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Essential oils and isolated essential oil compounds are known to exert various pharmacological effects, such as antibacterial, antifungal, antiviral, anti-inflammatory, anti-immunomodulatory, antioxidant, and wound healing effects. Based on selected articles, this review deals with the potential antiviral and virucidal activities of essential oils and essential oil compounds together with their mechanism of action as well as in silico studies involving viral and host cell-specific target molecules that are indispensable for virus cell adsorption, penetration, and replication. The reported in vitro and in vivo studies highlight the baseline data about the latest findings of essential oils and essential oil compounds antiviral and virucidal effects on enveloped and non-enveloped viruses, taking into account available biochemical and molecular biological tests. The results of many in vitro studies revealed that several essential oils and essential oil compounds from different medicinal and aromatic plants are potent antiviral and virucidal agents that inhibit viral progeny by blocking different steps of the viral infection/replication cycle of DNA and RNA viruses in various host cell lines. Studies in mice infected with viruses causing respiratory diseases showed that different essential oils and essential oil compounds were able to prolong the life of infected animals, reduce virus titers in brain and lung tissues, and significantly inhibit the synthesis of proinflammatory cytokines and chemokines. In addition, some in vitro studies on hydrophilic nano-delivery systems encapsulating essential oils/essential oil compounds exhibited a promising way to improve the chemical stability and enhance the water solubility, bioavailabilty, and antiviral efficacy of essential oils and essential oil compounds.

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.

In this review, results of randomized double-blind controlled clinical trials (RCTs) with extracts of Serenoa repens fruits at a dose of 320 mg/d for the treatment of lower urinary tract symptoms (LUTS) are assessed. Of the RTCs conducted for up to 6 months, a benefit was seen in three of three RTCs with ethanolic, in eight of nine RTCs with hexane, and in one of two RTCs with CO2 extracts. Of the RTCs conducted for more than 6 months, a benefit was seen in two RTCs with hexane and in one RTC with CO2 extracts, whereas one RTC with an ethanolic, two RTCs with hexane, and one RTC with CO2 extracts did not show positive results. As LUTS are dynamic conditions with strong spontaneous fluctuation over time, the majority of patients might expect improvement of single symptoms and thus of quality of life, particularly as the extracts are well tolerated even in long-term treatment.

Background: Propolis consists of a complex mixture of resinous substances collected by honeybees from different plant sources. The objective of this study was to investigate the chemical composition, biological activities, and synergistic properties with antibiotics of propolis samples collected from various geographic origins (Germany, Ireland, and Czech Republic). Methods: The chemical composition of the propolis was analyzed by Gas Liquid Chromatography-Mass Spectrometry (GLC-MS) and High-performance liquid chromatography (HPLC). The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were evaluated by the standard broth microdilution method, while synergistic interactions were assessed by checkerboard dilution and time-kill curve assays. Results: HPLC and GLC-MS analyses revealed that ethanol extract of propolis (EEP) and water extracts of propolis (WEP) contained more than 100 different phytochemicals. The most abundant compounds were aromatic alcohols, aromatic acids, cinnamic acid and its esters, fatty acids, and flavanone (chrysin). Czech propolis showed the highest phenolic content (129.83 ± 5.9 mg CAE/g) followed by Irish propolis and German propolis. Furthermore, Irish propolis exhibited the highest value of total flavonoid content (2.86 ± 0.2 mg QE/g) and antioxidant activity (IC50 = 26.45 µg/mL). All propolis samples showed moderate antibacterial effect against Gram-positive microorganisms with MIC ranging from 0.08 mg/mL to 2.5 mg/mL. Moreover, EEP exhibited moderate activity against Gram-negative bacteria with MIC between 0.6 mg/mL to 5 mg/mL. In addition, EEP displayed moderate antifungal activity (MIC values between 0.6–2.5 mg/mL). The results obtained from time kill-kinetic assay and checkerboard dilution test of two-drug combinations between EEP and antibiotics such as vancomycin, oxacillin, and levofloxacin indicate mainly synergistic interactions against drug-resistant microbial pathogens including MRSA and VRE. Conclusions: The propolis extract synergistically enhanced the efficacy of antibiotics, especially those acting on cell wall synthesis (vancomycin and oxacillin) against drug-resistant microorganisms.

