In vitro and in vivo evaluation of the anti-infective potential of the essential oil extracted from the leaves of Plectranthus amboinicus (lour.) spreng against Klebsiella pneumoniae and elucidation of its mechanism of action through proteomics approach.

ETHNOPHARMACOLOGICAL RELEVANCE: Members of Plectranthus genus such as Plectranthus amboinicus (Lour.) Spreng is a well-known folkloric medicine around the globe in treating several human ailments such as cardiovascular, respiratory, digestive, urinary tract, skin and infective diseases. Its therapeutic value is primarily attributed to its essential oil. Although several properties of Plectranthus amboinicus essential oil have been documented, its mechanism of action and safety has not been completely elucidated. AIM OF THE STUDY: To investigate the anti-infective potential of Plectranthus amboinicus essential oil against Klebsiella pneumoniae using in vitro and in vivo bioassays and identify its mode of action. The study was conducted to scientifically validate the traditional usage of Plectranthus amboinicus oil and propose it as a complementary and alternative medication to combat Klebsiella pneumoniae infections due to emerging antibiotic resistance problem. MATERIALS AND METHODS: Plectranthus amboinicus essential oil was extracted through steam distillation and was chemically characterized using Gas Chromatography Mass Spectrometry (GC-MS). The antibacterial activity was assessed using microbroth dilution assay, metabolic viability assay and growth curve analysis. The mode of action was elucidated by the proteomics approach using Nano-LC-MS/MS followed by in silico analysis. The results of proteomic analysis were further validated through several in vitro assays. The cytotoxic nature of the essential oil was also confirmed using adenocarcinomic human alveolar basal epithelial (A549) cells. Furthermore, the safety and in vivo anti-infective efficacy of Plectranthus amboinicus essential oil was evaluated through survival assay, CFU assay and histopathological analysis of vital organs using zebrafish as a model organism. RESULTS: The chemical characterization of Plectranthus amboinicus essential oil revealed that it is predominantly composed of thymol. Thymol rich P. amboinicus essential oil demonstrated potent inhibitory effects on Klebsiella pneumoniae growth, achieving a significant reduction at a concentration of 400 µg/mL within 4 h of treatment The nano-LC-MS/MS approach unveiled that the essential oil exerted its impact by disrupting the antioxidant defense system and efflux pump system of the bacterium, resulting in elevated cellular oxidative stress and affect the biosynthesis of biofilm. The same was validated through several in vitro assays. Furthermore, the toxicity of Plectranthus amboinicus essential oil determined using A549 cells and zebrafish survival assay established a non-toxic concentration of 400 µg/mL and 12.5 µg/mL respectively. The results of anti-infective potential of the essential oil using Zebrafish as a model organism demonstrated significantly improved survival rates, reduced bacterial load, alleviated visible signs of inflammation and mitigated the adverse effects of infection on various organs, as evidenced by histopathological analysis ensuring its safety for potential therapeutic application. CONCLUSION: The executed in vitro and in vivo assays established the effectiveness of essential oil in inhibiting bacterial growth by targeting key proteins associated with the bacterial antioxidant defense system and disrupted the integrity of the cell membrane, highlighting its critical role in addressing the challenge posed by antibiotic-resistant Klebsiella pneumoniae.

Sesquiterpene Acids and Lactones from Inula Confertiflora with their Antibacterial Activities.

The phytochemical investigation of the leaves of Inula confertiflora, a medicinal plant endemic to Ethiopia, led to the isolation of 15 terpenoids; 1ß-hydroxy-α-costic acid (1), 3α-hydroxycostic acid (2), isotelekin (3), asperilin (4), carabrone (5), carpesioline (6), graveolide (7), inuviscolide (8), 8-epi-inuviscolide (9), 1ß,4ß-dihydroxy-5α(H)-guaia-10(14),11(13)-dien-8α,12-olide (10), isoinuviscolide (11), 4ß,10ß-dihydroxy-5α(H)-1,11(13)-guaidien-8α,12-olide (12), 4ß,10ß-dihydroxy-1ß(H)-5α(H)-guai-11(13)-en-8α,12-olide (13), 4ß,10α-dihydroxy-1ß(H)-5α(H)-guai-11(13)-en-8α,12-olide (14), 4ß,10α-dihydroxy-1α(H)-5α(H)-guai-11(13)-en-8α,12-olide (15). Herein, structural elucidation and full NMR data for compound 1 are presented for the first time. The structures were elucidated using NMR, HRESIMS, and by comparison with literature data. The relative configurations were defined by NOESY correlations and single-crystal X-ray crystallography. Herein, crystallography data of 6 and 7 were reported for the first time. The antibacterial efficacy of some of the isolated compounds was evaluated against two commonly dispersed environmental strains of Escherichia coli and Staphylococcus aureus. Compounds 1, 3, 6, 7, and 8 exhibited moderate antibacterial activities against the tested organisms. The chemotaxonomic significance of compounds is discussed.

