Efficacy and Mechanisms of Flavonoids against the Emerging Opportunistic Nontuberculous Mycobacteria

Zein and resveratrol Schiff base nanocomplexes: An efficient delivery system to enhance the antibacterial efficacy of berberine

Plant-derived bactericides with limited drug resistance and environmental friendliness are promising alternatives to traditional chemical bactericides. Berberine (BBR) is a natural product with excellent biological activity against bacteria. Novel pesticide delivery systems were designed and constructed based on the plant-derived zein resveratrol (RSV) and its derivative 4-((E)-((2-hydroxyphenyl)imino)methyl)-5-((E)-4-hydroxystyryl)benzene-1,3-diol (XF) to improve the efficacy of BBR. BBR@Zein-RSV and BBR@Zein-XF nanoparticles (NPs) had uniform dispersion and were approximately 119.19 and 86.82 nm, with encapsulation rates of 55.71 % and 83.34 %, respectively. BBR@Zein-RSV and BBR@Zein-XF NPs used dual pH and redox reaction mechanisms to achieve a controlled release into the environment. Especially, BBR@Zein-XF NPs exhibited antibacterial activity against Xanthomonas oryzae pv. oryzicola with an EC50 value of 0.98 mg/L. Additionally, it showed excellent protective (51.52 %) and curative (48.17 %) effects against rice bacterial leaf streaks. NPs could inhibit biofilm formation and extracellular polysaccharide production but promote reactive oxygen species levels, thereby destroying the integrity of bacteria and eventually leading to cell death. Proteomic analysis revealed that BBR@Zein-XF NPs regulated the expression of phosphoenolpyruvate carboxykinase and lactoylglutathione lyase, thereby influencing plant growth, energy metabolism, and maintaining a normal redox state. This study provides new ideas for extensively utilizing plant-derived antibacterial agents by developing innovative and eco-friendly nano-pesticides.

The role of mycobacteremia screening in enhancing non-tuberculous mycobacteria detection in hospitalized persons with HIV

Among hospitalized severely immunocompromised persons with HIV (PWH), non-tuberculous mycobacteria (NTM) may be under-diagnosed due to non-specific symptoms undifferentiable with other opportunistic infections. To evaluate the prevalence of NTM mycobacteremia and how screening for mycobacteremia assistant with identification of NTM infections, this study retrospectively analyzed 1,136 hospitalized PWH with CD4 counts <200 cells/μL, who underwent mycobacteremia screening at a tertiary hospital in Nanjing, China, between July 2018 and December 2023. The prevalence of non-tuberculous mycobacteremia was 5.8% (95% CI, 4.6-7.3%), with a higher prevalence of 8.6% (95% CI, 6.7-10.9%) in patients with CD4 counts <50 cells/μL, compared to 1.4% (95% CI, 0.6-3.0%) in those with CD4 counts ≥50 cells/μL. Mycobacterium avium complex (MAC) was the predominant pathogen, representing 95% (95% CI, 86.7-98.3%) of positive blood cultures, though it accounted for only 66.2% (95% CI, 54.3-76.3%) of NTM species isolated from respiratory samples. The sensitivity of mycobacterial blood cultures (MBC) in diagnosing all culture-proven NTM infections was 63.9% (95% CI, 54.0-72.8%), increasing to 75.7% (95% CI, 64.8-84.0%) in patients with CD4 counts <50 cells/μL. Notably, mycobacteremia served as the sole microbiological evidence in approximately 25% of all culture-proven NTM infections during initial hospitalization, where other specimen sources failed to yield conclusive evidence. These findings underscore the importance of mycobacteremia screening in improving the detection of NTM infections among severely immunocompromised hospitalized patients, especially those with CD4 counts <50 cells/μL, and highlight the value of incorporating MBC into diagnostic protocols to enhance clinical management of these high-risk individuals.

