Combinatorial activity of flavonoids with antibiotics against drug resistant Staphylococcus aureus

The use of resistance-modifying agents is a potential strategy that is used to prolong the effective life of antibiotics in the face of increasing antibiotic resistance. Since certain flavonoids are potent bacterial efflux pump inhibitors, we assessed morin, rutin, quercetin, hesperidin, and (+)-catechin for their combined activity with the antibiotics ciprofloxacin, tetracycline, erythromycin, oxacillin, and ampicillin against drug-resistant strains of Staphylococcus aureus, including methicillin-resistant S. aureus. Four established methods were used to determine the combined efficacy of each combination: microdilution checkerboard assays, time-kill determinations, the Etest, and dual disc-diffusion methods. The cytotoxicity of the flavonoids was additionally evaluated in a mouse fibroblast cell line. Quercetin and its isomer morin decreased by 3- to 16-fold the minimal inhibitory concentration of ciprofloxacin, tetracycline, and erythromycin against some S. aureus strains. Rutin, hesperidin, and (+)-catechin did not promote any potentiation of antibiotics. Despite the potential cytotoxicity of these phytochemicals at a high concentration (fibroblast IC50 of 41.8 and 67.5mg/L, respectively), quercetin is commonly used as a supplement for several therapeutic purposes. All the methods, with exception of the time-kill assay, presented a high degree of congruence without any apparent strain specificity.This work was supported by Operational Program for Competitiveness Factors—COMPETE, FCT/MEC (PIDDAC), and FEDER through Projects Bioresist—PTDC/EBB-EBI/ 105085/2008; Phytodisinfectants—PTDC/DTP-SAP/1078/ 2012 (COMPETE: FCOMP-01-0124-FEDER-028765) and the PhD grants awarded to Ana Abreu (SFRH/BD/84393/ 2012) and Anabela Borges (SFRH/BD/63398/2009). The authors are very grateful to Professor Simon Gibbons (De- partment of Pharmaceutical and Biological Chemistry, The School of Pharmacy, UCL School of Pharmacy, London) for providing the bacterial strains.info:eu-repo/semantics/publishedVersio

Antioxidant activity of flavonoids of different polarity, assayed by modified ABTS cation radical decolorization and EPR technique

Modified ABTS cation radical decolorization assay and EPR technique were applied to screen the antioxidant activity of three flavonoids with different polarity: 7-O-β-[2-O-feruloyl-β-glucuronopyranosyl (1→2) glucuronopyranoside] (tricine), 4'-methoxy-5,7-dihydroxyflavone 6-C-β-glucopyranoside (isocytisoside) and I 3' II 8 biapigenine (amentoflavone), with nonpolar all-trans β-carotene used as standard carotenoid molecule. The ABTS [2,2'- azino-bis(3-ethylbenzthiazoline-6-sulphonic acid] cation radical decolorization assay was modified as follows: (1) measurements extended up to 8 days after preparation, (2) method adapted for flavonoids with different polarity and β-carotene, (3) concentrations in the 0.01-10 μM range of both trolox and antioxidants in order to use the same experimental conditions for both this technique and EPR measurement

Porównanie zawartości wybranych związków fenolowych w owocach Vaccinium macrocarpon Ait. i Vaccinium oxycoccos L.

The genus Vaccinium L. (Ericaceae), comprises about 450 species including V. macrocarpon Ait. (Cranberry, American Cranberry), Vaccinium oxycoccos L. (Small cranberry, marsh whortleberry), V. microcarpos (Turcz. Ex Rupr.) Schmalh., syn. V. oxycoccos. In natural conditions they grow in acidic and wet peatbog type soils in the cooler areas of the Northern Hemisphere. V. macrocarpon is native to the northern and eastern parts of North America (Canada, United States). V. oxycoccos and V. microcarpos are grown in northern Europe and northern Asia, whereas V. oxycoccos also grows in the northern part of North America.W owocach Vaccinium macrocarpon i V. oxycoccos oznaczono zawartość flawonoidów, proantocyjanidyn, metodami opisanymi w Farmakopei Europejskiej V oraz całkowitą zawartość związków fenolowych, z odczynnikiem Folin-Ciocalteu. Zawartość flawonoidów wynosiła 0,27% i 0,09% w przeliczeniu na hyperozyd; proantocyjanidyn 2,05% i 0,92% w przeliczeniu na chlorek cyjanidyny; całkowita zawartość związków fenolowych 1,88% i 0,98% w przeliczeniu na kwas galusowy, w owocach V. macrocarpon i V. oxycoccos, odpowiednio

Hedera helix jako roslina lecznicza

Hederae folium is used for the treatment of respiratory tract diseases with intense mucous formation, respiratory tract infections and in irritating cough which stems from common cold. According to clinical experiments, the effectiveness and tolerance of ivy preparations is good. The major compounds responsible for the biological activity are triterpene saponins. Ivy leave extracts exhibit spasmolytic/antispasmodic, anti-inflammatory, antimicrobial, analgesic, anthelmintic, antitrypanosomial, antileishmanial, antitumor, antimutagenic, moluscocidal, antioxidant and antithrombin activities.Hederae folium stosuje się w leczeniu schorzeń dróg oddechowych z nadmiernym wydzielaniem śluzu, w infekcjach dróg oddechowych oraz w męczącym kaszlu. Badania kliniczne potwierdzają skuteczność i dobrą tolerancję preparatów zawierających wyciąg z liści bluszczu. Głównymi składnikami odpowiedzialnymi za aktywność biologiczną są saponiny triterpenowe. Wyciągi z liści bluszczu wykazują różne typy aktywności: spazmolityczną/przeciwskurczową, przeciwzapalną, przeciwdrobnoustrojową, przeciwbólową, przeciwrobaczą, przeciwnowotworową, antymutagenną, antyoksydacyjną, przeciwzakrzepową oraz przeciwpierwotniakową i przeciwmięczakową