74 results about "Antimicrobial peptides" patented technology

This invention provides an antimicrobial peptide spray, its preparation method, and its application in the prevention and treatment of peristomal skin infections. The spray comprises, by weight percentage, 0.05%-0.5% of a complex antimicrobial peptide, 0.1%-5% of a moisturizing and repairing film-forming matrix, 0.05%-0.2% of a buffer, 0.8%-1.2% of an isotonic regulator, 0.01%-0.5% of a stabilizer, and 0.005%-0.05% of a metal ion chelating agent, with the balance being water for injection. The complex antimicrobial peptide is composed of bovine lactoferrin antimicrobial peptide, sericin oligopeptide, and buckwheat-derived anti-inflammatory active peptide in a weight ratio of (3-5):(2-3):1. This spray possesses four core functions: broad-spectrum antibacterial activity, inhibition of bacterial biofilm, anti-inflammatory and soothing effects, and skin barrier repair. It is less likely to induce bacterial resistance, does not irritate damaged skin around the stoma, and can effectively prevent and treat peristomal skin infections.

This invention discloses an antimicrobial peptide PA targeting multidrug-resistant Gram-negative bacteria and its application. The amino acid sequence of the antimicrobial peptide PA is shown in SEQ ID NO.1. The antimicrobial peptide PA provided by this invention has a significant antibacterial effect against multidrug-resistant Gram-negative bacteria, and has a rapid bactericidal onset, no hemolysis or cytotoxicity, does not cause nephrotoxicity after treatment, and has good biosafety. It can be used for the treatment of bacterial infections and can also be applied to other scenarios that require bactericidal or antibacterial growth inhibition.

This invention discloses a *Bacillus laterosporus* strain for the stable production of nonribosomal cyclic lipolipeptide and its construction method. The M1A gene in the Bogorol biosynthetic gene cluster is knocked out using CRISPR-Cas9 technology to block the Bogorol pathway, which competes with Brevicidine for substrates. Subsequently, the pMCCas9-S48 plasmid, which integrates S8 and S41 sgRNAs and their homologous arms as repair templates, is used to simultaneously knock out S8 and S41 family peptidase genes, preventing the expression of extracellular degradation enzymes. This invention also provides the application of the above strain in the preparation of nonribosomal cyclic lipolipeptide of Brevicidine and a method for preparing the nonribosomal cyclic lipolipeptide. This strain, through reducing metabolic competition and preventing product degradation, exhibits rapid cell growth, stable production of Brevicidine, and significantly reduced degradation rate, resulting in a 66.13% increase in fermentation yield compared to the unmodified strain. This invention solves the problems of degradation and unstable yield in the production of Brevicidine, provides an effective technical approach for the industrial production of Brevicidine, and provides important technical support for the development and application of novel antimicrobial peptide drugs.

This invention belongs to the field of antimicrobial peptide technology, and particularly relates to a broad-spectrum antimicrobial peptide with low hemolytic activity and its applications, as well as a broad-spectrum antibacterial drug. The antimicrobial peptide is named AY6, and its amino acid sequence is shown in SEQ ID NO.1. Antimicrobial peptide AY6 exhibits significant antibacterial effects against both Gram-positive and Gram-negative bacteria, with a bactericidal rate far exceeding that of traditional antibiotics, enabling highly effective responses to bacterial infections. AY6 has low hemolytic activity and good biocompatibility, making it suitable for medical anti-infective applications. The antimicrobial peptide provided in this application has a short sequence, is easy to synthesize chemically, can save on large-scale production costs, and has broad application prospects.

The application provides a composite antibacterial peptide preparation, a preparation method and application. The composite antibacterial peptide preparation comprises a first defensin, a second defensin, a first cecropin and a second cecropin. The amino acid sequence of the first defensin is shown in SEQ ID NO:1, the amino acid sequence of the second defensin is shown in SEQ ID NO:2, the amino acid sequence of the first cecropin is shown in SEQ ID NO:3, and the amino acid sequence of the second cecropin is shown in SEQ ID NO:4. Compared with a single antibacterial peptide, the composite antibacterial peptide preparation has good stability, and shows good inhibitory effect on various gram-positive bacteria, gram-negative bacteria and fungi.