Antimycobacterial Precatorin A Flavonoid Displays Antibiofilm Activity against Mycobacterium bovis BCG

The aim of this study was to evaluate the potential antibiofilm activity of Rhynchosia precatoria (R. precatoria) compounds over Mycobacterium bovis BCG (M. bovis BCG) as a model for Mycobacterium tuberculosis (Mtb). We evaluated the antibiofilm activity as the ability to both inhibit biofilm formation and disrupt preformed biofilms (bactericidal) of R. precatoria compounds, which have been previously described as being antimycobacterials against Mtb. M. bovis BCG developed air-liquid interface biofilms with surface attachment ability and drug tolerance. Of the R. precatoria extracts and compounds that were tested, precatorin A (PreA) displayed the best biofilm inhibitory activity, as evaluated by biofilm biomass quantification, viable cell count, and confocal and atomic force microscopy procedures. Furthermore, its combination with isoniazid at subinhibitory concentrations inhibited M. bovis BCG biofilm formation. Nonetheless, neither PreA nor the extract showed bactericidal effects. PreA is the R. precatoria compound responsible for biofilm inhibitory activity against M. bovis BCG.

Protective effect of the total flavonoids from Clinopodium chinense against LPS-induced mice endometritis by inhibiting NLRP3 inflammasome-mediated pyroptosis

ETHNOPHARMACOLOGICAL RELEVANCE

Clinopodium chinense (Benth.) O. Kuntze (C. chinense) is a Chinese herbal medicine used in treating gynecological hemorrhagic diseases for hundreds of years. Flavonoids are one kind of the major components in C. chinense. The flavonoids of C. chinense (TFC) have a vital role in treating endometritis but the underlying therapeutic mechanisms of TFC against endometritis have been rarely reported.

AIM OF THE STUDY

To elucidate the therapeutic effect and possible mechanisms of TFC against lipopolysaccharide (LPS)-induced endometritis in vivo and LPS-induced primary mouse endometrial epithelial cells (MEECs) injury in vitro.

MATERIALS AND METHODS

The holistic phytochemicals of the TFC and TFC-contained serum were screened and identified using UPLC-Q-TOF-MS. The model of endometritis was established by intrauterine injection of LPS (5 mg/mL) into female BALB/c mice, and the model mice were treated with TFC for 7 days. The value of MPO was measured by Myeloperoxidase assay kit, the pathological changes in the endometrium were evaluated using H&E staining and transmission electron microscope (TEM), the secretions of IL-18, IL-1β and TNF-α were determined by ELISA kits, the mRNA expressions of IL-18, IL-1β and TNF-α were determined by RT-PCR assay, and the protein levels of TLR4, IKBα, p-IKBα, p65, p-p65, caspase-1, ASC, NLRP3 and GSDMD were measured by Western blot. Subsequently, MEECs were isolated from the uterus of pregnant female mice, injured by LPS for 24 h and incubated with the TFC-contained serum. Finally, cell viability, LDH release, hoechst 33342/PI staining, immunofluorescence staining, scanning electron microscope observation, ELISA assay, RT-PCR detection and Western blot analysis were carried out to further validate the therapeutic effect and the underlying mechanisms of TFC.

RESULTS

A total of 6 compounds in the plasma of mice after being intragastric administrated of TFC were identified. The results in vivo showed that TFC significantly reduced MPO value and alleviated pathological injury of the endometrium. Furthermore, TFC significantly decreased the serum IL-18, IL-1β and TNF-α levels, and the mRNA levels of IL-18, IL-1β and TNF-α. TFC also inhibited the expressions of TLR4, p-IKBα, p-p65, caspase-1, ASC, NLRP3 and GSDMD. Besides, compared with the model group in MEECs cells, TFC-contained serum prevented pyroptosis, decreased the levels of IL-18 and IL-1β, and inhibited the mRNA expressions of IL-18, IL-1β and GSDMD. TFC-contained serum also reversed the activation of NLRP3 inflammasome caused by nigericin, and restrainted the translocation of NF-κB into nuclear.

CONCLUSIONS

TFC protects mice endometritis from the injury of LPS via suppressing the activation of NLRP3 inflammasome and pyroptosis, the underlying mechanisms of which were related to restraining the TLR4/NF-κB/NLRP3 pathway activation.

Pneumonia due to Mycobacterium cosmeticum in a patient with systemic sclerosis: A case report

Pulmonary infection due to Mycobacterium cosmeticum was reported in only two patients previously. More studies are warranted to define its characteristics and treatments. We report a systemic sclerosis patient who had a pulmonary infection due to M. cosmeticum and then successfully recovered after treatment with combination antibiotic regimen.

