Antibacterial activity of flavonoids and their structure-activity relationship: An update review

Plant secretions and volatiles contribute to the evolution of bacterial antibiotic resistance in soil-crop system

The exponential growth of antibiotic-resistant bacteria and antibiotic-resistant genes (ARGs) in soil-crop systems in recent years has posed a great challenge to ecological security and human health. While many studies have documented the residues of ARGs in soils and crops, but little is known about who drives the proliferation of ARGs in farming systems and what their underlying mechanisms are. Herein, we explored the occurrence and proliferating behavior of ARGs in soil-crop environments in terms of root secretions and plant volatiles. This review highlighted that plant root secretions and volatile organic compounds (VOCs) served as key substances mediating the development of antibiotic resistance in the soil-crop system. Still, there is controversy here as to plant root secretions promote the ARGs proliferation or inhibit. Some studies indicated that root secretions can suppress the colonization of ARGs, mainly attributed by the production of blunted metabolic enzymes and blocking of cellular exocytosis systems. Whereas the others have evidenced that root secretions can promote ARGs proliferation, primarily by altering the structure of microbial communities to influence species interactions and thus indirectly affect the proliferation of ARGs. Also, VOCs can act as molecular signals to convey antibiotic resistance information to their neighbors, which in turn drive the up-regulation of ARGs expression. Even so, the mechanism by which VOC-driven antibiotic resistance acquisition and proliferation need to be further probed. Overall, this review contributed to the development of products and technologies to impede the ARGs proliferation in agricultural environment.

Optimizing hydrogel performance composed of Japanese pagoda tree extract loaded-gelatin-sodium alginate-polyethylene oxide for biomedical applications: Influence incorporated calcium-based metal organic frameworks and zinc oxide NPs

Gelatin/sodium alginate/polyethylene oxide hydrogel was synthesized by self-gelation method and utilized to achieve enhanced mechanical strength. Japanese pagoda, tree extracts rich in flavonoids and isoflavonoids was incorporated to enhance tissue repair along with ZnO-NPs to provide the hydrogel with necessary antimicrobial and other desirable biological properties. The inclusion of Ca-BDC MOF enhanced hydrogel matrix by providing more surface area and the presence of calcium ion needed for tissue regeneration. Results revealed that composite hydrogel displayed suitable gelation time and swelling rate that was further improved by incorporating the plant extract, ZnO-NPs, and Ca-BDC MOF. The efficacy of the tested formulations to suppress or stop the growth of multi-drug-resistant human pathogens was assessed using both microbial turbidity and zone of inhibition assays. The optimal hydrogel loaded with (20 % plant extract, 0.25 % ZnO and 0.1 % Ca-BDC MOF) formula have stronger antimicrobial effects against Gram-positive bacteria as well as yeast cells than it did against Gram-negative bacteria. Statistically, this formula has recorded a higher percentage of biofilm inhibition on Bacillus cereus (93.45 ± 2.91 %), and Candida krusei (78.48 ± 6.44 %), followed by Klebsiella pneumoniae (76.93 ± 3.65 %). Composite hydrogel loaded with (Japanese pagoda tree extract, ZnO-NPs, Ca-BDC MOF) could be exploited as promising biocompatible antimicrobial biomaterial for biomedical applications.

Aristolochia species (Aristolochiaceae) from the Americas, a review of their traditional medicinal uses, phytochemistry, and pharmacological properties

Aristolochia is a pantropical genus with important pharmacological properties. Despite making up 75 % of the global Aristolochia, the species from the Americas have received comparatively little research attention. Here, we exhaustively review the ethnopharmacology and phytochemistry of Aristolochia species from the Americas, based upon 238 literature references and specimen vouchers of 28 Americas herbaria. The resulting database encompasses 919 records on 95 Aristolochia species with 129 documented traditional medicinal uses. South America and Mexico displayed the highest prevalence of traditional medicinal uses at the regional and national levels, respectively. The most recurrent medicinal uses included treatments against poisonous animals (17.6 %), gastrointestinal diseases (15.1 %), and gynecological diseases (9.89 %). American Aristolochia species produce secondary metabolites such as lignans, diterpenes, sesquiterpenes, isoquinoline and protopine type alkaloids, aristolactams, and aristolochic acids that have been shown to have substantial therapeutic potential. These compounds exhibit various properties, such as neurotrophic effects, inhibition of myotoxicity, anticholinergic and antihistaminic activities, relaxation of the tracheal muscle, as well as antibacterial, antifungal, antiprotozoal activity and, antispasmodic effects. However, in vivo and toxicity tests remain scarce. For example, less than 5 % of the publications focus on isolating aristolochic acids, known for their association with nephropathy and urothelial cancer. We found no instances of hazardous or fatal incidents resulting from traditional uses, despite their known toxicity. This is likely because traditional healers are aware of the hazards and dosage quantities. Finally, we identified crucial future directions for Aristolochia studies based on promising bioprospecting studies; relatively understudied infrageneric groups; poorly known traditional uses, and species-specific chemical compounds without further studies.

Extraction technology, component analysis, and the immunomodulatory effects in immunosuppressed broilers of total flavonoids extract from the thorns of Gleditsia sinensis Lam

Spina Gleditsiae is the dry thorns from Gleditsia sinensis Lam. (G. sinensis), exhibits the effect of reducing swelling and toxins, and draining pus. Flavonoids are the primary active constituents of Spina Gleditsiae, but their extraction technology has not been studied systematically. Relevant studies revealed that Spina Gleditsiae shown certain immunomodulatory effects, but its mechanism was still unclear. This research was carried out about the extraction process, chemical composition, and the effects on the immune function of total flavonoids extract (TFE). The extraction conditions of TFE were investigated by response surface methodology, and the major components were preliminarily analyzed and inferred by ultra performance liquid chromatography- quadrupole-time-of-flight-mass spectrum method. The immunomodulatory effect of TFE was evaluated by cyclophosphamide induced immunosuppressed broilers. The yield of TFE was 1.80 % under the following optimized conditions: ethanol concentration 50 %, extraction time 20 min, and the ratio of solvent to material 50:1 ml/g. In addition, the main chemical components in the TFE have been preliminarily identified based on related literature and mass spectrometry information. Meanwhile, the TFE could mitigate the immunosuppressive state caused by cyclophosphamide in broilers by improving the histomorphology of immune organs, increasing the index of immune organ, elevating the serum levels of IL-2, IFN-β, and IFN-γ, and raising the titer of Newcastle disease antibodies in the serum. Furthermore, the immunoregulatory effects of these flavonoids were found to be closely related to the enhancement of the relative expression level of key genes and proteins in the TLR4-MyD88/TICAM-NF-κB signaling pathway. The findings of the study suggest that TFE derived from the thorns of G. sinensis holds promise as an enhanced traditional Chinese medicine with the capability to potentially bolster immune function.

Multi-target mechanisms and potential applications of quercetin in the treatment of acne vulgaris

Acne vulgaris, a prevalent inflammatory dermatosis, afflicts approximately 90% of adolescents globally. Despite the efficacy of conventional therapies, including antibiotics and retinoids, their use is frequently limited by adverse effects and the emergence of drug resistance. Quercetin, a naturally occurring flavonoid, has garnered significant attention owing to its diverse biological activities, encompassing anti-inflammatory, antioxidant, antimicrobial, and immunomodulatory properties. This review comprehensively explores the multi-target mechanisms of quercetin in the treatment of acne, focusing on its ability to modulate inflammatory cytokine production, oxidative stress pathways, sebaceous gland activity, and microbial populations. Additionally, quercetin promotes skin barrier repair and reduces post-inflammatory hyperpigmentation and scarring through its antioxidant and anti-fibrotic effects. Despite promising in vitro and preclinical findings, challenges such as quercetin's low bioavailability and lack of robust clinical evidence necessitate further research. Advanced delivery systems, including nanoparticles and combination therapies, may optimize its therapeutic potential. This review provides insights into the molecular mechanisms and clinical applications of quercetin, highlighting its potential as a safe and effective alternative for acne management.