The goal of this study was to investigate the antimicrobial activity of bee venom and its main component, melittin, alone or in two-drug and three-drug combinations with antibiotics (vancomycin, oxacillin, and amikacin) or antimicrobial plant secondary metabolites (carvacrol, benzyl isothiocyanate, the alkaloids sanguinarine and berberine) against drug-sensitive and antibiotic-resistant microbial pathogens. The secondary metabolites were selected corresponding to the molecular targets to which they are directed, being different from those of melittin and the antibiotics. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were evaluated by the standard broth microdilution method, while synergistic or additive interactions were assessed by checkerboard dilution and time-kill curve assays. Bee venom and melittin exhibited a broad spectrum of antibacterial activity against 51 strains of both Gram-positive and Gram-negative bacteria with strong anti-MRSA and anti-VRE activity (MIC values between 6 and 800 µg/ml). Moreover, bee venom and melittin showed significant antifungal activity (MIC values between 30 and 100 µg/ml). Carvacrol displayed bactericidal activity, while BITC exhibited bacteriostatic activity against all MRSA and VRE strains tested (reference strains and clinical isolates), both compounds showed a remarkable fungicidal activity with minimum fungicidal concentration (MFC) values between 30 and 200 µg/ml. The DNA intercalating alkaloid sanguinarine showed bactericidal activity against MRSA NCTC 10442 (MBC 20 µg/ml), while berberine exhibited bacteriostatic activity against MRSA NCTC 10442 (MIC 40 µg/ml). Checkerboard dilution tests mostly revealed synergism of two-drug combinations against all the tested microorganisms with FIC indexes between 0.24 and 0.50, except for rapidly growing mycobacteria in which combinations exerted an additive effect (FICI = 0.75–1). In time-kill assays all three-drug combinations exhibited a powerful bactericidal synergistic effect against MRSA NCTC 10442, VRE ATCC 51299, and E. coli ATCC 25922 with a reduction of more than 3log10 in the colony count after 24 h. Our findings suggest that bee venom and melittin synergistically enhanced the bactericidal effect of several antimicrobial agents when applied in combination especially when the drugs affect several and differing molecular targets. These results could lead to the development of novel or complementary antibacterial drugs against MDR pathogens.

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.

Die Kunst, mit Pflanzen und deren Zubereitungen zu heilen, zahlt zweifellos zu den altesten kulturellen Errungenschaften der Menschheit. Archaologische Funde aus prahistorischer Zeit deuten darauf hin, dass der Mensch Pflanzen nicht nur als Nahrungsmittel, Bau- und Bekleidungsmaterial zu nutzen wusste, sondern auch zu Heilzwecken.

Pflanzen mit abfuhrender Wirkung (pflanzliche Laxantia) konnen ganz unterschiedliche Wirkstoffe, wie z. B. Anthranoide, Rizinusol, Harze, Schleime, osmotisch wirkende Zuckeralkohole und Fruchtsauren enthalten. Im Buch werden Heilpflanzen bzw. pflanzliche Drogen behandelt, die als Wirkstoffe Anthranoide (Aloe), Schleime (Lein) und Rizinusol (Wunderbaum) fuhren.

Die pharmakologische Wirkung von Heilpflanzen bzw. Heilpflanzenzubereitungen beruht in erster Linie auf deren Gehalt an biologisch wirksamen sekundaren Pflanzeninhaltsstoffen. Es handelt sich hierbei meist um niedermolekulare Naturstoffe, die aus dem Primarstoffwechsel abgeleitet sind und im Organismus von Tier und Mensch eine biologische Wirkung auslosen. In der Regel kommt die pharmakologische Gesamtwirkung einer Heilpflanzenzubereitung dadurch zustande, dass die darin enthaltenen unterschiedlichen Naturstoffe pleiotrope (Wirkung auf verschiedene Zielstrukturen), synergistische oder additive Wirkungsqualitaten zeigen. Im nachfolgenden Abschnitt werden einige wichtige biologisch wirksame sekundare Pflanzeninhaltsstoffe vorgestellt. Fur tiefere Einsichten in die chemische Struktur, Biosynthese und pharmakologische Wirkung dieser Naturstoffe sei auf das Studium von einschlagigen Lehrbuchern verwiesen (vgl. hierzu u. a. Hansel 1996; Wagner 1999; Hansel u. Sticher 2007).

