In vitro susceptibility of Helicobacter pylori to protolichesterinic acid from the lichen Cetraria islandica

Phytochemical composition and antitumor activity of a new arctic lichen Anamylopsora pakistanica

For the first-time, chemical composition and in vitro antitumor activity was investigated of a newly described lichen Anamylopsora pakistanica Usman & Khalid from the second highest plateau of the world (Deosai Plains, Pakistan). HPLC-UV method was used for identification of secondary metabolites and the acetone extract had higher values of TPC (41.90 mg GA/g) and TFC (75.37 mg RE/g) as compared to methanol extract. As chemical constituents 5,7-dihydroxy-6-methylphthalide, haematommic acid and alectorialic acid, were identified as major compounds. Atranol, alectorialin, gyrophoric acid and usnic acid were detected as minor substances. Acetone and methanol extracts induced a dose-dependent and time-dependent decrease in the viability of three types of tumour cells HeLa, HCT116 and MDA-MB-231. This lichen extract can induce S phase arrest in HeLa as compared to the untreated cells. Extract of this unique lichen, A. pakistanica, can be used safely as a significant source of biologically active compounds.

Two-step isolation of the two major paraconic acids of Cetraria islandica

The lichen Cetraria islandica is traditionally used as a demulcent for the symptomatic treatment of irritations of the mouth and throat and associated dry cough, as well as for the treatment of temporary loss of appetite. In addition to depsides and depsidones, thalli contain paraconic acids, a group of secondary metabolites commonly found in lichens and fungi. Among those, protolichesterinic acid has shown promising pharmacological activities. However, the efficient isolation of paraconic acids is quite complex due to their very similar chemical structures and their weak ultraviolet absorption. In the present work, a two-step isolation protocol of protolichesterinic acid and lichesterinic acid from a complex paraconic acid mixture is described using Sephadex LH20 column chromatography and fast centrifugal partition chromatography. Final purities higher than 95% and recoveries above 50% are achieved. Additionally, reliable qualitative techniques for detecting and differentiating paraconic acids are described. Finally, some data on compound stability and enantiomeric purity are shown.

The Genus Cetraria s. str.-A Review of Its Botany, Phytochemistry, Traditional Uses and Pharmacology

The genus Cetraria s. str. (Parmeliaceae family, Cetrarioid clade) consists of 15 species of mostly erect brown or greenish yellow fruticose or subfoliose thallus. These Cetraria species have a cosmopolitan distribution, being primarily located in the Northern Hemisphere, in North America and in the Eurasia area. Phytochemical analysis has demonstrated the presence of dibenzofuran derivatives (usnic acid), depsidones (fumarprotocetraric and protocetraric acids) and fatty acids (lichesterinic and protolichesterinic acids). The species of Cetraria, and more particularly Cetraria islandica, has been widely employed in folk medicine for the treatment of digestive and respiratory diseases as decoctions, tinctures, aqueous extract, and infusions. Moreover, Cetraria islandica has had an important nutritional and cosmetic value. These traditional uses have been validated in in vitro and in vivo pharmacological studies. Additionally, new therapeutic activities are being investigated, such as antioxidant, immunomodulatory, cytotoxic, genotoxic and antigenotoxic. Among all Cetraria species, the most investigated by far has been Cetraria islandica, followed by Cetraria pinastri and Cetraria aculeata. The aim of the current review is to update all the knowledge about the genus Cetraria covering aspects that include taxonomy and phylogeny, morphology and distribution, ecological and environmental interest, phytochemistry, traditional uses and pharmacological properties.

Itaconic acid derivatives: structure, function, biosynthesis, and perspectives

Itaconic acid possessing a vinylidene group, which is mainly produced by fungi, is used as a biobased platform chemical and shows distinctive bioactivities. On the other hand, some fungi and lichens produce itaconic acid derivatives possessing itaconic acid skeleton, and the number of the derivatives is currently more than seventy. Based on the molecular structures, they can be categorized into two groups, alkylitaconic acids and α-methylene-γ-butyrolactones. Interestingly, some itaconic acid derivatives show versatile functions such as antimicrobial, anti-inflammatory, antitumor, and plant growth-regulating activities. The vinylidene group of itaconic acid derivatives likely participates in these functions. It is suggested that α-methylene-γ-butyrolactones are biosynthesized from alkylitaconic acids which are first biosynthesized from acyl-CoA and oxaloacetic acid. Some modifying enzymes such as hydroxylase and dehydratase are likely involved in the further modification after biosynthesis of their precursors. This contributes to the diversity of itaconic acid derivatives. In this review, we summarize their structures, functions, and biosynthetic pathways together with a discussion of a strategy for the industrial use. KEY POINTS: • Itaconic acid derivatives can be categorized into alkylitaconic acids and α-methylene-γ-butyrolactones. • The vinylidene group of itaconic acid derivatives likely participates in their versatile function. • It is suggested that α-methylene-γ-butyrolactones are biosynthesized from alkylitaconic acids which are first synthesized from acyl-CoA and oxaloacetic acid.

Structure-Activity-Relationship and Mechanistic Insights for Anti-HIV Natural Products

Acquired Immunodeficiency Syndrome (AIDS), which chiefly originatesfroma retrovirus named Human Immunodeficiency Virus (HIV), has impacted about 70 million people worldwide. Even though several advances have been made in the field of antiretroviral combination therapy, HIV is still responsible for a considerable number of deaths in Africa. The current antiretroviral therapies have achieved success in providing instant HIV suppression but with countless undesirable adverse effects. Presently, the biodiversity of the plant kingdom is being explored by several researchers for the discovery of potent anti-HIV drugs with different mechanisms of action. The primary challenge is to afford a treatment that is free from any sort of risk of drug resistance and serious side effects. Hence, there is a strong demand to evaluate drugs derived from plants as well as their derivatives. Several plants, such as Andrographis paniculata, Dioscorea bulbifera, Aegle marmelos, Wistaria floribunda, Lindera chunii, Xanthoceras sorbifolia and others have displayed significant anti-HIV activity. Here, weattempt to summarize the main results, which focus on the structures of most potent plant-based natural products having anti-HIV activity along with their mechanisms of action and IC50 values, structure-activity-relationships and important key findings.