Chenopodium murale Juice Shows Anti-Fungal Efficacy in Experimental Oral Candidiasis in Immunosuppressed Rats in Relation to Its Chemical Profile

Chenopodium murale (Syn. Chenopodiastrum murale) (amaranthaceae) is used in the rural Egypt to treat oral ulcers in newborn children. The current study aimed to discover new natural products suitable for treating candidiasis disease with minimal side effects. Characterization of bioactive compounds by LC-QTOF-HR-MS/MS from Chenopodium murale fresh leaves' juice (CMJ) was carried out in order to elucidate their potential anti-fungal and immunomodulatory effects in oral candidiasis in immunosuppressed rats. An oral ulcer candidiasis model was created in three stages: (i) immunosuppression by drinking dexamethasone (0.5 mg/L) for two weeks; (ii) Candida albicans infection (3.00 × 10⁶ viable cell/mL) for one week; and (iii) treatment with CMJ (0.5 and 1.0 g/kg orally) or nystatin (1,000,000 U/L orally) for one week. Two doses of CMJ exhibited antifungal effects, for example, through a significant reduction in CFU/Petri (236.67 ± 37.86 and 4.33 ± 0.58 CFU/Petri), compared to the Candida control (5.86 × 10⁴ ± 1.21 CFU/Petri), p ≤ 0.001. In addition, CMJ significantly induced neutrophil production (32.92% ± 1.29 and 35.68% ± 1.77) compared to the Candida control level of 26.50% ± 2.44. An immunomodulatory effect of CMJ at two doses appeared, with a considerable elevation in INF-γ (103.88 and 115.91%), IL-2 (143.50, 182.33%), and IL-17 (83.97 and 141.95% Pg/mL) compared with the Candida group. LC-MS/MS analysis operated in negative mode was used for tentative identification of secondary (SM) metabolites based on their retention times and fragment ions. A total of 42 phytoconstituents were tentatively identified. Finally, CMJ exhibited a potent antifungal effect. CMJ fought Candida through four strategies: (i) promotion of classical phagocytosis of neutrophils; (ii) activation of T cells that activate IFN-γ, IL-2, and IL-17; (iii) increasing the production of cytotoxic NO and H₂O₂ that can kill Candida; and (iv) activation of SOD, which converts superoxide to antimicrobial materials. These activities could be due to its active constituents, which are documented as anti-fungal, or due to its richness in flavonoids, especially the active compounds of kaempferol glycosides and aglycone, which have been documented as antifungal. After repetition on another type of small experimental animal, their offspring, and an experimental large animal, this study may lead to clinical trials.

Possible Side Effects of Polyphenols and Their Interactions with Medicines

Polyphenols are an important component of plant-derived food with a wide spectrum of beneficial effects on human health. For many years, they have aroused great interest, especially due to their antioxidant properties, which are used in the prevention and treatment of many diseases. Unfortunately, as with any chemical substance, depending on the conditions, dose, and interactions with the environment, it is possible for polyphenols to also exert harmful effects. This review presents a comprehensive current state of the knowledge on the negative impact of polyphenols on human health, describing the possible side effects of polyphenol intake, especially in the form of supplements. The review begins with a brief overview of the physiological role of polyphenols and their potential use in disease prevention, followed by the harmful effects of polyphenols which are exerted in particular situations. The individual chapters discuss the consequences of polyphenols’ ability to block iron uptake, which in some subpopulations can be harmful, as well as the possible inhibition of digestive enzymes, inhibition of intestinal microbiota, interactions of polyphenolic compounds with drugs, and impact on hormonal balance. Finally, the prooxidative activity of polyphenols as well as their mutagenic, carcinogenic, and genotoxic effects are presented. According to the authors, there is a need to raise public awareness about the possible side effects of polyphenols supplementation, especially in the case of vulnerable subpopulations.

Promising Antimycobacterial Activities of Flavonoids against Mycobacterium sp. Drug Targets: A Comprehensive Review

Tuberculosis (TB) caused by the bacterial pathogen Mycobacterium tuberculosis (Mtb) remains a threat to mankind, with over a billion of deaths in the last two centuries. Recent advancements in science have contributed to an understanding of Mtb pathogenesis and developed effective control tools, including effective drugs to control the global pandemic. However, the emergence of drug resistant Mtb strains has seriously affected the TB eradication program around the world. There is, therefore, an urgent need to develop new drugs for TB treatment, which has grown researchers’ interest in small molecule-based drug designing and development. The small molecules-based treatments hold significant potential to overcome drug resistance and even provide opportunities for multimodal therapy. In this context, various natural and synthetic flavonoids were reported for the effective treatment of TB. In this review, we have summarized the recent advancement in the understanding of Mtb pathogenesis and the importance of both natural and synthetic flavonoids against Mtb infection studied using in vitro and in silico methods. We have also included flavonoids that are able to inhibit the growth of non-tubercular mycobacterial organisms. Hence, understanding the therapeutic properties of flavonoids can be useful for the future treatment of TB.

