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Pathogenic biofilm-associated bacteria that adhere to biological or nonbiological surfaces are a big challenge to the healthcare and food industries. Antibiotics or disinfectants often fail in an attempt to eliminate biofilms from those surfaces. Based on selected experimental research, this review deals with the potential biofilm-inhibiting, virulence factor-reducing, and biofilm-eradicating activities of essential oils and single essential oil compounds using Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Chromobacterium violaceum as model organisms. In addition, for the bacteria reviewed in this overview, different essential oils and essential oil compounds were reported to be able to modulate the expression of genes that are involved in the formation of autoinducer molecules, biofilms, and virulence factors. The anti-quorum sensing activity of some essential oils and single essential oil compounds was demonstrated using the gram-negative bacterium C. violaceum. Reporter strains of this bacterium produce the violet-colored compound violacein whose synthesis is regulated by quorum sensing autoinducer molecules called acylhomeserinlactones. Of great interest was the discovery that enantiomeric monoterpenes affected the quorum sensing regulation system in different ways. While the (+)-enantiomers of carvone, limonene, and borneol increased violacein formation, their (−)-analogues inhibited violacein production.For the successful eradication of biofilms and the bacteria living inside them, it is absolutely necessary that the lipophilic volatile substances can penetrate into the aqueous channels of biofilms. As shown in recent work, hydrophilic nano-delivery systems encapsulating essential oils/essential oil compounds with antibacterial effects may contribute to overcome this problem.

Combinations of two or more drugs, which affect different targets, have frequently been used as a new approach against resistant bacteria. In our work we studied the antimicrobial activity (MIC, MBC) of individual drugs (the phenolic monoterpene thymol, EDTA and vancomycin), of two-drug interactions between thymol and EDTA in comparison with three-drug interactions with vancomycin against sensitive and resistant bacteria. Thymol demonstrated moderate bactericidal activity (MBC between 60 and 4000μg/ml) while EDTA only exhibited bacteriostatic activity over a range of 60-4000μg/ml. MICs of vancomycin were between 0.125 and 16μg/ml against Gram-positive and between 32 and 128μg/ml against Gram-negative bacteria. Checkerboard dilution and time-kill curve assays were performed to evaluate the mode of interaction of several combinations against Methicillin-resistant Staphylococcus aureus (MRSA NCTC 10442) and Escherichia coli (ATCC 25922). Checkerboard data indicate indifferent interaction against Gram-positive (FICI=1-1.3) and synergy against Gram-negative bacteria (FICI≈0.4), while time kill analyses suggest synergistic effect in different combinations against both types of bacteria. It is remarkable that the combinations could enhance the sensitivity of E. coli to vancomycin 16-fold to which it is normally insensitive. We have provided proof for the concept, that combinations of known antibiotics with modern phytotherapeutics can expand the spectrum of useful therapeutics.

The species-rich and diverse genus Pimpinella is mainly distributed in Europe and Asia; a few species occur in Africa. Yet, the Javanian Pimpinella, P. pruatjan, which has been used as an aphrodisiac in Indonesian traditional medicine, was studied for the first time in the context of chemical composition, as well as phylogeny analysis and antimicrobial activity. We examined the chemical composition of the essential oil (EO) from aerial parts of P. pruatjan by gas liquid chromatography-mass spectrometry (GLC-MS). The main component of EO was (Z)-γ-bisabolene. Several oxygenated monoterpenes, oxygenated sesquiterpenes, and sesquiterpenes were also detected. The genetic relationship of Pimpinella pruatjan Molk. to other Pimpinella species was reconstructed using nucleotide sequences of the nuclear DNA marker ITS (Internal Transcribed Spacer). P. pruatjan clusters as a sister group to the African Pimpinella species. The EO did not exhibit an apparent antimicrobial activity.

Lipid rafts are involved in the life cycle of many viruses. In this study, we investigated the role of lipids in the life cycle of vesicular stomatitis virus (VSV). Cholesterol depletion by pretreatment of BHK cells or VSV particles with methyl-beta-cyclodextrin (MbetaCD), a cholesterol-sequestering drug, inhibited the production of VSV dramatically. This effect was reversible, and virus production was restored by the addition of cholesterol, indicating that the reduction was caused by the loss of cholesterol in the cell membrane and virus, respectively. Cholesterol depletion at the adsorption stage also reduced the production of VSV significantly, but in contrast, only had a limited effect on virus production at the post-entry stage. Inhibition of sphingomyelin by myriocin treatment only showed a minor effect on VSV production. However, reduction of cholesterol and sphingomyelin at the same time dramatically reduced VSV production, showed a significant synergistic effect. These results suggest that lipid rafts play an important role in the life cycle of VSV.