This invention discloses an antimicrobial peptide SI-20 and its application in the preparation of antimicrobial drugs, belonging to the field of biomedical technology. The amino acid sequence of the antimicrobial peptide SI-20 is shown in SEQ ID NO.2. The antimicrobial peptide SI-20 provided by this invention has a highly efficient killing ability against a variety of Gram-negative / positive bacteria, effectively retaining antimicrobial activity while significantly reducing cytotoxicity and improving therapeutic efficacy. Simultaneously, this antimicrobial peptide SI-20 exhibits good stability in serum environments and under heat treatment, strongly inhibits biofilm formation, and possesses rapid and efficient antimicrobial properties, providing a highly promising candidate resource for the development of highly effective and low-toxicity antimicrobial drugs, with broad application potential.

This invention discloses an antimicrobial peptide cAMP-1 derived from the intestinal microorganisms of wild rodents and its applications, belonging to the field of biotechnology. The amino acid sequence of the antimicrobial peptide cAMP-1 is shown in SEQ ID NO:1. The antimicrobial peptide cAMP-1 exhibits highly efficient, rapid, and safe antimicrobial activity against Streptococcus suis type II. It significantly inhibits bacterial growth even at low concentrations, with a minimum inhibitory concentration (MIC) of 16 µg / mL. Time-kinetic kinetics results show that the antimicrobial peptide can kill all Streptococcus suis type II within 30 min and 15 min at concentrations of 2×MIC and 4×MIC, respectively. Furthermore, within several times the effective concentration range, the peptide exhibits almost no hemolytic activity and low cytotoxicity within a safe dosage range, demonstrating its promising application as a novel anti-infective candidate drug.

This invention discloses the antimicrobial peptide PJX13 and its application in the control of citrus canker. The sequence of the antimicrobial peptide PJX13 is AcKKFWKLRRWVKWIGNH2. It can effectively inhibit and kill *Xanthomonas citrus* by disrupting the cell membrane integrity of pathogens, leading to leakage of intracellular substances. It effectively inhibits the expansion of lesions on both detached citrus leaves and living plants, and can be formulated into an antimicrobial product against *Xanthomonas citrus* for the control of citrus canker. Furthermore, the antimicrobial peptide PJX13 can also inhibit *Escherichia coli*, *Staphylococcus aureus*, and *Bacillus oryzae*, and can be used to prepare broad-spectrum antimicrobial products. This invention is beneficial for the control of citrus canker, and has advantages such as being environmentally friendly and unlikely to induce drug resistance.

This invention discloses a strain of *Pediococcus pentosaceus* RL-10 and its application in bio-acidification rice soaking and bacterial cellulose production, belonging to the field of microbial technology. The preservation number of *Pediococcus pentosaceus* RL-10 is CCTCC NO: M 20252428. This invention is the first to use *Pediococcus pentosaceus* as a strain for bio-acidification rice soaking. Using rice soaking water as a production substrate, *Acetobacter Hansenulatus* and strain RL-10 are co-cultured in situ to produce bacterial cellulose loaded with antimicrobial peptides. Under certain process conditions, acidification of rice soaking by strain RL-10 can rapidly increase acidity and shorten soaking time. The bacterial cellulose production process of this invention is simple and low-cost; verification shows that the bacterial cellulose prepared by the method of this invention has high yield and good antibacterial activity, meeting the requirements of large-scale industrial production.

This invention relates to Bacillus vesiculosus antimicrobial peptides and their application in food preservation, belonging to the field of biotechnology. The amino acid sequence of the antimicrobial peptide is shown in SEQ ID NO: 1. The antimicrobial peptide provided by this invention is a novel antimicrobial peptide in structure, enriching the antimicrobial peptide database; this antimicrobial peptide can effectively inhibit the normal growth of Fusarium oxysporum, has a broad antimicrobial spectrum, and has potential development and application prospects; this antimicrobial peptide can effectively extend the refrigerated shelf life of dragon fruit, and has good application prospects in fruit preservation.

