Antimicrobial and antibiofilm activity of secondary metabolites of lichens against methicillin-resistant Staphylococcus aureus strains from cystic fibrosis patients.

Aim: Three secondary metabolites of lichens - usnic acid, atranorin and fumarprotocetraric acid - were evaluated for their in vitro antibacterial and antibiofilm activities against three strains each of methicillin-susceptible and methicillin-resistant Staphylococcus aureus (MRSA) from cystic fibrosis patients.

Materials & Methods: Antibacterial activity was assessed by broth microdilution, while antibiofilm activity was evaluated by spectrophotometry or viable count.

Results: Usnic acid was significantly more active than atranorin against planktonic cells, while fumarprotocetraric acid exhibited no activity.

Antibacterial activity of selected metabolites from Chilean lichen species against methicillin-resistant staphylococci.

The in vitro antibacterial activities of eight compounds isolated from lichens, collected in several Southern regions of Chile (including Antarctica), were evaluated against methicillin-resistant clinical isolates strains of Staphylococcus aureus, Staphylococcus haemolyticus and Staphylococcus warneri. The minimum inhibitory concentrations, calculated in microdilution, were ranging from 8 µg mL(-1) for sphaerophorin to 1024 µg mL(-1) for fumarprotocetraric acid. These findings suggest, however, that the natural compounds from lichens are good candidates for the individuation of novel templates for the development of new antimicrobial agents or combinations of drugs for chemotherapy.

A new jasmonic acid stereoisomeric derivative induces apoptosis via reactive oxygen species in human prostate cancer cells.

With the aim of identifying novel agents with antigrowth and pro-apoptotic activity on prostate cancer cells, in the present study, we evaluated the effect of a (-)-jasmonic acid derivative, the 3-hydroxy-2(S)-(2Z-butenyl)-cyclopentane-1(S)-acetic acid, obtained by biotransformation, on cell growth in androgen-sensitive (LNCaP) and androgen-insensitive (DU-145) human prostate cancer cells. The results obtained show that the new compound was able to inhibit the growth of both prostate cancer cells. In addition, our data seem to indicate that the apoptosis evocated by this new molecule, at least in part, appears to be associated with an increase of reactive oxygen species (ROS) production.

Lichen depsides and depsidones reduce symptoms of diseases caused by tobacco mosaic virus (TMV) in tobacco leaves.

Two depsides and five depsidones, isolated from lichens, were tested to determine their in vivo protective effects on tobacco leaves challenged with tobacco mosaic virus (TMV). The results indicate that most of these compounds are able to reduce either the number and/or the size of necrotic lesions following virus infection. Pannarin, 1'-chloro-pannarin and stictic acid provided the more effective protective results, reducing by at least 45% the number and size of lesions.

Cytotoxic activity and antioxidant capacity of purified lichen metabolites: an in vitro study.

The purpose of this study was to investigate the effects of six lichen metabolites (diffractaic acid, lobaric acid, usnic acid, vicanicin, variolaric acid, protolichesterinic acid) on proliferation, viability and reactive oxygen species (ROS) level towards three human cancer cell lines, MCF-7 (breast adenocarcinoma), HeLa (cervix adenocarcinoma) and HCT-116 (colon carcinoma). Cells were treated with different concentrations (2.5-100 μM) of these compounds for 48 h.

In vitro antimicrobial activity of pannarin alone and in combination with antibiotics against methicillin-resistant Staphylococcus aureus clinical isolates.

The in vitro antimicrobial activities of pannarin, a depsidone isolated from lichens, collected in several Southern regions of Chile (including Antarctica), was evaluated alone and in combination with five therapeutically available antibiotics, using checkerboard microdilution assay against methicillin-resistant clinical isolates strains of Staphylococcus aureus. MIC(90), MIC(50), as well as MBC(90) and MBC(50), were evaluated. A moderate synergistic action was observed in combination with gentamicin, whilst antagonism was observed in combination with levofloxacin.

The incubation of 13α,17-dihydroxystemodane with Cephalosporium aphidicola.