Essential oils from anise, hyssop, thyme, ginger, camomile and sandalwood were screened for their inhibitory effect against herpes simplex virus type 2 (HSV-2) in vitro on RC-37 cells using a plaque reduction assay. Genital herpes is a chronic, persistent infection spreading efficiently and silently as sexually transmitted disease through the population. Antiviral agents currently applied for the treatment of herpesvirus infections include acyclovir and its derivatives. The inhibitory concentrations (IC50) were determined at 0.016%, 0.0075%, 0.007%, 0.004%, 0.003% and 0.0015% for anise oil, hyssop oil, thyme oil, ginger oil, camomile oil and sandalwood oil, respectively. A clearly dose-dependent virucidal activity against HSV-2 could be demonstrated for all essential oils tested. In order to determine the mode of the inhibitory effect, essential oils were added at different stages during the viral infection cycle. At maximum noncytotoxic concentrations of the essential oils, plaque formation was significantly reduced by more than 90% when HSV-2 was preincubated with hyssop oil, thyme oil or ginger oil. However, no inhibitory effect could be observed when the essential oils were added to the cells prior to infection with HSV-2 or after the adsorption period. These results indicate that essential oils affected HSV-2 mainly before adsorption probably by interacting with the viral envelope. Camomile oil exhibited a high selectivity index and seems to be a promising candidate for topical therapeutic application as virucidal agents for treatment of herpes genitalis.

Aqueous extracts from species of the Lamiaceae family were examined for their antiviral activity against Herpes simplex virus (HSV). Extracts from lemon balm (Melissa officinalis), peppermint (Mentha x piperita), prunella (Prunella vulgaris), rosemary (Rosmarinus officinalis), sage (Salvia officinalis) and thyme (Thymus vulgaris) were screened. Their inhibitory activity against Herpes simplex virus type 1 (HSV-1), type 2 (HSV-2) and an acyclovir-resistant strain of HSV-1 (ACV (res)) was tested in vitro on RC-37 cells in a plaque reduction assay. The 50% inhibitory concentrations (IC (50)) of the extracts for HSV plaque formation were determined in dose-response studies. All test compounds showed a high antiviral activity against HSV-1, HSV-2 and ACV (res). In order to identify the mode of antiviral action, the extracts were added to the cells or viruses at different stages of infection. Both types of Herpes virus including ACV (res) were considerably neutralized after treatment with the extracts prior to infection. At maximum non-cytotoxic concentrations of the extracts, plaque formation was significantly reduced by > 90% for HSV-1 and HSV-2 and > 85% for ACV (res). In time-response studies over a period of 2 hours, a clearly time-dependent activity was demonstrated. These results indicate that the extracts affect HSV before adsorption, but have no effect on the intracellular virus replication. Therefore, the extracts exert their antiviral effect on free HSV and offer a chance to use them for topical therapeutic application against recurrent HERPES infections.

In this open clinical trial conducted in 10 veterinary practices, Ginkgo leaf extract was administered as a dietary supplement to 42 elderly dogs (mean age 11.4 years) at a daily dose of 40 mg/ 10 kg body weight for 8 weeks. The "severity of the geriatric condition" in dogs with a history of geriatric behavioural disturbances (mean duration 12 months), was significantly reduced after 8 weeks of treatment (P = 0.0002). The positive effect was already apparent after 4 weeks. Thirty-six % of the dogs were completely free of clinical signs at study end. Overall efficacy of treatment as judged by the investigator was good or very good in 79% of the dogs. Five of six clinical sign scores (disorientation, sleep/activity changes, behavioural changes, general behaviour and general physical condition/vitality) also showed a significant decrease over the treatment period. In conclusion, these findings provide promising results that could increase the quality of life in the elderly dog and, as a consequence, that of the pet owner. The Ginkgo leaf extract appears to be an efficacious agent that provides a safe dietary supplement for the elderly dog with age-related behavioural disturbances.

The inhibitory activity of manuka oil against Herpes simplex virus type 1 (HSV-1) and Herpes simplex virus type 2 (HSV-2) was tested in vitro on RC-37 cells (monkey kidney cells) using a plaque reduction assay. In order to determine the mode of antiviral action of the essential oil, manuka oil was added at different times to the cells or viruses during the infection cycle. Both HSV types were significantly inhibited when the viruses were pretreated with manuka oil 1 h prior to cell infection. At non-cytotoxic concentrations of the essential oil, plaque formation was significantly reduced by 99.5 % and 98.9 % for HSV-1 and HSV-2, respectively. The 50 % inhibitory concentration (IC (50)) of manuka oil for virus plaque formation was determined at 0.0001 % v/v ( = 0.96 microg/mL) and 0.00006 % v/v ( = 0.58 microg/mL) for HSV-1 and HSV-2, respectively. On the other hand, pretreatment of host cells with the essential oil before viral infection did not affect plaque formation. After virus penetration into the host cells only replication of HSV-1 particle was significantly inhibited to about 41 % by manuka oil. Flavesone and leptospermone, two characteristic ss-triketones of manuka oil, inhibited the virulence of HSV-1 in the same manner as the essential oil itself. When added at non-cytotoxic concentrations to the virus 1 h prior to cell infection, plaque formation was reduced by 99.1 % and 79.7 % for flavesone and leptospermone, respectively.