This invention relates to the field of crop disease control technology, specifically to a composition containing antimicrobial peptides that enhances crop disease resistance. The composition comprises a synergistic and stable antimicrobial peptide carrier, a toad antimicrobial peptide (Buforin), cephalosporin B, and an antimicrobial peptide activator loaded onto the synergistic and stable antimicrobial peptide carrier. This invention prepares the synergistic and stable antimicrobial peptide carrier by reacting a mixture of cystamine, kasugamycin, and sorbitol glycidyl ether. This carrier enables precise controlled release of antimicrobial peptides at target sites, significantly prolongs the half-life of antimicrobial peptides in plants, solves the problems of easy degradation and short duration of action of conventional antimicrobial peptides, and synergistically enhances the stability of antimicrobial peptides, preventing aggregation or inactivation during loading and storage, thereby improving the bioavailability and persistence of antimicrobial peptides in field application.

This invention discloses a biomimetic corncob scaffold with piezoelectric, antibacterial, osteogenic, and healing-promoting functions, comprising: extraction of corncob cellulose nanofibers (CNF); preparation of 3D printing ink; 3D printing of a porous scaffold; loading of antimicrobial peptides and BMP-2 onto a GelMA+PAAM composite hydrogel; and composite preparation of the scaffold and hydrogel. Under external stimulation, the scaffold generates a microcurrent / surface charge, directly disrupting bacterial cell membranes; it avoids drug release and resistance issues, employing a physical mechanism of action with a sustainable response. The microcurrent / electric field generated by the piezoelectric effect simulates the bioelectric environment of natural bone, directly stimulating osteoblast proliferation and differentiation, and promoting mineralization; it mimics the natural anisotropic porous structure of the corncob, facilitating nutrient transport and cell migration; the piezoelectric material itself provides both antibacterial and osteogenic functions, achieving synergistic and unified mechanisms; it is suitable for harsh environments, biodegradable, and has flexible activation methods.

This invention discloses an antimicrobial peptide, its pharmaceutical composition, and its applications. The invention optimizes the structure of the antimicrobial peptide through deuteration modification technology, significantly enhancing its targeted binding ability to β-1,3-D-glucan synthase. The affinity of this antimicrobial peptide for the aforementioned target is 9-27 times that of the control peptide. In vitro assays show that its minimum inhibitory concentration (MIC) against nine standard Candida strains is consistently 0.002 μg / mL, exhibiting significantly superior activity compared to fluconazole, anidoxurine, and the control peptide. It also exhibits extremely low cytotoxicity against L02 human normal hepatocytes. In in vivo experiments, in a neutropenic mouse model of Candida albicans infection, the antimicrobial peptide at all doses showed superior reduction in renal fungal load compared to anidoxurine and the control peptide. The antimicrobial peptide of this invention combines highly efficient anti-Candida activity, low cytotoxicity, and excellent in vivo efficacy, providing a safe and effective candidate drug for the treatment of drug-resistant candidiasis and possessing good clinical translational value.

This invention discloses a method for rapidly screening highly efficient α-helical antimicrobial peptides and its application. The method includes extracting hydrophobic cluster scores HCS3_HF and / or HCS4_HF from the peptide sequences to be screened, and screening the peptide sequences based on the values ​​of these features. Using known low-MIC α-helical antimicrobial peptides as multi-centroid references, precise selection of candidate peptides is achieved through feature value ranges. This invention constructs a screening system based on the structure-activity relationship of the synergistic effect of hydrophobic clusters at positions i+3 and i+4 of the hydrophobic surface. This system can efficiently identify α-helical antimicrobial peptides with low minimum inhibitory activity from a vast sequence space without relying on large-scale training data, significantly shortening the antimicrobial peptide development cycle.

Antimicrobial peptides of general formula XX1X2C X3X4X5CXXX&XgCYX10X11CX12X13 are provided. Also provided are certain formulations containing these peptides and methods of using these peptides for treating skin infections in an animal in need thereof. 20 24 21 96 45 12 S ep 2 02 4 S e p 2 0 2 4 A N T I M I C R O B I A L P E P T I D E S A N D M E T H O D S O F U S I N G S A M E A B S T R A C T 2 0 2 4 2 1 9 6 4 5 1 2

This invention discloses a method for efficiently extracting and enriching sludge-based antimicrobial peptides from activated sludge, belonging to the field of activated sludge resource recycling and utilization. The invention removes impurities from the activated sludge by releasing intracellular and extracellular proteins through low-temperature hot alkaline hydrolysis, followed by enzymatic hydrolysis with proteases to obtain a crude extract containing peptides of different molecular weights. Further purification involves primary purification to remove impurities and secondary purification to separate amino acids and peptides from the organic matter mixture, yielding purified antimicrobial peptide products of different molecular weights. Antimicrobial activity is assessed using an inhibition zone assay, resulting in a highly effective antimicrobial sludge-based antimicrobial peptide molecular template. This template is used to prepare a magnetic molecularly imprinted polymer (Fe3O4@MIPs). Fe3O4@MIPs are then used to adsorb and enrich the highly effective antimicrobial sludge-based antimicrobial peptides in the crude extract. After elution with an eluent, highly effective antimicrobial sludge-based antimicrobial peptides are obtained.

