ABSTRACT
BACKGROUND: A number of bio-active secondary metabolites have been identified and reported for several Hypericum species. Many studies have reported the potential use of the plant extracts against several pathogens. However, Hypericum triquetrifolium is one of the least studied species for its antimicrobial activity. The aim of the present study was to evaluate the cytotoxic effect of the essential oils of Hypericum triquetrifolium as well as their antimicrobial potential against coxsakievirus B3 and a range of bacterial and fungal strains. METHODS: The essential oils of Hypericum triquetrifolium harvested from five different Tunisian localities (Fondouk DJedid, Bou Arada, Bahra, Fernana and Dhrea Ben Jouder) were evaluated for their antimicrobial activities by micro-broth dilution methods against bacterial and fungal strains. In addition, the cytotoxic effect and the antiviral activity of these oils were carried out using Vero cell lines and coxsakievirus B3. RESULTS: The results showed a good antibacterial activities against a wide range of bacterial strains, MIC values ranging between 0.39-12.50 mg/ml and MBC values between 1.56-25.0 mg/ml. In addition, the essential oils showed promising antifungal activity with MIC values ranging between 0.39 µg/mL and 12.50 µg/mL; MFC values ranged between 3.12 µg/mL and 25.00 µg/mL; a significant anticandidal activity was noted (MIC values comprised between 0.39 µg/mL and 12.50 µg/mL). Although their low cytotoxic effect (CC50 ranged between 0.58 mg/mL and 12.00 mg/mL), the essential oils did not show antiviral activity against coxsakievirus B3. CONCLUSION: The essential oils obtained from Hypericum triquetrifolium can be used as antimicrobial agents and could be safe at non cytotoxic doses. As shown for the tested essential oils, comparative analysis need to be undertaken to better characterize also the antimicrobial activities of Hypericum triquetrifolium extracts with different solvents as well as their purified fractions and their pure secondary metabolites.
Subject(s)
Anti-Bacterial Agents/pharmacology , Antifungal Agents/pharmacology , Antiviral Agents/pharmacology , Hypericum/chemistry , Oils, Volatile/pharmacology , Plant Extracts/pharmacology , Animals , Bacteria/drug effects , Chlorocebus aethiops , Enterovirus B, Human/drug effects , Fungi/drug effects , Vero CellsABSTRACT
The essential oils were obtained by hydro-distillation of the aerial part of Salvia officinalis L. cultivated in Sfax gardens, Tunisia. The obtained oils were analyzed by gas chromatography-mass spectrometry (GC-MS) and 44 compounds were identified. Strong bactericidal and fungicidal effects were shown using the NCCLS broth dilution, EN 1275 and EN 1276 standard methods. The minimal cidal concentrations (MCCs) values ranged from 0.031 to 0.25 microLmL(-1). The essential oils concentrations of 0.5% and 1% (v/v) resulted in a reduction in viability higher than 5 and 4 log units per mL for the standard bacteria and fungi, respectively, within a contact time of 5 min. Using an air sampler and an aroma dispenser, vaporisation of 0.25 mLm(-3) of S. officinalis essential oils resulted in (72%, 73% and 70%) and (54%, 55% and 55%) reduction of the total microbial count and the total count of yeasts and moulds, after a residence time of 1h, 6h and 24h in a selected testing room, respectively. S. officinalis essential oils showed a potent vapour activity against a panel of bacteria, yeasts and fungi. This supported their use as a natural eco-friendly disinfectant to manage airborne microbes.