Photoinactivation of non-tuberculous mycobacteria using Zn-phthalocyanine loaded into liposomes

Non-tuberculous mycobacteria are a heterogeneous group of environmental bacteria and other than the well-known Mycobacterium tuberculosis complex and Mycobacterium leprae. They could cause localized or disseminated infections. Mycobacterium chelonae and Mycobacterium fortuitum are among the most clinically relevant non-tuberculous mycobacteria species. The infections treatment is complex since they are resistant to antituberculosis drugs and the biofilm formation makes them impermeable to several antibiotics. Antimicrobial photodynamic therapy (aPDT) constitutes an alternative to eliminate pathogens, principally those antimicrobials resistant. Among explored photosensitizers, phthalocyanines are considered excellent, but with a disadvantage: a lack solubility in aqueous media. Consequently, several nanocarriers have been studied in the last years. In this work, a Zn-phthalocyanine into liposomes was evaluated to photoinactivate M. fortuitum and M. chelonae. The results show a higher photodynamic activity of ZnPc into liposomes respect to solution. Furthermore, M. fortuitum was more sensible to aPDT than M. chelonae.

Antibacterial activities of polyphenols against foodborne pathogens and their application as antibacterial agents

Polyphenols are secondary metabolites produced in higher plants. They are known to possess various functional properties in the human body. Polyphenols also exhibit antibacterial activities against foodborne pathogens. Their antibacterial mechanism is based on inhibiting bacterial biofilm formation or inactivating enzymes. Food-derived polyphenols with such antibacterial activity are natural preservatives and can be used as an alternative to synthetic preservatives that can cause side effects, such as allergies, asthma, skin irritation, and cancer. Studies have reported that polyphenols have positive effects, such as decreasing harmful bacteria and increasing beneficial bacteria in the human gut microbiota. Polyphenols can also be used as natural antibacterial agents in food packaging system in the form of emitting sachets, absorbent pads, and edible coatings. We summarized the antibacterial activities, mechanisms and applications of polyphenols as antibacterial agents against foodborne bacteria.

Therapeutic Values of Earthworm Species Extract from Azad Kashmir as Anticoagulant, Antibacterial, and Antioxidant Agents

Aims

Current research aimed to explore the therapeutic values of different earthworms as antibacterial, anticoagulant, and antioxidant agents.

Methods

Ten different earthworms, i.e., Amynthas corticis, Amynthas gracilis, Pheretima posthuma, Eisenia fetida, Aporrectodea rosea, Allolobophora chlorotica, Aporrectodea trapezoides, Polypheretima elongata, Aporrectodea caliginosa, and Pheretima hawayana, were collected and screened for biological activities. Antibacterial effect analysis of earthworm species was done against fourteen bacterial pathogens, i.e., Escherichia coli, Serratia marcescens, Streptococcus pyogenes, Staphylococcus epidermidis, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa (1), Salmonella typhimurium, Shigella flexneri, Enterobacter amnigenus, Serratia odorifera, Pseudomonas aeruginosa (2), Staphylococcus warneri, and Lactobacillus curvatus, via agar well diffusion, crystal violet, MTT, agar disc diffusion, and direct bioautography assays. Antioxidant potential was evaluated through ABTS and DPPH assays. Lipolytic, proteolytic, and amylolytic assays were done for lipase, protease, and amylase enzymes confirmation. In vitro anticoagulant effects were examined in the blood samples by measuring prothrombin time.

Results

Results revealed that all earthworm extracts showed the inhibition of all tested bacterial pathogens except P. aeruginosa (1), P. aeruginosa (2), S. warneri, and L. curvatus. The maximum zone of inhibition of E. coli was recorded as 14.66 ± 0.57 mm by A. corticis, 25.0 ± 0.0 mm by P. posthuma, 20.0 ± 0.0 mm by E. fetida, and 20.0 ± 0.0 mm by A. trapezoid. Cell proliferation, biofilm inhibition, the synergistic effect of extracts along with antibiotics, and direct bioautography supported the results of agar well diffusion assay. Similarly, P. hawayana, A. corticis, A. caliginosa, and A. trapezoids increase the prothrombin time more efficiently compared to other earthworms. A. corticis, A. gracilis, A. rosea, A. chlorotica, P. elongata, and A. trapezoides showed maximum DPPH scavenging potential effect.