New polyketides and sesquiterpenoids from the deep-sea sulphide-derived fungus Phoma sp. 3A00413.

Phoma fungi are known to produce a diverse range of natural products which possess various biological activities such as antifungal, antimicrobial, insecticidal, cytotoxic, and immunomodulatory effects. In our present study, we have isolated two novel polyketides (1 and 3), one new sesquiterpenoid (2), and eight known compounds (4-11) from the culture of Phoma sp. 3A00413, a deep-sea sulphide-derived fungus. The structures of compounds 1-3 were elucidated using NMR, MS, NMR calculation, and ECD calculation. In vitro antibacterial activities of all the isolated compounds were evaluated against Escherichia coli, Vibrio parahaemolyticus vp-HL, Vibrio parahaemolyticus, Staphylococcus aureus, Vibrio vulnificus, and Salmonella enteritidis. Compounds 1, 7, and 8 exhibited weak inhibition against Staphylococcus aureus growth, while compounds 3 and 7 showed weak inhibition against Vibrio vulnificus growth. Importantly, compound 3 demonstrated exceptional potency against Vibrio parahaemolyticus, with a minimum inhibitory concentration (MIC) of 3.1 µM.

Multi-drug resistant ESKAPE pathogens and the uses of plants as their antimicrobial agents.

Infections by ESKAPE (Enterococcus sp., Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) pathogens cause major concern due to their multi-drug resistance (MDR). The ESKAPE pathogens are frequently linked to greater mortality, diseases, and economic burden in healthcare worldwide. Therefore, the use of plants as a natural source of antimicrobial agents provide a solution as they are easily available and safe to use. These natural drugs can also be enhanced by incorporating silver nanoparticles and combining them with existing antibiotics. By focussing the attention on the ESKAPE organisms, the MDR issue can be addressed much better.

New polyphenolic glycosides from the stems of Caesalpinia cucullata and their inhibitory effect on methicillin-resistant Staphylococcus aureus with different ways.

Anti-virulence strategy represents an emerging alternative strategy in the war against increasing prevalence of methicillin-resistant Staphylococcus aureus (MRSA) due to its milder selection pressure on bacterial resistance. Sortase A (SrtA), as an important virulence factor, is a membrane-localized cysteine transpeptidase which anchors cell surface proteins to the cell wall. Natural products in medicinal plants are the source of targeting bacterial virulence factors. Here, we found polyphenolic glycosides (1-15), including thirteen new derivatives isolated from the stems of Caesalpinia cucullata, exhibited weak to moderate SrtA inhibitory activity without affecting the growth of MRSA, and compound 7 (53.7 % inhibition at 100 µM) was superior to the positive control curcumin. Meanwhile, compounds 2, 4 and 8 could effectively reduce the dose of ceftiofur in combination in vitro with fractional inhibitory concentration index (FICI) ranging from 0.188 to 0.375, which meant polyphenolic glycosides have got antibacterial activity with different ways. Here, we reported all new compounds structures determined by spectroscopy methods and their antibacterial activities, together, the relationship between structures with the inhibitory efficiency. The results indicated that polyphenolic glycosides could be used as promising therapeutic agents to prevent resistance development for S. aureus infections.

Phytochemical Analysis and Antibacterial Activity of Achillea coarctata Poir. Essential Oils.