Synthesis and characterization of novel chiral derivatizing agents containing β-keto-anthracene adducts (KAAs) by 1H-NMR: aromatic influence and chiral alcohol absolute configuration determination

New chiral derivatizing agents and the effect of aromatic rings were investigated for absolute configuration of chiral alcohols via¹H-NMR.

High Antimicrobial Efficacy, Antioxidant Activity, and a Novel Approach to Phytochemical Analysis of Bioactive Polyphenols in Extracts from Leaves of Pyrus communis and Pyrus pyrifolia Collected During One Vegetative Season

Dried leaf samples of Pyrus communis L. var. 'Conference' and Pyrus pyrifolia Burm. f. (Nakai) var. 'Shinseiki' were subjected to the successful extraction procedures using various solvents, followed by filtering and/or drying liquid plant preparations under reduced pressure. As a result of this, for each Pyrus leaf sample examined, four dried residues were obtained, including methanolic (EA), ethyl acetate (EC), water (EB), and the residue obtained from aqueous solution (ED). Antiradical activity of these preparations was measured using the ABTS^+• assay, and antimicrobial activity was examined using various strains of bacteria and yeasts. The highest antiradical activity was observed for EC from leaves of P. communis var. 'Conference' collected in May, but the highest average antibacterial activity was noted for EC residues from P. pyrifolia var. 'Shinseiki' collected in May. Antibacterial activity positively correlated with concentration of hydroquinone in extracts. No antifungal activity was observed for any extract. In addition, qualitative and quantitative analyses of active polyphenolic components in extracts from Pyrus were performed. Hydroquinone and hydroxycinnamic acid derivatives were analyzed using a new optimized method comprising reversed-phase high-performance liquid chromatography (RP-LC) coupled with simultaneous photodiode-array and fluorescence detection.

An Antifungal Mechanism of Protolichesterinic Acid from the Lichen Usnea albopunctata Lies in the Accumulation of Intracellular ROS and Mitochondria-Mediated Cell Death Due to Apoptosis in Candida tropicalis

Candida species causes superficial and life-threatening systemic infections and are difficult to treat due to the resistance of these organism to various clinically used drugs. Protolichesterinic acid is a well-known lichen compound. Although the antibacterial activity of protolichesterinic acid has been reported earlier, the antifungal property and its mechanism of action are still largely unidentified. The goal of the present investigation is to explore the anticandidal activity and mechanism of action of protolichesterinic acid, especially against Candida tropicalis. The Minimum Inhibitory Concentration (MIC) value was established through microdilution techniques against four Candida species and out of four species tested, C. tropicalis showed a significant effect (MIC: 2 μg/ml). In the morphological interference assay, we observed the enhanced inhibition of hyphae when the cells were treated with protolichesterinic acid. Time-kill assay demonstrated that the maximum rate of killing was recorded between 2 and 6 h. C. tropicalis exposed to protolichesterinic acid exhibited an increased ROS production, which is one of the key factors of fungal death. The rise in ROS was due to the dysfunction of mitochondria caused by protolichesterinic acid. We confirmed that protolichesterinic acid-induced dysfunction of mitochondria in C. tropicalis. The damage of cell membrane due to protolichesterinic acid treatment was confirmed by the influx of propidium iodide and was further confirmed by the release of potassium ions. The treatment of protolichesterinic acid also triggered calcium ion signaling. Moreover, it commenced apoptosis which is clearly evidenced by Annexin V and propidium iodide staining. Interestingly protolichesterinic acid recorded excellent immunomodulatory property when tested against lymphocytes. Finally protolichesterinic acid showed low toxicity toward a normal human cell line Foreskin (FS) normal fibroblast. In in vivo test, protolichesterinic acid significantly enhanced the survival of C. tropicalis infected Caenorhabditis elegans. This investigation proposes that the protolichesterinic acid induces apoptosis in C. tropicalis via the enhanced accumulation of intracellular ROS and mitochondrial damage, which leads fungal cell death via apoptosis. Our work revealed a new key aspect of mechanisms of action of protolichesterinic acid in Candida species. This article is the first study on the antifungal and mechanism of action of protolichesterinic acid in Candida species.

Investigation of antioxidant, antimicrobial and toxicity activities of lichens from high altitude regions of Nepal

BACKGROUND

Several lichen species are reported to be used tradiationally in many theraupatic practices. Many lichen species are reported as sources of several bioactive natural compounds. Several lichen species of Nepal are so far chemically unexplored.

METHODS

The morphological, anatomical and phytochemical characteristics of lichens were compared for the taxonomic identification of the species. Methanol- water extract of lichens were sub fractionated into hexane, dichloromethane and methanol fractions for bioactivity assays. Antimicrobial activities of extracts were evaluated agaisnt pathogenic bacteria and fungal species. DPPH test was used for antioxidant potential evaluation. Brineshrimp test was perfermed to evaluate toxicity of the extracts.

RESULTS

A total of 84 lichen specimens were collected and identified from Annapurna Conservation Area (ACA) Nepal. The specimens were identified as belonging to 19 genera and 47 species. Methanol fractions of 16 specimens and dichloromethane (DCM) fractions of 21 lichens specimens showed antioxidant activities comparable with commercial standards (BHA, Butylated hydroxyanisole, IC50=4.9±0.9 μg/mL) even at crude extract level. Similarly, the DCM fraction of 17 lichens showed potential antimicrobial activity against a Gram-positive bacterium (Staphylococcus aureus KCTC3881) and DCM fractions of 45 lichens showed antimicrobial activity against a Gram-negative bacterium (Klebsiella pneumoniae KCTC2242). DCM fractions of three lichens showed antifungal activity against the yeast, Candida albicans KCTC 7965. Likewise, methanol fractions of 39 lichens and DCM fractions of 74 lichens showed strong toxicity against brine shrimp nauplii with more than 80% mortality.