The biotransformation of 13α,17-dihydroxystemodane (3) with the fungus Cephalosporium aphidicola afforded 13α,17,18-trihydroxystemodane (4), 3β,13α,17-tri-hydroxystemodane (5), 13α,17-dihydroxy-stemodan-18-oic acid (6), 3β,11β,13α,17-tetra-hydroxystemodane (7), 11β,13α,17,18-tetrahydroxystemodane (8) and 3β,13α,17,18-tetra-hydroxystemodane (9). The hydroxylation at C-18 of the substrate points to a biosynthetically-directed transformation, because aphidicolin (2) is hydroxylated at this carbon. However, the C-3(β) and C-11(β) hydroxylations seem to indicate a xenobiotic biotransformation.

In vitro interaction of usnic acid in combination with antimicrobial agents against methicillin-resistant Staphylococcus aureus clinical isolates determined by FICI and ΔE model methods.

The in vitro antimicrobial activities of usnic acid were evaluated in combination with five therapeutically available antibiotics, using checkerboard microdilution assay against methicillin-resistant clinical isolates strains of Staphylococcus aureus. MIC₉₀, MIC₅₀, as well as MBC₉₀ and MBC₅₀, were evaluated. A synergistic action was observed in combination with gentamicin, while antagonism was observed with levofloxacin.

Boldo prevents UV light and nitric oxide-mediated plasmid DNA damage and reduces the expression of Hsp70 protein in melanoma cancer cells.

Objectives: This study was designed to investigate the potential protective effect of a methanolic extract of Peumus boldus leaves on UV light and nitric oxide (NO)-mediated DNA damage. In addition, we investigated the growth inhibitory activity of this natural product against human melanoma cells (M14).

Methods: Boldine, catechin, quercetin and rutin were identified using a HPLC method.

Volatile organic components from fresh non-edible Basidiomycetes fungi.

The compounds responsible for the characteristic odor of eight fresh non-edible Basidiomycetes fungi were evaluated. The volatile organic compounds from the fresh samples present in the headspace of a sealed vial were determined by solid-phase microextraction gas chromatography-mass spectrometry, using a PDMS/DVB fiber. A total of twenty-eight components were identified, the most frequent being 1-octen-3-ol and 3-octanone.

Rosmarinus officinalis extract inhibits human melanoma cell growth.

Rosmarinus officinalis L. is receiving increasing attention due to its anti-inflammatory and antioxidative constituents. Our recent studies showed that R.

Cyclohexanones from Mimulus glabratus and M. luteus.

The phytochemical study of Mimulus glabratus A.Gray allowed the isolation of two cyclohexenones: the new compound 6-chlorohalleridone 1 and halleridone 2. Halleridone was also identified in Mimulus luteus L.

Biotransformation of two ent-Pimara-9(11),15-diene derivatives by Gibberella fujikuroi.

The incubation of 19-hydroxy-13-epi-ent-pimara-9(11),15-diene (4) with Gibberella fujikuroi gave 8 alpha,19-dihydroxy-9 alpha,11alpha-epoxy-13-epi-ent-pimara-15-ene (6), 7-oxo-11 alpha,19-dihydroxy-13-epi-ent-pimara-8(9),15-diene (7), 7-oxo-11beta,19-dihydroxy-13-epi-ent-pimara-8(9),15-diene (9), and 8 alpha,19-dihydroxy-9 alpha,11 alpha:15,16-diepoxy-13-epi-ent-pimarane (11), while the feeding of 13-epi-ent-pimara-9(11),15-diene-19-oic acid (5) with this fungus afforded 1-oxo-2 alpha,9 alpha-dihydroxy-13-epi-ent-pimara-11,15-dien-19-oic acid (13), 1-oxo-2 beta,9 alpha-dihydroxy-13-epi-ent-pimara-11,15-dien-19-oic acid (14), 13-epi-ent-pimara-9(11),15-dien-1,19-dioic acid 1,2-lactone (15), and 1-oxo-12 beta-hydroxy-13-epi-ent-pimara-9(11),15-dien-19-oic acid (16). In both biotransformations, the main reaction was the epoxidation of the 9(11)-double bond, followed by rearrangement to afford allylic alcohols. The formation of lactone 15 represents the first time that a Baeyer-Villiger oxidation has been observed in a microbiological transformation with this fungus.

