[show abstract][hide abstract] ABSTRACT: 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. Atranorin was the most effective in counteracting adhesion to polystyrene, although usnic acid was more active against MRSA. Usnic acid and atranorin showed comparable activity against biofilm formation, although atranorin was more active against MRSA. Usnic acid was significantly more active than atranorin against preformed biofilms. Conclusion: Secondary metabolites of lichens may be considered to be 'lead compounds' for the development of novel molecules for the treatment of S. aureus infections in cystic fibrosis patients.
[show abstract][hide abstract] ABSTRACT: 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.
Natural product research 10/2012; · 1.01 Impact Factor
[show abstract][hide abstract] ABSTRACT: 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.
Cancer letters 08/2012; 326(2):199-205. · 4.86 Impact Factor
[show abstract][hide abstract] ABSTRACT: 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. Real Time PCR assays were used to explore the target of action against TMV by examining the response behavior of genes involved in the plant defense mechanism. The application of the lichen substances did not lead to changes in the transcriptional levels of pathogen-related (PR1a), allene oxide synthase 2 (AOS2) or oxophytodienoate reductase (OPR3) genes. Thus, the protection observed in the tobacco leaves treated with the lichen compounds may be mediated by a mechanism which does not involved the SA- or JA-mediated defensive plant response. A possible structure-activity relationship is presented.
[show abstract][hide abstract] ABSTRACT: 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. All combinations with erythromycin were indifferent, whilst variability was observed for clindamycin and oxacillin combinations. Data from checkerboard assay were analysed and interpreted using the fractional inhibitory concentration index and the response surface approach using the ΔE model. Discrepancies were found between both methods for some combinations. In order to asses cellular lysis after exposure to pannarin, cell membrane permeability assay was performed. The treatment with pannarin produces bactericidal activity without significant calcein release, consistent with lack of lysis or even significant structural damage to the cytoplasmic membrane. Furthermore, pannarin shows low hemolytic activity and moderate cytotoxic effect on peripheral blood mononuclear cells. These findings suggest that the natural compound pannarin might be a good candidate for the individualization of novel templates for the development of new antimicrobial agents or combinations of drugs for chemotherapy.
Phytomedicine: international journal of phytotherapy and phytopharmacology 03/2012; 19(7):596-602. · 2.97 Impact Factor
[show abstract][hide abstract] ABSTRACT: 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.
[show abstract][hide abstract] ABSTRACT: 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. The combination with erythromycin showed indifference, while variability was observed for clindamycin and oxacillin. Data from checkerboard assay were analysed and interpreted using the fractional inhibitory concentration index (FICI) and the response surface approach using the ΔE model. Discrepancies were found between both methods for some combinations. These could mainly be explained by the failure of FIC approach, being too much subjective and sensitive to experimental errors. These findings, beside confirm the well known antimicrobial activity of usnic acid, suggest, however, that this substance might be a good candidate for the individuation of novel templates for the development of new antimicrobial agents or combinations of drugs for chemotherapy.
Phytomedicine: international journal of phytotherapy and phytopharmacology 11/2011; · 2.97 Impact Factor
[show abstract][hide abstract] ABSTRACT: 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 five lichen secondary metabolites the depsides atranorin (1), diffrattaic (2) and divaricatic (3) acids, the depsidone vicanicin (4) and the protolichesterinic acid (5) on cell growth in androgen-sensitive (LNCaP) and androgen-insensitive (DU-145) human prostate cancer cells. The cell viability was measured using MTT assay. LDH release, a marker of membrane breakdown, was also measured. For the detection of apoptosis, the evaluation of DNA fragmentation (COMET assay) and caspase-3 activity assay were employed. The expression of Bcl-2, Bax, TRAIL, COX-2, NOS2 and Hsp70 proteins was detected by western blot analysis. Generation of reactive oxygen species was measured by using a fluorescent probe. It was observed that atranorin (1), diffrattaic (2) and divaricatic (3) acids showed a lower activity inhibiting the prostate cancer cells only at more high concentrations (25 and 50μM). Whereas compounds vicanicin (4) and protolichesterinic acid (5) showed a dose-response relationship in the range of 6.25-50μM concentrations in DU-145 and LNCaP cells, activating an apoptotic process. The novel finding, in the present study, is that apoptosis induced by these compounds appears to be mediated, at least in part, via the inhibition of Hsp70 expression, that may be correlated with a modulation of redox-sensitive mechanisms. The combination of vicanicin (4) and protolichesterinic acid (5) with other anti-prostate cancer therapies could be considered a promising strategy that warrants further in vivo evaluation.