CONCLUSION

Such biological activity-rich lichen specimens warrant further research on exploration of natural products with antioxidant, antimicrobial and anti cancer (toxic) potential.

Antimicrobial and Antiradical Activity of Extracts Obtained from Leaves of Five Species of the Genus Bergenia: Identification of Antimicrobial Compounds

An important focus of modern medicine is the search for new substances and strategies to combat infectious diseases, which present an increasing threat due to the growth of bacterial resistance to antibiotics. Another problem concerns free radicals, which in excess can cause several serious diseases. An alternative to chemical synthesis of antimicrobial and antiradical compounds is to find active substances in plant raw materials. We prepared extracts from leaves of five species of the genus Bergenia: B. purpurascens, B. cordifolia, B. ligulata, B. crassifolia, and B. ciliata. Antimicrobial and antiradical features of extracts and raw materials were assessed, and the quantities of phenolic compounds were determined. We also evaluated, using high-performance liquid chromatography, the amounts of arbutin and hydroquinone, compounds related to antimicrobial activity of these raw materials. The strongest antiradical properties were shown by leaves of B. crassifolia and B. cordifolia, the lowest by leaves of B. ciliata. The antiradical activity of extracts showed a strong positive correlation with the amount of phenols. All raw materials have significant antimicrobial properties. Among them, the ethyl acetate extracts were the most active. Antimicrobial activity very weakly correlated with the amount of arbutin, but correlated very strongly with the contents of both hydroquinone and phenolic compounds. Additional experiments using artificially prepared mixtures of phenolic compounds and hydroquinone allowed us to conclude that the most active antimicrobial substance is hydroquinone.

Analysis of Polyphenolic Compounds in Extracts from Leaves of Some Malus domestica Cultivars: Antiradical and Antimicrobial Analysis of These Extracts

In this study, methanol, ethyl acetate, water extracts, and precipitate were obtained from leaves of Malus domestica cultivars: Golden delicious, Jonagold, Elstar, Ligol, and Mutsu. Antiradical activity of these extracts was measured using the ABTS^+∙ radical, and antimicrobial activity was measured with the disk-diffusion method. Phenolic compounds were measured with the colorimetric method and identified with high performance liquid chromatography (HPLC). The highest antiradical activity was observed for the Jonagold variety, and in particular strong activity was noted for ethyl acetate extracts. Antimicrobial activity was observed against strains of Staphylococcus aureus, Enterococcus faecalis, and the fungus Candida glabrata. Particularly susceptible to the extracts activity appeared to be Staphylococcus aureus, but the growth of Candida glabrata was inhibited in the presence of ethyl acetate extracts. With the HPLC method we identified a high amount of phloridzin (above 500 mg per g of ethyl acetate extracts), lower amounts of hyperoside, isoquercitrin, and quercitrin, and traces of p-hydroxybenzoic and chlorogenic acids. The contribution of phloridzin to antiradical activity of methanol and ethyl acetate extracts was very high (above 90%). In water extract the contribution of phloridzin was between 38.9 and 55.2%, chlorogenic acid 22.7 and 36.1%, and hyperoside 12.2 and 13.3%.

Secondary metabolites from cetrarioid lichens: Chemotaxonomy, biological activities and pharmaceutical potential

BACKGROUND

Lichens, as a symbiotic association of photobionts and mycobionts, display an unmatched environmental adaptability and a great chemical diversity. As an important morphological group, cetrarioid lichens are one of the most studied lichen taxa for their phylogeny, secondary chemistry, bioactivities and uses in folk medicines, especially the lichen Cetraria islandica. However, insufficient structure elucidation and discrepancy in bioactivity results could be found in a few studies.

PURPOSE

This review aimed to present a more detailed and updated overview of the knowledge of secondary metabolites from cetrarioid lichens in a critical manner, highlighting their potentials for pharmaceuticals as well as other applications. Here we also highlight the uses of molecular phylogenetics, metabolomics and ChemGPS-NP model for future bioprospecting, taxonomy and drug screening to accelerate applications of those lichen substances.

CHAPTERS

The paper starts with a short introduction in to the studies of lichen secondary metabolites, the biological classification of cetrarioid lichens and the aim. In light of ethnic uses of cetrarioid lichens for therapeutic purposes, molecular phylogeny is proposed as a tool for future bioprospecting of cetrarioid lichens, followed by a brief discussion of the taxonomic value of lichen substances. Then a delicate description of the bioactivities, patents, updated chemical structures and lichen sources is presented, where lichen substances are grouped by their chemical structures and discussed about their bioactivity in comparison with reference compounds. To accelerate the discovery of bioactivities and potential drug targets of lichen substances, the application of the ChemGPS NP model is highlighted. Finally the safety concerns of lichen substances (i.e. toxicity and immunogenicity) and future-prospects in the field are exhibited.

CONCLUSION

While the ethnic uses of cetrarioid lichens and the pharmaceutical potential of their secondary metabolites have been recognized, the knowledge of a large number of lichen substances with interesting structures is still limited to various in vitro assays with insufficient biological annotations, and this area still deserves more research in bioactivity, drug targets and screening. Attention should be paid on the accurate interpretation of their bioactivity for further applications avoiding over-interpretations from various in vitro bioassays.

Enzymatic resolution of α-methyleneparaconic acids and evaluation of their biological activity

Both enantiomers of three biologically relevant paraconic acids-MB-3, methylenolactocin, and C75-were obtained with enantioselectivities up to 99% by kinetic enzymatic resolutions. Good enantiomeric excesses were obtained for MB-3 and methylenolactocin, using α-chymotrypsin and aminoacylase as enantiocomplementary enzymes, while C75 was resolved with aminoacylase. They all were evaluated for their antiproliferative, antibacterial, and antifungal activities, showing weak effects and practically no difference between enantiomers in each case. At high concentrations (16-64 µg/mL), (-)- C75 acted as an antimicrobial agent against Gram-positive bacteria.