Tierarzten in der Kleintierpraxis ist bekannt, dass sich vor allem Haustiere, wie Hund, Katze, Kaninchen, Meerschweinchen oder Ziervogel, mit Arzneimitteln, Pestiziden, verschiedenen Reinigungsmitteln sowie Nahrungs- und Genussmitteln vergiften konnen.

Auch in der 3., vollstandig aktualisierten und erweiterten Auflage gibt das bewahrte Buch eine systematische und praxisnahe Einfuhrung in die Anwendung von Heilpflanzen in der Veterinarpraxis. Nach Indikationsgebieten geordnet werden zu jeder relevanten Pflanze die botanischen Eigenschaften, die Inhaltsstoffe und ihre Wirkungen, die Anwendungsgebiete mit exakten Dosierungen und Rezepturen und mogliche unerwunschte Wirkungen sowie rechtliche Regelungen zur Anwendung beschrieben; zusatzlich werden alle Pflanzen durch eine oder mehrere Abbildungen veranschaulicht. Neu in der 3. Auflage sind die Beschreibungen 8 weiterer Pflanzen, die Angabe der verfugbaren Pflanzenpraparate zu jeder Heilpflanze, Hinweise auf spezifische Regelungen zur Anwendung in der Schweiz sowie eine Liste ausgewahlter Bezugsquellen im deutschsprachigen Raum. Eine neu eingefuhrte ubersichtliche Tabelle erleichtert fur die wichtigen Anwendungsgebiete die Suche nach den geeigneten Heilpflanzen. Einfuhrende Kapitel zu den pharmakologischen und rechtlichen Grundlagen sowie ein ausfuhrlicher Anhang mit Begriffserklarungen und Listen zum Nachschlagen runden die Darstellung ab.

In diesem Kapitel werden Heilpflanzen zusammengefasst, die bei Appetitlosigkeit, dyspeptischen Beschwerden und Entzundungen der Magen-Darm-Schleimhaut zur Anwendung kommen. Es handelt sich dabei um eine heterogene Gruppe von Heilpflanzen mit ganz unterschiedlichen sekundaren Pflanzenstoffen.

Bei der Anwendung von Heilpflanzen und deren Zubereitungen sind im Bereich der Veterinarmedizin tierartspezifische Unterschiede zu beachten.

Die Haut stellt fur den Organismus die auserste Begrenzung gegenuber der Umwelt dar. Sie schutzt die darunter gelegenen Gewebe und Organe vor chemischen, mechanischen und physikalischen Schadigungen von ausen und verhindert somit das Eindringen von unerwunschten Krankheitskeimen. Die Haut erfullt auserdem wichtige Aufgaben bei der Regulation des Wasserund Warmehaushaltes.

In den letzten Jahrzehnten haben sich in unserer westlichen modernen Gesellschaft der Stellenwert und der Umgang mit unseren Haustieren wesentlich verandert. Die Grunde hierfur sind vielfaltig.

Heilpflanzen mit sedativer Wirkung werden in der Veterinarmedizin vorwiegend bei Neurosen verschiedenen Charakters, Unruhe- und Angstzustanden, Reizbarkeit und nervos bedingten Magen-Darm-Storungen angewendet.

Wie alle Arzneimittel unterliegt auch die Abgabe verschreibungspflichtiger oder nicht fur den Verkehr auserhalb der Apotheke freigegebener Veterinarphytopharmaka in Deutschland den Bestimmungen des § 43 Arzneimittelgesetz (AMG) und durfen dem Tierhalter nur durch den Tierarzt oder auf Verschreibung des Tierarztes ausgehandigt werden.

Entzundungen der Haut bzw. Schleimhaut konnen lokal oder auch als generalisiertes Geschehen auftreten. Ihre Genese ist in der Regel ein komplizierter Prozess, an dem viele verschiedene Faktoren, wie Psyche, Haltung, Pflege, Infektionen, chemische Agentien, Sonneneinwirkung, allergische oder andere Krankheitsursachen, beteiligt sein konnen. Typisch fur eine oberflachliche Hautentzundung sind verklebte Haare mit deutlichen Entzundungsherden, Juckreiz, Schuppen und haarlose Stellen.

