Antibacterial and antioxidant activities of Origanum compactum essential oil

In the present study, essential oil of Origanum compactum was analysed and its chemical composition was identified by gas chromatography coupled to mass spectrometry (GC-MS). Among thirty two assayed constituents, carvacrol (30.53%), thymol (27.50%) and its precursor g-terpinene (18.20%) were found to be the major components. The oil was investigated for its in vitro antibacterial activity against a panel of standard reference strains using well diffusion and broth dilution methods. In solid medium, the oil was found to be remarkably active against all tested strains except Pseudomonas which showed resistance. In liquid medium the Minimum Inhibitory Concentrations (MICs) and Minimum Bactericidal Concentration (MBCs) ranged from 0.0078 to 0.25% (v/v). The antioxidant activity was investigated by three different methods; 1,1-diphenyl-2-picryl-hydrasyl (DPPH) radical scavenging assay, -carotenebleaching test and reducing power. The results of this study revealed evidence that the essential oil of O. compactum possesses a good antioxidant effect with all assays; the antioxidant activity isdependent on the oil concentration and can be attributed to the phenolic compounds present in the oil

Development and application of a microplate method to evaluate the efficacy of essential oils against Penicillium italicum Wehmer, Penicillium digitatum Sacc. and Colletotrichum musea (Berk. M.A. Curtis) Arx, three postharvest fungal pathogens of fruits

A microbioassay was developed for evaluating the in vitro antifungal activity of 30 preselected essential oils. A template based on 10 serial dilutions with eight replicates per dilution arranged on two 96-well ELISA plates was used as a reproducible and standardized design to identify the in vitro effectiveness of these essential oils against Penicillium italicum Wehmer, Penicillium digitatum Sacc. and Colletotrichum musea (Berk. M.A. Curtis) Arx, three postharvest fungal pathogens, on fruits. Growth of mycelium was monitored by measuring optical density (492 nm). Cinnamomum zeylanicum, Cinnamomum verum and Eugenia caryophyllus were found to be still active against all the three pathogens even at 100 ppm. Compared to other methods, this microbioassay proved to be a rapid, reproducible, and efficient method for testing the efficacy of essential oils that inhibit spore germination in P. italicum, P. digitatum and C. musea. The assay requires relatively small amounts of essential oils

Screening of essential oil as potential postharvest biogungicide

Plant extracts, such as essential oils (EOs), have been known for centuries for their ability to prevent and/or to cure diseases through their fungicidal and bactericidal effect. In this project we evaluated the fungicidal activity of 90 essential oils on several pathogens associated with post-harvest diseases (Botrytis cinerea, Penicillium expensum, Pectobacterium atrosepticum and Pectobacterium carotovorum). The efficacy of the EOs was first tested in vitro using 96 wells ELISA microplates. This step allowed the selection of 9 EOs, sufficiently effective (complete growth inhibition up to 72 hours of contact with pathogen in liquid of medium) against these pathogens to be tested under in-vivo conditions. The phytotoxicity of the selected EOs was then tested on apples, pears and potatoes. While no phytotoxicity was observed when the EOs were applied on intact fruits and tubers, a clear toxicity was observed when EOs were applied on wounded fruits. For the EOs showing a moderate toxicity, the in-vivo tests were carried on by inoculating the pathogens into wounded apples (P. expensum), pears (B. cinerea) and potatoes (P. atrosepticum and P. carotovorum) treated with lower EOs concentration. At these concentration, the EOs showed less phytotoxicity but also a lower efficiency (30% in the best case)