Effects of anti-proliferative lichen metabolite, protolichesterinic acid on fatty acid synthase, cell signalling and drug response in breast cancer cells

BACKGROUND

The lichen compound (+)-protolichesterinic acid (+)-PA, isolated from Iceland moss, has anti-proliferative effects on several cancer cell lines. The chemical structure of (+)-PA is similar to a known fatty acid synthase (FASN) inhibitor C75.

AIMS

To test whether the anti-proliferative activity of (+)-PA is associated with effects on FASN and HER2 (human epidermal growth factor receptor 2) and major signalling pathways. Synergism between (+)-PA and lapatinib, a HER2 active drug, was also evaluated.

MATERIALS AND METHODS

Pure compound was isolated by preparative high-performance liquid chromatography (HPLC) and purity of (+)-PA analyzed by analytical HPLC. Cell viability was assessed using Crystal violet staining. FASN and HER2 expression was estimated by immunofluorescence. The Meso Scale Discovery (MSD)(®) assay was used to measure activation of ERK1/2 and AKT. Synergism was estimated by the CalcuSyn software.

RESULTS

Treatment with (+)-PA increased FASN expression in SK-BR-3 cells, which overexpress FASN and HER2, implying a compensatory response to inhibition of FASN activity. HER2 expression was decreased suggesting secondary downregulation. ERK1/2 and AKT signalling pathways were inhibited, probably due to reduced levels of HER2. No effects were observed in T-47D cells. Synergism between (+)-PA and lapatinib was observed in the SK-BR-3 cells.

CONCLUSION

Results suggest that the primary effect of (+)-PA is inhibition of FASN activity. Synergistic effects with lapatinib were seen only in SK-BR-3 cells, and not T-47D cells, further supporting the notion that (+)-PA acts by inhibiting FASN with secondary effects on HER2 expression and signalling. (+)-PA could therefore be a suitable agent for further testing, alone or in combination treatment against HER2-overexpressing breast cancer.

Estonian folk traditional experiences on natural anticancer remedies: from past to the future

CONTEXT

Despite diagnostic and therapeutic advancements, the burden of cancer is still increasing worldwide. Toxicity of current chemotherapeutics to normal cells and their resistance to tumor cells highlights the urgent need for new drugs with minimal adverse side effects. The use of natural anticancer agents has entered into the area of cancer research and increased efforts are being made to isolate bioactive products from medicinal plants.

OBJECTIVE

To lead the search for plants with potential cytotoxic activity, ethnopharmacological knowledge can give a great contribution. Therefore, the attention of this review is devoted to the natural remedies traditionally used for the cancer treatment by Estonian people over a period of almost 150 years.

METHODS

Two massive databases, the first one stored in the Estonian Folklore Archives and the second one in the electronic database HERBA ( http://herba.folklore.ee/ ), containing altogether more than 30 000 ethnomedicinal texts were systematically reviewed to compile data about the Estonian folk traditional experiences on natural anticancer remedies.

RESULTS AND CONCLUSION

As a result, 44 different plants with potential anticancer properties were elicited, 5 of which [Angelica sylvestris L. (Apiaceae), Anthemis tinctoria L. (Asteraceae), Pinus sylvestris L. (Pinaceae), Sorbus aucuparia L. (Rosaceae), and Prunus padus L. (Rosaceae)] have not been previously described with respect to their tumoricidal activities in the scientific literature, suggesting thus the potential herbal materials for further investigations of natural anticancer compounds.

Antimicrobial Property of Extracts of Indian Lichen against Human Pathogenic Bacteria

Context. Usnea ghattensis G. Awasthi (Usneaceae) endemic fruticose lichen found growing luxuriantly in Northern Western Ghats of India, it also contains Usnic acid as a major chemical and tested against some human pathogenic bacteria. Objective. To explore antimicrobial properties of Usnea ghattensis against some human pathogenic bacteria. Materials and Methods. The lichen was extracted in acetone, methanol, and ethanol. In vitro antimicrobial activity was tested initially by Kirby-Bauer technique of disc diffusion method and was confirmed by minimum inhibitory concentration using Broth microdilution method according to the NCCLS guidelines. Results. Ethanol extract was most effective against Bacillus cereus and Pseudomonas aeruginosa with a zone of inhibition 29.8 ± 0.6 mm and 12.3 ± 0.5 mm diameters at a concentration of 0.2 mg/mL. Acetone and methanol extract demonstrated almost similar activity against Staphylococcus aureus and the zone of inhibition was 24.6 ± 0.5 and 24.7 ± 0.4 mm. Only methanol extract was showing activity against Streptococcus faecalis with a 13.5 ± 0.8 mm zone. MIC value noted against Staphylococcus aureus and Streptococcus faecalis was 6.25 μg/mL and 25 μg/mL, whereas against Bacillus cereus and Pseudomonas aeruginosa, MIC calculated was 3.125 μg/mL and 200 μg/mL, respectively. Conclusion. The present study demonstrates the relatively higher activity of this lichen against not only gram (+) but significantly also against gram (−) bacteria. This indicates that this lichen might be a rich source of effective antimicrobial agents.

Biopharmaceutical potential of lichens

CONTEXT

Lichens are composite organisms consisting of a symbiotic association of a fungus (the mycobiont) with a photosynthetic partner (the phytobiont), usually either a green alga or cyanobacterium. The morphology, physiology and biochemistry of lichens are very different from those of the isolated fungus and alga in culture. Lichens occur in some of the most extreme environments on the Earth and may be useful to scientists in many commercial applications.

OBJECTIVE

Over the past 2 decades, there has been a renewed and growing interest in lichens as a source of novel, pharmacologically active biomolecules. This review summarizes the past and current research and development trends in the characterization and use of lichens and their bioactive compounds in traditional medicine and other biopharmaceutical applications of commercial interest.

METHODS

The present review contains 10 illustrations and 188 references compiled from major databases including Science Direct, Chemical Abstracts, PubMed and Directory of Open Access Journals.

