) was investigated using electrochemistry and in situ controlled-potential electrolytic electron spin resonance (ESR) measurements in ,-dimethylformamide with density functional theory (DFT) calculations. The quasireversible cyclic voltammogram of dioxygen/O , modified in the presence of piceatannol, indicated that the electrogenerated O was scavenged by piceatannol via proton-coupled electron transfer. Differences in the reactivities of piceatannol and 5-[()-2-(4-hydroxyphenyl)ethen-1-yl]benzene-1,3-diol (-resveratrol) toward O , originating from the presence of the benzene-1,2-diol (catechol) moiety, were observed in the voltammograms and ESR measurements. The electrochemical and computational results show that the reaction mechanism is a concerted two-proton-coupled electron transfer (2PCET) via the catechol moiety of piceatannol. The stilbene moiety of piceatannol kinetically promotes 2PCET via its catechol moiety. These findings indicate that piceatannol is a better O scavenger than catechol and -resveratrol.

    Read More on PubMed
  • Piceatannol is a natural compound found in plants and can be derived from resveratrol. While resveratrol has been extensively researched for its effects and how the body processes it, there are concerns about its use. These concerns include its limited absorption in the body, the need for specific dosages, potential interactions with other drugs, lack of standardization, and limited clinical evidence to support its benefits. Interestingly, Piceatannol, another compound derived from resveratrol, has received less attention from researchers but appears to offer advantages. It has better bioavailability and seems to have a more favorable therapeutic profile compared to resveratrol. Surprisingly, no previous attempts have been made to explore or predict the metabolites of piceatannol when it interacts with the enzyme cytochrome P450. This study aims to fill that gap by predicting how piceatannol is metabolized by cytochrome P450 and assessing any potential toxicity associated with its metabolites. This research is interesting because it's the first of its kind to investigate the metabolic fate of piceatannol, especially in the context of cytochrome P450. The findings have the potential to significantly contribute to the field of piceatannol research, particularly in the food industry where this compound has applications and implications.

    Read More on PubMed
  • Piceatannol, resveratrol's derivative, and a valuable polyphenol has managed to become one of the most remarkable candidate molecules for drug development research, with its high bioactive properties and higher stability. On the other hand, the very low amount of piceatannol in plants which are its natural source increases the cost and limits the commercialization possibilities of the product. To overcome this bottleneck, a limited number of studies have recently shown that it is possible to produce piceatannol from the resveratrol precursor much cheaper by regioselective hydroxylation catalyzed by bacteria isolated from the soil, and the search for new bacteria of similar nature in new ecosystems has gained popularity. The aim of our study, which was prepared within this framework, is the bacterial isolate with regioselective hydroxylation potential obtained as a result of selective isolation steps; determination of resveratrol hydroxylation potentials and piceatannol product yields, investigation of possibilities to increase piceatannol yield with optimization trials and identification of isolates with the highest yield. For this purpose, 200 bacterial isolates capable of resveratrol hydroxylation were obtained from soil samples taken from Erzurum (Turkey) and its surroundings by using selective media. In the continuation of the study; resveratrol hydroxylation trials were carried out with these isolates and 55 active isolates capable of producing piceatannol by regioselective hydroxylation were selected. Then, yield improvement studies of active isolates were carried out by using different carbon sources and optimizing the culture conditions. As a result, a culture collection was created by identifying the 6 most active bacterial isolates with commercialization potential using conventional and molecular methods. These are 4 Gram-positive (Rhodococcus sp., Rhodococcus erythropolis, Paeniglutamicibacter sp., Arthrobacter sp.) and 2 Gram-negative (Shinella sp., Ensifer adhaerens) bacterial isolates. As a result of the optimization studies, three of these isolates used phenol as a biocatalyst, while the other three increased the production yield of piceatannol by using 4-hydroxyphenylacetic acid.

    Read More on PubMed

Proudly Supported By:

Grateful for our sponsors' invaluable support!