The Mechanism by Which Luteolin Disrupts the Cytoplasmic Membrane of Methicillin-Resistant Staphylococcus aureus

Mechanistic Insights into the Membrane Permeabilization Activity of Antimicrobial Prenylated Isoflavonoids: A Comparative Study of Glabridin, Wighteone, and Lupiwighteone

Prenylated isoflavonoids have shown remarkable antimicrobial activity. Previous studies showed that the antimicrobial compounds glabridin and wighteone induced membrane permeabilization in microbial cells. Other compounds, such as lupiwighteone, showed no antimicrobial activity. In this study, the permeabilization efficacy and interaction with lipid bilayers of glabridin, wighteone, and lupiwighteone were assessed in vitro and in silico using model membranes. Permeabilization of liposomes by glabridin and wighteone confirmed the lipid bilayer as the primary target. Notably, lupiwighteone did not induce the permeabilization of liposomes. Molecular dynamics (MD) simulations were used to study the interaction of these compounds with phospholipid membranes. The calculated potential of mean force profiles for the three molecules correlated with liposome permeabilization, indicating a favorable intercalation inside the lipid bilayer for wighteone, followed by glabridin, and an unfavorable intercalation for lupiwighteone. Additionally, MD simulations indicated that the location of glabridin and wighteone in the membrane was just below the head groups. Furthermore, this study underscored the importance of partitioning between polar and hydrophobic areas for prenylated isoflavonoids, which conceivably determines the membrane insertion and, subsequently, the antimicrobial activity. Overall, this study showed that interactions with and permeabilization of the lipid bilayer are key factors for the antimicrobial activity of these compounds.

Effect of Luteolin on cadmium-inhibited bone growth via suppressing osteoclastogenesis in laying chickens

Luteolin (Lut) is a flavonoid derived from several plant sources. Cadmium (Cd) is a widespread environmental contaminant and potential toxin with detrimental effects on animal health. However, the effect of Lut on Cd-induced inhibition of bone growth in laying chickens remains unclear. This study investigates the effects of Lut on Cd-induced inhibition of bone growth in the femur and tibia of laying chickens. A total of sixty 1-d-old green-eggshell yellow feather laying chickens were randomly assigned to 4 groups after a 5-d acclimation period: basal diet (Con), cadmium chloride (CdCl2, Cd), Lut, and Lut + Cd. Bone microstructure, serum biomarkers of bone remodeling, the levels of Cd, calcium (Ca), phosphorus (P), and trace metal elements were assessed using the micro-computed tomography (Micro-CT), enzyme-linked immunosorbent assay (ELISA), and microwave digestion, respectively. Bone remodeling biomarkers, late endosomal/lysosomal adaptor and MAPK and mTOR activator 1 (LAMTOR1), as well as the phosphorylation of AMP-activated protein kinase α (AMPKα) and protein kinase B (Akt), were quantified using the qRT-PCR and western blot. The results indicated that Lut effectively mitigated Cd-induced bone mass loss compared to the Cd group, resulting in increased bone volume (BV), bone surface/BV (BS/BV), connectivity density (Conn.Dn), and the length and weight of the femur and tibia in laying chickens. Mechanistically, compared to the Cd group, Lut restored the ratio of osteoprotegerin (OPG)/receptor activator of NF-κB ligand (RANKL) in serum and bone tissue, enhanced the expression of bone morphogenetic protein-2 (BMP-2), runt-related transcription factor 2 (Runx2), osteocalcin (OCN), and Osterix (OSX), while reducing the levels of Ca, Cd, and alkaline phosphatase (ALP) activity, as well as the expression of osteopontin (OPN), c-Fos, osteoclast stimulatory-transmembrane protein (OC-STAMP), tartrate-resistant acid phosphatase, cathepsin K (CTSK), matrix metalloprotein-9 (MMP-9), LAMTOR1, and the phosphorylation of AMPKα and Akt. Therefore, Lut alleviates Cd-induced damage to the femur and tibia of chickens by promoting osteogenesis and inhibiting osteoclastogenesis, positioning Lut as a potential therapeutic plant extract for enhancing bone growth in laying chickens.