RESULTS

Lichen morphology, symbiosis, diversity and bioactivities including enzyme inhibitory, antimicrobial, antifungal, antiviral, anticancer, anti-insecticidal and antioxidant actions were reviewed and summarized. Recent progress in lichens and lichen-forming fungi was discussed with emphasis on their potential to accelerate commercialization of lichen-based products.

CONCLUSIONS

Lichens are an untapped source of biological activities of industrial importance and their potential is yet to be fully explored and utilized. Lichen-derived bioactive compounds hold great promise for biopharmaceutical applications as antimicrobial, antioxidant and cytotoxic agents and in the development of new formulations or technologies for the benefit of human life.

Antimicrobial activity of Northwestern Mexican plants against Helicobacter pylori

Helicobacter pylori is the major etiologic agent of such gastric disorders as chronic active gastritis and gastric carcinoma. Over the past few years, the appearance of antibiotic-resistant bacteria has led to the development of better treatments, such as the use of natural products. This study evaluated the anti-H. pylori activity of 17 Mexican plants used mainly in the northwestern part of Mexico (Sonora) for the empirical treatment of gastrointestinal disorders. The anti-H. pylori activity of methanolic extracts of the plants was determined by using the broth microdilution method. The 50% minimum inhibitory concentrations ranged from less than 200 to 400 μg/mL for Castella tortuosa, Amphipterygium adstringens, Ibervillea sonorae, Pscalium decompositum, Krameria erecta, Selaginella lepidophylla, Pimpinella anisum, Marrubium vulgare, Ambrosia confertiflora, and Couterea latiflora and were greater than 800 μg/mL for Byophyllum pinnatum, Tecoma stans linnaeus, Kohleria deppena, Jatropha cuneata, Chenopodium ambrosoides, and Taxodium macronatum. Only Equisetum gigantum showed no activity against H. pylori. This study suggests the important role that these plants may have in the treatment of gastrointestinal disorders caused by H. pylori. The findings set the groundwork for further characterization and elucidation of the active compounds responsible for such activity.

A phylogenetic analysis of the boreal lichen Mycoblastus sanguinarius (Mycoblastaceae, lichenized Ascomycota) reveals cryptic clades correlated with fatty acid profiles

Lichens are a prominent feature of northern conifer forests and a large number of species are thought to be circumboreal. Whether or not circumboreal lichen species really constitute monophyletic groups has seldom been tested. We investigated molecular phylogenetic patterns in the mycobiont of Mycoblastus sanguinarius, a well known epiphytic lichen species of the boreal forest, based on material collected from across the high latitude northern hemisphere. A three-locus dataset of internal transcribed spacer rDNA, translation elongation factor 1-α and replication licensing factor Mcm7 DNA sequences revealed that material treated until now as belonging to M. sanguinarius does indeed form a monophyletic group within the genus and is distinct from a strongly supported Mycoblastus affinis. The M. sanguinarius complex appears closely related to the rare Mycoblastus glabrescens, which is currently known only from the Pacific Northwest and was rediscovered during the present study. However, within M. sanguinarius s.lat. in the northern hemisphere, two deeply divergent and morphologically coherent species can be recovered, one of which matches the southern hemisphere species Mycoblastus sanguinarioides and turns out to be widespread in North America and Asia, and one of which corresponds to M. sanguinarius s.str. Both M. sanguinarius and M. sanguinarioides exhibit additional low-level genetic differentiation into geographically structured clades, the most prominent of which are distributed in East Asia/eastern North America and western North America/Europe, respectively. Individuals from these lowest-level clades are morphologically indistinguishable but chemical analyses by thin layer chromatography revealed that each clade possesses its own fatty acid profile, suggesting that chemical differentiation precedes morphological differentiation and may be a precursor to speciation.

Thin layer chromatography analysis of antioxidant constituents of lichens from Antarctica

Antioxidant agents against reactive oxygen species can be used for several cosmetic and medicinal applications. Methanol-water (90:10 v/v) extracts of five polar lichen species--namely Stereocaulon alpinum Laurer (Stereocaulaceae); Ramalina terebrata Hook and Taylor (Ramalinaceae); Caloplaca sp. (Teloschistaceae); Lecanora sp. (Lecanoraceae); and Caloplaca regalis (Vain.)Zahlbr (Teloschistaceae) from King George Island (Antarctica)--were analyzed using thin layer chromatography (TLC) followed by a DPPH (2,2-diphenyl-1-picrylhydrazyl) spray technique. The experimental data showed that 33-50% of the major constituents of the test extracts were active antioxidants. Stereocaulon alpinum and R. terebrata showed a higher number (50%) of antioxidant constituents, although their activities were comparatively weak. The strength of antioxidant activity in terms of discoloration of DPPH was shown to be stronger by the constituents of S. alpinum, C. regalis and C. sp. In addition, phenolic content in these Antarctic lichen extracts was in the range of 17-47 mg/g, supporting the antioxidant data of TLC analysis. Thus, these results suggest that Antarctic lichen contains a variety of strong antioxidant constituents. Therefore, further study of the laboratory culture of lichen is warranted to investigate possible commercial production, followed by isolation and characterization of the active antioxidant agents, which can be used against various oxidative stress-related diseases.

Determination of genotoxic, antigenotoxic and cytotoxic potential of the extract from lichen Cetraria aculeata (Schreb.) Fr. in vitro

Naturally occurring compounds can have protective effects towards mutagens and carcinogens as shown by numerous studies. In the present study, the genotoxic/antigenotoxic activities of the extract from lichen Cetraria aculeata (Schreb.) Fr., which has been identified as an antibacterial agent in former studies, were investigated against known mutagens such as 4-nitro-o-phenylenediamine (4-NPD) and 2-aminofluorene (2-AF) in TA98 and TA100 strains of Salmonella typhimurium in the presence or absence of metabolic activity. Further genotoxicity/antigenotoxicity of the extract against mitomycin C for micronucleus formation was also evaluated in human lymphocytes. The cytotoxic effects of the extract on mammalian cells were investigated in three different cell line types by MTT assay. The results obtained show that the extract of C. aculeata has a significant antigenotoxic activity in bacterial systems, but not in mammalian cells and cytotoxic activity in some mammalian cancer cells. However, it was not mutagenic in all systems. The findings suggest that the lichen extract may have a possible therapeutic potential and therefore this must be further investigated by other multiple in vitro bioassays for the development of therapeutic agents.

