Native and endemic Iranian Nepeta spp.: powerful antimicrobial agents.

Pathogenic microorganisms are more or less successfully treated by synthetic chemical compounds, whose residues often cause serious health problems. Plant specialized metabolites with antimicrobial properties have for a long time been the focus of both medicine and pharmacology. This study was conducted to evaluate the in vitro antimicrobial activity of methanol extracts of selected endemic and native Iranian Nepeta species against some of the most important pathogenic bacteria and fungi. The results indicated that N. kotschyi leaf extract was the most efficient against the tested bacteria, with Pseudomonas aeruginosa being the most sensitive and fungal species were more susceptible to the extracts than bacterial strains. Nepeta spp. extracts showed a strong antifungal activity against micromycetes, except for quite resistant Aspergillus niger. Antibacterial MIC values (mg.mL-1) ranged from 0.01 (N. kotschyi) to 0.20 (N. crassifolia), while antifungal MIC values ranged from 0.02 (N. crassifolia, N. kotschyi, N. menthoides, and N. cataria) to 0.13 (N. crassifolia and N. menthoides). When compared to positive controls, in most cases the extracts performed much better. The recorded antimicrobial activity candidates the selected 4 endemic and native Iranian Nepeta spp. as prospective and promising antimicrobial agents to be used in both pharmacology and biotechnology.

Serum Zinc Concentration in Patients with Alopecia Areata.

Alopecia areata is an autoimmune non-scarring disease in which the exact mechanism that induces loss of immune privilege is unknown. Zinc is important for DNA stability and repair mechanisms that are essential in maintaining normal hair growth. Zinc deficiency has been investigated as an important factor in many autoimmune diseases, and may have a possible role in the aetiopathogenesis of alopecia areata. This study included 32 patients with severe forms of alopecia areata, and 32 age- and sex-matched healthy controls. When comparing serum zinc levels in these 2 groups, statistically significantly lower zinc concentrations were found in the alopecia areata group (p = 0.017). Detected zinc deficiency was statistically more prevalent in patients with alopecia areata (p = 0.011). Evaluating patients with alopecia areata, a statistically significant negative correlation between serum zinc levels and severity of the disease was found (ρ = 0.006). The results indicate that zinc serum assessment is necessary in patients with alopecia areata. Low serum zinc levels were found to correlate with severity of alopecia areata. Given that most severe forms of alopecia areata are frequently most treatment-resistant, additional randomized control trials examining zinc supplementation are necessary to investigate its potential role in the restoration of hair follicles.

Short communication: Cheese supplemented with Thymus algeriensis oil, a potential natural food preservative.

The essential oil of Thymus algeriensis was analyzed as a potential preservative in soft cheese. We developed a novel method to test the preserving properties of essential oil in soft cheese. Contamination incidence of Penicillium aurantiogriseum was absent after 30 d of storage at 4°C with 25 µL of essential oil added. The antimicrobial activity was tested against 8 bacteria and 8 fungi. Thymus algeriensis oil showed inhibitory activity against tested bacteria at 0.03 to 0.09 mg/mL, and bactericidal activity was achieved at 0.05 to 0.15 mg/mL. For antifungal activity, minimum inhibitory concentrations ranged between 0.01 and 0.04 mg/mL and minimum fungicidal concentrations between 0.01 and 0.04 mg/mL. Furthermore, the oil was also screened for antiradical activity using the 1,1-diphenyl-2-picrylhydrazyl assay. The results showed that the oil was active and achieved half-maximal inhibitory activity at 0.132 mg/mL. We used gas chromatography, gas chromatography-mass spectrometry, and nuclear magnetic resonance spectrometry to investigate the volatile compounds from the oil. Carvacrol was identified as the main compound in the oil, represented by 80.9% of the total constituents, followed by p-cymene (7.7%).

Lignin model compound in alginate hydrogel: a strong antimicrobial agent with high potential in wound treatment.

Nowadays bacterial resistance to known antibiotics is a serious health problem. In order to achieve more efficient treatment, lately there is an effort to find new substances, such as certain biomaterials, that are non-toxic to humans with antibiotic potential. Lignins and lignin-derived compounds have been proposed to be good candidates for use in medicine and health maintenance. In this study, the antibacterial activity of the lignin model polymer dehydrogenate polymer (DHP) in alginate hydrogel (Alg) was studied. The obtained results show that DHP-Alg has strong antimicrobial activity against several bacterial strains and biofilms and does not have a toxic effect on human epithelial cells. These results strongly suggest its application as a wound healing agent or as an adjunct substance for wound treatments.

In vitro antibiofilm activity of the freshwater bryozoan Hyalinella punctata: a case study of Pseudomonas aeruginosa PAO1.

The antibiofilm and possible antiquorum sensing effects against the strain Pseudomonas aeruginosa PAO1 of five crude extracts of the freshwater bryozoan Hyalinella punctata (Hancock, 1850) were evaluated in vitro for the first time. H. punctata ethyl acetate extract (HpEtAc) exhibited the highest antibiofilm activity reducing the biofilm formation of P. aeruginosa PAO1 in the range of 80.63-88.13%. While all tested extracts reduced the twitching motility of the aforementioned bacterial strain, HpEtAc showed to be the most effective. Finally, at a concentration of 0.5 MIC, the same extract mostly inhibited the production of pyocyanin by P. aeruginosa PAO1 (71.53%). In comparison both with the positive controls used (streptomycin and ampicillin, 67.13 and 69.77%, respectively), HpEtAc was found to inhibit pyocyanin in a higher extent. An extensive chemical characterisation of this particular extract may result in isolation and identification of novel lead compounds targeting P. aeruginosa, an opportunistic human pathogen.