Natural Antimicrobial Compounds as Promising Preservatives: A Look at an Old Problem from New Perspectives

Antimicrobial compounds of natural origin are of interest because of the large number of reports regarding the harmfulness of food preservatives. These natural products can be derived from plants, animal sources, microorganisms, algae, or mushrooms. The aim of this review is to consider known antimicrobials of natural origin and the mechanisms of their action, antimicrobial photodynamic technology, and ultrasound for disinfection. Plant extracts and their active compounds, chitosan and chitosan oligosaccharide, bioactive peptides, and essential oils are highly potent preservatives. It has been experimentally proven that they possess strong antibacterial capabilities against bacteria, yeast, and fungi, indicating the possibility of their use in the future to create preservatives for the pharmaceutical, agricultural, and food industries.

Luteolin Functionalized Zinc Oxide Nanoparticles for Cancer Therapy Based on Autophagy Activation and EMT Inhibition

Natural bioactive compounds have become increasingly important antitumor and antimicrobial agents due to their high therapeutic potential and low systemic toxicity. However, they also have significant drawbacks like nontumor targeting and low bioavailability, which limit their wide therapeutic applications. There is an urgent need for a safe and compatible nanoparticle-mediated drug delivery system for the efficient transport of drug candidates into tumor tissues. In this paper, amine-modified zinc oxide nanoparticles are synthesized to load luteolin. The functionalized nanoparticles exhibit good synergistic effects in terms of antitumor and antibacterial activities. They show significant induction of oxidative stress and antitumor effects, while no significant inhibitory effect on normal cells is observed, suggesting that the nanocomposites have good targeting of cancer cells. Autophagy activation and EMT inhibition effects are studied to explain the good antitumor performances. The prepared nanocomposites are demonstrated to be attractive candidates for cancer therapy.

The effects of plant flavones on the membrane boundary potential and lipid packing stress

Here we have revealed the effects of different plant flavones on the physicochemical properties of model lipid membranes. We have demonstrated that baicalein increases the boundary potential of membranes composed of phosphatidylcholine, while wogonin does not affect it. Other flavones tested reduce membrane boundary potential, with this ability increasing among scutellarein, chrysin, apigenin, morin, fisetin, and luteolin. Molecular dynamics simulations demonstrate connection of alteration in boundary potential with the preferential orientation of intrinsic flavone dipole moments in membranes. We have also shown that flavones reduce the melting point of phosphatidylcholine, and this ability increases in the series of luteolin, morin, wogonin, scutellarein, apigenin, baicalein, chrysin, and fisetin. The introduction of baicalein, chrysin and fisetin also leads to a significant decrease in the sharpness of the lipid phase transition. We have hypothesized that the localization of flavones in the glycerol backbone or in the C1-C8 methylene region of lipid hydrocarbon chains leads to an increase in the area per lipid and, as a consequence, to an expansion of the lipid melting peak. Replacement of neutral phosphatidylcholine with negatively charged phosphatidylserine affects the membrane-modifying activity of flavones which given the externalization of phosphatidylserine on the surface of cancer cells may be crucial in the flavone anticancer effects.

The antibacterial properties of branched peptides based on poly(l-arginine): In vitro antibacterial evaluation and molecular dynamic simulations

The emergence of bacterial strains resistant to antibiotics is a major issue in the medical field. Antimicrobial peptides are widely studied as they do not generate as much resistant bacterial strains as conventional antibiotics and present a broad range of activity. Among them, the homopolypeptide poly(l-arginine) presents promising antibacterial properties, especially in the perspective of its use in biomaterials. Linear poly(l-arginine) has been extensively studied but the impact of its 3D structure remains unknown. In this study, the antibacterial properties of newly synthesized branched poly(l-arginine) peptides, belonging to the family of multiple antigenic peptides, are evaluated. First, in vitro activities of the peptides shows that branched poly(l-arginine) is more efficient than linear poly(l-arginine) containing the same number of arginine residues. Surprisingly, peptides with more arms and more residues are not the most effective. To better understand these unexpected results, interactions between these peptides and the membranes of Gram positive and Gram negative bacteria are simulated thanks to molecular dynamic. It is observed that the bacterial membrane is more distorted by the branched structure than by the linear one and by peptides containing smaller arms. This mechanism of action is in full agreement with in vitro results and suggest that our simulations form a robust model to evaluate peptide efficiency towards pathogenic bacteria.

