Investigations of Olive Oil Industry By-Products Extracts with Potential Skin Benefits in Topical Formulations

Abstract

The by-products of olive oil industry are a major ecological issue due to their phenolic content, highly toxic organic load, and low pH. However, they can be recovered and reused, since their components have antioxidant, anti-inflammatory, and photoprotector properties. In this work, oil-in-water creams containing three different olive oil industry by-products extracts were produced without the use of organic solvents. First, the extracts were thoroughly characterized in vitro for cytotoxicity, inhibition of skin enzymes, and antioxidant and photoprotection capacities. Safety studies were then performed, including ocular and skin irritation tests, ecotoxicity evaluation, and in vivo Human Repeat Insult Patch Test. The results obtained in this initial characterization supported the incorporation of the extracts in the cream formulations. After preparation, the creams were characterized for their organoleptic, physicochemical, droplet size and rheological properties, and microbial contamination. The results showed that all formulations were semi-solid creams, with stable pH, compatible with the skin, without microbial contamination, and with the expected droplet size range. The rheological analysis showed shear-thinning behavior with yield stress, with the viscosity decreasing with increasing shear rate. The oscillatory results suggest that the creams have a strong network structure, being easily rubbed into the skin. Finally, compatibility, acceptability and antioxidant efficacy were evaluated in vivo, in human volunteers. No adverse reactions were observed after application of the formulations on skin and the cream with the highest concentrations of phenolic compounds showed the highest antioxidant efficiency. In conclusion, the results suggest that olive oil industry by-products extracts have valuable properties that favor their re-use in the cosmetic industry. The example presented here showed their successful incorporation into creams and their impact in these formulations’ appearance, pH, and rheological performance, as well as their in vivo compatibility with skin and antioxidant efficiency.

Development of Olive Oil and α-Tocopherol Containing Emulsions Stabilized by FucoPol: Rheological and Textural Analyses

“…FucoPol was used to prepare emulsions with four different oils commonly used in cosmetic products' formulations, namely, castor oil [35][36][37][38], paraffin oil [39][40][41], almond oil [42,43] and olive oil [44][45][46][47][48]. Castor oil is a natural oil that acts as an antimicrobial, anti-inflammatory, antioxidant, wound healing, vasoconstrictive [49] and UV-protective agent [50].…”

Development, Characterization, and Clinical Investigation of a New Topical Emulsion System Containing a Castanea sativa Spiny Burs Active Extract

“…As matter of fact, formulation A (gray line) showed a reduction in dynamic viscosity (η) value as the shear rate (Ύ) increased (viscosity values range from 315.79 mPa•s to 151.030 mPa•s) (Figure 4a). This behavior is typical of non-Newtonian fluids, such as creams, gels, lotions, and emulsions [5,48]. The profile indicates the semi-flexible molecular structure of A, with a low flow resistance; aggregates are rapidly broken into their elements, the droplets lining up at a high shear rate supports the formulation's ability to spread on the skin [21].…”

“…Among exogenous antioxidants, natural derivatives, such as carotenoids and polyphenols are effective, widely present in plants, and potentially induce fewer side effects than synthetic ones [3,4]. There is great interest among researchers and industry in the recovery of antioxidant molecules from waste and by-products of the agri-food chains [5].…”

“…Oil in water (O/W) emulsions (creams) are widely used for pharmaceutical and cosmetic applications [4]. Due to their biphasic nature, emulsions are able to incorporate and stabilize vegetable ingredients composed of a mixture of molecules with different polarities and solubility [5]. Moreover, creams are generally characterized by ease of application, pleasant skin feeling, and desiderate aesthetic by users [4].…”

Biological Effects of Maslinic Acid on Human Epithelial Cells Used in Tissue Engineering

“…Several natural molecules were recently proposed to exert a positive biological effect on human cell physiology. Although their role on human keratinocyte cultures has not been determined to date, it has been suggested that several components of the Olea europaea olive oil may be potentially beneficious for the skin due to their topical antioxidant effect ( Nunes et al, 2021 ). In fact, it has been demonstrated that olive oil extracts favor skin wound healing through NOS-2 and NFE2L2factors ( Schanuel et al, 2019 , 2).…”