[show abstract][hide abstract] ABSTRACT: 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).
Boldine, catechin, quercetin and rutin were identified using a HPLC method. The extract was incubated with plasmid DNA and, before irradiating the samples with UV-R, H(2) O(2) was added. For analysis of DNA single-strand breaks induced by NO, the experiments were performed by incubating the extract with Angeli's salt. In the study on M14 cell line, cell viability was measured using MTT assay. Release of lactate dehydrogenase, a marker of membrane breakdown, was also measured. For the detection of apoptosis, the evaluation of DNA fragmentation (COMET assay) and caspase-3 activity assay were employed. The expression of heat shock protein 70 (Hsp70) was detected by Western blot analysis. Generation of reactive oxygen species was measured by using a fluorescent probe.
The extract (demonstrating the synergistic effect of the constituents boldine and flavonoids), showed a protective effect on plasmid DNA and selectively inhibited the growth of melanoma cells. But a novel finding was that apoptosis evoked by this natural product in M14 cells, appears to be mediated, at least in part, via the inhibition of Hsp70 expression, which may be correlated with a modulation of redox-sensitive mechanisms.
These results confirm the promising biological properties of Peumus boldus and encourage in-vivo investigations into its potential anti-cancer activity.
The Journal of pharmacy and pharmacology. 09/2011; 63(9):1219-29.
[show abstract][hide abstract] ABSTRACT: Background: Several studies have shown that (-)-Jasmonic acid, (+)-7-iso-Jasmonic acid and its methyl ester, methyl jasmonate, have anti-cancer activity in vitro and in vivo, exhibiting selective cytotoxicity towards cancer cells. The degree of activity of these molecules is strongly related to their stereochemistry. The biotransformation of known compounds, natural or synthesized, related to interesting biological activities, generates new molecules displaying new improved properties compared with the original ones, increasing its value and providing new more effective products. Therefore, based on the above rationales and observations, in this work a biotransformation protocol to modify the chemical structure of the plant hormone jasmonic acid by using the fungus Gibberella fujikuroi was established. Results: The three jasmonic acid derivatives obtained, 3(S)-Hydroxy-2(R)-(2Z-pentenyl)-cyclopentane-1(R)-acetic acid (1), 3(R)-Hydroxy-2(R)-(2Z-pentenyl)-cyclopentane-1(R)-acetic acid (2), 3-Hydroxy-2(S)-(2Z-pentenyl)-cyclopentane-1(S)-acetic acid (3), were tested for cell-growth inhibition activity towards the human cancer epithelial cell line, the oral squamous carcinoma cells (KB). The results obtained show that jasmonic acid derivatives (1-3) are active on human cancer cells examined in different concentration ranges, with IC50 value less than of 25 µM. The compound 3, with the same molecular structure of compounds 1 and 2, but with different stereochemistry, was more active confirming that the activity of jasmonate compounds is related to their stereochemistry and to substituents in the cyclopentane ring. In this study, we also tested the potential proapoptotic activity of compound 3, and our data suggest that it, as other jasmonate compounds, is able to trigger apoptotic death in cancer cells. This event may be correlated at an elevation of reactive oxygen species (ROS). Administration of N-acetylcysteine (NAC) prevented compound 3 cytotoxicity. Conclusions: This work shows for the by first time the production of hydroxylated derivatives of JA by biotransformation. The activity observed of these compounds in cancer cells is higher than the observed with JA and is strongly related to its stereochemistry.