Nano-scale drug delivery systems for luteolin: advancements and applications

Luteolin (Lu) is a naturally occurring flavonoid compound with a diverse array of pharmacological activities, including anti-tumor, anti-inflammatory, antibacterial, and neuroprotective properties. However, the therapeutic efficacy and clinical application of Lu are significantly hindered by inherent limitations, such as poor water solubility, short half-life, low bioavailability, and potential off-target toxicity. Recent studies have demonstrated that the utilization of nanocarriers presents a promising strategy to enhance the solubility of Lu, prolong its circulation time, and improve its targeting ability. Despite numerous reviews over the past few decades having focused on the source, pharmacological activities, and molecular mechanisms of Lu, there exists a conspicuous gap in the literature regarding a comprehensive review of Lu-loaded nanoformulations and their applications. To address this gap, we present an exhaustive overview of the advancements and applications of nano-scale drug delivery systems specifically designed for Lu. These platforms encompass micelles, nanocarrier-based systems, emulsified drug delivery systems, and vesicular drug delivery systems. We provide detailed insights into the synthetic materials, preparation methods, physicochemical properties, and significant outcomes associated with these nanoformulations. This systematic review will be particularly valuable to researchers seeking novel avenues in the field of nano-delivery strategies and exploring the potential clinical applications of Lu.

Mitigation of Insulin Resistance by Natural Products from a New Class of Molecules, Membrane-Active Immunomodulators

Insulin resistance (IR), accompanied by an impaired cellular glucose uptake, characterizes diverse pathologies that include, but are not limited to, metabolic disease, prediabetes and type 2 diabetes. Chronic inflammation associated with deranged cellular signaling is thought to contribute to IR. The key molecular players in IR are plasma membrane proteins, including the insulin receptor and glucose transporter 4. Certain natural products, such as lipids, phenols, terpenes, antibiotics and alkaloids have beneficial effects on IR, yet their mode of action remains obscured. We hypothesized that these products belong to a novel class of bioactive molecules that we have named membrane-active immunomodulators (MAIMs). A representative MAIM, the naturally occurring medium chain fatty acid ester diethyl azelate (DEA), has been shown to increase the fluidity of cell plasma membranes with subsequent downstream effects on cellular signaling. DEA has also been shown to improve markers of IR, including blood glucose, insulin and lipid levels, in humans. The literature supports the notion that DEA and other natural MAIMs share similar mechanisms of action in improving IR. These findings shed a new light on the mechanism of IR mitigation using natural products, and may facilitate the discovery of other compounds with similar activities.

A new approach to overcoming antibiotic-resistant bacteria: Traditional Chinese medicine therapy based on the gut microbiota

With the irrational use of antibiotics and the increasing abuse of oral antibiotics, the drug resistance of gastrointestinal pathogens has become a prominent problem in clinical practice. Gut microbiota plays an important role in maintaining human health, and the change of microbiota also affects the activity of pathogenic bacteria. Interfering with antibiotic resistant bacteria by affecting gut microbiota has also become an important regulatory signal. In clinical application, due to the unique advantages of traditional Chinese medicine in sterilization and drug resistance, it is possible for traditional Chinese medicine to improve the gut microbial microenvironment. This review discusses the strategies of traditional Chinese medicine for the treatment of drug-resistant bacterial infections by changing the gut microenvironment, unlocking the interaction between microbiota and drug resistance of pathogenic bacteria.

An optimized antimicrobial peptide analog acts as an antibiotic adjuvant to reverse methicillin-resistant Staphylococcus aureus

The misuse of antibiotics in animal protein production has driven the emergence of a range of drug-resistant pathogens, which threaten existing public health security. Consequently, there is an urgent need to develop novel antimicrobials and new infection treatment options to address the challenges posed by the dramatic spread of antibiotic resistance. Piscidins, a class of fish-specific antimicrobial peptides (AMPs), are regarded as promising therapies for biomedical applications. Progress towards potential analogs from the piscidin family has been hampered by unenforceable structural optimization strategies. Here, we leverage a strategy of bioinformatics analysis combined with molecular dynamics (MD) simulation to identify specific functional hotspots in piscidins and rationally design related analogues. As expected, this approach yields a potent and non-toxic PIS-A-1 that can be used as an antibiotic adjuvant to reverse methicillin-resistant Staphylococcus aureus (MRSA) pathogens. Remarkably, the structural optimization scheme and application strategy proposed here will contribute richer therapeutic options for the safe production of animal protein.