A comparative study on edible Agaricus mushrooms as functional foods.

Agaricus bisporus is a cultivated mushroom; A. bitorquis, A. campestris and A. macrosporus are edible mushrooms growing wild in nature. A chemical characterization was carried out with samples that originated in Serbia. Antioxidant, antimicrobial and anti-quorum sensing properties of their methanolic and ethanolic extracts were assessed. A. campestris had the lowest caloric value and total sugar content and showed the highest concentration in organic and phenolic acids, as also in tocopherols (mainly γ-tocopherol). In general, the methanolic extracts showed higher antioxidant, but lower antibacterial and antifungal potential than ethanolic ones. Sub-inhibitory concentrations of the ethanolic extracts demonstrated reduction of virulence factors, AQ inhibition zones, twitching and swimming motility. The biofilm forming capability of P. aeruginosa PAO1 was also reduced in a concentration-dependent manner at sub-MIC values. The extracts of the tested Agaricus species are a promising source of antioxidant, antimicrobial and antiquorum sensing compounds.

Extracts of three Laserpitium L. species and their principal components laserpitine and sesquiterpene lactones inhibit microbial growth and biofilm formation by oral Candida isolates.

Antimicrobial properties of extracts of underground parts of three Laserpitium L. (Apiaceae) species, namely Laserpitium latifolium L., Laserpitium zernyi Hayek and Laserpitium ochridanum Micevski, were investigated. The investigated species are widely used as functional foods, as spices and for preparations in traditional medicine for treating complaints connected with infection and inflammation. Furthermore, antimicrobial and antibiofilm effects of laserpitine, the most abundant compound in the chloroform extract of L. latifolium, and guaianolide sesquiterpene lactones, such as, isomontanolide, montanolide and tarolide, principal components of the extracts of L. zernyi and L. ochridanum were assessed. The antimicrobial activity was tested using the microdilution method against five pathogenic bacteria and five fungi, as well as in the microplate biofilm assay on two Candida clinical isolates (C. albicans and C. krusei). Among the extracts, L. latifolium showed the most prominent activity. Isolated metabolites exerted higher effects against fungal than against bacterial strains, isomontanolide being the most active. Interestingly, all constituents showed higher potential on inhibition of biofilm formation than fluconazole, a reference compound. Tested metabolites may be good novel agents with high antifungal and antibacterial potential that might find practical applications in food industry as food preservatives in order to retard the growth of food spoiling microbes, but only after detailed safety assessments.

Chemical characterization and biological activity of Chaga (Inonotus obliquus), a medicinal "mushroom".

ETHNOPHARMACOLOGICAL RELEVANCE: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Bioactive composition, antimicrobial activities and the influence of Agrocybe aegerita (Brig.) Sing on certain quorum-sensing-regulated functions and biofilm formation by Pseudomonas aeruginosa.

Agrocybe aegerita (Brig.) Sing is a basidiomycete, white rot fungus. Antimicrobial activities and the antiqourum effect on Pseudomonas aeruginosa of an A. aegerita methanolic extract were investigated. The extract showed very good antimicrobial activity against all the tested microorganisms in a dose dependent manner. Effects of the Sub-MIC, MIC and 2MIC of the A. aegerita methanolic extract regulated the virulence factors in the quorum sensing (QS) test, as well as biofilm formation on P. aeruginosa. Sub-inhibitory and inhibitory concentrations of the extract demonstrated the reduction of virulence factors such as pyocyanin production, twitching and swimming motility. The biofilm forming capability of P. aeruginosa PAO1 was also reduced in a concentration-dependent manner. Furthermore, the chemical composition of the methanolic extract was determined considering its phenolic composition. The methanolic extract of A. aegerita can be a very good source of bioactive substances. This research is of great importance due to the prevalence of drug-resistant microorganisms.

In vitro evaluation of antimicrobial activity of the freshwater sponge Ochridaspongia rotunda (Arndt, 1937).

The antimicrobial activity of five crude extracts (aqueous, methanol, ethyl acetate, acetone and methylene chloride) of the freshwater sponge Ochridaspongia rotunda (Arndt, 1937) was evaluated in vitro by using microdilution method against eight bacterial and eight fungal strains for the first time. The extracts were proven to be active in varying degrees against all the bacteria and fungi tested. O. rotunda methanol extract exhibited the highest antibacterial activity (minimum inhibitory concentration (MIC) 7.5-15.0 µg/mL and minimum bactericidal concentration 15-30 µg/mL), while its acetone extract exhibited the most promising antifungal activity (MIC 7.5-45.0 µg/mL and minimum fungicidal concentration 15-60 µg/mL). The extracts were more effective against the bacteria and fungi screened compared with the positive controls (streptomycin and ampicillin for bacteria and bifonazole and ketoconazole for fungi, respectively). According to the experimental data obtained, this deepwater sponge species may be considered as a gold mine of new antimicrobial substances with significant and broad-range activity.