Anti-Helicobacter pylori activities of six Iranian plants

BACKGROUND

Helicobacter pylori is the major worldwide cause of bacterial gastrointestinal infections in adults and children. Antibiotic therapy and a combination of two or three drugs have been widely used to eradicate these infections. However, development of drug resistance in bacteria calls for new sources of drugs, and plants seem to be a logical source of new antibacterial compounds.

METHODS

The anti-H. pylori activities of six native Iranian plants (Glycyrrhiza aspera, Juglans regia, Ligustrum vulgare, Thymus kotschyanus, Trachyspermum copticum and Xanthium brasilicum) and seven antibiotics were determined against 70 clinical isolates from children using the disk susceptibility assay. Minimum inhibitory concentrations were also measured for the biologically active extracts. One extract with the best anti-H. pylori activity was fractionated by silica gel and thin layer chromatography and the active compounds were identified by hydrogen nuclear magnetic resonance ((1)HNMR) spectroscopy.

RESULTS

All plant extracts showed anti-H. pylori activity by the disk sensitivity method, but the most active extracts were those from X. brasilicum and T. copticum. In fact, the anti-H. pylori activities of the two extracts were superior to the disk antibiotic susceptibility profile. Minimum inhibitory concentrations were within the range of 31.25-250 micro g/ml. Fractionation and chemical identification of the extract from X. brasilicum showed the presence of two substances, a flavonoid and a xanthanolide.

CONCLUSIONS

Due to the rise in antibiotic resistance, new sources of anti-H. pylori drugs are needed. The use of medicinal plants and/or their chemical components may have potential benefit in eradicating such problems.

Efficacy of sulforaphane in eradicating Helicobacter pylori in human gastric xenografts implanted in nude mice

Sulforaphane, an isothiocyanate abundant in the form of its glucosinolate precursor in broccoli sprouts, has shown in vitro activity against Helicobacter pylori. We evaluated the effect of sulforaphane in vivo against this bacterium by using human gastric xenografts in nude mice. H. pylori was completely eradicated in 8 of the 11 sulforaphane-treated grafts. This result suggests that sulforaphane might be beneficial in the treatment of H. pylori-infected individuals.

In vitro anti-Helicobacter pylori activity of Greek herbal medicines

In this paper, we have studied the anti-Helicobacter pylori effect of 70 Greek plant extracts and a number of commercially available herbs used traditionally in folk medicine against gastric ailments, peptic ulcer included. The extracts of Anthemis melanolepis, Cerastium candidissimum, Chamomilla recutita, Conyza albida, Dittrichia viscosa, Origanum vulgare and Stachys alopecuros have been proved active against one standard strain and 15 clinical isolates of H. pylori.

In vitro susceptibility of Helicobacter pylori to isoquinoline alkaloids from Sanguinaria canadensis and Hydrastis canadensis

Methanol extracts of the rhizomes of Sanguinaria canadensis, and the roots and rhizomes of Hydrastis canadensis, two plants used traditionally for the treatment of gastrointestinal ailments, were screened for in vitro antibacterial activity against 15 strains of Helicobacter pylori. The rhizome extracts, as well as a methanol extract of S. canadensis suspension-cell cultures inhibited the growth of H. pylori in vitro, with a MIC50 range of 12.5-50.0 microg/ml. Three isoquinoline alkaloids were identified in the active fraction. Sanguinarine and chelerythrine, two benzophenanthridine alkaloids, inhibited the growth of the bacterium, with an MIC50 of 50.0 and 100.0 microg/ml, respectively. Protopine, a protopine alkaloid, also inhibited the growth of the bacterium, with a MIC50 of 100 microg/ml. The crude methanol extract of H. canadensis rhizomes was very active, with an MIC50 of 12.5 microg/ml. Two isoquinoline alkaloids, berberine and beta-hydrastine, were identified as the active constituents, and having an MIC50 of 12.5 and 100.0 microg/ml, respectively.

Anti-Helicobacter pylori flavonoids from licorice extract

Licorice is the most used crude drug in Kampo medicines (traditional Chinese medicines modified in Japan). The extract of the medicinal plant is also used as the basis of anti-ulcer medicines for treatment of peptic ulcer. Among the chemical constituents of the plant, glabridin and glabrene (components of Glycyrrhiza glabra), licochalcone A (G. inflata), licoricidin and licoisoflavone B (G. uralensis) exhibited inhibitory activity against the growth of Helicobacter pylori in vitro. These flavonoids also showed anti-H. pylori activity against a clarithromycin (CLAR) and amoxicillin (AMOX)-resistant strain. We also investigated the methanol extract of G. uralensis. From the extract, three new isoflavonoids (3-arylcoumarin, pterocarpan, and isoflavan) with a pyran ring, gancaonols A[bond]C, were isolated together with 15 known flavonoids. Among these compounds, vestitol, licoricone, 1-methoxyphaseollidin and gancaonol C exhibited anti-H. pylori activity against the CLAR and AMOX-resistant strain as well as four CLAR (AMOX)-sensitive strains. Glycyrin, formononetin, isolicoflavonol, glyasperin D, 6,8-diprenylorobol, gancaonin I, dihydrolicoisoflavone A, and gancaonol B possessed weaker anti-H. pylori activity. These compounds may be useful chemopreventive agents for peptic ulcer or gastric cancer in H. pylori-infected individuals.

