Flavonoids are dietary components and the most ubiquitous phenolic compounds found in nature, showing a range of pharmacological activities including antiviral action. This study describes the antiviral screening of 60 different flavones and flavonols against human rotavirus (Wa-1 strain) as well as their cytotoxicity in MA104 cells. Cytotoxicity was investigated by cell morphology assessment and antirotavirus activity by cytopathic effect inhibition. Results were expressed as CC(50) and IC(50), respectively, in order to calculate the selectivity index (SI = CC(50)/IC(50)) of each compound. Structure-activity relationships (SAR) were proposed based on antirotavirus activity.
In this study, we analyzed the antimicrobial activity of extracts harvested from 17 endophytic fungi isolated from the medicinal plant Schinus terebinthifolius. Morphological and molecular analyses indicated that these fungal species belonged to the genera Alternaria, Bjerkandera, Colletotrichum, Diaporthe, Penicillium, and Xylaria. Of the endophytes analyzed, 64.7 % produced antimicrobial compounds under at least one of the fermentation conditions tested. Nine isolates produced compounds that inhibited growth of Staphylococcus aureus, four produced compounds that inhibited Candida albicans, and two that inhibited Pseudomonas aeruginosa. The fermentation conditions of the following endophytes were optimized: Alternaria sp. Sect. Alternata-LGMF626, Xylaria sp.-LGMF673, and Bjerkandera sp.-LGMF713. Specifically, the carbon and nitrogen sources, initial pH, temperature, and length of incubation were varied. In general, production of antimicrobial compounds was greatest when galactose was used as a carbon source, and acidification of the growth medium enhanced the production of compounds that inhibited C. albicans. Upon large-scale fermentation, Alternaria sp. Sect. Alternata-LGMF626 produced an extract containing two fractions that were active against methicillin-resistant S. aureus. One of the extracts exhibited high activity (minimum inhibitory concentration of 18.52 µg/mL), and the other exhibited moderate activity (minimum inhibitory concentration of 55.55 µg/mL). The compounds E-2-hexyl-cinnamaldehyde and two compounds of the pyrrolopyrazine alkaloids class were identified in the active fractions by gas chromatography-mass spectrometry.
Citrus black spot disease, caused by the phytopathogen Phyllosticta citricarpa, depreciates the market value of citrus fruits and prevents their exportation to disease-free regions. It may also reduce the productivity of citrus fruit orchards. To identify an alternative to conventional disease control measures, isolates of Diaporthe terebinthifolii, active against P. citricarpa, were selected from an endophytic fungal population of Schinus terebinthifolia leaves. Different culture media were screened to identify the culture medium that afforded the most efficient production of biologically active extracts. A particular fraction (fraction VI) of the extract completely protected orange leaves by inhibiting the germination of P. citricarpa conidia with a minimum inhibitory concentration of 0.003 μg.mL-1. The active constituents in D. terebinthifolii extract fractions were identified by gas chromatography coupled to mass spectrometry as verbanol, phenylethyl alcohol, verbenyl acetate and methyl hexadecanoate. The results obtained strongly suggest the existence of a synergistic effect among the metabolites produced. Thus, these fungal metabolites could be used to control the CBS disease. As the asexual spores of P. citricarpa play an important role in fruit lesion development and disease dispersion, fungal extracts that inhibit the spore germination can be used as an effective alternative for directional disease control.
The phytochemical profile and antimicrobial activity of cultivar (cv.) extracts of Lotus uliginosus (cvs. Trojan and Serrano), L. tenuis (cv. Larrañaga) and L. corniculatus (cv. São Gabriel) were investigated. The phytochemical analysis revealed tannins, coumarins and flavonoids in all extracts, with variations among cultivars, showing genotypic variability. By High Performance Liquid Chromatographic method, the cvs. Larrañaga and São Gabriel showed the highest percentage of catechin and epicatechin, respectively, and presented rutin, which was not detected in the other ones. These genotypes showed antifungal activity but not antibacterial one. The cv. Larrañaga inhibited the mycelia growth of Alternaria sp. and Fusarium graminearum while the cv. São Gabriel was active only against Alternaria sp. The cultivars showed the greatest amounts of secondary metabolites and demonstrated significant activity against filamentous fungi. The results provide a direction for further research about pharmacological use of Lotus spp.
Alkoxyflavonols were synthesized by the Algar‐Flynn‐Oyamada (AFO) cyclization of chalcones. Hydroxyflavonols were prepared by dealkylation of methoxyflavonols by refluxing in hydroiodic acid. The alkoxyflavonols 3‐hydroxy‐2‐(2,3,4‐trimethoxy‐phenyl)‐ 4H‐chromen‐4‐one (6), 2‐(4‐ethoxyphenyl)‐3‐hydroxy‐4H‐ chromen‐4‐one (7), 2‐(4‐butoxyphenyl)‐3‐hydroxy‐4H‐ chromen‐4‐one (10), and 2‐(3‐n‐butoxyphenyl)‐3‐hydroxy‐4H‐ chromen‐4‐one (11) as well as the trihydroxy derivative 3‐hydroxy‐ 2‐(3,4,5‐trihydroxyphenyl)‐4H‐chromen‐4‐one (18) displayed high anti‐inflammatory activity in carrageenin‐induced rat paw edema. Additionally, the inhibition of enzymes of the arachidonic acid cascade by the derivatives was investigated in vitro. In contrast to the natural compound quercetin, the com‐pounds were more potent inhibiting cyclooxygenase‐1 than 5‐lipoxygenase except for 3‐hydroxy‐7‐methoxy‐2‐(4‐methoxyphenyl)‐ 4H‐chromen‐4‐one (5). No correlation between the antiinflammatory activity in the rat paw edema test and the inhibition of 5‐lipoxygenase or cyclooxygenase‐1 could be observed. In conclusion, the present results suggest that other effects than inhibition of these enzymes of the arachidonic acid cascade are important for the anti‐inflammatory activity of the investigated alkoxyflavonols.
The potential of a plant with medicinal and nutritional properties, Anredera cordifolia, is reviewed. Its common names include “Bertalha” and “folha gorda” and it is popularly used for wound healing and against fungal infections and other types of infection. Its pharmacological properties have been widely investigated and acknowledged, especially with regard to its antibacterial activity, which improves the healing of wounds infected by Staphylococcus aureus, and to its antifungal activity against Candida albicans. It is an unconventional food plant, with leaves and aerial tubers used as food prepared in varied ways. It is also considered an invasive plant in several countries and thus classified as a weed. Its characteristics of a Brazilian native plant, with proven medicinal properties and unconventional use as food, underlie our study on its ecology and botanical classification, as well as the pharmacological assays and screening of chemical constituents.
Introduction:We compared the prevalence and antimicrobial susceptibility of non-fermenting gram-negative bacilli (NFGNB) isolated from clinical samples at a Brazilian tertiary care hospital in 2008 and 2013. Methods: Collected data included patient's name, age, sex, inpatient unit, laboratory record number, type of biological material, culture test result, and antimicrobial susceptibility of isolated strains. Results: Out of 19,112 culture tests analyzed, 926 (4.8%) were positive for NFGNB. Among these, 45.2% were metallo-beta-lactamase (MBL) producing strains. Conclusion: Between 2008 and 2013, the number of MBL-producing NFGNB isolates increased by 21.5%, which was accompanied by a consequent reduction in susceptibility to antimicrobials.
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