Two Helichrysum italicum extracts, OPT-1 (rich in phenolic acids) and OPT-2 (rich in total phenols and flavonoids), were prepared using hydroxypropyl-β-cyclodextrin (HP-β-CD)-assisted extraction. The prepared extracts were rich in phenolic compounds, including flavonoids and phenolic acids. GC-MS analysis of the extracts identified neryl acetate, neo-intermedeol, β-selinene, γ-curcumene, italidione I, and nerol as the main volatile components of the extracts, as well as plant sterols, γ-sitosterol, campesterol, and stigmasterol. The antioxidant (DPPH radical scavenging, reducing power, and a carotene linoleic acid assay) and cosmeceutical (anti-hyaluronidase, anti-tyrosinase, anti-lipoxygenase, ovalbumin anti-coagulation, and a UV-absorption assay) activity of the extracts in most of the assays was better than the activity of the applied positive controls. Especially low were the IC₅₀ values of the extracts in the anti-hyaluronidase (14.31 ± 0.29 μL extract/mL and 19.82 ± 1.53 μL extract/mL for OPT-1 and OPT-2, respectively) and the anti-lipoxygenase (0.96 ± 0.11 μL extract/mL and 1.07 ± 0.01 μL extract/mL for OPT-1 and OPT-2, respectively) assays. The extracts were non-toxic to HaCaT cells in concentrations of up to 62.5 µL extract/mL assuring their status as excellent candidates for cosmeceutical product development appropriate for direct use in cosmetic products without solvent evaporation.

Helichrysum italicum is a plant traditionally used for skin-related disorders that is becoming an increasingly popular ingredient in cosmetic products. In this work, a “green” ultrasound-assisted extraction method for H. italicum phenolics was developed using skin-friendly cyclodextrins (CDs). Extraction conditions needed for the greatest yield of target compounds (total phenolics, phenolic acids, and flavonoids) were calculated. The composition of the extracts was determined using LC-MS and spectrophotometric methods. Among the tested CDs, 2-hydroxylpropyl-beta-CD (HP-β-CD) was the best suited for extraction of target phenolics and used to prepare two optimized extracts, OPT 1 (the extract with the highest phenolic acid content) and OPT 2 (the extract with the highest total phenol and flavonoid content). The extracts were prepared at 80 °C, using 0.089 g of plant material/g solvent (0.6 mmol of HP-β-CD), with or without addition of 1.95% (w/w) lactic acid. The main metabolite in both extracts was 3,5-O-dicaffeoylquinic acid. It was found that the addition of lactic acid greatly contributes to the extraction of arzanol, a well-known anti-inflammatory agent. IC₅₀ values of the anti-elastase (22.360 ± 0.125 μL extract/mL and 20.067 ± 0.975 for OPT-1 and OPT-2, respectively) and anti-collagenase (12.035 ± 1.029 μL extract/mL and 14.392 ± 0.705 μL extract/mL for OPT-1 and OPT-2, respectively) activities of the extracts surpassed those of the applied positive controls, namely ursolic and gallic acids. This activity deems the prepared extracts promising ingredients for natural cosmetics, appropriate for direct use in cosmetic products, removing the need for the evaporation of conventional solvents.

Laurus nobilis L., Lauraceae, bay laurel, has been traditionally used for its various therapeutic properties, and in recent years has been gaining interest for its potential applications in skincare products. However, the biological effects of bay laurel, particularly its hydrosols, a water fraction obtained during essential oil production, remain unexplored. The objective of this study was to identify the volatile compounds in L. nobilis hydrosols (LnHYs) from different coastal regions of Croatia (north, middle, and south Adriatic) and to evaluate their potential safety and efficacy for dermatological applications. Upon isolating LnHYs using microwave-assisted extraction, LnHY volatiles were identified and quantified using gas chromatography and mass spectrometry. Oxygenated monoterpenes were the dominant compounds in all LnHYs (61.72–97.00%), with 1,8-cineole being the most abundant component (52.25–81.89%). The physical and chemical parameters of LnHYs were investigated to assess their purity and quality. Biological activity (cytotoxicity and wound-healing effect) was tested on the human keratinocyte cell line (HaCaT), selected as the experimental model due to its relevance to skin biology. Additionally, contents of polyphenolic substances, antioxidative effects using the Oxygen Radical Absorbance Capacity (ORAC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) methods, and the antimicrobial activity of LnHYs toward five skin microorganisms were determined. All tested hydrosols showed similar biological activity, with only minor differences. Cytotoxicity studies indicated the safety of the dermatological application of LnHYs, and the results of the wound-healing assay showed their neutral to mildly positive effect. Considering the growing use of bay laurel preparations in pharmaceutical and cosmetic applications, extensive studies on their biological activity, quality, and safety are essential to either support or regulate their use in humans.

The composition of an essential oil (EO) depends on both the plant’s genetic constitution and environmental factors. In this study, the leaves of female bay laurel (Laurus nobilis L., family Lauraceae) plants were collected each month in the period from 15 January to 15 December 2022. Twelve obtained leaf samples were hydrodistilled in a Clevenger apparatus and analyzed using gas chromatography–mass spectrometry (GC-MS). A total of 44 compounds were detected in EO and 39 compounds were identified based on MS spectra and RIs (retention indices), accounting for 99.44–99.94% of the oil. The EO consisted almost entirely of monoterpenes (95.56–99.28%) and small quantities of phenylpropanoids, sesquiterpenes and other compounds. The major volatile compound was 1,8-cineole (49.79–64.94%), followed by α-terpinyl acetate (7.14–11.96%), sabinene (3.16–9.01%), linalool (1.77–8.03%), α-pinene (1.46–4.49%), β-pinene (1.55–3.69%) and α-terpineol (0.99–4.77%). The ANOVA indicated statistically significant changes in the composition of the EO over one year. The contents of eugenol, methyl eugenol and elemicin, which are responsible for the spicy aroma of the leaves, were highest during flowering (March) and at the time of fruit ripening (October, November). The harvest time of the leaves can be adjusted to obtain leaves rich in the desired compounds according to whether they are to be used as a spice, medicine or repellent.