Essential oils obtained from different parts of Achillea coarctata species (inflorescences, stem and leaves and the whole aerial part) collected on four different locations in Serbia have been investigated to evaluate the chemical composition and antibacterial activity of isolated oils. The aim of this study was to determine differences in the chemical composition of essential oils obtained from different plant parts and how different type of substrate as well as different climate conditions affect the chemical composition of essential oils. Oxigenated terpenes were reported to be the major constituents in almost all examinated samples with 1,8-cineole, caryophyllene oxide and cis-cadin-4-en-7-ol identified as dominant compounds. Disk diffusion assay was used to determine antibacterial activity against two Gram-positive (Bacillus subtilis subsp. spizizenii ATCC 6633 and Staphylococcus aureus ATCC 6538) and three Gram-negative bacteria (Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 9027 and Salmonella abony ATCC 6017). The obtained results showed that essential oils obtained from A. coarctata exhibit significant antibacterial activity against tested bacteria strains. The best inhibitory effect was observed against S. aureus, while on the other hand P. aeruginosa showed high level of resistance to almost all examined essential oils.

Leucine-Rich, Potent Anti-Bacterial Protein against Vibrio cholerae, Staphylococcus aureus from Solanum trilobatum Leaves.

A 24 kDa leucine-rich protein from ion exchange fractions of Solanum trilobatum, which has anti-bacterial activity against both the Gram-negative Vibrio cholerae and Gram-positive Staphylococcus aureus bacteria has been purified. In this study, mass spectrometry analysis identified the leucine richness and found a luminal binding protein (LBP). Circular dichroism suggests that the protein was predominantly composed of α- helical contents of its secondary structure. Scanning electron microscopy visualized the characteristics and morphological and structural changes in LBP-treated bacterium. Further in vitro studies confirmed that mannose-, trehalose- and raffinose-treated LBP completely inhibited the hemagglutination ability towards rat red blood cells. Altogether, these studies suggest that LBP could bind to sugar moieties which are abundantly distributed on bacterial surface which are essential for maintaining the structural integrity of bacteria. Considering that Solanum triolbatum is a well-known medicinal and edible plant, in order to shed light on its ancient usage in this work, an efficient anti-microbial protein was isolated, characterized and its in vitro functional study against human pathogenic bacteria was evaluated.

Antioxidant and Antimicrobial Activities of Chemically-Characterized Essential Oil from Artemisia aragonensis Lam. against Drug-Resistant Microbes.

This study investigated the chemical composition, antioxidant and antimicrobial activity of essential oil extracted from Artemisia aragonensis Lam. (EOA). Hydrodistillation was employed to extract EOA. Gas chromatography with flame ionization detection (GC-FID) and gas chromatography-mass spectrometry analyses (GC-MS) were used to determine the phytochemical composition of EOA. Antioxidant potential was examined in vitro by use of three tests: 2.2-diphenyl-1-picrilhidrazil (DPPH), ferric reducing activity power (FRAP) and total antioxidant capacity assay (TAC). Agar diffusion and microdilution bioassays were used to assess antimicrobial activity. GC/MS and GC-FID detected 34 constituents in the studied EOA. The major component was Camphor (24.97%) followed by Borneol (13.20%), 1,8 Cineol (10.88%), and Artemisia alcohol (10.20%). EOA exhibited significant antioxidant activity as measured by DPPH and FRAP assays, with IC50 and EC50 values of 0.034 ± 0.004 and 0.118 ± 0.008 mg/mL, respectively. EOA exhibited total antioxidant capacity of 7.299 ± 1.774 mg EAA/g. EOA exhibited potent antibacterial activity as judged by the low minimum inhibitory concentration (MIC) values against selected clinically-important pathogenic bacteria. MIC values of 6.568 ± 1.033, 5.971 ± 1.033, 7.164 ± 0.0 and 5.375 ± 0.0 µg/mL were observed against S. aureus, B. subtills, E. coli 97 and E. coli 57, respectively. EOA displayed significant antifungal activity against four strains of fungi: F. oxysporum, C. albicans, A. flavus and A. niger with values of 21.50 ± 0.43, 5.31 ± 0.10, 21.50 ± 0.46 and 5.30 ± 0.036 µg/mL, respectively. The results of the current study highlight the importance of EOA as an alternative source of natural antioxidant and antibacterial drugs to combat antibiotic-resistant microbes and free radicals implicated in the inflammatory responses accompanying microbial infection.