Design and fabrication of pH-responsive skin scaffolds based on carrageenan and konjac glucomannan for accelerated wound healing

The aim of this study was to utilize pH-responsive hydrogel skin scaffolds to achieve the sustained release of bioactive compounds (BCs) to promote wound healing. ZIF-8@flavanone nanoparticles were successfully synthesized through microfluidic channels and integrated into a hydrogel scaffold consisting of carrageenan (KC) and konjac glucomannan (KGM) to create a pH-responsive composite hydrogel scaffold. The unique pore structure of ZIF-8 efficiently loaded the active material, and the coordination bonds were disrupted in a slightly acidic environment, allowing the release of flavonoids. The natural macromolecular polysaccharides KC and KGM have good biocompatibility, and as a moist but not wet hydrogel scaffold substrate, they more closely resemble the growth environment of cells and are more favorable for wound healing. The hydrogel scaffolds developed in this study had a tensile strength of 1.15 MPa, an elongation at break of 320 %, good biocompatibility, a relative cell viability of 99.6 %, relative antimicrobial rate of 96.3 % (E. coli) and 95.8 % (S. aureus), respectively, and a release rate of 43.3 % at a pH of 5.0, and a wound closure rate at 15 d of 90.5 %, contributing to the improvement of wound healing performance and providing new possibilities for customized antimicrobial wound dressings.

Research Progress on the Antibacterial Activity of Natural Flavonoids

The use of antibiotics has greatly improved the treatment of bacterial infections; however, its abuse and misuse has led to a rapid rise in multidrug-resistant (MDR) bacteria. Therefore, the search for new antimicrobial strategies has become critical. Natural flavonoids, a class of widely existing phytochemicals, have gained significant research interest for their diverse biological activities and antibacterial effects on various drug-resistant bacteria. This review summarizes the latest research progress on flavonoids, with a particular focus on several flavonoids exhibiting certain antibacterial activity, and explores their antibacterial mechanisms, including disruption of cell membranes and cell walls, inhibition of proteins and nucleic acids, interference with signal transduction, suppression of efflux pump activity, and inhibition of biofilm formation and virulence factor production. Additionally, we have reviewed the synergistic combinations of flavonoids with antibiotics, such as the combination of quercetin with colistin or EGCG with tetracycline, which significantly enhance therapeutic efficacy.

Kaempferol Mitigates Pseudomonas aeruginosa-Induced Acute Lung Inflammation Through Suppressing GSK3β/JNK/c-Jun Signaling Pathway and NF-κB Activation

Background: Pseudomonas aeruginosa, one of the common bacterial pathogens causing nosocomial pneumonia, is characterized as highly pathogenic and multidrug-resistant. Kaempferol (KP), a natural flavonoid, has been shown to exhibit effectiveness in treating infection-induced lung injury. Methods: We applied network pharmacology to explore the underlying mechanisms of KP in treating P. aeruginosa pneumonia and further validated them through a mouse model of acute bacterial lung infection and an in vitro macrophage infection model. Results: The in vivo studies demonstrated that treatment with KP suppressed the production of proinflammatory cytokines, including TNF, IL-1β, IL-6, and MIP-2, and attenuated the neutrophil infiltration and lesions in lungs, leading to an increased survival rate of mice. Further studies revealed that KP treatment enhanced the phosphorylation of GSK3β at Ser9 and diminished the phosphorylation of JNK, c-Jun, and NF-κB p65 in lungs in comparison to the mice without drug treatment. Consistently, the in vitro studies showed that pretreatment with KP reduced the activation of GSK3β, JNK, c-Jun, and NF-κB p65 and decreased the levels of the proinflammatory cytokines in macrophages during P. aeruginosa infection. Conclusions: KP reduced the production of proinflammatory cytokines by inhibiting GSK3β/JNK/c-Jun signaling pathways and NF-κB activation, which effectively mitigated the P. aeruginosa-induced acute lung inflammation and injury, and elevated the survival rates of mice.

Unveiling the synergistic effect of icariin and azole drugs on Candida albicans

Introduction and Method

The current study explores the synergistic effects of icariin, a flavonoid found in plants of the genus Epimedium, in ombination with selected antifungal agents, against Candida albicans in vitro.

Results

This flavonoid significantly enhanced the in vitro effect of fluconazole, by decreasing the minimum inhibitory concentration against C. albicans. This effect was also observed when combining icariin with ketoconazole and itraconazole of the azole family respectively. Interestingly, no activity-enhancing effect was observed when icariin was combined with other classes of antifungals, such as amphotericin B or caspofungin.

Discussion

We conclude that icariin may increase the sensitivity of C. albicans to azoles via a cell membrane mediated mechanism, based on our results from FUN-1 microscopy and coincubation with cell wall and cell membrane stressors. Further research is required to explore these effects in clinical isolates, particularly fluconazole-resistant C. albicans, with a view towards the clinical application of icariin as a co-adjuvant in antifungal azole therapy.

Quercetin and Silybin Decrease Intracellular Replication of Piscirickettsia salmonis in SHK-1 Cell

Piscirickettsia salmonis is the pathogen that has most affected the Chilean salmon industry for over 30 years. Considering the problems of excessive use of antibiotics, it is necessary to find new strategies to control this pathogen. Antivirulence therapy is an alternative to reduce the virulence of pathogens without affecting their growth. Polyphenolic compounds have been studied for their antiviral capacity. In this study, the capacity of quercetin and silybin to reduce the intracellular replication of P. salmonis in SHK-1 cells was evaluated. For this, three different infection protocols in Salmon Head Kidney-1(SHK-1) cells were used: co-incubation for 24 h, pre-incubation for 24 h prior to infection, and post-incubation for 24 h after infection. In addition, the effect of co-incubation in rainbow trout intestinal epithelial cells (RTgutGC) and the effect on the phagocytic capacity of SHK-1 cells were evaluated. The results obtained showed that quercetin and silybin decreased the intracellular replication of P. salmonis in SHK-1 cells when they were co-incubated for 24 h; however, they did not have the same effect in RTgutGC cells. On the other hand, both compounds decreased the phagocytosis of SHK-1 cells during co-incubation. These results are promising for the study of new treatments against P. salmonis.

Unravelling Chemical Profile, Antioxidant, Anti-Alzheimer and Antimicrobial Potentials of Three Propolis From Northeastern Regions of Algeria: In Vitro and In Silico Evaluation

This study investigates the pharmaceutical potential both in vitro and in silico of ethanolic propolis extract from three Algerian regions namely Tahir-Jijel (TAH), Oued Athmania-Mila (ATH) and Oued Zhor-Skikda (OZ). Twenty-three compounds were identified via a high-performance liquid chromatography-diode array detector, with key constituents including caffeic acid, cynarin, chrysin, naringin and hesperetin. Moreover, antioxidant and anti-Alzheimer activities were assessed by multiple assays. Antimicrobial activity was tested against four pathogens and one yeast. The TAH extract showed the highest antioxidant activity, and ATH exhibited the strongest anticholinesterase activity. Extracts demonstrated potent inhibition against Staphylococcus aureus and Micrococcus luteus ATCC 4698. Docking studies revealed that cynarin was the most potent acetylcholinesterase inhibitor, and quercetin was the most potent butyrylcholinesterase inhibitor. These compounds were found to bind to both the catalytic site and the peripheral site, showing greater inhibitory potency than galantamine.

One Earth-One Health (OE-OH): Antibacterial Effects of Plant Flavonoids in Combination with Clinical Antibiotics with Various Mechanisms

Background/Objectives: Antimicrobial resistance (AMR) poses a significant threat to human health, and combination therapy has proven effective in combating it. It has been reported that some plant flavonoids can enhance the antibacterial effects of antibiotics and even reverse AMR. This study systematically evaluated the synergistic effects of plant flavonoids and clinical antibiotics. Methods: The antibacterial activities of thirty-seven plant flavonoids and nine clinical antibiotics with various antimicrobial mechanisms were determined using the microbroth dilution method. Subsequently, the combined effects of twelve plant flavonoids presenting definite MICs against Staphylococcus aureus with these nine antibiotics were determined using the checkerboard test, together with those of thirty-two plant flavonoids presenting definite MICs against Escherichia coli with these nine antibiotics. Results: Plant flavonoids in combination with antibiotics present extensive synergistic effects, and 25% of combinations exhibited synergy against S. aureus and 50% against E. coli, particularly with antibiotics affecting cell membranes or ribosomes. Conclusions: The findings align with the drug selection principle of synergistic combinations and suggest that plant flavonoids could extensively enhance antibiotic efficacy. Considering that various metabolites from microorganisms, plants, and animals on the Earth would definitely impact the evolution of AMR, together with the rules, key factors, and important principles of drug combination for preventing AMR, we further propose the "One Earth-One Health (OE-OH)" concept, emphasizing ecosystem interactions in AMR prevention.