St. John’s Wort ( Hypericum perforatum ): A Plurivalent Raw Material for Modern and Traditional Therapies St. John’s Wort is one of the oldest and one of the best e

Objectives Drug combinations consisting of the DNA intercalating benzophenanthridine alkaloid sanguinarine, the chelator EDTA with the antibiotic streptomycin were tested against several Gram-positive and Gram-negative bacteria, including multi-resistant clinical isolates. Methods Microdilution, checkerboard and time kill curve methods were used to investigate the antibacterial activity of the individual drugs and the potential synergistic activity of combinations. Key findings Sanguinarine demonstrated a strong activity against Gram-positive and Gram-negative bacteria (minimum inhibitory concentrations, MIC = 0.5–128 μg/ml), while streptomycin was active against Gram-negative strains (MIC = 2–128 μg/ml). EDTA showed only bacteriostatic activity. Indifference to synergistic activity was seen in the two-drug combinations sanguinarine + EDTA and sanguinarine + streptomycin (fractional inhibitory concentration index = 0.1–1.5), while the three-drug combination of sanguinarine + EDTA + streptomycin showed synergistic activity against almost all the strains (except methicillin-resistant Staphylococcus aureus), as well as a strong reduction in the effective doses (dose reduction index = 2–16 times) of sanguinarine, EDTA and streptomycin. In time kill studies, a substantial synergistic interaction of the three-drug combination was detected against Escherichia coli and Klebsiella pneumoniae. Conclusions The combination of drugs, which interfere with different molecular targets, can be an important strategy to combat multidrug resistant bacteria.

A combination of antimicrobial drugs has a potential to overcome multidrug resistant pathogens. In our study we tested the combination of an antimicrobial DNA-intercalating alkaloid (sanguinarine), a chelator (EDTA) with a standard antibiotic (vancomycin), i.e. drugs, which differ in their mode of action. The antibacterial activities of individual substances and of two-drug and three-drug combinations were evaluated for 34 strains of Gram-positive and Gramnegative bacteria (among them 23 clinical isolates) which are not sensitive for vancomycin. MIC and MBC values were determined for each drug individually. Sanguinarine demonstrated a strong activity against all the strains; its activity was comparable to that of antibiotics (MIC = 0.5 - 128 µg/ml). Time kill pharmacokinetics were studied for different concentrations of sanguinarine. A sanguinarine concentration of 16 x MIC was bactericidal against both Gram-positive and Gram-negative strains within 4 to 6 h of incubation. EDTA has only bacteriostatic activity against both Gram-positive and Gram-negative bacteria. As expected, vancomycin is active against Gram-positive bacteria (MIC = 0.125 - 16 µg/ml) but much weaker against Gram-negative bacteria (MIC = 4 - 128 µg/ml). Using the checkerboard design, two- and threedrug combinations were evaluated. Additive and synergistic effects were recorded for all sanguinarine + EDTA and sanguinarine + EDTA + vancomycin combinations against Gram-negative bacteria. Time kill assays indicated that only the combination of 1 x MIC sanguinarine + 1 x MIC EDTA + 1 x MIC vancomycin resulted in a synergistic interaction against MRSA. In the combination assays Gram-negative bacteria became sensitive for vancomycin. More experiments are needed to demonstrate that such a combination strategy also works under in vivo conditions and is clinically relevant.

The biosynthesis of epoxypseudoisoeugenol-2-methylbutyrate (EPB), a rare phenylpropanoid of the genus Pimpinella , was investigated in vitro by means of a leaf-differentiating callus culture of Pimpinella anisum . In an effort to corroborate an earlier proposed biosynthetic pathway of EPB, the step between p -coumaryl alcohol and ( E )-anethole was reinvestigated. Further feeding experiments with 14 C-labelled precursors and preliminary studies at the enzyme level clearly revealed that anol, and not p -methoxycinnamyl alcohol as previously asserted, is an obligatory intermediate in EPB biosynthesis. S-Adenosyl- l -methionine: anol- O -methyltransferase, a key enzyme in EPB biosynthesis, was demonstrated and characterized for the first time.

The genus Pimpinella contains rare phenylpropanoids. The 1-(E)-propenyl-2-hydroxy-5-methoxy benzene skeleton of these compounds is called pseudoisoeugenol. To study the biosynthesis of these compounds, we set up a tissue culture of Pimpinella anisum (PAD) that selectively promoted the production of epoxy-pseudoisoeugenol-(2-methylbutyrate), termed EPB. This compound served as the final molecule of the biosynthetic pathway in all labelling experiments conducted. The putative precursors were labelled with 13 C or 14 C. The incorporation of the label was followed by 13 C-NMR-spectroscopy and liquid scintillation, respectively. Based on our labelling experiments as well as on enzymic reactions in a cell homogenate we proposed a genaral biosynthetic pathway for EPB. The biosynthetic sequence found was L-phenylalanine, trans-cinnamic acid, p-coumaric acid, p-coumaric aldehyde, p-coumaric alcohol, anol and trans-anethol. The biosynthetic step leading from trans-anethol to pseudo-isoeugenol involves migration of the side chain during the introduction of the second OH-group in the molecule (NIH-shift). The final biosynthetic steps to form EPB must be acylation and epoxidation of the propenyl double bond of pseudoisoeugenol.