Sulforaphane inhibits extracellular, intracellular, and antibiotic-resistant strains of Helicobacter pylori and prevents benzo[a]pyrene-induced stomach tumors

Gastric infection with Helicobacter pylori is a cosmopolitan problem, and is especially common in developing regions where there is also a high prevalence of gastric cancer. These infections are known to cause gastritis and peptic ulcers, and dramatically enhance the risk of gastric cancer. Eradication of this organism is an important medical goal that is complicated by the development of resistance to conventional antimicrobial agents and by the persistence of a low level reservoir of H. pylori within gastric epithelial cells. Moreover, economic and practical problems preclude widespread and intensive use of antibiotics in most developing regions. We have found that sulforaphane [(-)-1-isothiocyanato-(4R)-(methylsulfinyl)butane], an isothiocyanate abundant as its glucosinolate precursor in certain varieties of broccoli and broccoli sprouts, is a potent bacteriostatic agent against 3 reference strains and 45 clinical isolates of H. pylori [minimal inhibitory concentration (MIC) for 90% of the strains is Collapse

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MESH Headings

• Agaricales
• Amoxicillin/pharmacology
• Animals
• Anticarcinogenic Agents/pharmacology
• Benzo(a)pyrene
• Brassica
• Clarithromycin/pharmacology
• Drug Resistance, Microbial
• Female
• Helicobacter pylori/drug effects
• Helicobacter pylori/growth & development
• Helicobacter pylori/isolation & purification
• Humans
• Isothiocyanates
• Metronidazole/pharmacology
• Mice
• Mice, Inbred ICR
• Phytotherapy
• Stomach Neoplasms/chemically induced
• Stomach Neoplasms/microbiology
• Stomach Neoplasms/prevention & control
• Sulfoxides
• Thiocyanates/pharmacology

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Grants

• R01 CA094076 NCI NIH HHS
• CA 94076 NCI NIH HHS

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Affiliation(s)

Jed W Fahey Lewis B. and Dorothy Cullman Cancer Chemoprotection Center, Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205-2185, USA.
Xavier Haristoy
Patrick M Dolan
Thomas W Kensler
Isabelle Scholtus
Katherine K Stephenson
Paul Talalay
Alain Lozniewski

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Determination of antioxidant and antimicrobial activities of Rumex crispus L. extracts

The antioxidant activities, reducing powers, 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activities, amount of total phenolic compounds, and antimicrobial activities of ether, ethanol, and hot water extracts of the leaves and seeds of Rumex crispus L. were studied. The antioxidant activities of extracts increase with increasing amount of extracts (50-150 microg). However, the water extracts of both the leaves and seeds have shown the highest antioxidant activities. Thus, addition of 75 microg of each of the above extracts to the linoleic acid emulsion caused the inhibition of peroxide formation by 96 and 94%, respectively. Although the antioxidant activity of the ethanol extract of seed was lower than the water extract, the difference between these was not statistically significant, P > 0.05. Unlike the other extracts, 75 microg of the ether extract of seeds was unable to show statistically significant antioxidant activity, P > 0.05 (between this extract and control in that there is no extract in the test sample). Among all of the extracts, the highest amount of total phenolic compound was found in the ethanol extract of seeds, whereas the lowest amount was found in the ether extract of seeds. Like phenolic compounds, the highest reducing power and the highest DPPH scavenging activity were found in the ethanol extract of seeds. However, the reducing activity of the ethanol extract of seeds was approximately 40% that of ascorbic acid, whereas in the presence of 400 microg of water and ethanol extracts of seeds scavenging activities were about 85 and 90%, respectively. There were statistically significant correlations between amount of phenolic compounds and reducing power and between amount of phenolic compounds and percent DPPH scavenging activities (r = 0.99, P < 0.01, and r = 0.864, P < 0.05, respectively) and also between reducing powers and percent DPPH scavenging activities (r = 0.892, P < 0.05). The ether extracts of both the leaves and seeds and ethanol extract of leaves had shown antimicrobial activities on Staphylococcus aureus and Bacillus subtilis. However, none of the water extracts showed antimicrobial activity on the studied microorganisms.

A comparison of the use of complementary therapies in Australia and Iceland

The use of complementary therapies in Iceland and Australia is compared in this paper, along with information regarding research into native plants in both countries. Attitudes towards complementary therapists from the medical profession are discussed, and the use of complementary medicine by pregnant women and midwives is given special emphasis.

Comparison of antioxidant and antimicrobial activities of tilia (Tilia argentea Desf ex DC), sage (Salvia triloba l.), and black tea (Camellia sinensis) extracts

The antioxidant activity of the water extract of Tilia argentea Desf ex DC was determined by the thiocyanate method. The antioxidant activity of the water extract increased with the increasing amount of lyophilized extract (50-400 microg) added into the linoleic acid emulsion. Statistically significant effect was determined in 100 microg and higher amounts. Antioxidant activities of water extracts of tilia (Tilia argentea Desf ex DC), sage (Salvia triloba L.), and two Turkish black teas commercially called Rize tea and young shoot tea (Camellia sinensis) were compared. For comparison studies, 100 microg portions of extracts were added into test samples. All samples were able to show statistically significant antioxidant effect. Both of the tea extracts showed highest antioxidant activities, nevertheless, differences between tilia and sage and tilia and tea were not statistically significant (for both cases p > 0.05). Like antioxidant activity, the reducing power of water extract of Tilia argentea Desf ex DC was also concentration dependent. Even in the presence of 50 microg of extract, the reducing power was significantly higher than that of the control (p < 0.05) in which there was no extract. Unlike antioxidant activity, the highest reducing power activity was shown by sage extract. Among the tea extracts, young shoot extract was the most effective one, however, it had significantly lower activity than sage (p < 0.05). Although tea flower had the lowest reducing power activity, it was higher than that of tilia. But this difference was not statistically significant (p > 0.05). From these results, we could suggest that although the reducing power of a substance may be an indicator of its potential antioxidant activity, there may not always be a linear correlation between these two activities. In addition, antimicrobial activities of each of the above extracts were studied by disk diffusion methods on different test microorganisms. None of the extracts showed antibacterial activity on the studied microorganisms.

