Background: Olive pomace, a byproduct of olive oil production, represents approximately 85% of the processed material and poses environmental risks when improperly discarded. Its composition is rich in polyphenols with potential for cosmetic use, especially in skin barrier care. Objective: To develop a natural extract rich in antioxidants from olive pomace using sustainable solvents (water and 1,3-propanediol) for skin barrier support. Methods: The phenolic composition and in vitro biological activities of the extracts were analyzed. Results: The extracts demonstrated a reducing capacity (15 to 33 mg GAE/g) and flavonoid content (4 to 5 mg QE/g). In addition, their antioxidant capacity was proven through the inhibition of the DPPH radical (7% to 91%) and ABTS (7% to 95%) and the reduction in oxidation in the beta-carotene/linoleic acid system (6% to 35%), presenting results superior to those of tocopherol acetate. The hydroxytyrosol and oleuropein compounds, ranging from 28 to 54 and 51 to 85 µg/mL, respectively, were quantified via HPLC. The extract with the highest levels of hydroxytyrosol and oleuropein was analyzed via UHPLC-QqTOF-MS, and 33 compounds were identified. This extract showed antiglycation activity (24% to 40%). The incorporation of this extract into a cosmetic emulsion resulted in sufficient antioxidant capacity to replace tocopherol acetate. Conclusions: The use of effective extraction techniques and nontoxic solvents ensures the sustainability and safety of the extract for application as a natural cosmetic ingredient, aiming to promote the health and integrity of the skin barrier.

The chemotherapeutic all-trans retinoic acid (ATRA) used in the treatment of Acute Promyelocytic Leukemia has adverse effects on its oral administration, with which we incorporated a system of drugs, the nanocapsules, in order to have a possible improvement in solubility, photosensitivity, lower toxicity, generating pharmacological efficacy. The objective was to evaluate and compare the hemolytic and coagulation activity of the free drug (AL), nanoencapsulated (NA) and the white nanocapsules (NB) by analyzing the results of hemolysis, Prothrombin Time (PT) and Activated Partial Thromboplastin Time (APTT). We developed a prospective study of treatments at different concentrations of 0.25; 0.5; 1.0; 1.5; 2.0; 2.5 μg/mL. For the first test, all concentrations showed hemolytic activity, but when compared to NA with ATRA it is observed that these carriers induced lower hemolytic toxicity. In the PT test the nanoparticles at the two lowest concentrations remained in the physiological range (12 - 15 seconds). For the APTT test the three lowest concentrations remained within the control (25 - 35 seconds). Thus, we believe there is a promising benefit of using these nanoparticles developed and no doubt further studies will be performed to confirm the responses obtained here.

Solar ultraviolet (UV) radiation is a major contributor to skin damage, making the regular use of broad-spectrum sunscreens essential for effective photoprotection. However, the long-term efficacy of sunscreen formulations is limited by the photoinstability of some organic UV filters, particularly avobenzone. Licuri oil (Syagrus coronata) is a naturally derived Brazilian palm oil that represents a promising alternative to medium-chain triglycerides (MCTs) as an oily core for polymeric nanocapsules. Therefore, this study aimed to develop Eudragit^® RS 100-based cationic nanocapsules using licuri oil for avobenzone encapsulation and to incorporate them into hyaluronic acid (HA) or xanthan gum (XG) hydrogels. The nanocapsules ranged from 125 to 158 nm, with a polydispersity index (PDI) of less than 0.2, positive zeta potential (+11 to +13 mV), and encapsulation efficiency above 98%. After 48 h of UVA exposure, the nanocapsule formulations retained 51% and 52% of their initial avobenzone content for the licuri oil- and MCT-based systems, respectively, compared with only 10% for free avobenzone, indicating a marked improvement in photostability following nanoencapsulation. Additionally, licuri oil nanocapsules exhibited increased antioxidant activity compared to MCT-based nanocapsules in both DPPH and ABTS assays. The nanocapsule suspensions were classified as non- to slightly irritating in the Hen’s Egg Test–Chorioallantoic Membrane (HET-CAM) assay. After incorporation into the hydrogels, the resulting formulations exhibited pseudoplastic and thixotropic behavior, with HA-based hydrogels providing higher UV absorption than XG-based hydrogels. Furthermore, no transdermal permeation of avobenzone was observed from either the HA- or XG-based hydrogel formulations, and the HA hydrogel containing licuri oil nanocapsules showed higher stratum corneum retention. These findings demonstrate the potential of licuri oil as an effective alternative to MCTs as the oily core of polymeric nanocapsules for topical formulations containing encapsulated avobenzone.