Antibacterial activity of plant essential oils against indigenously characterized methicillin-resistant Staphylococcus aureus (MRSA).

Plant essential oils were evaluated for antimicrobial activity against Methicillin-resistant Staphylococcus aureus (MRSA). The isolates (n=03) were procured from Institute of Microbiology, UVAS Lahore, Pakistan. After biochemical and 16S rRNA gene-based PCR characterization, accession numbers were retrieved from NCBI i.e. MW344063.1, MW344064.1 and MW344065.1. These isolates exhibited molecular positivity by multiplex PCR for mecA, coa and eta toxin genes. Moreover, these isolates exhibited resistance to cefoxitin, ampicillin, amoxicillin, penicillin, amoxicillin clavulanate, ciprofloxacin, erythromycin and gentamicin. The antibiotic resistant isolates were evaluated for antimicrobial activity of plant essential oils. The highest zone of inhibition (mean ZOI±S.D.) was measured for Cinnamomum verum (22.67±1.52 mm) followed by Eucalyptus globulus (18.67±2.51 mm) and Syzygium aromaticum (12.67±2.51 mm). Lowest mean MIC value (0.33±0.11 mg/mL) was recorded for E. globulus . Eucalyptus globulus was processed for fractionation by column chromatography and n-hexane, chloroform, n-hexane + chloroform and ethyl-acetate fractions were evaluated for antibacterial activity. Lowest mean MIC (10.04±5.80 mg/mL) was recorded for E. globulus n-hexane fraction. Cell survival percentage of BHK21 cell line was 51.7% at 54.87mg/mL concentration of E. globulus n-hexane fraction. Through gas chromatography-mass spectrometry (GC-MS) analysis of n-hexane fraction, benzene was found abundant (29.9%) as active compound. It was concluded that E. globulus n-hexane fraction exhibited significantly promising results against MRSA .

Bioactive Compounds of Ganoderma boninense Inhibited Methicillin-Resistant Staphylococcus aureus Growth by Affecting Their Cell Membrane Permeability and Integrity.

Some species of Ganoderma, such as G. lucidum, are well-known as traditional Chinese medicine (TCM), and their pharmacological value was scientifically proven in modern days. However, G. boninense is recognized as an oil palm pathogen, and its biological activity is scarcely reported. Hence, this study aimed to investigate the antibacterial properties of G. boninense fruiting bodies, which formed by condensed mycelial, produced numerous and complex profiles of natural compounds. Extract was cleaned up with normal-phase SPE and its metabolites were analyzed using liquid chromatography-mass spectrometry (LCMS). From the disc diffusion and broth microdilution assays, strong susceptibility was observed in methicillin-resistant Staphylococcus aureus (MRSA) in elute fraction with zone inhibition of 41.08 ± 0.04 mm and MIC value of 0.078 mg mL-1. A total of 23 peaks were detected using MS, which were putatively identified based on their mass-to-charge ratio (m/z), and eight compounds, which include aristolochic acid, aminoimidazole ribotide, lysine sulfonamide 11v, carbocyclic puromycin, fenbendazole, acetylcaranine, tigecycline, and tamoxifen, were reported in earlier literature for their antimicrobial activity. Morphological observation via scanning electron microscope (SEM), cell membrane permeability, and integrity assessment suggest G. boninense extract induces irreversible damage to the cell membrane of MRSA, thus causing cellular lysis and death.

Tabernaecorymine A, an 18-normonoterpenoid indole alkaloid with antibacterial activity from Tabernaemontana corymbosa.

Tabernaecorymine A, an 18-normonoterpenoid indole alkaloid with conjugated (E)-3-aminoacrylaldehyde fragment was obtained from the stem bark of Tabernaemontana corymbosa. Its structure was elucidated by extensive spectroscopic data analyses, and further verified by ACD/structure elucidator, electronic circular dichroism (ECD) analyses and density functional theory (DFT) chemical shift predictions. The compound exhibited significant antibacterial bioactivity against Streptococcus dysgalactiae with an MIC value of 3.12 µg/mL, which is better than the plant drug berberine.

