Objectives
The chemical composition, antimicrobial and synergistic effect, and cytotoxic activity of Citrus limon (lemon), Piper nigrum (green pepper) and Melaleuca alternifoila (tea tree) essential ...oils (EOs) were investigated.
Methods
Chemical analyses of essential oils were tested by GC‐FID and GC‐MS spectroscopy. The antimicrobial activity assay was conducted using microdilution method against several oral bacteria and Candida spp. originating from the humans with oral disorders. The synergistic antimicrobial activity was evaluated using checkerboard method. The cytotoxicity evaluation of EOs was assessed using MTT test.
Key findings
Limonene (37.5%) and β‐pinene (17.9%) were the major compounds in C. limon oil, β‐pinene (34.4%), δ‐3‐carene (19.7%), limonene (18.7%) and α‐pinene (10.4%) in P. nigrum oil and terpinen‐4‐ol (38.6%) and γ‐terpinene (21.7%) in M. alternifolia oil. The broad‐spectrum antimicrobial activity was achieved by tested three EOs, with C. limon oil being the strongest against bacteria and M. alternifolia oil strongest against fungi. The EOs demonstrated synergism; their combined application revealed an increase in antimicrobial activity. All tested essential oils showed lower cytotoxic activity in comparison with the positive control, and the obtained results confirmed a dose‐dependent activity.
Conclusions
The results of this study encourage use of tested EOs in development of a novel agent intended for prevention or therapy of corresponding oral disorders.
Lignins and lignin-derived compounds are known to have antibacterial properties. The wound healing agents in the form of dressings produce faster skin repair and decrease pain in patients. In order ...to create an efficient antimicrobial agent in the form of dressing in the treatment of chronic wounds, a composite hydrogel of bacterial cellulose (BC) and dehydrogenative polymer of coniferyl alcohol (DHP), BC-DHP, was designed. Novel composite showed inhibitory or bactericidal effects against selected pathogenic bacteria, including clinically isolated ones. The highest release rate of DHP was in the first hour, while after 24 h there was still slow release of small amounts of DHP from BC-DHP during 72 h monitoring. High-performance liquid chromatography coupled with mass-spectrometry showed that BC-DHP releases DHP oligomers, which are proposed to be antimicrobially active DHP fractions. Scanning electron microscopy and atomic force microscopy micrographs proved a dose-dependent interaction of DHP with BC, which resulted in a decrease of the pore number and size in the cellulose membrane. The Fourier-transform infrared absorption spectra of the BC-DHP showed that DHP was partly bound to the BC matrix. The swelling and crystallinity degree were dose-dependent. All obtained results confirmed BC-DHP composite as a promising hydrogel for wounds healing.
•Novel composite BC-DHP in form of dressing showed inhibitory/bactericidal effect.•BC-DHP showed highest release of the active substance during the first 24 h.•Released active compounds were oligomers of coniferyl alcohol.•High swellability of hydrogel confirmed its potential role in chronic wound healing.
This manuscript deals with the synthesis and computational and experimental evaluation of the antimicrobial activity of twenty-nine 4-(indol-3-yl)thiazole-2-amines and 4-ιndol-3-yl)thiazole ...acylamines. An evaluation of antibacterial activity against Gram (+) and Gram (−) bacteria revealed that the MIC of indole derivatives is in the range of 0.06–1.88 mg/mL, while among fourteen methylindole derivatives, only six were active, with an MIC in the range of of 0.47–1.88 mg/mL. S. aureus appeared to be the most resistant strain, while S. Typhimurium was the most sensitive. Compound 5x was the most promising, with an MIC in the range of 0.06–0.12 mg/mL, followed by 5d and 5m. An evaluation of these three compounds against resistant strains, namely MRSA P. aeruginosa and E. coli, revealed that they were more potent against MRSA than ampicillin. Furthermore, compounds 5m and 5x were superior inhibitors of biofilm formation, compared to ampicillin and streptomycin, in terms Compounds 5d, 5m, and 5x interact with streptomycin in additive manner. The antifungal activity of some compounds exceeded or was equipotent to those of the reference antifungal agents bifonazole and ketoconazole. The most potent antifungal agent was found to be compound 5g. Drug likeness scores of compounds was in a range of −0.63 to 0.29, which is moderate to good. According to docking studies, E. coli MurB inhibition is probably responsible for the antibacterial activity of compounds, whereas CYP51 inhibition was implicated in antifungal activity. Compounds appeared to be non-toxic, according to the cytotoxicity assessment in MRC-5 cells.