Evaluation of selected lichens from iceland for cancer chemopreventive and cytotoxic activity

Cancer chemopreventive effects of organic extracts from 29 species of lichens collected in Iceland were evaluated using a panel of in vitro bioassays whereby extracts were tested for potential to induce quinone reductase (QR) and differentiation of human promyelocytic leukemia (HL-60) cells, inhibit cyclooxygenase-1 (COX-1), phorbol ester-induced ornithine decarboxylase (ODC), aromatase and sulfatase, as well as for antioxidant, estrogenic/anti-estrogenic and antiproliferative activity. In addition, the extracts were tested for cytotoxicity against 12 cancer cell lines. The most significant results were exhibited by extracts from Xanthoria elegans and Alectoria nigricans , which respectively, induced QR activity (concentration to double activity = 4.8 µg/ml) and inhibited phorbol ester-induced ODC activity with mouse 308 cells in culture (IC 50 = 2.6 µg/ml). Moderate inhibition of [ 3 H]thymidine incorporation with HL-60 cells was exhibited by the Peltigera leucophlebia extract. Several extracts prevented estrogen formation from estrogen precursors by inhibiting the enzymatic activities of aromatase ( Sphaerophorus globosus , Cetrariella delisei , Melanelia hepatizon ) and sulfatase ( Cladonia gracilis , Sphaerophorus fragilis , S. globosus ). None of the extracts demonstrated significant cytotoxic effects with selected cell lines.

Garlic or jalapeño peppers for treatment of Helicobacter pylori infection

OBJECTIVE

There have been a number of reports that natural foods such as garlic, honey, and capsaicin can inhibit Helicobacter pylori in vitro and each report has suggested the natural ingredient be used for treatment of the infection. We investigated whether garlic or capsaicin-containing peppers would actually inhibit H. pylori in vivo.

METHODS

We performed a prospective crossover study in healthy H. pylori-infected adults. We used the urea breath test to assess the status of the H. pylori infection. On separate days subjects received three test meals consisting of beef, tortillas, and salad with one of the following: fresh garlic (10 sliced cloves), capsaicin (six sliced fresh jalapeños), two tablets of bismuth subsalicylate (Pepto-Bismol, positive control), or nothing added (negative control). Breath testing was done before the first meal, the evening meal, and the following morning. At least 2 days elapsed between the test substances.

RESULTS

Twelve subjects participated (seven men, five women), with an average age of 41.4 yr, range 27-51 yr. Ten subjects received garlic, six received jalapeños, and 11 received bismuth. Neither garlic nor capsaicin had any in vivo effect on H. pylori (median urease activity 28.5 vs 39.8 and 43.7 vs 46.6 before and after garlic and jalapeños, respectively) (p > 0.8). Bismuth had a marked inhibitory effect (median 55.8 vs 14.3 before and after bismuth) (p < 0.001), respectively.

CONCLUSIONS

This study did not support a role for either garlic or jalapeños in the treatment of H. pylori infection. Caution must be used when attempting to extrapolate data from in vitro studies to the in vivo condition.

Antimycobacterial activity of lichen metabolites in vitro

Several compounds, whose structures represent the most common chemical classes of lichen metabolites, were screened for in vitro activity against Mycobacterium aurum, a non-pathogenic organism with a similar sensitivity profile to M. tuberculosis. Of the compounds tested, usnic acid from Cladonia arbuscula exhibited the highest activity with an MIC value of 32 microg/ml. Atranorin and lobaric acid, both isolated from Stereocaulon alpinum, salazinic acid from Parmelia saxatilis and protolichesterinic acid from Cetraria islandica all showed MIC values >/=125 microg/ml.

Anti-proliferative effects of lichen-derived inhibitors of 5-lipoxygenase on malignant cell-lines and mitogen-stimulated lymphocytes

Several lichen species have been used traditionally as medicinal plants. It has previously been shown that two low-molecular-weight lichen metabolites, lobaric acid isolated from Stereocaulon alpinum Laur. and protolichesterinic acid isolated from Cetraria islandica L. (Ach.), have in-vitro inhibitory effects on arachidonate 5-lipoxygenase. We have studied the effects of these compounds on cultured cells from man, including three malignant cell-lines (T-47D and ZR-75-1 from breast carcinomas and K-562 from erythro-leukaemia), as well as normal skin fibroblasts and peripheral blood lymphocytes. Both test substances caused a significant reduction in DNA synthesis, as measured by thymidine uptake, in all three malignant cell-lines; the dose inducing 50% of maximum inhibition (ED50) was between 1.1 and 24.6 microg mL(-1) for protolichesterinic acid and between 14.5 and 44.7 microg mL(-1) for lobaric acid. The breast-cancer cell-lines were more sensitive than K-562. The proliferative response of mitogen-stimulated lymphocytes was inhibited with a mean ED50 of 8.4 microg mL(-1) and 24.5 microg mL(-1) for protolichesterinic acid and lobaric acid, respectively. These concentrations are of the same order of magnitude as the IC50 values in the 5-lipoxygenase assay. Significant cell death (assessed by the MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-( 4-sulfophenyl)-2H-tetrazolium) assay and trypan blue exclusion) occurred in the three malignant cell-lines at protolichesterinic acid and lobaric acid concentrations above 20 and 30 microg mL(-1), respectively. In K-562 morphological changes consistent with apoptosis were detected. Up to 38% cell death was observed at 20 microg mL(-1) for protolichesterinic acid and 15 microg mL(-1) for lobaric acid in mitogen-stimulated lymphocytes but unstimulated lymphocytes were clearly less sensitive. In contrast, the DNA synthesis, proliferation and survival of normal skin fibroblasts were not affected at doses up to 20 microg mL(-1) for protolichesterinic acid and 30 microg mL(-1) for lobaric acid. We conclude that the anti-proliferative and cytotoxic effects observed might be related to the 5-lipoxygenase inhibitory activity of protolichesterinic acid and lobaric acid. These results open up the opportunity for future studies of these lichen metabolites with regard to their anti-tumour and anti-inflammatory properties.