Eucalyptus globulus Labill (Myrtaceae) is the principal source of eucalyptus oil in the world and has been used as an antiseptic and for relieving symptoms of cough, cold, sore throat, and other infections. The oil, well known as 'eucalyptus oil' commercially, has been produced from the leaves. Biological properties of the essential oil of fruits from E. globulus have not been investigated much.The present study was performed to examine the antimicrobial activity of the fruit oil of E. globulus (EGF) and the leaf oils of E. globulus (EGL), E. radiata Sieber ex DC (ERL) and E. citriodora Hook (ECL) against multidrug-resistant (MDR) bacteria. Furthermore, this study was attempted to characterize the oils as well as to establish a relationship between the chemical composition and the corresponding antimicrobial properties.The chemical composition of the oils was analyzed by GLC-MS. The oils and isolated major components of the oils were tested against MDR bacteria using the broth microdilution method.EGF exerted the most pronounced activity against methicillin-resistant Staphylococcus aureus (MIC ~ 250 µg/ml). EGF mainly consisted of aromadendrene (31.17%), whereas ECL had citronellal (90.07%) and citronellol (4.32%) as the major compounds. 1,8-cineole was most abundant in EGL (86.51%) and ERL (82.66%).The activity of the oils can be ranked as EGFECLERL ~ EGL. However, all the oils and the components were hardly active against MDR Gram-negative bacteria. Aromadendrene was found to be the most active, followed by citronellol, citronellal and 1,8-cineole.

Objectives The aim was to determine the chemical composition of the essential oil of Kadsura longipedunculata and the biological activity of the oil and its major components. Methods The essential oil from stem bark of Kadsura longipedunculata was analysed by capillary gas chromatography (GLC/FID) and gas chromatography–mass spectrometry (GLC/MS). The ability of the oil to reduce diphenylpicrylhydrazine (DPPH•) was used to evaluate the antioxidant activity. Inhibition of both lipoxygenase and prostaglandin E2 was used to assess the anti-inflammatory activity. Antimicrobial activity was studied in vitro against a range of bacteria and fungi using diffusion and microdilution methods. Inhibition of trypanosome proliferation was assessed using resazurin as vital stain. The in-vitro cytotoxicity of the essential oil on six human cancer cell lines (HepG2, MIA PaCa-2, HeLa, HL-60, MDA-MB-231 and SW-480) was examined using the MTT assay. Key findings Fifty compounds, representing 97.63% of total oil, were identified. δ-Cadinene (21.79%), camphene (7.27%), borneol (6.05%), cubenol (5.12%) and δ-cadinol (5.11%) were found to be the major components of the oil. The oil exerted a good antimicrobial activity against all Gram-positive bacteria tested, including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecalis. Streptococcus pyogenes and S. agalactiae were the most sensitive bacteria with a minimal inhibitory concentration (MIC) of 60 µg/ml oil. The essential oil showed a moderate fungicidal activity against yeasts, but it did not show any activity against Gram-negative bacteria. The essential oil showed a good trypanocidal activity in Trypanosoma b. brucei with an IC50 value of 50.52 ± 0.029 µg/ml. Radical scavenging activity had an IC50 value of 3.06 ± 0.79 mg/ml. 5-Lipoxygenase inhibition (IC50 = 38.58 µg/ml) and prostaglandin E2 production inhibition (28.82% at 25 µg/ml) accounted for anti-inflammatory activity of the oil. The oil exhibited some degree of cytotoxic activity against MIA PaCa-2, HepG-2 and SW-480 cell lines with IC50 values of 133.53, 136.96 and 136.62 µg/ml, respectively. The oil increased caspase 3/7 activity (an indicator of apoptosis) 2.5–4 fold in MIA Paca-2 cells. Camphene and borneol did not show antioxidant activity. However, both compounds exhibited some degree of antimicrobial, trypanocidal, anti-inflammatory and cytotoxic activity. Conclusions This investigation provided evidence for, and confirmed the efficacy of, K. longipedunculata, a traditionally used Chinese medicinal plant for the treatment of inflammation and infection.

Rose oil is the essential oil extracted from the petals of the damask rose. It is an ingredient of cosmetic as well as health care products and it is used in folk medicine and in aromatherapy. It is well known that essential oils are able to permeate the skin whereas the lipophilic properties of the compounds as well as the application site have an influence on their permeation behaviour. In this paper, we investigated the influence of the application site on the permeation of rose oil.We tested the permeation of rose oil and its major ingredients through human heat-separated epidermis of abdominal skin, breast skin, and skin from the upper arm.We found that no application site is suited best for all substances tested to permeate the skin. It depends on the structure of the essential oil ingredients which application site should be chosen for topical application, which is already known for pharmaceuticals. Furthermore, when investigating the permeation of essential oils, we found that not only the P(app) value but also the lag-time should be considered.The application site of substances to permeate the skin has a great influence on the permeation behaviour. As essential oils are volatile mixtures and their retention on the surface of the skin amounts only to a few hours, the lag-time should be considered in addition to the P(app)-value.