Exploring Antimicrobial Compounds from Agri-Food Wastes for Sustainable Applications

Transforming agri-food wastes into valuable products is crucial due to their significant environmental impact, when discarded, including energy consumption, water use, and carbon emissions. This review aims to explore the current research on the recovery of bioactive molecules with antimicrobial properties from agri-food waste and by-products, and discusses future opportunities for promoting a circular economy in its production and processing. Mainly, antibacterial molecules extracted from agri-food wastes are phenolic compounds, essential oils, and saponins. Their extraction and antimicrobial activity against a wide spectrum of bacteria is analyzed in depth. Also, their possible mechanisms of activity are described and classified based on their effect on bacteria, such as the (i) alteration of the cell membrane, (ii) inhibition of energy metabolism and DNA synthesis, and iii) disruption of quorum sensing and biofilm formation. These bioactive molecules have a wide range of possible applications ranging from cosmetics to food packaging. However, despite their potential, the amount of wastes transformed into valuable compounds is very low, due to the high costs relating to their extraction, technical challenges in managing supply chain complexity, limited infrastructure, policy and regulatory barriers, and public perception. For these reasons, further research is needed to develop cost-effective, scalable technologies for biomass valorization.

Chemical composition, antibacterial potential, and toxicity of the extracts from the stem bark of Hancornia speciosa Gomes (Apocynaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

Hancornia speciosa is a medicinal plant popularly used to treat different medical issues, including infectious diseases. Exploring the therapeutic potentialities of the extracts from medicinal plants combined with conventional antibiotic drugs is a promising horizon, especially considering the rising microbial resistance.

AIM OF THE STUDY

This study aimed to characterize the chemical composition of the ethereal (EEHS) and methanolic (MEHS) extracts of the stem bark of H. speciosa, and also evaluate their antibacterial and drug-modifying activity, and toxicity.

MATERIALS AND METHODS

The extracts were characterized by gas chromatography coupled to mass spectrometry (GC-MS). Additionally, total phenol and flavonoid contents were determined. The antibacterial and antibiotic-modifying activity was evaluated against strains of Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa using the serial microdilution method, obtaining the minimum inhibitory concentration (MIC). The toxicity assay was carried out using the Drosophila melanogaster model.

RESULTS

Thirty compounds were identified in the extracts of the stem bark of H. speciosa, with triterpenoids being predominant in both extracts. Additionally, fatty alcohols, carbohydrates, fatty acids, phenolic acids, and phytosterols were identified in both extracts. EEHS and MEHS extracts had considerable phenol contents (346.4 and 340.0 mg GAE/g, respectively). Flavonoids were detected in a lower proportion (7.6 and 6.9 mg QE/g, respectively). H. speciosa extracts did not display intrinsic antibacterial activity against the bacterial strains evaluated, however, they were capable of modifying the activity of gentamicin, erythromycin, and norfloxacin. EEHS increased the efficacy of norfloxacin against E. coli and S. aureus, reducing MIC values by 50%. MEHS potentiated the action of gentamicin against all bacterial strains, especially against E. coli. The extracts did not display toxicity at clinically relevant concentrations against D. melanogaster.

CONCLUSION

The stem bark of H. speciosa was considered a rich source of bioactive compounds. Our findings evidenced the therapeutic potential of H. speciosa extracts for the development of new pharmaceutical therapeutics against bacteria. Although the extracts did not exhibit intrinsic antibacterial activity, they enhanced the efficacy of commercial antibiotic drugs and were non-toxic at clinically relevant concentrations. Future studies are needed to elucidate the mechanisms of action of these extracts, ensuring their safety and efficacy.

Genus Monanthotaxis: a review on distribution, ethnomedicinal uses and phytochemistry

This article reviews the geographical distribution, ethnomedicinal applications, and phytochemistry of the genus Monanthotaxis Baill, tribe Uvariae of the family Annonaceae. The reviewed works of literature were collected from various electronic databases including Google Scholar, PubMed, Science Direct, The International Plant Names Index (IPNI), and Research Gate. During this review, ninety-eight species of the genus Monanthotaxis were found to be widely distributed in tropical Africa. Some of those species are used in folkloric medicine by various communities to manage diseases and disease conditions such as fever, vomiting, headache, stomach-ache, malaria, helminthiasis, and hysteria. In the past 44 years (1979 to 2023), one hundred and nineteen secondary metabolites with different biomedical potentials have been reported from this genus. The reported compounds are categorised into flavonoids, alkaloids, terpenoids, polyoxygenated cyclohexane, and cyclohexene derivatives, benzyl derivatives, cinnamic acid derivatives, and stilbenoids. Most of the reported compounds showed an array of bioactivities corroborating the use of some members of the genus in folkloric medicine.

Synergistic effect of phenylpropanoids and flavonoids with antibiotics against Gram-positive and Gram-negative bacterial strains

CONTEXT

The increase in bacterial resistance to currently available medications, which increases mortality rates, treatment costs is a global problem, and highlights the need for novel classes of antibacterial agents or new molecules that interact synergistically with antimicrobials.

OBJECTIVE

The current work explores the potential synergistic effects of certain natural phenylpropanoids and flavonoids on ciprofloxacin (CIP), ampicillin (AMP), gentamicin (GEN), and tetracycline (TET).

MATERIALS AND METHODS

The adjuvant role of cinnamic acid, p-coumaric acid, caffeic acid, ferulic acid, ferulic acid methyl ester, sinapic acid, apigenin, and luteolin was evaluated by determining the MIC (minimal inhibitory concentration) values of antibiotics in the presence of subinhibitory concentrations (200, 100, and/or 50 µM) of the compounds in Gram-positive and Gram-negative bacterial strains using a 2-fold broth microdilution method. The 96-well plates were incubated at 37 °C for 18 h, and dimethyl sulfoxide was used as a solvent control.

RESULTS

The combination of luteolin with CIP, reduced the MIC values of the antibiotic from 0.625 to 0.3125 µM and to 0.078 µM in 100 and 200 µM concentration, respectively, in sensitive Staphylococcus aureus. Sinapic acid decreased the MIC value of CIP from 0.625 to 0.3125 µM in S. aureus, from 1.56 to 0.78 µM in Klebsiella pneumoniae, and the MIC of GEN from 0.39 to 0.095 µM in Pseudomonas aeruginosa strains.

DISCUSSION AND CONCLUSIONS

These findings are useful in delaying the development of resistance, as the required antibacterial effect can be achieved with the use of lower concentrations of antibiotics.

Antimicrobial activities of natural flavonoids against foodborne pathogens and their application in food industry

The application of natural alternatives as food preservatives has gained much attention due to the escalating negative perception of synthetic preservatives among consumers and the spread of drug-resistance foodborne pathogens. Natural flavonoids have the potential to be employed for food safety due to their antimicrobial properties against a wide range of foodborne pathogenic microorganisms. In this perspective, we reviewed the antimicrobial activities of natural flavonoids, the mechanism of action, as well as their application for food safety and quality. Various strategies for the incorporation of flavonoids into food products were highlighted, including direct addition to food formulations, encapsulation as micro or nanocarriers, and incorporation into edible or active films and coatings. Furthermore, we discussed the current challenges of industrial application of flavonoids, and proposed future trends to enhance their potential as natural preservatives. This review provides a theoretical foundation for the further development and application of flavonoids for food safety.

Multi-omics Analysis of Klebsiella pneumoniae Revealed Opposing Effects of Rutin and Luteolin on Strain Growth

The emergence of pathogenic bacteria resistant to conventional antibiotics is becoming increasingly challenging. Plant-derived flavonoids are potential alternatives to antibiotics, owing to their antimicrobial properties. However, the molecular mechanisms through which they inhibit the growth of pathogenic microorganisms remain unclear. Therefore, Klebsiella pneumoniae ATCC700603 was separately incubated in two flavonoids to elucidate their inhibitory mechanism. Metabolomic and transcriptomic analyses were performed after 4-h incubation. In total, 5483 genes and 882 metabolites were identified. Compared to the untreated control, rutin and luteolin activated 507 and 374 differentially expressed genes (DEGs), respectively. However, the number of differential abundant metabolites (DAMs) remained the same. The top 10 correlated DEGs and DAMs were identified within each comparative group after a correlation analysis. Rutin induced the accumulation of unique metabolites and suppressed gene expression whereas luteolin did not. Our results explain the disparate effects of these two flavonoids and demonstrate the inhibitory mechanism of rutin on strain growth.