Die Galle ist fur die Verdauung und den Stoffwechsel wichtig. Praktische Bedeutung haben Pflanzen mit galletreibender Wirkung, deren Inhaltsstoffe die Bildung von Gallensaft und seine Absonderung in den Zwolffingerdarm unmittelbar beeinflussen.

Sowohl Stoffwechselprodukte als auch Arzneistoffe werden uber die Niere und dadurch mit dem Harn aus dem Korper eliminiert. Verschiedene Faktoren regulieren die Funktion der Nieren, die u. a. vom Zustand des zentralen und vegetativen Nervensystems, der Stoffwechsellage oder vom Herz- und Kreislaufsystem abhangig ist. Daraus geht hervor, dass die Diurese auf verschiedenen Wegen beeinflusst werden kann.

Unter Herzinsuffizienz versteht man eine Herzmuskelschwache, die durch unterschiedliche Faktoren, wie z. B. Herzklappenfehler, entzundliche und degenerative Herzmuskelerkrankungen oder Reizleitungsstorungen, hervorgerufen werden kann.

Durchfall kann durch ganz unterschiedliche Krankheiten verursacht werden, wie z. B. durch bakterielle und virale Infektionen, allergische Enteropathien, Tumoren und funktionelle Darmstorungen.

Katarrhalische Erkrankungen der oberen und unteren Atemwege sind meist infektios und treten akut auf. Im Vordergrund der Behandlung stehen bronchiolytische, sekretolytische und hustendampfende Masnahmen sowie die Starkung der korpereigenen Abwehrkrafte.

Heilpflanzen, die Stoffe mit hautreizender und durchblutungsfordernder Wirkung enthalten, werden zur Behandlung chronischer Entzundungen und rheumatischer Beschwerden im Alter angewendet.

Plant extracts and essential oils have been widely studied and used as antimicrobial agents in the last decades. In our study we investigated the antimicrobial activities of Olbas(®) Tropfen (in the following named Olbas), a traditionally used complex essential oil distillate, in comparison to its individual essential oil ingredients. Olbas (10 g) consists of three major components such as peppermint oil (5.3 g), eucalyptus oil (2.1 g), and cajuput oil (2.1 g) and of two minor constituents like juniper berry oil (0.3 g) and wintergreen oil (0.2 g). The composition of Olbas and the five individual essential oils were characterized by GLC-MS. According to GLC-MS analysis 1,8-cineol is the main component of the complex essential oil distillate followed by menthol and menthone. The minimum inhibitory and minimum microbicidal concentrations of Olbas and each of the single essential oils were evaluated in 17 species/strains of bacteria and fungi. Time-kill assay was performed to compare the microbicidal activity of Olbas and peppermint oil during several time intervals. Olbas displayed a high antimicrobial activity against all test strains used in this study, among them antibiotic resistant MRSA (methicillin-resistant Staphylococcus aureus) and VRE (vancomycin-resistant Enterococcus). Its antimicrobial activity was comparable to that of peppermint oil which was the most potent one of all individual essential oils tested. In the time kill assay Olbas as well as peppermint oil demonstrated similar microbicidal activities. Based on its wide antimicrobial properties Olbas can be a useful agent for the treatment of uncomplicated infections of skin and respiratory tract.

Background: Extracts and essential oils of medicinal plants are increasingly of interest as novel drugs for antiherpetic agents, since the herpes simplex virus (HSV) might develop resistance to commonly used antiviral drugs. Methods: An aqueous extract of Melissa officinalis as well as phenolic extract compounds, i.e. caffeic acid, p-coumaric acid and rosmarinic acid were examined for their antiviral activity against herpes simplex virus type 1 (HSV-1) in vitro. Results: When drugs were added to HSV-1-infected cells, no antiviral effect was observed as determined by plaque reduction assay and analysis of expression of viral protein ICP0. However, the Melissa extract demonstrated a high virucidal activity against HSV-1, even at very low concentrations of 1.5 µg/ml, whereas similar results for phenolic compounds were only achieved at 100 times higher concentrations. Besides the virucidal activity, the Melissa extract and rosmarinic acid inhibited HSV-1 attachment to host cells in a dose-dependent manner. These results indicate that rosmarinic acid was the main contributor to the antiviral activity of Melissa extract. However, the selectivity index of Melissa extract of 875 against HSV is superior to the selectivity indices of single constituents. Conclusion: Melissa extract exhibits low toxicity, is virucidal and affects HSV-1 attachment to host cells in vitro.