Introduction: Aqueous and ethanolic extracts of Cajanus cajan (Fabaceae) were examined in vitro for their antiviral activity against herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2). Materials and Methods: The antiviral activity was determined using a plaque reduction assay. The cytotoxic concentration (CC50) as well as the inhibitory concentration (IC50) of the extracts was determined from dose-response curves. Results: All extracts tested revealed a high antiviral activity against cell-free HSV-1 and HSV-2. The most active one was the Cajanus ethanol extract with IC50 values of 0.022 µg/ml for HSV-1 and 0.1 µg/ml for HSV-2. In order to identify the mode of antiviral action, the extracts were added to the host cells or viruses at different stages of infection. HSV-1 and HSV-2 were considerably inactivated when the viruses were pretreated with the extracts for 1 h prior to cell infection. At maximum non-cytotoxic concentrations of the extracts, plaque formation was significantly reduced by 95–99% for HSV-1 and HSV-2. In a time-dependent assay with cell-free HSV-1 over a period of 2 h, a clearly time-dependent effect was demonstrated whereby the Cajanus ethanol extract revealed a much higher activity than the Cajanus aqueous one. Conclusion: The results obtained indicate that the extracts affect HSV before cell adsorption, but have no effect on the intracellular virus replication. According to our findings, a thera-peutic application of Cajanus ethanolic extracts containing crEme or ointment as antiviral agent in recurrent HSV in-fection appears to be promising.

The effect of different essential oils as well as of isolated mono- and sesquiterpenes on the viability of bloodstream forms of Trypanosoma brucei, promastigotes of Leishmania major and human HL-60 cells was evaluated using the Almar Blue assay. Of the 12 essential oils and 8 terpenes investigated, only three essential oils, Melissa officinalis (balmmint) oil, Thymus vulgaris (thyme) oil, and Melaleuca alternifolia (tea tree) oil were about 50-fold and 80-fold more toxic to bloodstream forms of T. brucei than to HL-60 cells, respectively. Terpinen-4-ol, the main compound of the Australian tea tree oil, was even 1000-fold more toxic to trypanosomes than to the human cells. On the other hand, none of the essential oils and terpenes tested were more toxic to promastigotes of L. major than to HL-60 cells.

Hydroalcoholic extracts and pressed juice from Echinacea pallida were phytochemically characterised by HPLC-MS analyses. Ferulic and caffeic acid derivatives were identified as major constituents. All tested extracts and pressed juice from Echinacea pallida exhibited a low cytotoxic activity on monkey kidney cells in vitro. The inhibitory activity of Echinacea against herpes simplex virus types 1 and 2 (HSV-1, HSV-2) was analysed with plaque reduction assays. All hydroalcoholic extracts exhibited high levels of antiviral activity against both types of herpesvirus in a dose-dependent manner. Plaque formation was significantly reduced by more than 99 % or completely absent. Pressed juice from E. pallida revealed the highest antiviral activity against HSV-1 and HSV-2 when compared to hydroalcoholic Echinacea extracts and even highly diluted Echinacea pressed juice still inhibited viral infectivity. Hydroalcoholic extracts were quite active against herpetic infection when HSV-1 or HSV-2 were pretreated with the extracts. In contrast, Echinacea pressed juice revealed antiviral activity during all phases of the viral replication cycle. Additionally, Echinacea pressed juice demonstrated protection of cells against viral infection. In conclusion, hydroalcoholic E. pallida extracts interfere with free herpesvirus but pressed juice is able to interact with herpesvirus inside and outside the cell as well as to protect cells against viral infection, probably by interfering with virus attachment. Hydroalcoholic extracts and pressed juice from E. pallida demonstrated high selectivity indices, a necessary prerequisite for a potential topical treatment of herpetic infections. Different types of Echinacea preparations, such as commercial tinctures, tablets, and teas, are expected to offer different antiviral profiles.

The abundant use of anti-infective agents resulted in the emergence of drug-resistant bacteria, fungi, and viruses. To overcome the increasing resistance of pathogenic microbes, a variety of medicinal plants have been screened worldwide for their antimicrobial properties. The aim is to find new, effective antimicrobial agents with novel modes of actions. Essential oils derived from aromatic medicinal plants have been reported to exhibit exceptionally good antimicrobial effects against bacteria, yeasts, filamentous fungi, and viruses. The progress of this expanding scientific field will be documented by the most important results published in the last decade.

Phellodendron amurense Rupr. bark extracts were examined for antioxidant activity, antimicrobial activity and antiviral activity on herpes simplex virus type 1 (HSV-1). Ethanol extract showed higher content of both total phenolic and flavonoid than aqueous extract. In DPPH (2, 2-diphenyl-1-picrylhydrazyl) assay, the concentration providing 50% inhibition (IC50) values were 6.73 ± 0.87 mg/ml and 4.26 ± 0.59 mg/ml for aqueous and ethanol extracts respectively. Ethanol extract had a much higher antimicrobial activity than aqueous extract. Furthermore, the antiviral activity of the ethanol extract on HSV-1 was also tested. The maximum noncytotoxic concentration was 44.12 μg/ml for RC-37 cells. Plaque formation was inhibited by 74±6% when HSV-1 was pretreated with the extract prior to adsorption, whereas pretreatment of the cells with the extract, added during adsorption or after the adsorption only exhibited above 10% antiviral effect. This study has to some extent validated the medicinal potential of P. amurense bark.

