Biological activities of extracts from cultivated Granadilla Passiflora alata

Research conducted in this study showed the influence of ethanol, acetone and ethyl acetate extracts of the outgrowth of cultivated Passiflora alata on microorganisms, as well as the antioxidant activity and the concentrations of total phenols, flavonoids and tannins. In vitro antimicrobial activities of extracts were studied on 27 species of microorganisms, of which 17 species of bacteria and 10 species of fungi. The strongest antimicrobial activity was detected on G+ bacteria while the activities on other species were moderate. Ethyl acetate extract showed the strongest effect. The concentrations of total phenols were examined by using Folin-Ciocalteu reagent and the obtained values ranged from 14.04 to 34.22 mg GA/g. By using aluminium chloride method, the concentrations of flavonoids were obtained and the values ranged from 33.19 to 62.30 mg RU/g. In determining the amount of tannins we used the method with buthanol-HCl reagent and the obtained value was 5.1 % of dry matter. The efficiency of antioxidation, which we identified through the reduction of DPPH, was in the range from 808.69 to 1107.79 μg/ml for a particular IC50, and AAI values were between 0.07 and 0.10. The best parameters were shown by ethanol extract. All data were statistically analyzed. Overall, extracts showed potential for further investigation and use

Bioactive extracts of Gentiana asclepiadea: antioxidant, antimicrobial, and antibiofilm activity

Extracts of the aerial parts and roots of the wild-growing medicinal plant Gentiana asclepiadea were analysed for their antimicrobial, antibiofilm, and antioxidant activity with quantification of the total phenolic and total flavonoid content. Antimicrobial activity was tested against pathogenic and spoilage bacteria, yeasts, and moulds using the microdilution method. The strongest antibacterial activity was detected on Bacillus species, where minimum inhibitory concentrations (MICs) of from 0.16 mg/mL to 5 mg/mL were obtained, while antifungal activity was low to moderate, with MICs between 1.25 and 20 mg/mL. In the crystal violet assay, the extracts inhibit 50% biofilm formation in the concentration range of from 2.12 to 37.04 mg/mL. Staphylococcus aureus, S. aureus ATCC 25923, and Pseudomonas aeruginosa ATCC 27853 biofilms were the most sensitive to the presence of extracts. The extracts rich in phenolic compounds showed good DPPH-scavenging activity, with EC50 values between 181.3 and 614.3 μg/mL for extracts of aerial parts and from 426.67 to >1000 μg/mL for root extracts. Even though G. asclepiadea has long been traditionally used, its biological activity is still insufficiently explored, so the obtained results are significant for contributing new knowledge about the plant's medicinal properties

New natural products from Clinopodium thymifolium (Scop.) Kuntze (Lamiaceae)

Clinopodium thymifolium (Scop.) Kuntze (syn. Micromeria thymifolia (Scop.) Fritsch) is an aromatic plant species widespread in the Mediterranean region, from north-eastern Italy across the Western Balkans to Hungary and Albania [1,2]. C. thymifolium has been used in folk medicine of the Mediterranean area for a long time [3]. Also, due to a high content of the essential oil in its leaves, it is used as a condiment and sometimes used in cooking [4,5]. For this reason, and the marked tendency to broaden the use of condiments and spices, some efforts are being made to introduce this plant as a new crop species (currently successfully cultivated in northern Italy) [4]. The beneficial effects of Lamiaceae species on human health have been frequently ascribed to essential-oil ingredients. Volatiles of C. thymifolium have been well studied – previous studies showed that the qualitative compositions of the investigated C. thymifolium oils were very mutually similar and dominated by oxygenated p-menthane monoterpenoids [6,7]. However, in this work, a comprehensive chemical analysis, in combination with detailed spectral analyses and chemical synthesis of selected compounds, has led to the identification of a series of esters of menthol stereoisomers in C. thymifolium essential oil, including some new natural products

Phytomedical investigation of Najas minor All. in the view of the chemical constituents

Plants are an abundant natural source of effective antibiotic compounds. Phytomedical investigations of certain plants haven’t still been conducted. One of them is Najas minor (N. minor), an aquatic plant with confirmed allelopathy. Research conducted in this study showed the influence of water and ethyl acetate extracts of N. minor on microorganisms, in the view of chemical profiling of volatile constituents and the concentrations of total phenols, flavonoids and tannins. Antimicrobial activity was defined by determining minimum inhibitory and minimum microbicidal concentrations using microdilution method. Influence on bacterial biofilm formation was performed by tissue culture plate method. The total phenolics, flavonoids and condensed tannins were determined by Folin-Ciocalteu, aluminum chloride and butanol-HCl colorimetric methods. Chemical profiling of volatile constituents was investigated by GC and GC-MS. Water extract didn't have antimicrobial activity below 5000 µg/mL. Ethyl acetate extract has shown strong antimicrobial activity on G+ bacteria - Staphylococcus aureus PMFKGB12 and Bacillus subtilis (MIC < 78.13 µg/mL). The best antibiofilm activity was obtained on Escherichia coli ATCC25922 (BIC50 at 719 µg/mL). Water extract had higher yield. Ethyl acetate extract had a significantly greater amount of total phenolics, flavonoids and tannins. As major constituent hexahydrofarnesyl acetone was identified. The ethyl acetate extract effected only G+ bacteria, but the biofilm formation of G-bacteria was suppressed. There was a connection between those in vivo and in vitro effects against pathogenic bacterial biofilm formation. All of this points to a so far unexplored potential of N. minor