Hygromycin A derivatives isolated from Streptomyces sp. PC-22 in the rhizosphere soil of Pulsatilla chinensis.

On the basis of the one strain-many compounds (OSMAC) strategy, two new hygromycin A derivatives (3, 4), together with six known compounds were isolated from a medicinal plant inter rhizospheric Streptomyces in Pulsatilla chinensis. The structures of 3 and 4 were elucidated using NMR and HRESIMS analyses. A plausible biosynthetic pathway for these compounds was discussed. All the compounds were evaluated for their antimicrobial and cytotoxic activities. Compound 5 exhibited potent inhibitory activity against S. aureus and B. subtilis with the MICs of 16 and 8 µg ml-1, while 4 showed weak inhibitory activity against S. aureus.

In vitro anti-Helicobacter pylori activity of Syzygium aromaticum and the preliminary mechanism of action.

ETHNOPHARMACOLOGICAL RELEVANCE: The dried flower bud of Syzygium aromaticum (L.) Merr. & L.M Perry (S. aromaticum) (Myrtaceae), also known as clove, was used in Traditional Chinese Medicine (TCM) to aid gastrointestinal function and treat stomach disorders including vomiting, flatulence and nausea. And it is a food homology medicine which is a promising candidate for H. pylori treatment. H. pylori is a Gram-negative bacterium that infects approximately 50% of the human population worldwide, which is closely related to multiple gastric diseases, including gastric cancer. However, there are still no sufficient studies on the anti-H. pylori activity of S. aromaticum, especially for the mechanism of action. AIM OF STUDY: This study aimed to study the antibacterial activities of S. aromaticum extracts on both antibiotic-sensitive and -resistant H. pylori strains, and to explore the underlying mechanisms of action. MATERIALS AND METHODS: The S. aromaticum extracts were obtained by heat reflux extraction and lyophilized to powder form. The phytochemical analyses were performed by High-performance liquid chromatography (HPLC) and UPLC-electrospray ionization mass spectrometry (ESI-MS). In vitro anti-H. pylori activity was evaluated by broth microdilution method. Mechanism of action studies included morphological observation using electron microscopy, determination of expression of virulence genes by reverse transcription quantitative polymerase chain reaction (RT-qPCR), genes expression profile identification by transcriptomic analysis, and exploration of anti-H. pylori infection mechanisms by network pharmacology analysis and western blotting validation. RESULTS: The S. aromaticum extracts, aqueous extract (AE) and 75% hydroalcoholic extract (HE), exerted significant antibacterial activities against both antibiotic-sensitive and -resistant H. pylori strains with MICs of 160∼320 µg/ml, without developing drug resistance. Among them, AE was bactericide to all the tested strains with MBCs of less than 4MIC, while HE was merely bacteriostatic to most of the tested strains with MBCs of 2MIC∼16MIC. Besides, they showed no antagonistic effects in combination with clarithromycin, metronidazole, levofloxacin, and amoxicillin. Additionally, these extracts altered the morphology and ultrastructure and down-regulated the virulence genes expression of H. pylori. And transcriptomic analysis showed that they regulated genes expression of multiple H. pylori biological processes, including tricarboxylic acid cycle (TAC) and pyruvate metabolic pathways. Furthermore, these extracts combated the abnormal activation of PI3K-Akt and MAPK signaling pathways caused by H. pylori infection. CONCLUSIONS: Overall, the present study firstly analyzed the chemical compositions of S. aromaticum extracts, and then confirmed their activities on both antibiotic-sensitive and -resistant H. pylori strains. In addition, the mechanisms of action of S. aromaticum extracts against H. pylori were found to be destroying the bacterial structure, down-regulating the expression of virulence genes, and interfering TAC and pyruvate metabolic pathways. Finally, S. aromaticum extracts were found to combated the abnormal activation of PI3K-Akt and MAPK signaling pathways to treat H. pylori infection. This study should accelerate further research and application of S. aromaticum against H. pylori infection.

Polysaccharide from edible alga Gloiopeltis furcata attenuates intestinal mucosal damage by therapeutically remodeling the interactions between gut microbiota and mucin O-glycans.