Conclusions

The coelomic fluid of earthworms possessed several bioactive compounds/enzymes/antioxidants that play an important role in the bacterial inhibition and act as anticoagulant agents. Therefore, the development of new therapeutic drugs from invertebrates could be effective and potential for the prevention of the emergence of multidrug-resistant bacteria.

Hydrolyzable tannins (ellagitannins), flavonoids, pentacyclic triterpenes and their glycosides in antimycobacterial extracts of the ethnopharmacologically selected Sudanese medicinal plant Combretum hartmannianum Schweinf

In Sudanese traditional medicine, decoctions, macerations, and tonics of the stem and root of Combretum hartmannianum are used for the treatment of persistent cough, a symptom that could be related to tuberculosis (TB). To verify these traditional uses, extracts from the stem wood, stem bark, and roots of C. hartmannianum were screened for their growth inhibitory effects against Mycobacterium smegmatis ATCC 14468. Methanol Soxhlet and ethyl acetate extracts of the root gave the strongest effects (MIC 312.5 and 625 µg/ml, respectively). HPLC-UV/DAD and UHPLC/QTOF-MS analysis of the ethyl acetate extract of the root led to the detection of 54 compounds, of which most were polyphenols and many characterized for the first time in C. hartmannianum. Among the major compounds were terflavin B and its two isomers, castalagin, corilagin, tellimagrandin I and its derivative, (S)-flavogallonic acid dilactone, punicalagin, and methyl-ellagic acid xylopyranoside. In addition, di-, tri- and tetra-galloyl glucose, combregenin, terminolic acid, cordifoliside D, luteolin, and quercetin-3-O-galactoside-7-O-rhamnoside-(2→1)-O-β-D-arabinopyranoside were characterized. Luteolin gave better growth inhibition against M. smegmatis (MIC 250 µg/ml) than corilagin, ellagic acid, and gallic acid (MIC 500-1000 µg/ml). Our study justifies the use of C. hartmannianum in Sudanese folk medicine against prolonged cough that could be related to TB infection. This study demonstrates that C. hartmannianum should be explored further for new anti-TB drug scaffolds and antibiotic adjuvants.

The Interactions between Polyphenols and Microorganisms, Especially Gut Microbiota

This review presents the comprehensive knowledge about the bidirectional relationship between polyphenols and the gut microbiome. The first part is related to polyphenols' impacts on various microorganisms, especially bacteria, and their influence on intestinal pathogens. The research data on the mechanisms of polyphenol action were collected together and organized. The impact of various polyphenols groups on intestinal bacteria both on the whole "microbiota" and on particular species, including probiotics, are presented. Moreover, the impact of polyphenols present in food (bound to the matrix) was compared with the purified polyphenols (such as in dietary supplements) as well as polyphenols in the form of derivatives (such as glycosides) with those in the form of aglycones. The second part of the paper discusses in detail the mechanisms (pathways) and the role of bacterial biotransformation of the most important groups of polyphenols, including the production of bioactive metabolites with a significant impact on the human organism (both positive and negative).

Green propolis as an adjuvant against nontuberculous mycobacteria

Abstract Natural products have been touted as important tools because of their vast potential for the development of compounds with antimicrobial activity and the possible inhibitory activity and/or adjuvant resistance mechanisms. Propolis has been empirically used for many years for the treatment of diseases, mainly due to its antioxidant, anti inflammatory and antimicrobial activities. This study aimed to evaluate the in vitro antimycobacterial activity of the ethanol extract of propolis alone and in combination with rifampicin (RIF), amikacin (AMI) and ciprofloxacin (CIP). The ethanol extract of propolis showed antibacterial activity against Mycobacterium chelonae and M. kansasii and was capable of increasing AMI, RIF and CIP activity in combination. On the other hand, compared to M. absecessus, M. fortuitum and M. avium, the extract was not active at 200 µg/mL and did not show pronounced adjuvant capacity when evaluated in association with the drugs. Based on these results, it can be concluded that the ethanol extract of propolis could be an alternative in the development of new drugs and can be used complementary with the current mycobacteriosis treatment.