Atherische Ole verschiedener Pflanzen sowie alkoholische Extrakte aus Lamiaceen (Lippenblutlern) haben sich bei In-vitro-Studien als auserordentlich wirksam gegen Herpes-simplex-Viren vom Typ 1 (HSV-1) erwiesen. Mithilfe des Plaquereduktionstests konnte gezeigt werden, dass die gepruften Pflanzenprodukte v.a. zellfreie Viren inaktivieren und somit deren Infektiositat sehr stark reduzieren oder ausschalten konnen. Zellfreie HS-Viren treten beim Patienten primar wahrend der Blaschenphase auf. Das Sekret der Blaschen ist hoch infektios und stellt eine wichtige Infektionsquelle fur suszeptible, noch seronegative Mitmenschen, insbesondere Kleinkinder dar. Alkoholische Extrakte aus Braunelle, Melisse und Pfefferminze zeigten in unseren experimentellen Studien einen dualen Wirkmechanismus, indem sie nicht nur zellfreie Viren inaktivierten, sondern bei Vorbehandlung der Wirtszellen die Infektion dieser Zellen mit HSV-1 um uber 80 % reduzierten. Der letzte Befund weist darauf hin, dass diese Extrakte die Virusanheftung an die Wirtszellen erfolgreich blockieren konnen. Interessanterweise waren sowohl die atherischen Ole als auch die Lamiaceen-Extrakte in der Lage, auch die Infektiositat von Aciclovir-resistenten Herpesviren entscheidend zu reduzieren. Diese Beobachtung durfte in erste Linie darauf zuruckzufuhren sein, dass der virale Replikationszyklus von HSV-1 durch Aciclovir und die Pflanzenprodukte an unterschiedlichen Stellen inhibiert wird. Erste klinische Studien lassen erkennen, dass Patienten mit rezidivierenden Lippenherpes-Episoden von der topischen Behandlung mit atherischen Olen und Melissenblattextrakten profitieren.

Essential oil of star anise as well as phenylpropanoids and sesquiterpenes, for example, trans-anethole, eugenol,β-eudesmol, farnesol,β-caryophyllene andβ-caryophyllene oxide, which are present in many essential oils, were examined for their antiviral activity against herpes simplex virus type 1 (HSV-1)in vitro. Antiviral activity was analyzed by plaque reduction assays and mode of antiviral action was determined by addition of the drugs to uninfected cells, to the virus prior to infection or to herpesvirus-infected cells. Star anise oil reduced viral infectivity by >99%, phenylpropanoids inhibited HSV infectivity by about 60–80% and sesquiterpenes suppressed herpes virus infection by 40–98%. Both, star anise essential oil and all isolated compounds exhibited anti-HSV-1 activity by direct inactivation of free virus particles in viral suspension assays. All tested drugs interacted in a dose-dependent manner with herpesvirus particles, thereby inactivating viral infectivity. Star anise oil, rich in trans-anethole, revealed a high selectivity index of 160 against HSV, whereas among the isolated compounds onlyβ-caryophyllene displayed a high selectivity index of 140. The presence ofβ-caryophyllene in many essential oils might contribute strongly to their antiviral ability. These results indicate that phenylpropanoids and sesquiterpenes present in essential oils contribute to their antiviral activity against HSV.