Gloiopeltis furcata is an edible alga that has long been consumed in China. However, the bioactive polysaccharides from G. furcata have been largely unexplored. Here, we show for the first time that a sulfated polysaccharide from G. furcata (SAO) could improve the integrity of the colonic epithelial layer and protect against dextran sulfate sodium-induced intestinal mucosal damage. Mechanistically, SAO attenuated colonic mucosal damage by therapeutically remodeling the interactions between gut microbiota and mucin O-glycans. Specifically, SAO increased the proportions of complex long-chain mucin O-glycans in the epithelial layer with two terminal N-acetylneuraminic acid residues and promoted the growth of probiotic bacteria including Roseburia spp. and Muribaculaceae. Altogether, our study demonstrates a novel application of SAO for the treatment of inflammatory bowel disease-associated mucosal damage and forms the basis to understand the therapeutic effects of natural polysaccharides from the perspective of symbiotic interactions between host mucin O-glycome and gut microbiome.

Histological assessment, anti-quorum sensing, and anti-biofilm activities of Dioon spinulosum extract: in vitro and in vivo approach.

Pseudomonas aeruginosa is an opportunistic bacterium causing several health problems and having many virulence factors like biofilm formation on different surfaces. There is a significant need to develop new antimicrobials due to the spreading resistance to the commonly used antibiotics, partly attributed to biofilm formation. Consequently, this study aimed to investigate the anti-biofilm and anti-quorum sensing activities of Dioon spinulosum, Dyer Ex Eichler extract (DSE), against Pseudomonas aeruginosa clinical isolates. DSE exhibited a reduction in the biofilm formation by P. aeruginosa isolates both in vitro and in vivo rat models. It also resulted in a decrease in cell surface hydrophobicity and exopolysaccharide quantity of P. aeruginosa isolates. Both bright field and scanning electron microscopes provided evidence for the inhibiting ability of DSE on biofilm formation. Moreover, it reduced violacein production by Chromobacterium violaceum (ATCC 12,472). It decreased the relative expression of 4 quorum sensing genes (lasI, lasR, rhlI, rhlR) and the biofilm gene (ndvB) using qRT-PCR. Furthermore, DSE presented a cytotoxic activity with IC50 of 4.36 ± 0.52 µg/ml against human skin fibroblast cell lines. For the first time, this study reports that DSE is a promising resource of anti-biofilm and anti-quorum sensing agents.

Secondary Metabolites from the Fresh Leaves of Pinus yunnanensis Franch.

Fifteen metabolites, including two flavonols (1-2), three lignans (3-5), and ten diterpenoids (6-15), were isolated from the leaves of Pinus yunnanensis. Among them, flavanonol (1) were identified as undescribed flavonol derivative with natural rarely B-ring fission lactone. Massive spectroscopic methods, the DP4+ probabilities and CD/ECD calculations were applied to establish the structure of component 1. Among these compounds, taxifolin (2) showed potent cytotoxicity, having IC50 values from 21.33 to 45.48 µg/mL, it also showed broad antibacterial activity against human pathogens with MIC values from 32 to 64 µg/mL.

Natural imidazole alkaloids as antibacterial agents against Pseudomonas syringae pv. actinidiae isolated from kiwi endophytic fungus Fusarium tricinctum.

Kiwi (Actinidia chinensis) plants are severely destroyed by canker disease which is caused by the bacterium Pseudomonas syringae pv. actinidiae (Psa). This program tries to find anti-Psa agents among secondary metabolites of endophytic fungi from kiwi plant itself. The chemical investigation on one kiwi endophytic fungi, Fusarium tricinctum, resulted in the isolation of nine new imidazole alkaloids, fusaritricines A-I (1-9) together with seven known analogues (10-16). The structures of new compounds were established by extensive spectroscopic methods. Compounds 2, 3, 9, and 13 showed good antibacterial activity against Psa with MIC values between 25 and 50 µg/mL. It is suggested that imidazole alkaloids should be potential anti-Psa agents.

In-vitro anti-Helicobacter pylori activity and preliminary mechanism of action of Canarium album Raeusch. fruit extracts.