This invention relates to the field of biomedical technology and discloses a broad-spectrum antimicrobial peptide and its applications. The invention obtains a broad-spectrum antimicrobial peptide H by mining non-classical open reading frames (ncORFs) in the human genome. Experimental verification shows that the broad-spectrum antimicrobial peptide H has significant inhibitory effects on both Gram-positive bacteria (Staphylococcus aureus ATCC 29213) and Gram-negative bacteria (Escherichia coli K88). Furthermore, the broad-spectrum antimicrobial peptide H can form an α-helix. The α-helix structure projection diagram shows that one side is rich in positively charged hydrophilic amino acid residues, and the other side is rich in hydrophobic amino acid residues, exhibiting good amphiphilicity. In addition, the broad-spectrum antimicrobial peptide H provided by this invention has low hemolytic activity and no cytotoxicity, ensuring in vivo safety while achieving highly efficient bactericidal activity. It also features a short synthetic sequence, small molecular weight, and is easy to chemically synthesize.

This invention provides a method for preparing an antimicrobial peptide composite material, comprising: S1 preparing a β-TCP / HyA porous substrate; S2 synthesizing mesoporous polydopamine (MPDA); S3 dispersing the β-TCP / HyA porous scaffold and the mesoporous polydopamine in deionized water for a second crosslinking reaction to form a β-TCP / HyA / MPDA composite suspension; and then adding the antimicrobial peptide KR to the β-TCP / HyA / MPDA composite suspension to induce a binding reaction, thereby obtaining the antimicrobial peptide composite material. This invention crosslinks β-tricalcium phosphate (β-TCP), hyaluronic acid (HyA), and mesoporous polydopamine (MPDA) to construct a multifunctional composite substrate that combines physical support, biocompatibility, and high-efficiency loading. The mesoporous structure of MPDA provides numerous anchoring sites for the antimicrobial peptide KR. Through MPDA adhesion and covalent fixation strategies for the antimicrobial peptide, high-density and high-activity loading of KR molecules is achieved, effectively solving the problems of easy detachment and "fixation leading to inactivation".

The invention relates to the field of biomedicine, and provides an application of a Gram-negative bacterium infection target Kdo in research and development of antibacterial drugs. An authorized antibacterial peptide Ly (PEG)-1 is used as a probe; through computer simulation, affinity determination and gene defect strain identification, the key action target is lipopolysaccharide (LPS) internal core Kdo (3-deoxy-D-mannan-octanone acid), Kdo is used as a key component of bacteria LPS and is a basis for maintaining Gram-negative bacteria cell wall integrity, LPS biosynthesis and biological activity exertion, and the Kdo is used as a key component of bacteria LPS. The deletion or modification can directly cause the loss of LPS function and the reduction of the viability of bacteria. At present, no antibacterial drug aiming at the target spot exists, the problem that in the prior art, no biomolecule capable of targeting Kdo to exert strong antibacterial activity exists is solved, and the biomolecule can be used for developing drugs for diagnosing or treating related diseases.

This invention discloses an antimicrobial peptide LR-24 and its application in the preparation of antimicrobial drugs, belonging to the field of biomedical technology. The amino acid sequence of the antimicrobial peptide LR-24 is shown in SEQ ID NO.2. The antimicrobial peptide LR-24 provided by this invention has a highly efficient killing ability against a variety of Gram-negative / positive bacteria and exhibits broad-spectrum stability. It maintains strong antimicrobial activity under conditions of salt ions, 50% serum, proteases, and high temperatures, improving the problem that the activity of antimicrobial peptides decreases in some complex environments. Furthermore, while maintaining antimicrobial activity, the antimicrobial peptide LR-24 shows significantly reduced hemolytic activity and cytotoxicity, making it a promising candidate for novel antimicrobial drugs with great clinical application potential.