Salmonella dry surface biofilm: morphology, single-cell landscape, and sanitization

In this study, Salmonella Typhimurium dry surface biofilm (DSB) formation was investigated in comparison with wet surface biofilm (WSB) development. Confocal laser scanning microscopic analysis revealed a prominent green cell signal during WSB formation, whereas a red signal predominated during DSB formation. Electron microscopy was also used to compare the features of DSB and WSB. Overall, WSB was unevenly scattered over the surface, whereas DSB was evenly dispersed. In contrast to WSB cells, which have a distinct plasma membrane and outer membrane layer, DSB cells are contained in large capsules and compressed. Next, microbiome single-cell transcriptomics was used to investigate the functional heterogeneity of the Salmonella DSB microbiome, with nine clusters successfully identified. Although over 60% of the dried cells were metabolically inactive, the rest of the Salmonella cells still demonstrated specific antioxidative and virulence capabilities, suggesting a possible concern for low-moisture food (LMF) safety. Finally, because sanitization in LMF industries must be conducted without water, a list of 39 flavonoids was tested for their combined effect with 70% isopropyl alcohol (IPA) against DSB, and morin induced the greatest reduction in the green:red ratio from 3.67 to 0.43. Significantly higher reductions of Salmonella viability in DSB were achieved by 10-, 100-, 1,000-, and 10,000-µg/mL morin (1.69 ± 0.25, 3.21 ± 0.23, 4.32 ± 0.24, and 5.18 ± 0.16 log CFU/sample reductions) than 70% IPA alone (1.55 ± 0.20 log CFU/sample reduction) (P < 0.05), indicating the potential to be formulated as a dry sanitizer for the LMF industry.IMPORTANCEDSB growth of foodborne pathogens in LMF processing environments is associated with food safety, financial loss, and compromised consumer trust. This work is the first comprehensive examination of the characteristics of Salmonella DSB while exploring its underlying survival mechanisms. Furthermore, morin dissolved in 70% IPA was proposed as an efficient dry sanitizer against DSB to provide insights into biofilm control during LMF processing.

The Potential of Plant Extracts Used in Cosmetic Product Applications-Antioxidants Delivery and Mechanism of Actions

Natural ingredients have been used in skincare products for thousands of years. The current focus is on novel natural bioactivities that shield the skin from UV rays and free radicals, among other damaging elements, while enhancing skin health. Free radicals significantly contribute to skin damage and hasten ageing by interfering with defence and restorative processes. Plants contain natural chemicals that can scavenge free radicals and have antioxidant capabilities. Plant materials are becoming increasingly popular as natural antioxidants related to the expanding interest in plant chemistry. This review focuses on the significance of medicinal plants in skin health and ageing and their potential as a source of antioxidant substances such as vitamins, polyphenols, stilbenes, flavonoids, and methylxanthines.

Experimental and theoretical studies on antioxidant and antibacterial properties of chitosan-gelatin functional composite films loaded with flavonoids

Chitosan-gelatin-flavonoid functional composite films were prepared with chitosan, gelatin, and three flavonoids (Naringenin, Apigenin, and Luteolin). The effect of three flavonoids on physical, antioxidant, and antibacterial properties of functional composite film was investigated from experimental and Density functional theory (DFT) simulations. The tensile strength, thermal stability, water solubility, water vapor permeability, antioxidant activity, and antibacterial activity of chitosan-gelatin-flavonoid functional composite films were improved with flavonoid (Naringenin, Apigenin, and Luteolin) incorporation. The release behavior of Apigenin from functional composite film was much lower than that of Naringenin or Luteolin. ABTS+ radical scavenging ability values of functional composite films followed: Luteolin (69.53 %) > Naringenin (41.39 %) > Apigenin (36.13 %). The antibacterial activities of functional composite films against Staphylococcus aureus followed: Luteolin (52.03 mm) > Apigenin (49.34 mm) > Naringenin (43.15 mm). The total number, location of hydroxyl groups on ring-B, and the unsaturation degree on pyrone ring of flavonoids influenced antioxidant and antibacterial activities of functional composite films. The minimum bond dissociation enthalpy values of flavonoids followed: Luteolin < Apigenin < Naringenin. The interaction energy of Apigenin-chitobiose was stronger than that of Naringenin or Luteolin. These results will shed light on flavonoid selection for functional composite films of food packaging.

In vitro antibacterial activity of Morinda citrifolia extracts against eight pathogenic bacteria species

Medical professionals continue to face a severe issue with the evolution of resistance to conventional antibiotics. The search for new novel compounds from plants has been proven to be the alternative solution. Morinda citrifolia is used traditionally for the treatment of infectious diseases. The present study investigates the antibacterial properties of M. citrifolia root, leaf, and fruit (fresh, dried, and fermented) extracts on three-gram-positive and five-gram-negative bacteria. The plant parts were processed and extracted in distilled water and ethanol (60%, 80%, and absolute (100%)). The antibacterial activities of the extracts were assessed in vitro using the agar well diffusion method, with Ciprofloxacin serving as the positive control. All the tests were conducted three times to obtain the average value of inhibition zones. Overall, root extracts showed the most significant antibacterial activity, followed by dried fruit, fermented fruit extract, fresh fruit, and the least leaf extract. Using one-way ANOVA and Tukey's post-hoc tests, the statistical analysis revealed significant differences in antibacterial activity among the extracts and solvent concentrations. The 100% ethanol extracts had significantly higher zones of inhibition compared to the other solvents. The most inhibitory activity was against Campylobacter spp. (21.33±1.80) for the 80% ethanol root extract. All the extracts of M. citrifolia were found to exhibit moderate antibacterial activity against all the bacteria pathogens. However, Enterococcus faecium, Campylobacter spp., and Bacillus cereus were most sensitive to all the plant extracts while Shigella spp. and Klebsiella spp. showed resistance to most extracts. This observed difference is significant for each strain extract depending on the bacteria strain and the type of solvent extract (p < 0.001). The findings indicate a promising antimicrobial potential of M. citrifolia extracts.

Medicinal plants as a potential resource for the discovery of novel structures towards cancer drug resistance treatment

Despite extensive research in chemotherapy, global cancer concerns persist, exacerbated by the challenge of drug resistance, which imposes economic and medical burdens. Natural compounds, particularly secondary metabolites from medicinal plants, present promising avenues for overcoming cancer drug resistance due to their diverse structures and essential pharmacological effects. This review provides a comprehensive exploration of cancer cell resistance mechanisms and target actions for reversing resistance and highlights the in vitro and in vivo efficacy of noteworthy alkaloids, flavonoids, and other compounds, emphasizing their potential as therapeutic agents. The molecular properties supporting ligand interactions are thoroughly examined, providing a robust theoretical foundation. The review concludes by discussing methods including quantitative structure-activity relationships and molecular docking, offering insights into screening potential candidates. Current trends in clinical treatment, contributing to a holistic understanding of the multifaceted approaches to address cancer drug resistance are also outlined.

Bioactivity-Guided Isolation of Secondary Metabolites from Camellia fascicularis: Antioxidative Antibacterial Activities and Anti-Inflammatory Hypoglycemic Molecular Docking

Camellia fascicularis is a valuable ornamental, edible, and medicinal plant with promising prospects for bioactivity development. We screened the bioactivity of eight fractions (Fr. A-I) obtained from the ethyl acetate phase of C. fascicularis via silica gel column chromatography. The results indicated that the anti-inflammatory, antioxidative, and antimicrobial active components were mainly found in Fr. B*, E, A, and H; Fr. A-G; and Fr. D-I, respectively. Bioactivity-guided isolation identified 18 secondary metabolites. Compounds 1, 3-5, 7, and 15-18 were isolated from the genus Camellia for the first time in this study, whereas the other compounds were also isolated from this plant for the first time. The structures of these compounds were elucidated through comprehensive spectroscopic techniques. Compounds 1, 9-11, 28, 30, and 31 demonstrated antioxidative activities comparable to those of ascorbic acid, whereas the remaining compounds exhibited diminished antioxidative activity. In terms of antimicrobial activity, compounds 7, 18, 22, and 27 exerted inhibitory potency against Pseudomonas aeruginosa, similar to tetracycline (MIC: 125 µg/mL). Other compounds showed moderate to weak inhibitory effects against Staphylococcus aureus and Escherichia coli (MIC: 250-500 µg/mL). Molecular docking revealed that compounds 2, 36, 41, and 65 showed strong binding affinity for 8ET0, whereas compounds 2, 36, 38, 40, 63, and 65 showed strong binding affinity for 3A4A. This research further increased the diversity of the secondary metabolites of C. fascicularis, laying a foundation for the subsequent development and utilization of this species.