Sakuranetin interacting with cell membranes models: Surface chemistry combined with molecular simulation

Sakuranetin, a natural compound with activity in lipidic biointerfaces, was isolated from Baccharis retusa and studied with two models of lipid membranes: Langmuir monolayers and Molecular Simulation. For that, the mammalian lipid DPPC was chosen. Sakuranetin condensed the monolayers at high surface pressures, decreased the surface compressional modulus, reduced the molecular order of the acyl chains (diminution of all-trans/gauche conformers ratio), and increased the heterogeneity of the interface, forming aggregates. Molecular simulation data gave information on the bioactive compound's most favorable thermodynamic positions along the lipid monolayer, which was the lipid-air interface. These combined results lead to the conclusion that this lipophilic compound may interact with the lipidic layers, preferentially at the lipid-air interface, to minimize the free energy, and reaches this conformation disturbing the thermodynamic, structural, mechanical, rheological, and morphological properties of the well-packed DPPC monolayer.

Molecular Basis for Luteolin as a Natural TatD DNase Inhibitor in Trueperella pyogenes

TatD960 and TatD825 are DNases that contribute to biofilm formation and virulence in Trueperella pyogenes (T. pyogenes). Luteolin is a natural flavonoid commonly found in plants that exhibits antimicrobial capacity. Our study aims to investigate the effects of luteolin on TatD DNases as a natural inhibitor. In this research, the expression of tatD genes and TatD proteins in T. pyogenes treated with luteolin was detected, and then the effect of luteolin on the hydrolysis of DNA by TatD DNases was analyzed using agarose gel electrophoresis. Moreover, the interactions between luteolin and TatD DNases were tested using surface plasmon resonance (SPR) assays and molecular docking analysis. After 1/2 MIC luteolin treatment, the transcription of tatD genes and expression of TatD proteins appeared to be reduced in 80–90% of T. pyogenes (n = 20). The gel assay revealed that luteolin can inhibit the activity of TatD DNases. The SPR assay showed that the KD values of luteolin to TatD960 and TatD825 were 6.268 × 10⁻⁶ M and 5.654 × 10⁻⁶ M, respectively. We found through molecular docking that hydrogen bonding is predominant in the interaction of luteolin and TatD DNases. Our data indicate that luteolin inhibited the ability of TatD DNases by decreasing their binding to DNA. The current study provides an insight into the development of luteolin as a DNase inhibitor in preventing biofilm formation and virulence in T. pyogenes.

Luteolin Phosphate Derivatives Generated by Cultivating Bacillus subtilis var. Natto BCRC 80517 with Luteolin

Luteolin (LUT), a plant-derived flavone, exhibits various bioactivities; however, the poor aqueous solubility hampers its applications. Here, we revealed bioconversion of LUT by Bacillus subtilis BCRC 80517, yielding three water-soluble phosphate conjugates. These derivatives were identified as luteolin 4'-O-phosphate (L4'P), luteolin 3'-O-phosphate (L3'P), and luteolin 7-O-phosphate (L7P) by LC-ESI-MS/MS and NMR. Besides, we found that Bacillus subtilis BCRC 80517 was able to convert different levels of LUT but showed a limited conversion rate. By observing bacterial morphology with transmission electron microscopy and confocal fluorescence microscopy, we found that LUT disrupted the bacterial membrane integrity, which explained the incomplete conversion. Additionally, we revealed a spontaneous intramolecular transesterification of L4'P to L3'P, the thermodynamically more stable form, under acidic conditions and proposed the possible mechanism involving a cyclic phosphate as the intermediate. This study provides insight into development of a potent structural modification strategy to enhance the solubility of LUT through biophosphorylation.

Antibacterial Modes of Herbal Flavonoids Combat Resistant Bacteria

The increasing dissemination of multidrug resistant (MDR) bacterial infections endangers global public health. How to develop effective antibacterial agents against resistant bacteria is becoming one of the most urgent demands to solve the drug resistance crisis. Traditional Chinese medicine (TCM) with multi-target antibacterial actions are emerging as an effective way to combat the antibacterial resistance. Based on the innovative concept of organic wholeness and syndrome differentiation, TCM use in antibacterial therapies is encouraging. Herein, advances on flavonoid compounds of heat-clearing Chinese medicine exhibit their potential for the therapy of resistant bacteria. In this review, we focus on the antibacterial modes of herbal flavonoids. Additionally, we overview the targets of flavonoid compounds and divide them into direct-acting antibacterial compounds (DACs) and host-acting antibacterial compounds (HACs) based on their modes of action. We also discuss the associated functional groups of flavonoid compounds and highlight recent pharmacological activities against diverse resistant bacteria to provide the candidate drugs for the clinical infection.