Extracts of medicinal plants are increasingly of interest as novel drugs for antimicrobial and antiviral agents, since microorganisms might develop resistance to commonly used antimicrobial or antiviral agents.Ethanolic extracts from Lamiaceae plants prunella, peppermint, rosemary and thyme were phytochemically characterised. The inhibitory activity of four 20% ethanolic plant extracts and four 80% ethanolic extracts against herpes simplex virus (HSV) strains was tested in cell culture.Rosmarinic acid, a typical compound in Lamiaceae species, was identified in the extracts except for thyme 20% ethanolic extract. In addition, some other phenolic compounds such as apigenin- and luteolin-derivatives were identified in different amounts. All extracts exhibited high and concentration-dependent levels of antiviral activity against free acyclovir-sensitive and acyclovir-resistant HSV-1 strains with 50% inhibitory concentrations of 0.05-0.82 microg/ml. Mechanistically, exposure of free virions as well as host cells to prunella and peppermint 80% ethanolic extracts at maximum non-cytotoxic concentrations prior to infection reduced plaque formation drastically. Thus, both extracts revealed a dual mode of action similar to aqueous lemon balm extracts.Since infectivity of acyclovir-susceptible and acyclovir-resistant HSV strains was significantly reduced with Lamiaceae extracts, the results obtained indicate that ethanolic plant extracts affected herpesvirus prior to and during adsorption and in a different way than acyclovir. Based on its dual mode of action, e.g. antiviral effect against free virions and blocking virus attachment to host cells, prunella and peppermint 80% ethanolic extracts are promising antiviral agents in recurrent herpes labialis for topical therapeutic applications.

Background Aqueous extracts from leaves of well known species of the Lamiaceae family were examined for their potency to inhibit infection by human immunodeficiency virus type 1 (HIV-1). Results Extracts from lemon balm (Melissa officinalis L.), peppermint (Mentha × piperita L.), and sage (Salvia officinalis L.) exhibited a high and concentration-dependent activity against the infection of HIV-1 in T-cell lines, primary macrophages, and in ex vivo tonsil histocultures with 50% inhibitory concentrations as low as 0.004%. The aqueous Lamiaceae extracts did not or only at very high concentrations interfere with cell viability. Mechanistically, extract exposure of free virions potently and rapidly inhibited infection, while exposure of surface-bound virions or target cells alone had virtually no antiviral effect. In line with this observation, a virion-fusion assay demonstrated that HIV-1 entry was drastically impaired following treatment of particles with Lamiaceae extracts, and the magnitude of this effect at the early stage of infection correlated with the inhibitory potency on HIV-1 replication. Extracts were active against virions carrying diverse envelopes (X4 and R5 HIV-1, vesicular stomatitis virus, ecotropic murine leukemia virus), but not against a non-enveloped adenovirus. Following exposure to Lamiaceae extracts, the stability of virions as well as virion-associated levels of envelope glycoprotein and processed Gag protein were unaffected, while, surprisingly, sucrose-density equilibrium gradient analyses disclosed a marked increase of virion density. Conclusion Aqueous extracts from Lamiaceae can drastically and rapidly reduce the infectivity of HIV-1 virions at non-cytotoxic concentrations. An extract-induced enhancement of the virion's density prior to its surface engagement appears to be the most likely mode of action. By harbouring also a strong activity against herpes simplex virus type 2, these extracts may provide a basis for the development of novel virucidal topical microbicides.

Unorganized callus and leaf/root-differentiating callus cultures of Pimpinella major have been established in liquid nutrient medium. Their capacity to accumulate rare phenylpropanoids such as epoxy-pseudoisoeugenol tiglate, epoxy-anol tiglate and anol tiglate was compared with that of seedlings and whole plants. The unorganized callus cultures were not able to accumulate any phenylpropanoids. In comparison, the leaf/root-differentiating callus culture promoted the accumulation of epoxy-pseudoisoeugenol tiglate (up to 90 mg/100 g fr.wt.) but not that of anol-derivatives. The accumulated amount of EPT in PMD-SH was comparable with that in plant seedlings.