Antibacterial effects of Kampo products against pneumonia causative bacteria

Community-acquired pneumonia is caused primarily by bacterial infection. For years, antibiotic treatment has been the standard of care for patients with bacterial pneumonia, although the emergence of antimicrobial-resistant strains is recognized as a global health issue. The traditional herbal medicine Kampo has a long history of clinical use and is relatively safe in treating various diseases. However, the antimicrobial effects of Kampo products against pneumonia-causative bacteria remain largely uncharacterized. In this study, we investigated the bacteriological efficacy of 11 Kampo products against bacteria commonly associated with pneumonia. Sho-saiko-To (9), Sho-seiryu-To (19), Chikujo-untan-To (91) and Shin'i-seihai-To (104) inhibited the growth of S. pneumoniae serotype 3, a highly virulent strain that causes severe pneumonia. Also, the growth of S. pneumoniae serotype 1, another highly virulent strain, was suppressed by treatment with Sho-saiko-To (9), Chikujo-untan-To (91), and Shin'i-seihai-To (104). Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against these strains ranged from 6.25-50 mg/mL and 12.5-25 mg/mL, respectively. Furthermore, Sho-saiko-To (9), Chikujo-untan-To (91), and Shin'i-seihai-To (104) suppressed the growth of antibiotic-resistant S. pneumoniae isolates. Additionally, Sho-saiko-To (9) and Shin'i-seihai-To (104) showed growth inhibition activity against Staphylococcus aureus, another causative agent for pneumonia, with MIC ranging from 6.25-12.5 mg/mL. These results suggest that some Kampo products have antimicrobial effects against S. pneumoniae and S. aureus, and that Sho-saiko-To (9) and Shin'i-seihai-To (104) are promising medicines for treating pneumonia caused by S. pneumoniae and S. aureus infection.

Insights into Catechin-Copper Complex Structure and Biologic Activity Modulation

Compounds of natural origin found in varying quantities in plant-based products constitute a highly significant category, possessing structural significance as well as the capacity to regulate oxidative processes. The activity of these compounds may be modulated by the composition of the biological environment in which they operate, the pH of the environment, or the presence of metal cations in plants or plant extracts. A successful complexation reaction was mainly confirmed by FT-IR, observing the shift from the original transmittance of catechin bonds, especially O-H ones. This work shows the synthetic methodology and the optimization process that took place to synthesize a catechin-copper complex, which demonstrated antioxidant activity. It was tested for iron chelation ability, hydroxyl radicals, and the inhibition of lipoxygenase (15-LOX). An antidiabetic assay was performed by determining the inhibition of alpha-amylase and alpha-glucosidase, finding that the synthesized complex had similar inhibitory potential as pure catechin. The antibacterial tests showed results against Staphylococcus aureus and the antifungal properties of the complex against Candida albicans.

Recent Progress in Terrestrial Biota Derived Antibacterial Agents for Medical Applications

Conventional antibiotic and multidrug treatments are becoming less and less effective and the discovery of new effective and safe antibacterial agents is becoming a global priority. Returning to a natural antibacterial product is a relatively new current trend. Terrestrial biota is a rich source of biologically active substances whose antibacterial potential has not been fully utilized. The aim of this review is to present the current state-of-the-art terrestrial biota-derived antibacterial agents inspired by natural treatments. It summarizes the most important sources and newly identified or modified antibacterial agents and treatments from the last five years. It focuses on the significance of plant- animal- and bacteria-derived biologically active agents as powerful alternatives to antibiotics, as well as the advantages of utilizing natural antibacterial molecules alone or in combination with antibiotics. The main conclusion is that terrestrial biota-derived antibacterial products and substances open a variety of new ways for modern improved therapeutic strategies. New terrestrial sources of known antibacterial agents and new antibacterial agents from terrestrial biota were discovered during the last 5 years, which are under investigation together with some long-ago known but now experiencing their renaissance for the development of new medical treatments. The use of natural antibacterial peptides as well as combinational therapy by commercial antibiotics and natural products is outlined as the most promising method for treating bacterial infections. In vivo testing and clinical trials are necessary to reach clinical application.

Recent advances in dietary polyphenols (DPs): antioxidant activities, nutrient interactions, delivery systems, and potential applications

Dietary polyphenols (DPs) have garnered growing interest because of their potent functional properties and health benefits. Nevertheless, the antioxidant capabilities of these substances are compromised by their multifarious structural compositions. Furthermore, most DPs are hydrophobic and unstable when subjected to light, heat, and varying pH conditions, restricting their practical application. Delivery systems based on the interactions of DPs with food constituents such as proteins, polypeptides, polysaccharides, and metal ions are being created as a viable option to improve the functional activities and bioavailability of DPs. In this review, the latest discoveries on the dietary sources, structure-antioxidant activity relationships, and interactions with nutrients of DPs are discussed. It also innovatively highlights the application progress of polyphenols and their green nutraceutical delivery systems. The conclusion drawn is that the various action sites and structures of DPs are beneficial for predicting and designing polyphenols with enhanced antioxidant attributes. The metal complexation of polyphenols and green encapsulation systems display promising outcomes for stabilizing DPs during food processing and in vivo digestion. In the future, more novel targeted delivery systems of DPs for nutrient fortification and intervention should be developed. To expand their usage in customized food products, they should meet the requirements of specific populations for personalized food and nutrition.

Multifunctional pH-responsive hydrogel dressings based on carboxymethyl chitosan: Synthesis, characterization fostering the wound healing

Antibiotic abuse is increasing the present rate of drug-resistant bacterial wound infections, producing a significant healthcare burden globally. Herein, we prepared a pH-responsive CMCS/PVP/TA (CPT) multifunctional hydrogel dressing by embedding the natural plant extract TA as a nonantibiotic and cross-linking agent in carboxymethyl chitosan (CMCS) and polyvinylpyrrolidone (PVP) to prompt wound healing. The CPT hydrogel demonstrated excellent self-healing, self-adaptive, and adhesion properties to match different wound requirements. Importantly, this hydrogel showed pH sensitivity and exhibited good activity against resistant bacteria and antioxidant activity by releasing TA in case of bacterial infection (alkaline). Furthermore, the CPT hydrogel exhibited coagulant ability and could rapidly stop bleeding within 30 s. The biocompatible hydrogel effectively accelerated wound healing in a full-thickness skin defect model by thickening granulation tissue, increasing collagen deposition, vascular proliferation, and M2-type macrophage polarization. In conclusion, this study demonstrates that multifunctional CPT hydrogel offers a candidate material with potential applications for infected skin wound healing.

Quercetin, the Potential Powerful Flavonoid for Human and Food: A Review

Flavonoids occur naturally in different types of fruits and vegetables, including tea, cabbage, cauliflower, elderberries, cranberries, red apples, lettuce, pears, spinach, green hot peppers, white and red onions, kale, blueberries, and nuts. Among these flavonoids is quercetin, a potent natural antioxidant and cytotoxic substance with a number of therapeutic functions. Nowadays, quercetin is a common ingredient in many nutraceutical and cosmeceutical products due to its antioxidant properties. Its antibacterial effects and possible action mechanisms have been explored in many studies. From these, it has been established that quercetin stops the activity of numerous Gram-negative and -positive bacteria, fungi, and viruses. This review clarifies the plant sources and extraction methods of quercetin, as well as its medicinal applications as an antibacterial, antifungal, antiviral, and antioxidant agent, with a particular emphasis on the underlying mechanisms of its biological activity. The mechanism of its antimicrobial effect involves damaging the cell membrane-e.g., by changing its permeability, preventing biofilm formation, reducing the mitochondrial expression of virulence factors, and inhibiting protein and nucleic-acid synthesis. Moreover, quercetin has been shown to impede the activity of a variety of drug-resistant bacterial strains, pointing to the possibility of using it as a strong antimicrobial substance against such strains. In addition, it has occasionally been demonstrated that specific structural alterations to quercetin can increase its antibacterial action in comparison to the parent molecule. Overall, this review synthesizes our understanding of the mode of action of quercetin and its prospects for use as a therapeutic material.