This invention relates to the field of antimicrobial peptide technology, specifically to an antimicrobial peptide for maintaining oral flora balance, its preparation method, and its application. The antimicrobial peptide for maintaining oral flora balance according to this invention includes any one of the following polypeptides (a)-(e): (a) a polypeptide whose amino acid sequence includes the amino acid sequence shown in SEQ ID NO. 1; (b) an amino acid sequence composed of amino acid residues shown in SEQ ID NO. 1; (c) a polypeptide formed by substituting and / or deleting and / or adding one or more amino acid residues to the amino acid sequence defined in (a) or (b); (d) a polypeptide having 99% or more, 95% or more, 90% or more, 85% or more, or 80% or more homology to the amino acid sequence defined in (a) or (b); (e) a polypeptide obtained by modifying the N-terminus and / or C-terminus of any one of the polypeptides defined in (a)-(d). The antimicrobial peptides of this invention, used to maintain oral flora balance, exhibit antibacterial and bactericidal activity against oral pathogens while not affecting the normal growth of beneficial bacteria. This balance is maintained, protecting gum health and freshening breath. These antimicrobial peptides are suitable for preparing oral antibacterial agents and related oral care products, regulating the balance of the oral microecology, and thus used to prevent and treat oral diseases, especially dental caries, periodontitis, oral mucosal diseases, and oral cancer. The antimicrobial peptides of this invention are relatively short, making chemical synthesis easier and allowing for direct synthesis into high-purity products. They also exhibit clear effects and have wide applications.

This invention discloses an antimicrobial peptide RY-10 and its application in the preparation of antimicrobial drugs, belonging to the field of biomedical technology. The amino acid sequence of the antimicrobial peptide RY-10 is shown in SEQ ID NO.2. The antimicrobial peptide RY-10 provided by this invention has a highly efficient killing ability against a variety of Gram-negative / positive bacteria, effectively retaining antimicrobial activity while significantly reducing cytotoxicity. Simultaneously, this antimicrobial peptide RY-10 can also produce synergistic antimicrobial effects with various antibiotics, showing significant application value in improving efficacy, overcoming antibiotic resistance, reducing drug dosage, delaying the development of drug resistance, and addressing complex infections. This invention provides a highly promising candidate material resource for the development of highly effective and low-toxicity antimicrobial drugs, and also provides an efficient, safe, and sustainable solution for developing novel combination therapies and addressing the global drug resistance crisis, possessing significant clinical application value and industrialization potential.

This invention relates to an antimicrobial peptide and its applications. The amino acid sequence of the antimicrobial peptide is at least one of the sequences shown in SEQ ID No. 1 to SEQ ID No. 8. The antimicrobial peptide exhibits excellent broad-spectrum antimicrobial activity, for example, against Acinetobacter spp. (…). Acinetobacter ), Pseudomonas aeruginosa ( Pseudomonas aeruginosa ) and Bacillus spp. ( Bacillus This bacterium possesses antibacterial activity. Against the backdrop of increasingly severe global bacterial resistance and the gradual ineffectiveness of traditional antibiotics against multidrug-resistant bacteria, this provides a new treatment option for carbapenem-resistant bacteria such as Acinetobacter baumannii, Pseudomonas aeruginosa, and Bacillus subtilis, which pose a significant threat to public health, and offers new possibilities for solving the clinical dilemma of "no available drugs."

This invention discloses a method for de novo design of antifungal peptides, the obtained peptides, and their applications. The method includes: S1 peptide library retrieval and amino acid preference analysis; S2 peptide design based on multiple parameters; S3 AI high-throughput screening of the peptide library to obtain candidate antifungal peptides. The amino acid sequences of the mentioned antifungal peptides are also disclosed in this invention as shown in SEQ ID Nos: 1 to 3. The antifungal peptides developed by this invention can specifically target and kill fungi such as Malassezia furfur without inhibiting the growth of other beneficial bacteria such as Propionibacterium acnes, thereby effectively regulating the skin surface microecological balance and maintaining skin health; solving the problem that current antimicrobial peptides, due to their broad-spectrum antibacterial properties, can disrupt the skin microecological balance and cause more serious skin diseases.

