Characterization of Portuguese Thymbra capitata, Thymus caespititius and Myrtus communis essential oils in topical formulations

Abstract

As the personal care industry evolves, formulators are seeking innovative solutions for their formulations' needs, and for ingredients that can offer multiple functions within formulations. Considering that essential oils (EOs) may present a wide spectrum of biological activities, the composition, antimicrobial and antioxidant activity of Portuguese Thymbra capitata, Thymus caespititius and Myrtus communis EOs were assessed in order to evaluate them as preservatives and antioxidants in topical emulsions. The in vivo safety application of some emulsions was also tested. T. capitata EO was mainly constituted by carvacrol (73%), whereas α‐terpineol (27%), p‐cymene (14%) and carvacrol (10%) dominated Th. caespititius EO, and 1,8‐cineole (37%) was dominant in M. communis EO. The minimum inhibitory concentration of T. capitata, Th. caespititius and M. communis EOs was 0.4 μg/mL against C. albicans and ranged between 0.4 and 30.7 μg/mL against A. brasiliensis. Gram‐positive bacteria were more susceptible to each EO than Gram‐negative bacteria. T. capitata EO showed significantly higher antioxidant activity than Th. caespititius and M. communis EOs. EOs incorporated in emulsions showed preservative activity against all microorganisms tested and T. capitata EO emulsions showed powerful reactive oxygen species (ROS) scavenging effects. A safety evaluation study was performed with 0.10% and 0.01% T. capitata EO emulsions according to the Human Repeat Insult Patch Test (HRIPT). All emulsions were considered safe for topical application. T. capitata, Th. caespititius and M. communis significantly improved the microbiological quality of the prepared emulsions and may constitute a powerful alternative to the current preservatives and antioxidants for use in topical formulations.

Star anise (Illicium verum Hook. f.) essential oil: Antioxidant properties and antibacterial activity against Acinetobacter baumannii

“…The analysis of the composition of volatiles was performed by gas chromatography (GC) for component quantification without response factors, and by gas chromatography–mass spectrometry (GC‐MS) for component identification, as previously described …”

Antimicrobial efficacy of Thymbra capitata (L.) Cav. essential oil loaded in self-assembled zein nanoparticles in combination with heat

“…Thanks to its recognized antimicrobial and antioxidant properties, it can be used as a preservative for foodstuffs and formulations (Delgado-Adámez et al, 2017;Falcó et al, 2018;Neves et al, 2017).…”

Development of a Portuguese smell test: A novel hospital compounding formulation to improve diagnosis of olfactory dysfunction

“…The sample was heated for 15 min at 40°C and compounds were desorbed from the fibber at 250°C. Data acquisition and control of the analytical conditions in the equipment were done with Shimadzu software, GC–MS solution, version 2.10 (Neves et al, 2017). The identification of the compounds was assigned by comparison of their retention indices, and GC–MS spectra from the libraries (NIST 21, 27, 107, 147, and Wiley 229).…”