Plant Flavonoids with Antimicrobial Activity against Methicillin-Resistant Staphylococcus aureus (MRSA)

Methicillin-resistant Staphylococcus aureus (MRSA) has become a serious threat to human public health and global economic development, and there is an urgent need to develop new antimicrobial agents. Flavonoids are the largest group of plant secondary metabolites, and the anti-S. aureus and anti-MRSA activities of flavonoids have now been widely reported. The aim of this Review is to describe plant-derived flavonoid active ingredients and their effects and mechanisms of inhibitory activity against MRSA in order to provide insights for screening novel antimicrobial agents. Here, 85 plant-derived flavonoids (14 flavones, 21 flavonols, 26 flavanones, 9 isoflavones, 12 chalcones, and 3 other classes) with anti-MRSA activity are reviewed. Among these flavonoids, flavones and isoflavones generally showed the most significant anti-MRSA activity (MICs: 1-8 μg/mL). The results of the present Review display that most of the flavonoids with excellent anti-MRSA activity were derived from Morus alba L. and Paulownia tomentosa (Thunb.) Steud. The antibacterial mechanism of flavonoids against MRSA is mainly achieved by disruption of membrane structures, inhibition of efflux pumps, and inhibition of β-lactamases and bacterial virulence factors. We hope this Review can provide insights into the development of novel antimicrobials based on natural products for treating MRSA infections.

In vitro antimicrobial and cytotoxic potential against colorectal cancer cell lines using ethanolic leaf extract of Sansevieria trifasciata (Agavaceae)

BACKGROUND

Sansevieria trifasciata, common name, mother-in-law's tongue, is a member of the Agavaceae family. We undertook this study to evaluate the cytotoxicity of S. trifasciata leaf extract against two cancer cell lines as well as its antibacterial activities against six bacterial strains.

MATERIALS AND METHODS

The investigated cell lines include primary colon epithelial (PCE) cells and human colorectal cancer cells; the studied bacterial strains are Staphylococcus aureus, Proteus vulgaris, Bacillus subtilis, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Escherichia coli. Using the agar well-diffusion method, various doses (5, 10, and 20 mg/mL) of plant extracts (ethanol and petroleum ether) were evaluated against each kind of bacterial strain. The minimal inhibitory doses were found using the two-fold serial dilution approach, with a range of 0.156-5 mg/mL.

RESULTS

Comparing extracts of S. trifasciata leaves to tetracycline (0.05 mg/mL), a common antibiotic, revealed a wide range of antibacterial activity. P. vulgaris and S. aureus were the most sensitive bacterial strains to ethanol and petroleum ether extracts, respectively. The MTT test was employed to ascertain the viable cell count of PCE cells and HCT-116. When various ethanol extract concentrations (7.8, 15.63, 31.25, 62.5, 125, 250, 500, and 1000 μg/mL) were tested against the cell lines, HCT-116's IC50, values were lower as compared to PCE. The IC50 values for HCT-116 and PCE cells ranged from 10.0 to 14.07 μg/mL and 92.9-216.9 μg/mL, respectively.

CONCLUSIONS

Ethanolic extract of S. trifasciata showed promising antibacterial and anticancer properties.

Flavonoidal alkaloids: Emerging targets for drug discovery from Nature's bounty

This paper explores the potential of flavonoid alkaloids, a unique class of compounds that contain both flavonoid and alkaloid structures, as emerging targets for drug discovery. These compounds exhibit diverse biological activities, such as anti-inflammatory, anti-cancer, and anti-diabetic effects, which are attributed to the combination of different flavonoid scaffolds and alkaloid groups. Flavonoid alkaloids have attracted researchers' attention due to their diverse structures and important bio-activities. Therefore, this review summarizes recent advances in the extraction, purification, structural characterization, synthesis pathways and biological activities of flavonoid alkaloids from natural sources. Finally, the potential prospects and challenges associated with this class of compounds in pharmacological research are discussed along with details of a mechanistic investigation and future clinical applications in this research field.

Enhancing the antioxidant potential of ESIPT-based naringenin flavonoids based on excited state hydrogen bond dynamics: A theoretical study

Exploring antioxidant potential of flavonoid derivatives after ESIPT process provides a theoretical basis for discovering compounds with higher antioxidant capacity. In this work, employing the density functional theory (DFT) and time-dependent density functional theory (TD-DFT) methods, the antioxidant potential of two citrus-derived naringenin flavonoids after ESIPT process is explored. Based on studies of ESIPT process including IMHB intensity variations, potential energy curves, and transition state, these molecules exist only in enol and keto⁎ forms due to ultra-fast ESIPT. The HOMOs are utilized to explore electron-donating capacity, demonstrating that the molecules in keto⁎ form is stronger than that in enol form. Furthermore, the atomic dipole moment corrected Hirshfeld population (ADCH) and Fukui functions indicate that the sites attacked by the electrophilic free radical of the two molecules in the keto⁎ form are O3 and O5' respectively, and both are more active than in the enol form. Overall, a comprehensive consideration of the ESIPT process and antioxidant potential of flavonoid derivatives will facilitate the exploration and design of substances with higher antioxidant capacity.

Total flavonoids of litchi Seed alleviates schistosomiasis liver fibrosis in mice by suppressing hepatic stellate cells activation and modulating the gut microbiomes

Infection with Schistosoma japonicum (S. japonicum) is an important zoonotic parasitic disease that causes liver fibrosis in both human and domestic animals. The activation of hepatic stellate cells (HSCs) is a crucial phase in the development of liver fibrosis, and inhibiting their activation can alleviate this progression. Total flavonoids of litchi seed (TFL) is a naturally extracted drug, and modern pharmacological studies have shown its anti-fibrotic and liver-protective effects. However, the role of TFL in schistosomiasis liver fibrosis is still unclear. This study investigated the therapeutic effects of TFL on liver fibrosis in S. japonicum infected mice and explored its potential mechanisms. Animal study results showed that TFL significantly reduced the levels of Interleukin-1β (IL-1β), Tumor Necrosis Factor-α (TNF-α), Interleukin-4 (IL-4), and Interleukin-6 (IL-6) in the serum of S. japonicum infected mice. TFL reduced the spleen index of mice and markedly improved the pathological changes in liver tissues induced by S. japonicum infection, decreasing the expression of alpha-smooth muscle actin (α-SMA), Collagen I and Collagen III protein in liver tissues. In vitro studies indicated that TFL also inhibited the activation of HCSs induced by Transforming Growth Factor-β1 (TGF-β1) and reduced the levels of α-SMA. Gut microbes metagenomics study revealed that the composition, abundance, and functions of the mice gut microbiomes changed significantly after S. japonicum infection, and TLF treatment reversed these changes. Therefore, our study indicated that TFL alleviated granulomatous lesions and improved S. japonicum induced liver fibrosis in mice by inhibiting the activation of HSCs and by improving the gut microbiomes.

A PLGA/Silk Fibroin Nanofibre Membrane Loaded with Natural Flavonoid Compounds Extracted from Green Cocoons for Wound Healing

The use of biodegradable materials combined with natural metabolites in wound dressings has received much attention. Flavonoids (FLs) from green cocoons, as metabolites, have antibacterial, antioxidant, anti-inflammatory, and other pharmacological effects. In this study, composite membranes of FL-loaded polylactic glycolic acid (PLGA)/silk fibroin (SF) were prepared by an electrospinning method. The prepared membranes, including SF, exhibited a good slow-release effect and cytocompatibility. An in vitro evaluation of the FL-loaded PLGA/SF membranes demonstrated good antioxidant, antibacterial, and anti-inflammatory properties. Animal experiments showed that the wound healing rate of PLGA/SF-2.5FL membranes within 15 days was 97.3%, and that of the control group was 72.5%. The PLGA/SF-2.5FL membranes shortened the inflammatory period of a full-layer wound model and promoted skin regeneration and wound healing by downregulating expression of the pro-inflammatory cytokines IL-1β and TNF-α and promoting expression of the growth factors VEGF, TGF-β, and EGF. In summary, the PLGA/SF-2.5FL composite nanofibre membrane with anti-inflammatory properties is an ideal wound dressing to promote acute wound healing.