The chemical composition and antibacterial activity of essential oils from 10 commonly consumed herbs: Citrus aurantium, C. limon, Lavandula angustifolia, Matricaria chamomilla, Mentha piperita, M. ...spicata, Ocimum basilicum, Origanum vulgare, Thymus vulgaris and Salvia officinalis have been determined. The antibacterial activity of these oils and their main components; i.e. camphor, carvacrol, 1,8-cineole, linalool, linalyl acetate, limonene, menthol, a-pinene, b-pinene, and thymol were assayed against the human pathogenic bacteria Bacillus subtilis, Enterobacter cloacae, Escherichia coli O157:H7, Micrococcus flavus, Proteus mirabilis, Pseudomonas aeruginosa, Salmonella enteritidis, S. epidermidis, S. typhimurium, and Staphylococcus aureus. The highest and broadest activity was shown by O. vulgare oil. Carvacrol had the highest antibacterial activity among the tested components.
represents one of the most common fungal pathogens. Due to its increasing incidence and the poor efficacy of available antifungals, finding novel antifungal molecules is of great importance. Camphor ...and eucalyptol are bioactive terpenoid plant constituents and their antifungal properties have been explored previously. In this study, we examined their ability to inhibit the growth of different
species in suspension and biofilm, to block hyphal transition along with their impact on genes encoding for efflux pumps (
and
), ergosterol biosynthesis (
), and cytotoxicity to primary liver cells. Camphor showed excellent antifungal activity with a minimal inhibitory concentration of 0.125-0.35 mg/mL while eucalyptol was active in the range of 2-23 mg/mL. The results showed camphor's potential to reduce fungal virulence traits, that is, biofilm establishment and hyphae formation. On the other hand, camphor and eucalyptol treatments upregulated
was positively regulated after eucalyptol application while camphor downregulated it. Neither had an impact on
expression. The beneficial antifungal activities of camphor were achieved with an amount that was non-toxic to porcine liver cells, making it a promising antifungal compound for future development. The antifungal concentration of eucalyptol caused cytotoxic effects and increased expression of efflux pump genes, which suggests that it is an unsuitable antifungal candidate.
The control of fungal pathogens is increasingly difficult due to the limited number of effective drugs available for antifungal therapy. In addition, both humans and fungi are eukaryotic organisms; ...antifungal drugs may have significant toxicity due to the inhibition of related human targets. Furthermore, another problem is increased incidents of fungal resistance to azoles, such as fluconazole, ketoconazole, voriconazole, etc. Thus, the interest in developing new azoles with an extended spectrum of activity still attracts the interest of the scientific community. Herein, we report the synthesis of a series of triazolium salts, an evaluation of their antifungal activity, and docking studies. Ketoconazole and bifonazole were used as reference drugs. All compounds showed good antifungal activity with MIC/MFC in the range of 0.0003 to 0.2/0.0006-0.4 mg/mL. Compound
exhibited the best activity among all tested with MIC/MFC in the range of 0.009 to 0.037 mg/mL and 0.0125-0.05 mg/mL, respectively. All compounds appeared to be more potent than both reference drugs. The docking studies are in accordance with experimental results.
•Composition of Diospyros virginiana methanol extract, phenolic profile.•Methanol extract, their isolated phenolic compounds have shown significant antimicrobial effect.•Flavonoid aglycones exhibited ...the strongest antimicrobial activity.
This study was carried out with the objective to investigate antibacterial and antifungal activities of Diospyros virginiana fruits (methanol 80%) extract and the phenolic compounds isolated from the extract. The in vitro antibacterial and antifungal assays were done against eight bacterial strains and against eight fungal species using microdilution method. Eight phenolic compounds, m-gallate, gallic acid, luteolin, quercetin, myricetin, myricetin 3-O-α-rhamnoside, myricetin 3-O-β-glucoside, and myricetin 3-O-β-glucuronide were isolated and identified by different spectroscopic tools (UV, 1H NMR, 13C NMR, MS). The results of the methanol extract of Diospyros virginiana fruits and its isolated phenolic compounds showed significant antibacterial and antifungal effects against all the tested microorganisms. The best results were obtained for flavonoid aglycones which showed strong antimicrobial activity against all the microorganisms tested. These results may help to discover new chemical classes of natural antimicrobial substances that could serve as selective agents for infectious disease chemotherapy and control.
In Russian traditional medicine, an extract from the mushroom Inonotus obliquus (Fr.) Pil´at is used as an anti-tumor medicine and diuretic. It has been reported that Inonotus obliquus has ...therapeutic effects, such as anti-inflammatory, immuno-modulatory and hepatoprotective effects. This study was designed to investigate the chemical composition and biological properties of aqueous and ethanolic extracts of Inonotus obliquus from Finland, Russia, and Thailand. Their antioxidative, antimicrobial, and antiquorum properties were tested as well as the cytotoxicity on various tumor cell lines.
