Purpose: Plant-derived essential oils are widely used as pharmacological drugs and fragrances. In this study, 16 natural essential oils and 14 single fragrance ingredients were investigated for their potential as antimicrobial agents.Methods: Paper disk diffusion assays were performed to assess the antimicrobial activities of the essential oils and single fragrance ingredients against Staphylococcus aureus , Staphylococcus epidermidis , Escherichia coli , Pseudomonas aeruginosa , Bacillus subtilis , Candida albicans , Aspergillus niger , and Malassezia furfur.Results: Cinnamon bark and neroli essential oils, which contain linalool, exhibited significant antimicrobial activities against S. aureus and C. albicans. The single fragrance ingredients citral, D -limonene, and hydroxycitronellal exhibited antibacterial effects against S. aureus and C. albicans. Cinnamon bark oil also showed good antifungal effects against A. niger and M. furfur . Clove essential oil, which contains eugenol as the main ingredient, showed antifungal effects against M. furfur, and aurantiol also exhibited antibacterial effects against M. furfur . S. aureus , E. coli, and P. aeruginosa , which are regulated in distributed cosmetics, were susceptible to the effects of cinnamon bark oil and phenylethyl alcohol. Bergamot and lavender oils exerted good antibacterial effects against S. aureus , but not S. epidermidis . In addition, rosemary oil, rose absolute, and phenylethyl alcohol, which showed good antifungal effects against C. albicans , had no or little antibacterial effect on S. epidermidis .Conclusion: Our results suggest that essential oils can be used as alternative preservatives and antimicrobial agents for atopic dermatitis and dandruff.

Purpose: Sedum kamtschaticum Fisch. (SK), a plant native to Korea, was studied as a natural preservative and antiaging cosmetic ingredient.Methods: The stems and roots of SK were separated; extracted through reflux with 70% ethanol; and fractionated with n-hexane, chloroform, ethyl acetate, n-butyl alcohol, and water. The ethyl acetate fractions were evaluated for their antiaging effects, including antiglycation activity and elastase and collagenase inhibitory activity. Their antimicrobial activity on seven microorganisms was evaluated using the paper disk diffusion method and challenge test. In addition, the stability of lotion formulations and skin penetration were assessed using the Franz diffusion cell method.Results: The ethyl acetate fractions of SK with the best antioxidant effects exhibited better antiglycation and collagenase-inhibitory activity than the positive control as well as excellent antibacterial effects against Escherichia coli and Staphylococcus aureus. Emulsion formulations containing 0.05% and 0.1% SK stem extract exhibited synergistic preservative effects. The SK stem extract displayed the ability to penetrate into an artificial membrane and human cadaver skin.Conclusion: SK extracts can be used as antiaging and antimicrobial cosmetic materials.

Eruca sativa is a commonly used edible plant in Italian cuisine. E. sativa 70% ethanol extract (ES) was fractionated with five organic solvents, including n-hexane (EHex), chloroform (ECHCl₃), ethyl acetate (EEA), n-butyl alcohol (EBuOH), and water (EDW). Ethyl acetate fraction (EEA) had the highest antioxidant activity, which was correlated with the total polyphenol and flavonoid content. ES and EEA acted as PPAR-α ligands by PPAR-α competitive binding assay. EEA significantly increased cornified envelope formation as a keratinocyte terminal differentiation marker in HaCaT cells. Further, it significantly reduced nitric oxide and pro-inflammatory cytokines (IL-6 and TNF-α) in lipopolysaccharide-stimulated RAW 264.7 cells. The main flavonol forms detected in high amounts from EEA are mono-and di-glycoside of each aglycone. The main flavonol form of EEA is the mono-glycoside of each aglycone detected, and the most abundant flavonol mono-glycoside is kaempferol 3-glucoside 7.4%, followed by quercetin-3-glucoside 2.3% and isorhamnetin 3-glucoside 1.4%. Flavonol mono-glycosides were shown to be a potent PPAR-α ligand using molecular docking simulation and showed the inhibition of nitric oxide. These results suggest that the flavonol composition of E. sativa is suitable for use in improving skin barrier function and inflammation in skin disorders, such as atopic dermatitis.

Kim B. Nat Prod Sci. 2019 Dec;25(4):341-347. https://doi.org/10.20307/nps.2019.25.4.341

In this study, we evaluated the skin barrier improvement effect of a natural liquid mineral extract of mica clay, commonly used in cosmetics. The mica particles have an average size of approximately 4.77 μm, with a range around 10 μm. The specific surface area is about 8.8 m²/g, the average pore volume is 0.02 cm³/g, and the pore size is 10.82 nm. The extraction process involved mixing the mineral materials with distilled water for 2 days. The final extraction solution contained approximately 6 mg/L of potassium, as determined using inductively coupled plasma optical emission spectrometry (ICP-OES). A cosmetic emulsion containing the natural illite liquid mineral extract was assessed for stability in pH, viscosity, color, and odor under various conditions, including 4 °C, 25 °C, 45 °C, temperature cycling, and daylight, over 3 months. A placebo-controlled clinical trial was conducted to evaluate the skin barrier improvement and soothing effects on skin damaged by sodium lauryl sulfate (SLS) exposure or tape stripping. The test product demonstrated a statistically significant improvement in transepidermal water loss (TEWL) and skin redness compared to the control product. Therefore, the natural illite liquid mineral extract appears to enhance skin barrier function and soothe damaged skin, suggesting its potential therapeutic benefits.

Purpose: This study aimed to contribute to the development of various cosmetic formulations by adding alkanediols of ethyl hexanediol, methylpropanediol, 2-butyl-2-ethyl-1,3-propanediol, and ethylhexylglycerin (mainly 1,2-octanediol and 1,2-hexanediol) to emulsion formulations to determine their emulsion phase stability as well as their preservation against microbial contamination.Methods: The alkanediols were added to the emulsions to assess their preservation effects and phase stability under various storage temperatures for 3 months. In addition, their fibroblast cytotoxicity and anti-bacterial activity against microorganisms were compared.Results: A greater preservation effect was observed with longer linear alkanediol alkyl carbon chain lengths. However, higher formulation content revealed instability in phase stability. Furthermore, evaluation of fibroblast cytotoxicity showed that the relationship between cell membrane disruption and antimicrobial activity was affected.Conclusion: Utilizing the correlation between cytotoxicity and antimicrobial activity because of the carbon number and diol chemical structure, these results are expected to contribute to the development of improved preservative boosters that provide synergistic effects in terms of antimicrobial activity against microbial contamination, human safety, and the phase stability of formulations in the future.