Aqueous and ethanolic extracts of Salvia officinalis (Lamiaceae) from two different locations (Garden and Swabian Mountains) were examined in vitro on RC-37 cells for their antiviral activity against herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) using a plaque reduction assay. The 50% inhibitory concentrations (IC50) of the extracts for HSV plaque formation were determined in dose-response studies. All extracts tested revealed a high virucidal activity against free HSV-1 and HSV-2. The experimental data exhibited a significant higher sensitivity of HSV against the extracts derived from Garden in comparison with those from Swabian Mountains. The most active one was the Garden 20% ethanol extract with IC50 values of 0.18 microg/ml for HSV-1 and 0.04 microg/ml for HSV-2. In order to identify the mode of antiviral action, the extracts were added to the host cells (RC-37) or viruses at different stages of infection. Independently of the location, both types of herpes viruses were considerably inactivated after treatment with the extracts prior to cell infection. Plaque formation was significantly reduced by >90% for HSV-1 and by >99% for HSV-2. Pretreatment of the host cells with both Garden and Swabian Mountains 20% and 40% ethanolic extracts prior to virus infection revealed a strong reduction of HSV-2 plaque formation by 94% and 70% (Garden) and 99% and 45% (Swabian Mountains), respectively. In time-activity studies with free HSV-1 over a period of 2h, a clearly time-dependent activity was demonstrated whereby the ethanolic extracts of both locations revealed a much higher activity than the aqueous ones. The 20% ethanolic extracts of both locations are of special interest and were effective when added to host cells and free virus. A topical application with a dual mode of action would be ideal against recurrent herpes infections.

Acyclovir-resistant clinical isolates of herpes simplex virus type 1 (HSV-1) were analyzed in vitro for their susceptibilities to essential oils of ginger, thyme, hyssop, and sandalwood. All essential oils exhibited high levels of virucidal activity against acyclovir-sensitive strain KOS and acyclovir-resistant HSV-1 clinical isolates and reduced plaque formation significantly.

Objective: To determine the antimicrobial activity of a distillate of Hamamelis (Aqua Hamamelidis ), United States Pharmacopoeia (USP) 23, and urea formulated as a topical dermatological preparation that contains both active ingredients. Methods: Using the simple occlusion test and expanded flora test, we conducted in vivo studies in 15 healthy volunteers. We also performed in vitro studies using the agar diffusion test. Results: The occlusion test and expanded flora test demonstrated significant antimicrobial activity for a product containing the Hamamelis distillate (90%) and urea (5%) among other ingredients. The expanded flora test demonstrated significant antimicrobial activity for both Hamamelis distillate and urea. The simple occlusion test showed the same tendency, but results were not significant. The agar diffusion test showed inhibition of Staphylococcus aureus and Candida albicans , among other organisms. Comparison with earlier studies of chlorhexidine digluconate and fuchsine using the same method showed that the antimicrobial activities of Hamamelis distillate and urea were relatively weak. This finding is supported by the weak inhibitory activity observed in the agar diffusion test (using 100% of the finished dosage form). Conclusion: Formulations of Hamamelis distillate and urea are mainly used for their antiinflammatory, hydrating, and barrier-stabilizing effects in dermatitis maintenance therapy. As bacterial colonization has a central role in the pathogenesis of atopic dermatitis and intertrigo, the antimicrobial activity of such products is considered a welcome, added benefit.

The lipophilic yeast Malassezia pachydermatis is part of the normal skin flora of most warm-blooded organisms. In a number of surveys it could be demonstrated that this yeast species might be involved in different skin diseases like seborrhoeic dermatitis, especially in dogs and cats. In order to look for an alternative therapeutic agent to the commonly used antimycotic and antiseptic synthetic substances the in vitro activity of Australian tea tree oil, the essential oil of Melaleuca alternifolia, against several strains of Malassezia pachydermatis was examined. All tested strains showed remarkably high susceptibility to tea tree oil. With these results the excellent antibacterial activity of tea tree oil is extended to a new group of fungal pathogens colonizing mainly mammals' skin. During the last ten years there was an increasing popularity of tea tree oil containing human health care products. The presented data open up new horizons for this essential oil as a promising alternative agent for topical use in veterinary medicine as well.

A transformed root culture of Coreopsis tinctoria was used to study the biosynthesis of 1′-isobutyryloxyeugenol-4-isobutyrate. Putative precursors labelled with 13 C were fed and incorporation was determined by 13 C NMR spectroscopy. Feeding experiments proved that this compound originates from the l -phenylalanine carbon skeleton without rearrangement of the side-chain. A loss of the carboxyl group and reintroduction of an ‘extra’ carbon atom from l -methionine was excluded. The acyl moieties originate from l -valine.

Several rare phenylpropanoids of the genus Pimpinella were tested for biological activity. Compounds with epoxy groups have a negative effect on the growth of plants, and they also show insecticidal and acaricidal activities.