Electronic Journal of Biotechnology ISSN. 01/2011;
[show abstract][hide abstract] ABSTRACT: With the aim of identifying novel agents with antigrowth and pro-apoptotic activity on prostate cancer cells, we assayed the effect of ergosterol peroxide and (22E)-ergosta-7,22-dien-5alpha-hydroxy-3,6-dione, a semisynthetic compound, against androgen-sensitive (LNCaP) and androgen-insensitive (DU-145) human prostate cancer cells. Our results indicate that after 72h of incubation, ergosterol peroxide and (22E)-ergosta-7,22-dien-5alpha-hydroxy-3,6-dione at micromolar concentrations exhibited an inhibitory effect on LNCaP and DU-145 cell growth (MTT assay), but the semisynthetic compound was the most active. In addition, our results indicate that apoptotic cell demise is induced in LNCaP and DU-145 cells. In fact, a significant increase of caspase-3 activity, not correlated to LDH release, marker of membrane breakdown, was observed in both cell lines treated with ergosterol peroxide and the semisynthetic compound. With respect to genomic DNA damage, determined by COMET and TUNEL assays, the results obtained show a significant increase in DNA fragmentation when compared with the untreated control. In conclusion, the results obtained in this study, demonstrating that ergosterol peroxide and (22E)-ergosta-7,22-dien-5alpha-hydroxy-3,6-dione attenuate the growth of prostate cells, at least in part, triggering an apoptotic process, permit to confirm the use of mushrooms as origin of compounds to be used as novel therapeutic agents for prostate cancer treatment, or as models for molecules more active and selective.
[show abstract][hide abstract] ABSTRACT: 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.
[show abstract][hide abstract] ABSTRACT: 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., together with dihydroalleridone 3, the naphtoquinone alpha-dunnione 4, ursolic acid and beta-sitosterol.
[show abstract][hide abstract] ABSTRACT: Rosmarinus officinalis L. is receiving increasing attention due to its anti-inflammatory and antioxidative constituents. Our recent studies showed that R. officinalis extract, containing 31.7% of carnosic acid, was able to counteract the deleterious effects of UV-R, by protecting plasmid DNA from hydroxyl radicals generated by UV-A. In this work, we evaluated the effects of this extract on pBR322 DNA cleavage induced by nitric oxide, and the growth inhibitory activity against two human melanoma cell lines, M14 and A375. The extract showed a protective effect on plasmid DNA damage, and at concentrations of 10-80 microg/mL was able to reduce significantly (p<0.001) the growth (MTT assay) of both melanoma cell lines. In addition, our results indicate that apoptotic cell demise is induced in M14 and A375 cells. No statistically significant increase in LDH release was observed in melanoma cells, correlated to a fragmentation of genomic DNA, determined by COMET assay.
[show abstract][hide abstract] ABSTRACT: 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.
Journal of Natural Products 02/2009; 72(1):87-91. · 3.29 Impact Factor
[show abstract][hide abstract] ABSTRACT: The hydrocarbon 9,13-epi-ent-pimara-7,15-diene has been obtained from its 18-hydroxy derivative by treatment with Ph3/CCl4 and subsequent reduction with tri-n-butyltin hydride. The incubation of this diterpene with the fungus Gibberella fujikuroi afforded 1α,9α-dihydroxy-7α,8α-epoxy-13-epi-ent-pimara-15-ene. The main difference between the biotransformation of the hydrocarbon and that of the corresponding 18-alcohol is that in the former, the rearrangement of the epoxy group to give 7-oxo-derivatives was not observed. However, the sequence of reactions 7α,8α-epoxidation, hydroxylation at C-9α and subsequent C-1α hydroxylation occurred in both biotransformations.
Phytochemistry Letters - PHYTOCHEM LETT. 01/2009; 2(4):201-203.