Antimicrobial Activity and Composition of Five Rosmarinus (Now Salvia spp. and Varieties) Essential Oils

Rosemary: Unrevealing an old aromatic crop as a new source of promising functional food additive-A review

Rosemary (Rosmarinus officinalis L.) is one of the most famous spice plants belonging to the Lamiaceae family as a remarkably beautiful horticultural plant and economically agricultural crop. The essential oil of rosemary has been enthusiastically welcome in the whole world for hundreds of years. Now, it is wildly prevailing as a promising functional food additive for human health. More importantly, due to its significant aroma, food, and nutritional value, rosemary also plays an essential role in the food/feed additive and food packaging industries. Modern industrial development and fundamental scientific research have extensively revealed its unique phytochemical constituents with biologically meaningful activities, which closely related to diverse human health functions. In this review, we provide a comprehensively systematic perspective on rosemary by summarizing the structures of various pharmacological and nutritional components, biologically functional activities and their molecular regulatory networks required in food developments, and the recent advances in their applications in the food industry. Finally, the temporary limitations and future research trends regarding the development of rosemary components are also discussed and prospected. Hence, the review covering the fundamental research advances and developing prospects of rosemary is a desirable demand to facilitate their better understanding, and it will also serve as a reference to provide many insights for the future promotion of the research and development of functional foods related to rosemary.

Chemical Composition and Antimicrobial Activity against the Listeria monocytogenes of Essential Oils from Seven Salvia Species

In recent years, essential oils (EOs) have received interest due to their antibacterial properties. Accordingly, the present study aimed to investigate the effectiveness of the EOs obtained from seven species of Salvia on three strains of Listeria monocytogenes (two serotyped wild strains and one ATCC strain), a bacterium able to contaminate food products and cause foodborne disease in humans. The Salvia species analysed in the present study were cultivated at the Botanic Garden and Museum of the University of Pisa, and their air-dried aerial parts were subjected to hydrodistillation using a Clevenger apparatus. The obtained EOs were analysed via gas chromatography coupled with mass spectrometry for the evaluation of their chemical composition, and they were tested for their inhibitory and bactericidal activities by means of MIC and MBC. The tested Eos showed promising results, and the best outcomes were reached by S. chamaedryoides EO, showing an MIC of 1:256 and an MBC of 1:64. The predominant compounds of this EO were the sesquiterpenes caryophyllene oxide and β-caryophyllene, together with the monoterpenes bornyl acetate and borneol. These results suggest that these EOs may possibly be used in the food industry as preservatives of natural origins.

In Vitro Antimicrobial Activity of Thymus vulgaris, Origanum vulgare, Satureja montana and Their Mixture against Clinical Isolates Responsible for Canine Otitis Externa

Otitis externa is a frequent inflammation among dogs, mainly caused by bacteria and yeasts that are often resistant to conventional drugs. The aim of the present study was to evaluate the in vitro antibacterial and antifungal activities of commercial essential oils (EOs) from Origanum vulgare, Satureja montana, and Thymus vulgaris, as well as a mixture of these three components, against 47 clinical bacterial strains (Staphylococcus sp., Streptococcus sp., Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Serratia marcescens) and 5 Malassezia pachydermatis strains, previously cultured from the ears of dogs affected by otitis externa. The tested Gram-positive bacteria were sensible to the analysed EOs with MICs ranging from 1.25% (v/v) to <0.0195% (v/v); Gram-negative isolates, mainly P. aeruginosa, were less sensitive with MICs from >10% (v/v) to 0.039% (v/v). M. pachydermatis isolates were sensitive to all EOs with MICs from 4.25% (v/v) to 2% (v/v). However, the mixture was active against all bacterial (except one P. aeruginosa strain) and fungal tested isolates. The three EOs and their mixture seem to be an interesting alternative for treating canine otitis externa when conventional antimicrobials are not active.