Effect of litreol on the viability of human cancer cells.

Members of the family Anacardiaceae are known to contain a number of biologically active substances, such as phenolic lipids, alkyl-catechols and alkyl-resorcinols. In the present study, human cancer cell lines, DU-145 cells (androgen-insensitive prostate cancer cells), KB cells (human epidermoid cells), and human melanoma cell line, M14, were treated for 72 h with 0.59-9.

New diterpenoids from Calceolaria polifolia.

Four new and seven known diterpenes have been isolated from the dichloromethane extract of the aerial parts of Calceolaria polifolia. The structures of the new compounds were established by spectroscopic evidence.

Pannarin inhibits cell growth and induces cell death in human prostate carcinoma DU-145 cells.

In the course of our continuing search for new natural anticancer compounds for treatment and/or prevention of prostate cancer, our laboratory has focused its search on poorly investigated lichen metabolites, sphaerophorin, pannarin and epiphorellic acid-1. To this end, we treated DU-145, a cell line resembling the last stage of prostate carcinoma, with different concentrations (6-50 micromol/l) of these compounds for 72 h. Our data clearly evidenced that these lichen metabolites inhibit the growth of human prostate carcinoma DU-145 cells, but pannarin exhibits a higher effect.

Antioxidant activity and antiproliferative action of methanolic extract of Geum quellyon Sweet roots in human tumor cell lines.

Geum quellyon Sweet, a perennial herb of the Rosaceae family, has been used in the traditional medicine of the Mapuche Amerindians of Chile to treat tooth neuralgia, gastric inflammation, prostatitis and to regulate menstruation, and for its diuretic and aphrodisiac properties. Although many benefits have been claimed for this plant, few scientific studies are available in the literature. In this study, we investigated the antioxidant activity of a methanolic extract of Geum quellyon roots.

Cytotoxic and apoptotic effects on hepatocytes of secondary metabolites obtained from lichens.

There are a large number of species of Antarctic lichens, and several studies describing the secondary metabolites present in these lichens, as well as the advances in understanding the chemistry of these metabolites, have been reported. In addition, some derivatives displaying interesting antibacterial effects have been described. The cytotoxic and apoptotic effects of 15 secondary metabolites (depsides, depsidones and usnic acid) obtained from Continental (Chilean) and Antarctic lichens were evaluated in primary cultures of rat hepatocytes.

Diterpenoids from Calceolaria inamoena.

Four 9-epi-ent-labdanes were isolated from the aerial parts of Calceolaria inamoena. Their structures, 2beta-hydroxy-9-epi-ent-labda8(17)-13(E)dien-15-oic acid, 2beta-hydroxy-9-epi-ent-labda8(17)-13(Z)dien-15-oic acid, 2beta-hydroxy-9-epi-ent-labda8(17)-13(E)dien-15-al and 2beta-hydroxy-9-epi-ent-labda-8(17)-13(Z)dien-15-al, were established by spectroscopic methods including by analysis of 2 dimensional heteronuclear correlation experiments 1H/13C (normal and long range), and NOE and gs-sel-1D-NOESY and TOCSY of their methyl ester or acetyl derivatives.

Microbial transformation of 18-hydroxy-9,13-epi-ent-pimara-7,15-diene by Gibberella fujikuroi.

The incubation of the diterpene 18-dihydroxy-9,13-epi-ent-pimara-7,15-diene (3) with the fungus Gibberella fujikuroi gave 14 metabolites, 4 and 6-18. The carbons functionalized were the C-20 methyl and all the secondaries, except C-12. The main reaction observed was the epoxidation of the 7,8-double bond, which rearranged to form 7-keto derivatives, such as 10-17, or the allylic alcohol 18.