The tested extract was subjected to conventional chemical study to identified organic acids and phenolic compounds. Antioxidative activity was measured by several different assays. Antimicrobial potential of extracts was tested by microdilution method, and antiquorum sensing activity and antibiofilm formation of Inonotus obliquus extracts was tested on Pseudomonas aeruginosa. Cytotoxicity of the extracts was tested on tumor cells (MCF-7, NCI-H460, HeLa and HepG2) and non-tumor liver cells primary cultures.
Oxalic acid was found as the main organic acid, with the highest amount in the aqueous extract from Russia. Gallic, protocatechuic and p-hydroxybenzoic acids were detected in all samples. Inonotus obliquus extracts showed high antioxidant and antimicrobial activity. Extracts were tested at subMIC for anti-quorum sensing (AQS) activity in Pseudomonas aeruginosa and all extracts showed definite AQS activity. The assays were done using twitching and swarming of bacterial cultures, and the amount of produced pyocyanin as QS parameters. All the extracts demonstrated cytotoxic effect on four tumor cell lines and not on primary porcine liver cells PLP2.
As the Inonotus obliquus presence in Chaga conks is limited, further purification is necessary to draw quantitative conclusions. The presence of AQS activity in medicinal mushrooms suggests a broader anti-infectious disease protection than only immunomodulatory effects.
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To scientifically validate their traditional use, phytochemical and bioactivity evaluation of Thymus serpyllum, Thymus algeriensis and Thymus vulgaris essential oils were done.
•Chemical composition ...and in vitro biological activity of Thymus essential oils (EO) were examined.•The main component of EOs was thymol (38.50–56.02%).•EOs exhibited strong antimicrobial, antioxidant/antiradical and antitumor activity.•This study succeeds in creating comparable and quantitative data for usage of Thymus oils against oral microorganisms.
Aromatic plant species of genus Thymus are important medicinal plants, highly recommended due to a range of therapeutic properties of their essential oils, commonly known as thyme oil: antirheumatic, antiseptic, antispasmodic, antimicrobial, cardiac, carminative, diuretic and expectorant. The oil is also beneficial in boosting the immune system and helps to fight colds, flu, infectious diseases and chills. It is proved to be a urinary antiseptic, being very helpful for cystitis and urethritis. Scientific validation of traditional uses, and phytochemical and bioactivity evaluation of essential oils from Thymus serpyllum, Thymus algeriensis and Thymus vulgaris were performed.
GC/MS analysis revealed thymol as a major component of T. algeriensis, T. vulgaris and T. serpyllum, with its contribution to the oil 56.0%, 48.9% and 38.5%, respectively. All three essential oils (EOs) exhibited a significant antimicrobial activity against all tested strains, the T. serpyllum oil being the most potent one (MIC 2.5–5μg/mL, MBC 5–10μg/mL; MIC 1–2μg/mL, MFC 2–4μg/mL). In addition, the T. serpyllum oil revealed the highest antioxidant activity in all conducted assays and it was the most effective one against all tested cell lines, presenting GI50 values of 7.02–52.69μg/mL. Moreover, none of the EOs showed toxicity at tested concentrations (>400μg/mL) for porcine liver primary cell culture. In addition to their well-known traditional use in food and cosmetics, the great potential of tested Thymus essential oils for application in oral diseases and anticancer treatments, encourage further investigation.
Due to the high incidence of fungal infections worldwide, there is an increasing demand for the development of novel therapeutic approaches. A wide range of natural products has been extensively ...studied, with considerable focus on flavonoids. The antifungal capacity of selected flavones (luteolin, apigenin), flavonols (quercetin), and their glycosylated derivatives (quercitrin, isoquercitrin, rutin, and apigetrin) along with their impact on genes encoding efflux pumps (
) and ergosterol biosynthesis enzyme (
) has been the subject of this study. Cytotoxicity of flavonoids towards primary liver cells has also been addressed. Luteolin, quercitrin, isoquercitrin, and rutin inhibited growth of
with the minimal inhibitory concentration of 37.5 µg/mL. The application of isoquercitrin has reduced
biofilm establishing capacities for 76%, and hyphal formation by yeast. In vitro treatment with apigenin, apigetrin, and quercitrin has downregulated
. Contrary to rutin and apigenin, isoquercitrin has upregulated
. Except apigetrin and quercitrin (90 µg/mL and 73 µg/mL, respectively inhibited 50% of the net cell growth), the examined flavonoids did not exhibit cytotoxicity. The reduction of both fungal virulence and expression of antifungal resistance-linked genes was the most pronounced for apigenin and apigetrin; these results indicate flavonoids' indispensable capacity for further development as part of an anticandidal therapy or prevention strategy.
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