Essential oils are complex natural mixtures, their main constituents, e.g. terpenes and phenylpropanoids, being responsible for their biological properties. Essential oils from eucalyptus, tea tree and thyme and their major monoterpene compounds alpha-terpinene, gamma-terpinene, alpha-pinene, p-cymene, terpinen-4-ol, alpha-terpineol, thymol, citral and 1,8-cineole were examined for their antiviral activity against herpes simplex virus type 1 (HSV-1) in vitro. These essential oils were able to reduce viral infectivity by >96%, the monoterpenes inhibited HSV by about >80%. The mode of antiviral action has been determined, only moderate antiviral effects were revealed by essential oils and monoterpenes when these drugs were added to host cells prior to infection or after entry of HSV into cells. However, both essential oils and monoterpenes exhibited high anti-HSV-1 activity by direct inactivation of free virus particles. All tested drugs interacted in a dose-dependent manner with herpesvirus particles thereby inactivating viral infection. Among the analysed compounds, monoterpene hydrocarbons were slightly superior to monoterpene alcohols in their antiviral activity, alpha-pinene and alpha-terpineol revealed the highest selectivity index. However, mixtures of different monoterpenes present in natural tea tree essential oil revealed a ten-fold higher selectivity index and a lower toxicity than its isolated single monoterpenes.

Aqueous and ethanol extracts of propolis were analysed phytochemically and examined for their antiviral activity in vitro. Different polyphenols, flavonoids and phenylcarboxylic acids were identified as major constituents. The antiviral effect of propolis extracts and selected constituents, e.g. caffeic acid (1), p-coumaric acid (2), benzoic acid (3), galangin (4), pinocembrin (5) and chrysin (6) against herpes simplex virus type 1 (HSV-1) was analysed in cell culture. The 50% inhibitory concentration (IC(50)) of aqueous and ethanol propolis extracts for HSV-1 plaque formation was determined at 0.0004% and 0.000035%, respectively. Both propolis extracts exhibited high levels of antiviral activity against HSV-1 in viral suspension tests, plaque formation was significantly reduced by >98%. In order to determine the mode of antiviral action of propolis, the extracts were added at different times during the viral infection cycle. Both propolis extracts exhibited high anti-HSV-1 activity when the viruses were pretreated with these drugs prior to infection. Among the analysed compounds, only galangin and chrysin displayed some antiviral activity. However, the extracts containing many different components exhibited significantly higher antiherpetic effects as well as higher selectivity indices than single isolated constituents. Propolis extracts might be suitable for topical application against herpes infection.

Herbal remedies are multicomponent mixtures by their nature as well as by pharmaceutical definition. Being a multicomponent mixture is not only a crucial property of herbal remedies, it also represents a precondition for interactions such as synergism or antagonism. Until now, only a few phytomedicines are accurately described concerning the interactions of their active components. The aim of this study was to search for interactions within such a naturally given multi-component mixture and to discuss the pharmaceutical and clinical impacts. The thyme oil chosen for the examination belongs to the essential oils with the most pronounced antimicrobial activity. Antibiotic activity of thyme oil and single active components were tested against six different strains of microorganisms. The checkerboard assay was used to search for interactions. The time-kill assay was used to verify the observed effects and to get information about the temporal resolution of the antimicrobial activity. The degree of the detected interactions corresponded with the demarcating FICI measure of 0.5, which separates the additive from the over-additive (synergistic) effects. Therefore, the observed effect was called a "borderline case of synergism" or, respectively, "partial synergism". Partial synergism was observed only in the presence of Klebsiella pneumoniae. Additive antimicrobial activity was observed for the combination of the two monosubstances carvacrol plus linalool and thymol plus linalool as well as with the combination of the two essential oils of the carvacrol and linalool chemotypes. An increase of the carvacrol oil concentration from one to two times the MIC resulted in a considerable acceleration of the kill-rate. Thyme oil is composed of several different components that show antimicrobial activity (at least: carvacrol, thymol and linalool). The antimicrobial activity of thyme oil is partly based on additive effects, which might especially enhance the rapidity of the antimicrobial action. In addition, a mixture of several active ingredients that varies in its composition from year to year and from lot to lot as is the case with herbal remedies may be more stable concerning the antimicrobial activity than mixtures containing just a single active component.

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.