ETHNOPHARMACOLOGICAL RELEVANCE: Canarium album Raeusch. belongs to the Burseraceae family. Its ripe fruits, known as Qing Guo (QG) in Traditional Chinese Medicine (TCM), are used to treat sore throat, cough, and fish or crab poisoning. QG was reported to have antibacterial activity, and it exerted excellent anti-Helicobacter pylori (H. pylori) activity in our screening of abundant TCM. However, few studies have reported its anti-H. pylori activity and mechanism. AIM OF STUDY: The commonly used eradication therapies for H. pylori infection are antibiotic-based therapies. With the increasing antibiotic resistance of H. pylori, interest in finding alternative therapies has been aroused. This study investigated the phytochemistry profile, in vitro anti-H. pylori activity and possible anti-bacterial mechanism of QG extracts. MATERIALS AND METHODS: QG extracts were obtained by heat reflux extraction, ultrasonic extraction or liquid-liquid extraction with different solvents. The quantitative and qualitative phytochemical analyses were performed by colorimetric determination, high-performance liquid chromatography (HPLC), and UPLC-electrospray ionization mass spectrometry (ESI-MS). In vitro anti- H. pylori activity was assessed by broth micro-dilution method. Mechanism of action studies included morphological observation using electron microscopy, urease inhibition assay and determination of expression of virulence genes by RT-qPCR. RESULTS: All QG extracts especially ethyl acetate extract (QGEAE) were rich in phenolic components, with the minimum inhibitory concentrations (MICs) on H.pylori of 39-625 µg/ml and minimum bactericidal concentrations (MBCs) of 78-1250 µg/ml. Both aqueous extract (QGAE) and QGEAE could induce the morphological and structural changes of H. pylori, inhibit urease activity with IC50 of 1093 µg/ml and 332.90 µg/ml, respectively, and down-regulate the virulence genes, such as vacA and cagA. CONCLUSIONS: QG may exhibit in vitro anti-H. pylori activity by inhibiting growth, destroying the bacterial structure and down-regulating the expression of virulence factors. Moreover, QG is the homology of food and TCM, which can be considered as a safe and convenient agent against H. pylori infection.

Antibacterial secondary metabolites from Vernonia auriculifera Hiern (Asteraceae) against MDR phenotypes.

Purification of the aerial parts of Vernonia auriculifera Hiern afforded steroids (1-2), flavonoids (3-5), and polyalcohol (6). Their structures were determined using spectral evidences as well as by comparison with reported data. Iodonitrotetrazolium chloride (INT) colorimetric assay was used to assess the antibacterial activity of the extract and isolates against 13 pathogenic strains. The crude extract showed strong antibacterial activity (MIC < 100 µg/mL) against the tested bacterial strains. When combined with an efflux pump inhibitor phenylalanine beta naphthylamide (PAßN), the inhibition potency of the extract was substantially enhanced with the lowest MIC value at 4 µg/mL. Compounds 5 and 6 showed moderate activity (MIC < 100 µg/mL) against 12/13 (92.3%), and 8/13 (61.5%) bacterial strains, respectively. A minimal bactericidal concentration (MBC)/minimal inhibitory concentration (MIC) ratio ≤ 4 indicated their bactericidal effect against Escherichia coli, Enterbacter aerogenes, Klebsiella pneumoniae, Providencia stuartii, Pseudomonas aeruginosa, and Staphylococcus aureus.

Skincare application of medicinal plant polysaccharides - A review.

Polysaccharides are macromolecules with important inherent properties and potential biotechnological applications. These complex carbohydrates exist throughout nature, especially in plants, from which they can be obtained with high yields. Different extraction and purification methods may affect the structure of polysaccharides and, due to the close relationship between structure and function, modify their biological activities. One of the possible applications of these polysaccharides is acting on the skin, which is the largest organ in the human body and can be aged by intrinsic and extrinsic processes. Skincare has been gaining worldwide attention not only to prevent diseases but also to promote rejuvenation in aesthetic treatments. In this review, we discussed the polysaccharides obtained from plants and their innovative potential for skin applications, for example as wound-healing, antimicrobial, antioxidant and anti-inflammatory, antitumoral, and anti-aging compounds.