Luteolin Inhibits the Biofilm Formation and Cytotoxicity of Methicillin-Resistant Staphylococcus aureus via Decreasing Bacterial Toxin Synthesis

Owing to the fact that luteolin has antibacterial activity against Staphylococcus aureus (S. aureus) and methicillin-resistant S. aureus (MRSA), its specific mechanism in MRSA is worthy of investigation, which is the focus of this study. Initially, the collected S. aureus strains were treated with luteolin. Then, the minimum inhibitory concentration (MIC) of luteolin against the S. aureus strains was measured by the broth microdilution. The growth curves, biofilm formation, and cytotoxicity of treated S. aureus were detected using a microplate reader. The live and dead bacteria were evaluated using confocal laser scanning microscopy, the bacterial morphology was observed using scanning electron microscopy, and the S. aureus colony-forming unit (CFU) numbers were assessed. The levels of alpha hemolysin (α-hemolysin), delta hemolysin (δ-hemolysin), and hlaA were detected via western blot and RT-PCR. The mortality of mouse model with S. aureus systemic infection was analyzed, and the levels of IL-6, IL-8, IL-10, and TNF-α were quantitated using ELISA. Concretely, the MIC of luteolin against MRSA N315 was 64 μg/mL. Luteolin at 16 μg/mL did not affect the growth of MRSA N315, but inhibited the biofilm formation and CFU, and promoted the morphological changes and death of MRSA N315. Luteolin decreased the cytotoxicity and the levels of α-hemolysin, δ-hemolysin, and hlaA in MRSA N315, elevated MRSA-reduced mice survival rate, and differentially modulated the inflammatory cytokine levels in MRSA-infected mice. Collectively, luteolin inhibits biofilm formation and cytotoxicity of MRSA via blocking the bacterial toxin synthesis.

Small Amphiphilic Peptides: Activity Against a Broad Range of Drug-Resistant Bacteria and Structural Insight into Membranolytic Properties

We report the synthesis and antibacterial activities of a series of amphiphilic membrane-active peptides composed, in part, of various nongenetically coded hydrophobic amino acids. The lead cyclic peptides, 8C and 9C, showed broad-spectrum activity against drug-resistant Gram-positive (minimum inhibitory concentration (MIC) = 1.5-6.2 μg/mL) and Gram-negative (MIC = 12.5-25 μg/mL) bacteria. The cytotoxicity study showed the predominant lethal action of the peptides against bacteria as compared with mammalian cells. A plasma stability study revealed approximately 2-fold higher stability of lead cyclic peptides as compared to their linear counterparts after 24 h of incubation. A calcein dye leakage experiment revealed the membranolytic effect of the cyclic peptides. Nuclear magnetic resonance spectroscopy and molecular dynamics simulation studies of the interaction of the peptides with the phospholipid bilayer provided a solid structural basis to explain the membranolytic action of the peptides with atomistic details. These results highlight the potential of newly designed amphiphilic peptides as the next generation of peptide-based antibiotics.

Characterization and Quantification of Luteolin-Metal Complexes in Aqueous Extract of Lonicerae Japonicae Flos and Huangshan Wild Chrysanthemum

Luteolin is a flavonoid compound widely found in vegetables, fruits, and medicinal plants. In this study, the reaction conditions for luteolin and five metal ions (Ca²⁺, Mg²⁺, Zn²⁺, Fe³⁺, and Cu²⁺) to form complexes in hot water were optimized, which was at a molar ratio of 1 : 1 for luteolin and metal ions at 90°C in a volume of 20 mL for 2 h, and the ability of luteolin to form complexes with Cu²⁺ was the strongest. The DPPH scavenging test showed that luteolin exerted a dose-dependent effect on the clearance of free radicals; luteolin-Cu²⁺ complexes and luteolin-Fe³⁺ complexes accentuated the clearance of free radicals. Furthermore, we used high performance liquid chromatography (HPLC) to analyze luteolin in samples from two medicinal plants, obtained from the dissolution of aqueous extracts in two different solvents. The results showed that the peak areas for luteolin in the samples dissolved in 20% formic acid-methanol were significantly larger than those from the samples dissolved in methanol alone, with increases in the peak area being 135.6% (Lonicerae Japonicae Flos), and 161.16% (Huangshan wild chrysanthemum). The aforementioned results indicate that complexes formed from organic compounds and metal ions are present in the decoction of a plant.