The Influence of Flavonoids with -Br, -Cl Atoms and -NO2, -CH3 Groups on the Growth Kinetics and the Number of Pathogenic and Probiotic Microorganisms

The pursuit of novel or modified substances based on a natural origin, like flavonoids, is essential in addressing the increasing number of diseases and bacterial resistance to antibiotics, as well as in maintaining intestinal balance and enhancing overall gut health. The primary goal of this research was to evaluate the impact of specific flavonoid compounds-chalcones, flavanones, and flavones-substituted with -Br, -Cl, -CH3, and -NO2 on both pathogenic and probiotic microorganisms. Additionally, this study aimed to understand these compounds' influence on standardized normal and pathologically altered intestinal microbiomes. 8-Bromo-6-chloroflavone 4'-O-β-D-(4″-O-methyl)-glucopyranoside and 8-bromo-6-chloroflavanone showed the most promising results as bactericidal agents. They significantly limited or inhibited the growth of pathogenic bacteria without adversely affecting the probiotic's growth. Digestion in vitro studies indicated that 6-methyl-8-nitroflavone and 8-bromo-6-chloroflavone positively modulated the gut microbiome by increasing beneficial bacteria and reducing potentially pathogenic microbes. This effect was most notable in microbiomes characteristic of older individuals and those recovering from chemotherapy or antibiotic treatments. This study underscores the therapeutic potential of flavonoid compounds, particularly those with specific halogen and nitro substitutions, in enhancing gut health.

Plant-Derived Antimicrobials and Their Crucial Role in Combating Antimicrobial Resistance

Antibiotic resistance emerged shortly after the discovery of the first antibiotic and has remained a critical public health issue ever since. Managing antibiotic resistance in clinical settings continues to be challenging, particularly with the rise of superbugs, or bacteria resistant to multiple antibiotics, known as multidrug-resistant (MDR) bacteria. This rapid development of resistance has compelled researchers to continuously seek new antimicrobial agents to curb resistance, despite a shrinking pipeline of new drugs. Recently, the focus of antimicrobial discovery has shifted to plants, fungi, lichens, endophytes, and various marine sources, such as seaweeds, corals, and other microorganisms, due to their promising properties. For this review, an extensive search was conducted across multiple scientific databases, including PubMed, Elsevier, ResearchGate, Scopus, and Google Scholar, encompassing publications from 1929 to 2024. This review provides a concise overview of the mechanisms employed by bacteria to develop antibiotic resistance, followed by an in-depth exploration of plant secondary metabolites as a potential solution to MDR pathogens. In recent years, the interest in plant-based medicines has surged, driven by their advantageous properties. However, additional research is essential to fully understand the mechanisms of action and verify the safety of antimicrobial phytochemicals. Future prospects for enhancing the use of plant secondary metabolites in combating antibiotic-resistant pathogens will also be discussed.

Molecular docking studies, DFT, and ADMET calculations of some flavonoids and their characteristic structural features involved in inhibition of pro-inflammatory enzymes

Inflammation is an immune system response triggered by pathogens, damaged cells, or stimuli. Some regulatory enzymes, such as phosphodiesterase, hyaluronidase, collagenase, and lipoxygenase, play an essential role in the inflammatory process. Polyphenolic compounds, such as flavonoids, are active suppressors of inflammatory cytokines, modulators of transcription factors, and inflammation-related pathways. A set of flavonoid structures was screened and docked against inflammation pathway enzymes. Amentoflavone has been shown to cause interactions with phosphodiesterase enzymes, while Bilobetin and Silibinin demonstrated an increase in binding energy with collagenase enzymes. The retrieved compounds from the docking study were subjected to DFT theory. The results showed that the LUMO orbital is located on the flavonoid part. The thermochemical parameters indicated that Silibinin is more stable than other compounds. The ADMET profile predicted that Silibinin can be used orally among the compounds. Silibinin can be introduced as a promising anti-inflammatory agent demonstrating phosphodiesterase and collagenase inhibitory properties.

Bioactivity-Guided Isolation of Secondary Metabolites with Antioxidant and Antimicrobial Activities from Camellia fascicularis

Camellia fascicularis has important ornamental, medicinal, and food values, which also have tremendous potential for exploiting bioactivities. We performed the bioactivity-guided (antioxidant and antimicrobial) screening of eight fractions obtained from the ethyl acetate phase of C. fascicularis. The antioxidant activity was measured by DPPH, ABTS, and FRAP, and the antibacterial activity was measured by the minimum inhibitory concentration (MIC) of Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus. The results of bioactivity-guided isolation indicated that the major antioxidant compounds in the ethanolic extracts of C. fascicularis may be present in fractions (Fr.) (A-G, obtained after silica gel column chromatography). Fr. (D-I, obtained after silica gel column chromatography) is a fraction of C. fascicularis with antimicrobial activity. The structures of compounds were determined by spectral analysis and nuclear magnetic resonance (NMR) combined with the available literature on secondary metabolites of C. fascicularis leaves. In this study, 17 compounds were identified, including four phenolics (1, 3-4, and 14), a phenylpropane (2), five terpenoids (5-7, 12, and 15), four flavonoids and flavonoid glycosides (8-10 and 16), and two lignins (13 and 17). Compounds 4-7, 13-15, and 17 were isolated from the genus Camellia for first time. The remaining compounds were also isolated from C. fascicularis for first time. The evaluation of antioxidant and antimicrobial activities revealed that compounds 1, 3, 9, 11, and 17 exhibited higher antioxidant activity than the positive control drug (ascorbic acid), and compounds 4, 8, 10, and 13 showed similar activity to ascorbic acid. The other compounds had weaker or no significant antioxidant activities. The MIC of antibacterial activity for compounds 4, 7, and 11-13 against P. aeruginosa was comparable to that of the positive control drug tetracycline at 125 µg/mL, and other secondary metabolites inhibited E. coli and S. aureus at 250-500 µg/mL. This is also the first report of antioxidant and antimicrobial activities of compounds 5-7, 13-15, and 17. The results of the study enriched the variety of secondary metabolites of C. fascicularis and laid the foundation for further research on the pharmacological efficacy and biological activity of this plant.

Coumarin derivatives ameliorate the intestinal inflammation and pathogenic gut microbiome changes in the model of infectious colitis through antibacterial activity

Coumarin, a phenolic compound, is a secondary metabolite produced by plants such as Tanga and Lime. Coumarin derivatives were prepared via Pechmann condensation. In this study, we performed in vitro and in vivo experiments to determine the antimicrobial and gut immune-regulatory functions of coumarin derivatives. For the in vitro antimicrobial activity assay, coumarin derivatives C1 and C2 were selected based on their pathogen-killing activity against various pathogenic microbes. We further demonstrated that the selected coumarin derivatives disrupted bacterial cell membranes. Next, we examined the regulatory function of the coumarin derivatives in gut inflammation using an infectious colitis model. In an in vivo infectious colitis model, administration of selected C1 coumarin derivatives reduced pathogen loads, the number of inflammatory immune cells (Th1 cells and Th17 cells), and inflammatory cytokine levels (IL-6 and IL-1b) in the intestinal tissue after pathogen infection. In addition, we found that the administration of C1 coumarin derivatives minimized abnormal gut microbiome shift-driven pathogen infection. Potential pathogenic gut microbes, such as Enterobacteriaceae and Staphylococcaceae, were increased by pathogen infection. However, this pathogenic microbial expansion was minimized and beneficial bacteria, such as Ligilactobacillus and Limosilactobacillus, increased with C1 coumarin derivative treatment. Functional gene enrichment assessment revealed that the relative abundance of genes associated with lipid and nucleotide metabolism was reduced by pathogen infection; however, this phenomenon was not observed in C1 coumarin derivative-treated animals. Collectively, our data suggest that C1 coumarin derivative is effective antibacterial agents that minimize pathogen-induced gut inflammation and abnormal gut microbiome modulation through their antibacterial activity.

Adsorption of Flavonoids in a Transcriptional Regulator TtgR: Relative Binding Free Energies and Intermolecular Interactions

Antimicrobial resistance in bacteria often arises from their ability to actively identify and expel toxic compounds. The bacterium strain Pseudomonas putida DOT-T1E utilizes its TtgABC efflux pump to confer robust resistance against antibiotics, flavonoids, and organic solvents. This resistance mechanism is intricately regulated at the transcriptional level by the TtgR protein. Through molecular dynamics and alchemical free energy simulations, we systematically examine the binding of seven flavonoids and their derivatives with the TtgR transcriptional regulator. Our simulations reveal distinct binding geometries and free energies for the flavonoids in the active site of the protein, which are driven by a range of noncovalent forces encompassing van der Waals, electrostatic, and hydrogen bonding interactions. The interplay of molecular structures, substituent patterns, and intermolecular interactions effectively stabilizes the bound flavonoids, confining their movements within the TtgR binding pocket. These findings yield valuable insights into the molecular determinants that govern ligand recognition in TtgR and shed light on the mechanism of antimicrobial resistance in P. putida DOT-T1E.