This application provides the use of an antimicrobial peptide in the preparation of skin care products. The antimicrobial peptide of this application can effectively inhibit *Propionibacterium acnes* and *Malassezia*, thereby preventing skin problems such as acne, skin inflammation, and dandruff caused by the overgrowth of these two bacteria. Therefore, the antimicrobial peptide of this application has skin care uses in inhibiting acne, relieving skin inflammation such as folliculitis, pityriasis versicolor, and seborrheic dermatitis, and in inhibiting dandruff, and has significant practical value.

This invention, based on deep learning and molecular dynamics simulations, yielded a novel antimicrobial peptide, yuce 4, designed using artificial intelligence, exhibiting highly efficient and broad-spectrum antimicrobial activity. The existence of the α-helix in yuce 4 was confirmed by nuclear magnetic resonance (NMR), circular dichroism (CD) chromatography, and Alphafold 2 three-dimensional structure prediction. Furthermore, mutants of yuce 4 were designed, showing a 4-8 fold increase in activity against Stenotrophomonas maltophilia WH006 and Pseudomonas aeruginosa PAO1, with several analogs achieving a MIC of 8 μg / mL. This invention also demonstrates the potential of deep learning and molecular dynamics simulations in accelerating the discovery of antimicrobial peptides and shows promise as an important tool for developing novel antimicrobial peptides.

This invention discloses an antiviral disinfectant wipe based on the synergistic effect of biocatalytic sterilization and physical membrane disruption, belonging to the field of disinfectant wipe technology. The disinfectant wipe contains the following raw materials in parts by weight: 85-95 parts spunlace nonwoven fabric, 0.08-0.15 parts modified antimicrobial peptides, 1.5-3 parts modified chitosan, 820-930 parts deionized water, 22-28 parts propylene glycol, 18-22 parts glycerin, 6-9 parts sodium cocoyl glycinate, 0.8-1.2 parts citric acid, 0.8-1.0 parts phenoxyethanol, and 4-7 parts aloe vera extract. This antiviral disinfectant wipe focuses on the synergistic effect of physical membrane disruption and catalytic sterilization. The raw material ratio is scientific, containing highly effective components such as modified antimicrobial peptides and modified chitosan, resulting in excellent sterilization and antiviral effects. The preparation process is standardized, with strict pretreatment of the nonwoven fabric, uniform solution dispersion, and controllable product liquid content. The addition of aloe vera extract makes it mild and non-irritating, allowing for flexible storage and high practicality.

A method for screening antimicrobial combination drug compositions based on a conditional diffusion model and its application include the following steps: First, an experimental dataset is constructed containing single-drug and pairwise combination antimicrobial measurement data of antibiotics, metalloids, and antimicrobial peptides. Then, combining multimodal structure / sequence characterization and concentration-related phenotypic information, generative modeling and discriminative scoring are integrated to explore and screen the antimicrobial combination space. Candidate combinations are initially screened under Staphylococcus aureus Newman strain, and then further verified in methicillin-resistant Staphylococcus aureus to see if their antimicrobial advantage can be retained under drug-resistant conditions. This invention organically combines the LightGBM scorer with the conditional diffusion model generation mechanism to construct a closed-loop system of generation, evaluation, and screening. This not only improves the diversity and exploratory nature of combinations but also enhances screening efficiency and accuracy, providing high-quality candidate combinations for subsequent experimental verification.

This invention relates to an antimicrobial peptide, a gel containing the same, and a method for preparing the same. The amino acid sequence of the antimicrobial peptide is shown in SEQ ID No. 1.

This invention discloses an intelligent programmed engineered probiotic system and its preparation method. The system uses probiotic strains as the engineered substrate bacteria, and is constructed by integrating the coding genes for superoxide dismutase (SOD), antimicrobial peptides (AMP), and a synchronized cleavage circuit (SLC) with the probiotic strains through genetic engineering technology. This invention also discloses a pH-responsive genetically engineered bacterial microsphere containing the aforementioned intelligent programmed engineered probiotic system, which is encapsulated in a carrier formed by the cross-linking reaction of sodium alginate and calcium chloride ions. The intelligent programmed engineered probiotic system and the accompanying pH-responsive genetically engineered bacterial microspheres constructed in this invention, through the synergistic design of the dual-function therapeutic modules SOD and AMP, and the programmed cleavage circuit SLC, simultaneously address the three core problems of IBD: oxidative stress, dysbiosis, and intestinal barrier damage.