Screening of essential oil as potential postharvest biogungicide

Plant extracts, such as essential oils (EOs), have been known for centuries for their ability to prevent and/or to cure diseases through their fungicidal and bactericidal effect. In this project we evaluated the fungicidal activity of 90 essential oils on several pathogens associated with post-harvest diseases (Botrytis cinerea, Penicillium expensum, Pectobacterium atrosepticum and Pectobacterium carotovorum). The efficacy of the EOs was first tested in vitro using 96 wells ELISA microplates. This step allowed the selection of 9 EOs, sufficiently effective (complete growth inhibition up to 72 hours of contact with pathogen in liquid of medium) against these pathogens to be tested under in-vivo conditions. The phytotoxicity of the selected EOs was then tested on apples, pears and potatoes. While no phytotoxicity was observed when the EOs were applied on intact fruits and tubers, a clear toxicity was observed when EOs were applied on wounded fruits. For the EOs showing a moderate toxicity, the in-vivo tests were carried on by inoculating the pathogens into wounded apples (P. expensum), pears (B. cinerea) and potatoes (P. atrosepticum and P. carotovorum) treated with lower EOs concentration. At these concentration, the EOs showed less phytotoxicity but also a lower efficiency (30% in the best case)

Smalto naturale green modificato con oli essenziali per il trattamento delle onicomicosi

Introduzione. Le onicomicosi (OM) sono infezioni fungine che possono interessare la lamina, la matrice o il letto dell’unghia. Rappresentano circa il 50% dei disturbi ungueali dei paesi industrializzati (1) e si manifestano con decolorazione, ispessimento e onicolisi dell’unghia. In questo contesto gli oli essenziali (OEs), composti aromatici naturali noti per la loro attività antimicrobica (2-4), stanno trovando il loro posto come nuove alternative per la prevenzione e il trattamento di tali infezioni. Lo scopo dello studio è stato di valutare l’efficacia antifungina di 7 OEs e di un MIX commerciale nei confronti di 10 funghi dermatofiti responsabili di OM al fine di formulare uno smalto green naturale (GNNP), da utilizzare a scopo preventivo o curativo. Materiali e Metodi. Il profilo chimico dei composti naturali è stato valutato tramite microestrazione in fase solida accoppiata alla gas cromatografia e spettrometria di massa ( SPME/GC-MS. Sono stati eseguiti test di micro-brodo diluizione per valutare l’efficacia antifungina e un sondaggio di gradimento olfattivo per selezionare il composto migliore. La SPME/GC-MS è stata utilizzata anche per valutare il rilascio nel tempo dei composti attivi dei 2 GNNP modificati con l’aggiunta dell’OE più efficace o del MIX (GNNP-m-OE/MIX). L’azione preventiva e curativa dei due GNNP-m è stata valutata con esperimenti ex vivo su unghie sane o colonizzate con T. mentagrophytes testando concentrazioni scalari di OE o MIX comprese tra 4% v/v e 1% v/v. Risultati. Dei 3 OEs che hanno mostrato la più elevata attività antifungina (C. giganteus, C. citratus e C.martini), il C. citratus (IC90=0.5% v/v, CC90=1% v/v) è stato preferito dal 46.67% dei partecipanti al sondaggio di gradimento e selezionato per formulare il GNNP-m-OE. Il picco massimo di rilascio dei componenti attivi delle due formulazioni GNNP-m è raggiunto al 3° giorno e si mantiene costante fino al 6° per GNNP-m-MIX. Al 4% i GNNP-m mostrano azione fungicida su tutti i ceppi, al 2% GNNP-m-OE su tutti tranne M. canis ma non risulta attivo all’1%; al 2% e 1% GNNP-m-MIX risulta invece attivo solo su T. rubrum (Fig. 1). Nei confronti di T. mentagrophytes, i dati degli esperimenti ex vivo mostrano l’azione preventiva di entrambi i GNNP-m al 4%, mentre GNNP-m-OE presenta anche azione curativa. Discussione. A concentrazioni diverse, i due GNNP-m inibiscono in parte o totalmente la crescita dei dermatofiti responsabili delle OM. In particolare, il GNNP-m-MIX presenta un’azione inibente e il rilascio dei suoi componenti è compatibile con un trattamento ogni 7 giorni, mentre il GNNP-m-OE mostra anche un’azione citocida sulle unghie colonizzate e può quindi agire come farmaco naturale, richiedendo però 2 applicazioni alla settimana. In conclusione, per il trattamento delle OM gli OEs possono considerarsi una valida risorsa naturale ad azione antifungina per lo sviluppo di nuovi approcci preventivi e terapeutici