Investigation of Drug for Pulmonary Administration-Model Pulmonary Surfactant Monolayer Interactions Using Langmuir-Blodgett Monolayer and Molecular Dynamics Simulation: A Case Study of Ketoprofen

Pulmonary administration is widely used for the treatment of lung diseases. The interaction between drug molecules and pulmonary surfactants affects the efficacy of the drug directly. The location and distribution of drug molecules in a model pulmonary surfactant monolayer under different surface pressures can provide vivid information on the interaction between drug molecules and pulmonary surfactants during the pulmonary administration. Ketoprofen is a nonsteroidal anti-inflammatory drug for pulmonary administration. The effect of ketoprofen molecules on the lipid monolayer containing 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) and 1,2-dipalmitoyl-sn-glycero-3-phospho-rac-glycerol (DPPG) is studied by surface pressure (π)-area (A) isotherms and compressibility modulus (C_s^-1)-surface pressure (π) isotherms. The location and distribution of ketoprofen molecules in a lipid monolayer under different surface pressures are explored by surface tension, density profile, radial distribution function (RDF), and the potential of mean force (PMF) simulated by molecular dynamics (MD) simulation. The introduction of ketoprofen molecules affects the properties of DPPC/DPPG monolayers and the location and distribution of ketoprofen molecules in monolayers with various surface pressures. The existence of ketoprofen molecules hinders the formation of liquid-condensed (LC) films and decreases the compressibility of DPPC/DPPG monolayers. The location and distribution of ketoprofen molecules in the lipid monolayer are affected by cation-π interaction between the choline group of lipids and the benzene ring of ketoprofen, the steric hindrance of the lipid head groups, and the hydrophobicity of ketoprofen molecule itself, comprehensively. The contact state of lipid head group with water is determined by surface pressure, which affects the interaction between drug molecules and lipids and further dominates the location and distribution of ketoprofen in the lipid monolayer. This work confirms that ketoprofen molecules can affect the property and the inner structure of DPPC/DPPG monolayers during breathing. Furthermore, the results obtained using a mixed monolayer containing two major pulmonary surfactants DPPC/DPPG and ketoprofen molecules will be helpful for the in-depth understanding of the mechanism of inhaled administration therapy.

Structural Basis for the Inhibition of the Autophosphorylation Activity of HK853 by Luteolin

The two-component system (TCS) is a significant signal transduction system for bacteria to adapt to complicated and variable environments, and thus has recently been regarded as a novel target for developing antibacterial agents. The natural product luteolin (Lut) can inhibit the autophosphorylation activity of the typical histidine kinase (HK) HK853 from Thermotoga maritime, but the inhibition mechanism is not known. Herein, we report on the binding mechanism of a typical flavone with HK853 by using solution NMR spectroscopy, isothermal titration calorimetry (ITC), and molecular docking. We show that luteolin inhibits the activity of HK853 by occupying the binding pocket of adenosine diphosphate (ADP) through hydrogen bonds and π-π stacking interaction structurally. Our results reveal a detailed mechanism for the inhibition of flavones and observe the conformational and dynamics changes of HK. These results should provide a feasible approach for antibacterial agent design from the view of the histidine kinases.

Microbial Biosynthesis of Antibacterial Chrysoeriol in Recombinant Escherichia coli and Bioactivity Assessment

Various flavonoid derivatives including methoxylated flavones display remarkable biological activities. Chrysoeriol is a methoxylated flavone of great scientific interest because of its promising anti-microbial activities against various Gram-negative and Gram-positive bacteria. Sustainable production of such compounds is therefore of pronounced interest to biotechnologists in the pharmaceutical and nutraceutical industries. Here, we used a sugar O-methyltransferase enzyme from a spinosyn biosynthesis gene cluster of Saccharopolyspora spinosa to regioselectively produce chrysoeriol (15% conversion of luteolin; 30 µM) in a microbial host. The biosynthesized chrysoeriol was structurally characterized using high-resolution mass spectrometry and various nuclear magnetic resonance analyses. Moreover, the molecule was investigated against 17 superbugs, including thirteen Gram-positive and four Gram-negative pathogens, for anti-microbial effects. Chrysoeriol exhibited antimicrobial activity against nine pathogens in a disc diffusion assay at the concentration of 40 µg per disc. It has minimum inhibitory concentration (MIC) values of 1.25 µg/mL against a methicillin-resistant Staphylococcus aureus 3640 (MRSA) for which the parent luteolin has an MIC value of sixteen-fold higher concentration (i.e., 20 µg/mL). Similarly, chrysoeriol showed better anti-microbial activity (~1.7-fold lower MIC value) than luteolin against Proteus hauseri, a Gram-negative pathogen. In contrast, a luteolin 4′-O-methylated derivative, diosmetin, did not exhibit any anti-microbial activities against any tested pathogen.