The effect of anise oil, dwarf-pine oil and chamomile oil against different thymidine-kinase-positive (aciclovir-sensitive) and thymidine-kinase-negative (aciclovir-resistant) herpes simplex virus type 1 (HSV-1) strains was examined. Clinical HSV-1 isolates containing frameshift mutations in the thymidine kinase (TK) gene, an insertion or a deletion, yield a non-functional thymidine kinase enzyme resulting in phenotypical resistance against aciclovir. The inhibitory activity of three different essential oils against herpes simplex virus isolates was tested in-vitro using a plaque reduction assay. All essential oils exhibited high levels of antiviral activity against aciclovir-sensitive HSV strain KOS and aciclovir-resistant clinical HSV isolates as well as aciclovir-resistant strain Angelotti. At maximum noncytotoxic concentrations of the plant oils, plaque formation was significantly reduced by 96.6–99.9%, when herpesviruses were preincubated with drugs before attachment to host cells. No significant effect on viral infectivity could be achieved by adding these compounds during the replication phase. These results indicate that anise oil, dwarf-pine oil and chamomile oil affected the virus by interrupting adsorption of herpesviruses and in a different manner than aciclovir, which is effective after attachment inside the infected cells. Thus the investigated essential oils are capable of exerting a direct effect on HSV and might be useful in the treatment of drug-resistant viruses. Chamomile oil did not reveal any irritating potential on hen's egg chorioallantoic membrane, demonstrated the highest selectivity index among the oils tested and was highly active against clinically relevant aciclovir-resistant HSV-1 strains.

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.

Recent years have seen an explosion of scientific papers that deal with drugs from the fruits of milk thistle and its active substances silymarin (standardized mixture of flavonolignanes), thus justifying an updated systematic review. Methods: Electronic databases identified silymarin, silibinin, silicristin or milk thistle as descriptors in >700 papers (34% published in last 5 years; 92% dealt with animal pharmacological). Only papers adequately reporting on experimental conditions, dosing, variables tested and statistics were analysed. Results: Silymarin was found to modify specifically the functions related to various transporters and receptors located in the cell membranes; that is, organic anion uptake transporter peptides (OATP), ABC transporters (P-gp), bile salt export pump, as well as TNF-a-dependent and possibly selectin-dependent phenomena. In the cytoplasm, some antioxidant properties and the inhibition of the lipoxygenase pathway seem quite selective and could concur to the antitoxic effects. Some effects like the inhibition of inducible nitric-oxide synthase, of nuclear factor κ B, and reduction of collagen synthesis are indicative of DNA/RNAmediated effects. Several studies using ‘in vitro’ and ‘in vivo’ cancer models suggest a potential of silymarin in such diseases. Topical and systemic silymarin has skin protective properties against UV-induced damage in epidermis and causes an up-regulation of tumour-suppressor genes p53- and p21CIP1. There were no data on hepatic viral replication, viremia or spontaneous tumours in the data examined. Conclusions: Data presented here do not solve the question about the complex mechanism(s) of action of the medicinal herbal drug silymarin. Silymarin may be a natural multi-functional and multi-target drug.

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.

Brackenridgea zanguebarica is a small tree that is used in traditional African medicine as a type of cure-all for many diseases, including the treatment of wounds. The yellow bark of B. zanguebarica was used for the preparation of an ethanolic extract, which was tested in various concentrations against eleven bacteria, Herpes simplex virus type 1 (HSV-1) and different human tumour cell lines. The extract that contains different polyphenolic substances like calodenin B. Cell growth inhibition, assessed via MTT-assay, was found in all tested human cell lines with IC50 values (concentration of extract that reduced cell viability by 50%) between 33 μg dry extract/mL for HL-60 human myeloid leukaemia cells and 93 μg dry extract/mL for HaCaT human keratinocytes. Staining with Annexin-V-FLUOS and JC-1 followed by subsequent analysis via flow cytometry revealed significant apoptosis-inducing properties. Analysis of caspase activity using a fluorogenic caspase-3 substrate showed a significant caspase activity in Jurkat T-cells after incubation with the extract. The bark extract had a pronounced activity against free HSV-1 and a strong antibacterial activity against Gram-positive strains (MICs: 6–24 μg dry extract/mL), which are often involved in skin infections. Additionally, no irritating properties of the extract could be observed in hen-egg test chorioallantoic membrane (HET-CAM) assay. These findings give a rationale for the traditional use of B. zanguebarica and are a basis for further analysis of the plant's components, their biological activity, and its use in modern phytotherapy.

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.