Mineral contents, antimicrobial profile, acute and chronic toxicity of the aqueous extract of Moroccan Thymus vulgaris in rodents

Moroccan flora is rich in plants used in traditional medicine, but the further scientific investigation is necessary. The aim of the research was to evaluate the nutritional content and antimicrobial activity of Moroccan Thymus vulgaris, as well as its possible acute and chronic toxicological effects on rodents. Inductively coupled plasma atomic emission spectroscopy (ICP-AES) was used to determine the mineral content. The antimicrobial activity was determined using a well-diffusion test, a minimum inhibitory concentration (MIC), and a minimum bactericidal/fungicidal concentration (MBC/MFC) assay. Acute and chronic toxicity studies were conducted in vivo on mice and rats, respectively. Following that, haematological, serum-biochemistry, and histological investigations were performed. Moroccan Thyme was shown to be a source of numerous minerals which are necessary for health promotion. All antimicrobial testing, disc diffusion, MIC, and MBC tests revealed that thyme had potent antibacterial activity against all microorganisms tested. Staphylococcus aureus was the most susceptible bacterium, followed by Salmonella enterica and Escherichia coli. Additionally, thyme exhibited great antifungal efficacy against Candida albicans. The acute toxicity results indicated that the aqueous extract of T. vulgaris is almost non-toxic when taken orally. According to the chronic toxicity study, the extract is generally safe when taken orally over an extended period of time. The biochemical and haematological characteristics of the serum and blood were within acceptable limits, and histological examination revealed no abnormalities. In conclusion, the findings of this investigation, confirm the antimicrobial efficacy of the aqueous extract of Moroccan T. vulgaris and its safety for experimental animals.

Halophyte Artemisia caerulescens L.: Metabolites from In Vitro Shoots and Wild Plants

Halophyte plants are potential resources to deal with the increasing soil salinity determined by climatic change. In this context, the present study aimed to investigate the germplasm conservation of Artemisia caerulescens collected in the San Rossore Estate (Pisa, Italy) through in vitro culture, biochemical properties, and the phytochemical composition of the volatile fraction of both in vitro shoots and different organs of wild plants (leaves, young and ripe inflorescences). The best medium tested for the shoot proliferation was MS, with the addition of 1 μM BA. Total polyphenol content and antioxidant activity were noticeable in both the inflorescences, while leaves and in vitro shoots showed lower amounts. Concerning the phytochemical investigation, the headspaces (HSs) and the essential oils (EOs) were characterized by oxygenated monoterpenes as the main chemical class of compounds in all samples, and with α- and β-thujone as the major constituents. However, the EOs were characterized by noticeable percentages of phenylpropanoids (23.6–28.8%), with brevifolin as the unique compound, which was not detected in the spontaneous volatile emissions of the same parts of the wild plant. Good amounts of EOs were obtained from different organs of the wild plant, comprising between 0.17% and 0.41% of the young and ripe inflorescences, respectively.

Anti-Staphylococcal Activity of Cinnamomum zeylanicum Essential Oil against Planktonic and Biofilm Cells Isolated from Canine Otological Infections

The aim of this study was to evaluate the phytochemical profile of Cinnamomum zeylanicum essential oil (CZEO) and their antimicrobial and antibiofilm activity against Staphylococcus strains isolated from canine otitis. First, the CZEO chemical composition was determined by gas chromatography-mass spectrometry (CG-MS). External otitis samples collected from dogs were submitted to staphylococcal isolation, followed by MALDI-TOF mass spectrometry identification. The antimicrobial action was tested against the isolates using the disk-diffusion and microdilution methods. The antibiofilm activity was evaluated by CZEO-based concentrations, subMIC for biofilm formation and supraMIC against preformed biofilm, quantified by crystal violet (CV) staining and CFU counting. The chemical analysis revealed that (E)-cinnamaldehyde, eugenol and (E)-cinnamyl acetate were the main compounds in the CZEO, representing 77.42, 8.17 and 4.50%, respectively. Two strains of three different species, S. saprophyticus, S. schleiferi and S. pseudintermedius, were identified. The disk-diffusion test showed an inhibitory zone diameter, ranging from 34.0 to 49.5 mm, while the MIC and MBC values were around 500 and 1000 µg/mL. SubMIC demonstrated an inhibition on biofilm formation against 4 out the 6 strains tested. On mature biofilm, the CZEO-based supraMIC groups had slightly change on biomass, however, the biofilm cell viability decreased the CFU in 3 magnitude orders.