The aim of the present study was to investigate the susceptibility of bacteria that play a role in respiratory tract and skin infections to the essential oils of catnip (Nepeta cataria), lemon catnip (N. cataria var. citriodora) and lemon balm (Melissa officinalis) with regard to their chemical composition. In addition, we wanted to assess whether antibiotic-resistant and -sensitive strains differ in their susceptibility to the oils and if there are cross resistances between standard antibiotics and essential oils. To evaluate the safety of topical application, cytotoxicity of the oils was studied in human keratinocyte and bronchial epithelial cell lines and irritation threshold concentrations were determined in ovo using the HET-CAM-test. The composition of the essential oils was analyzed by GC and GC-MS. Their MICs and MBCs were determined by a broth microdilution method against both reference strains from culture collections and clinical isolates with different susceptibility to standard antibiotics. Cytotoxicity was assessed by the MTT assay. Except for P. aeruginosa (MIC ≥2%), all reference strains tested were susceptible to catnip and lemon balm oils with MIC values ranging from 0.016 % to 0.25% (v/v). The clinical isolates were as susceptible to the oils (± 1 serial dilution) as the corresponding reference strains, regardless of their origin and resistance to standard antibiotics. The oils were cytotoxic to both keratinocytes and bronchial epithelial cells at CC50values from 0.0012% to 0.015% (v/v). Lemon balm oil, whose main components were monoterpene aldehydes, exhibited the highest antibacterial and cytotoxic activity, followed by lemon catnip oil, which contained mainly monoterpene alcohols, and catnip oil, which was characterized by nepetalactones. Our results provide a rationale for the use of catnip, lemon catnip and lemon balm oils in the complementary topical treatment of respiratory tract infections, as the oils show a high antibacterial activity against respiratory tract pathogens, including clinical isolates with reduced susceptibility to standard antibiotics. However, cytotoxicity must be considered in topical therapy.

A selection of structurally diverse components of essential oils was subjected to an antibacterial screening against the Gram-positive bacteria Staphylococcus aureus and Streptococcus pneumoniae as well as the Gram-negative bacteria Escherichia coli and Haemophilus influenzae using a broth microdilution method. In addition, the irritation potential of these substances to mucous membranes was evaluated by a modified HET-CAM (Hen's Egg Test-Chorioallantoic Membrane) assay. Minimum inhibitory concentrations (MIC) and irritation threshold concentrations (ITC) were compared in order to identify substances with a low mucous membrane irritation potential at the antibacterially effective concentration. Regarding the antibacterial activity, the most active substances were cinnamaldehyde, phenols, monoterpene alcohols and aldehydes. Oxygenated monoterpenes and phenylpropanoids without either alcohol or aldehyde function (ethers, ketones) showed moderate activity. Mono- and sesquiterpene hydrocarbons, as well as sesquiterpene alcohols, were more or less inactive against most of the bacteria tested, with the exception of Streptococcus pneumoniae whose growth was inhibited by sesquiterpenes at exceptionally low concentrations. In most cases, the irritation potential of the test compounds could also be traced back to their structural features. 2-Phenylethanol, monoterpene alcohols, phenols and aromatic aldehydes had the lowest ITC-values, followed by monoterpene aldehydes, ketones and ethers. In contrast, monoterpene hydrocarbons caused irritation only at higher doses. Of special interest was the fact that all the sesquiterpenes tested were not irritant even when applied undiluted to the chorioallantoic membrane (CAM).

Roots of three species of the genus Coreopsis (Compositae), C. tinctoria, C. lanceolata and C. grandiflora were investigated for the occurrence of phenylpropanoids. In addition to phenylpropanoids already known from other Coreopsis species some new derivatives of eugenol- and Z-coniferyl alcohol were found. In this report we present their structures together with their 1H NMR. 13C NMR and MS data. Two aromatic acetylenes - one of them not previously described for Coreopsis species - were identified as well.

The roots of PIMPINELLA SAXIFRAGA and P. MAJOR (umbelliferae) were reexamined for their “isoeugenol” derivatives. According to high field 1 H-NMR, 13 C-NMR, as well as MS-studies, the hitherto described substitution pattern (4-OH, 5-OMe) must be revised to be 2-OH and 5-OMe. A fatty acid ester of a phenylpropanoid was found, its structure was elucidated by 2D- 1 H-NMR ( 1 H- 1 H correlated COSY).

Localisation, accumulation and composition of the essential oil in different plant parts of MATRICARIA CHAMOMILLA L. were investigated. An organ specific distribution of individual components in the different essential oils could be shown. Only the essential oil of the roots contained the sesquiterpenes Chamomillol, Caryophyllen, Caryophyllenepoxide and the polyenes Chamomillaester I and II. The essential oil of MATRICARIA CHAMOMILLA roots is accumulated in schizogenous oil passages and oil cells restricted to the roots. Callus surface cultures of MATRICARIA CHAMOMILLA initiated from stems and flowerheads produced an essential oil similar to that of the root. It is exclusively accumulated in oil cells typical of the roots.

A leaf-differentiating tissue culture which produced substantial amounts of pseudoisoeugenol- (2-methylbutyrate) has been used to examine the origin of the pseudoisoeugenol skeleton. 14Cand 13C-labelling revealed ʟ-phenylalanine, trans-cinnamic acid and p-coumaric acid as precursors. 13C-labelled precursors proved to be especially useful.

The essential oil of chamomil roots has been investigated. Three sesquiterpenoids could be isolated and characterized by their retention time in reference to authentic substances and by their mass spectre. These are α-farnesene, β-farnesene and bisabololoxid A. Other sesquiterpenoids and polyentype substances are present and will be identified later.