Ethanol extract from Astilbe chinensis inflorescence suppresses inflammation in macrophages and growth of oral pathogenic bacteria

Chronic oral inflammation and biofilm-mediated infections drive diseases such as dental caries and periodontitis. This study investigated the anti-inflammatory and antibacterial potential of an ethanol extract from Astilbe chinensis inflorescence (GA-13-6) as a prominent candidate for natural complex substances (NCS) with therapeutic potential. In LPS-stimulated RAW 264.7 macrophages, GA-13-6 significantly suppressed proinflammatory mediators, including interleukin-6 (IL-6), tumor necrosis factor (TNF), and nitric oxide (NO), surpassing purified astilbin, a known bioactive compound found in A. chinensis. Furthermore, GA-13-6 downregulated the expression of cyclooxygenase-2 (COX2) and inducible nitric oxide synthase (iNOS), indicating an inhibitory effect on the inflammatory cascade. Remarkably, GA-13-6 exhibited selective antibacterial activity against Streptococcus mutans, Streptococcus sanguinis, and Porphyromonas gingivalis, key players in dental caries and periodontitis, respectively. These findings suggest that complex GA-13-6 holds the potential for the treatment or prevention of periodontal and dental diseases, as well as various other inflammation-related conditions, while averting the induction of antibiotic resistance.

Five Underutilized Ecuadorian Fruits and Their Bioactive Potential as Functional Foods and in Metabolic Syndrome: A Review

The Ecuadorian Amazon harbors numerous wild and cultivated species used as food, many of which are underutilized. This review explores the bioactive potential of five such fruits-Borojó (Alibertia patinoi); Chonta (Bactris gasipaes); Arazá (Eugenia stipitata); Amazon grape (Pourouma cecropiifolia), a wild edible plant; and Cocona (Solanum sessiliflorum)-and their applications against metabolic syndrome. This study highlights their health-promoting ingredients and validates traditional medicinal properties, emphasizing their significance in improving health and mitigating the effects of the Western diet. These fruits, integral to Ecuadorian cuisine, are consumed fresh and processed. Chonta is widely cultivated but less prominent than in pre-Hispanic times, Borojó is known for its aphrodisiac properties, Cocona is traditional in northern provinces, Arazá is economically significant in food products, and Amazon grape is the least utilized and researched. The fruits are rich in phenolics (A. patinoi, E. stipitata) and carotenoids (B. gasipaes, E. stipitata), which are beneficial in controlling metabolic syndrome. This study advocates for more research and product development, especially for lesser-known species with high phenolic and anthocyanin content. This research underscores the economic, cultural, and nutritional value of these fruits, promoting their integration into modern diets and contributing to sustainable agriculture, cultural preservation, and public health through functional foods and nutraceuticals.

The Development of a Method for Obtaining Tripleurospermum inodorum (L.) Sch. Bip. Herb Extract Enriched with Flavonoids and an Evaluation of Its Biological Activity

The development of new drugs derived from plant sources is of significant interest in modern pharmacy. One of the promising plant sources for introduction into pharmaceuticals is Tripleurospermum inodorum (L.) Sch. Bip., also known as Tripleurospermum perforatum (Merat.) M. This plant has been shown to possess various biological activities, including anti-inflammatory, antimicrobial, and antimycotic activities, among others. However, a review of the current literature reveals a paucity of studies investigating the chemical composition of the herb Tripleurospermum inodorum (L.) Sch. Bip. This study presents the development of a method for obtaining an extract of the herb Tripleurospermum inodorum (L.) Sch. Bip. enriched with flavonoids, harvested before flowering and butonization. This study focused on determining the optimal conditions for extraction, including the concentration of the extractant (ethanol), extraction time, raw material/extractant ratio, extraction frequency, complexation reaction time, amount of aluminum chloride solution, and amount of diluted acetic acid. The results indicate that herbs harvested during this specific period exhibited a higher flavonoid content compared to those collected during butonization and flowering. Moreover, this study demonstrated that the flavonoid content could exceed 7% mg REq/100 g D.W. through a one-hour extraction process. Furthermore, the flavonoid content was found to be 7.65 ± 0.03 mg REq/100 g D.W. following a three-minute ultrasound-assisted extraction process, followed by thermal extraction. A qualitative analysis identified a variety of phenolic compounds in the extract, such as chlorogenic acid, 5-O-p-coumaroylquinic acid, 1-O-p-coumaroylquinic acid, luteolin-7-glucoside, quercetin-3-glucoside, luteolin-7-rutinoside, 3,5-O-dicaffeoylquinic acid, quercetin-3-O-malonylglucoside, apigenin-7-glucoside, luteolin-3-malonylglucoside, cynarin, rhamnetin-3-(O-dimethyl rhamnosyl glucosylglucoside), and luteolin. Moreover, this study demonstrated the antimicrobial, anti-inflammatory, anticoagulant, anti-aggregation, and antioxidant activities of the aqueous alcoholic extract from T. inodorum herb (ETIH) against pathogens such as Staphylococcus aureus, Escherichia coli, and Candida albicans. Additionally, the extract exhibited comparable anti-inflammatory effects on diclofenac sodium. These findings contribute to the understanding of the potential pharmacological applications of the developed herb extract.

Natural product nanozymes of herbal extract galangin in managing hepatocellular carcinoma

Numerous local herbal extract species have been investigated as potential medicinal ingredients due to their promising anti-cancer properties. However, the primary constraint of the class of plant flavonoids lies in their low solubility and limited membrane permeability, leading to chemical instability and restricted bioavailability that impede biomedical applications. In this study, we have developed an ideal nanozyme-Galazyme, comprising galangin-loaded copper Nanozyme coated by DSPE-PEG, which amplifies oxidative stress to induce apoptosis via the regulation of reactive oxygen species (ROS) generation and mitogen-activated protein kinase (MAPK) activation. Galazyme exhibited significant peroxidase mimetic activity, demonstrating its potential to generate ROS and elevate oxidative stress. Upon uptake by HepG-2 cells, Galazyme efficiently converts excess hydrogen peroxide (H2O2) into highly reactive •OH radicals and upregulates MAPK expression, leading to the activation of Bax and Caspase 3, thereby promoting irreversible tumor cell apoptosis. Both in vitro and in vivo results demonstrate that Galazyme inhibits tumor cell growth and induces apoptosis by generating ample ROS and activating the MAPK pathway. Our study offers novel evidence supporting the enhancement of Galazyme-induced apoptosis through the upregulation of Bax and Caspase 3, along with the elucidation of the interaction between MAPK and apoptosis.

Natural Products with Potential Effects on Hemorrhoids: A Review

Hemorrhoid disease is a common anorectal disorder affecting populations worldwide, with high prevalence, treatment difficulties, and considerable treatment costs. Compared to other treatment options, medical therapy for hemorrhoids offers minimal harm, more dignity to patients, and is more economical. Unfortunately, there are few chemical hemorrhoid medications available clinically, which makes the search for efficacious, cost-effective, and environmentally friendly new medication classes a focal point of research. In this context, searching for available natural products to improve hemorrhoids exhibits tremendous potential. These products are derived from nature, predominantly from plants, with a minor portion coming from animals, fungi, and algae. They have excellent coagulation pathway regulation, anti-inflammatory, antibacterial, and tissue regeneration activities. Therefore, we take the view that they are a class of potential hemorrhoid drugs, prevention products, and medication add-on ingredients. This article first reviews the factors contributing to the development of hemorrhoids, types, primary symptoms, and the mechanisms of natural products for hemorrhoids. Building on this foundation, we screened natural products with potential hemorrhoid improvement activity, including polyphenols and flavonoids, terpenes, polysaccharides, and other types.

Applications of magnetic solid-phase extraction in the sample preparation of natural product analysis (2020-2023)

Sample preparation, including extraction, separation, and purification, is a vital process for natural product analysis. As an attractive sample pretreatment method, magnetic solid-phase extraction (MSPE) has gained plenty of attention, mainly due to its simpler operation, less consumption of organic solvents, and shorter processing time than traditional SPE. This updated review is devoted to summarizing the applications of MSPE based on different magnetic nanomaterials in the analysis of various natural products in complex matrixes, such as biological samples, plants, and Chinese herbal preparations in the past four years (2020-2023). The preparation and fabrication of different materials are briefly introduced. Furthermore, the extraction mechanism and interaction forces between adsorbent and analytes are elaborated, and the advantages and disadvantages of different adsorbents coupled with various analytical methods for MSPE of different natural products are summarized. Moreover, the future trends and opportunities for MSPE in the natural product analysis are discussed. It is expected that this work can provide updated information for future research on the applications of MSPE in such fields.