SQUALANE

Squalene is a polyunsaturated hydrocarbon with a formula of C₃₀H₅₀. Squalene can be found in certain fish oils, especially shark liver oil, in high amounts and some vegetable oils in relatively smaller amounts. Human sebum also contains 13% squalene as one of its major constituents. Squalane is a saturated derivative of squalene and also found in these sources. Interest in squalene has been raised after its characterization in shark liver oil which is used as a traditional medicine for decades. Several studies exhibited results that prove certain bioactivities for squalene and squalane. Up to date, anticancer, antioxidant, drug carrier, detoxifier, skin hydrating, and emollient activities of these substances have been reported both in animal models and in vitro environments. According to promising results from recent studies, squalene and squalane are considered important substances in practical and clinical uses with a huge potential in nutraceutical and pharmaceutical industries.

Vitamin E, a potent antioxidant, is widely used in cosmetics to combat skin aging, but its lipophilic nature poses challenges for dermal delivery. Squalane, a biocompatible carrier, may enhance the stability and skin permeation of vitamin E in oil-in-water (O/W) nanoemulsions. O/W nanoemulsions containing vitamin E were formulated using high shear homogenization with varying coconut oil-to-squalane ratios (0:3, 1:2, 2:1, 3:0). Physicochemical properties (particle size, polydispersity index, ζ-potential, pH, conductivity) were characterized. In vitro release kinetics were assessed via dialysis, quantified by HPLC, and skin permeation was evaluated using Franz diffusion cells with porcine ear skin. Nanoemulsions exhibited hydrodynamic diameters of 107.67 ± 7.57 to 134.38 ± 3.15 nm, polydispersity indices of 0.21-0.24, and ζ-potentials of -37.4 ± 0.80 to -45.3 ± 0.90 mV, indicating high stability ( p < 0.05, ANOVA). The encapsulation efficiency for vitamin E was >99% across all formulations. These properties were maintained over 90 days of storage at 25 ± 1 °C in the dark, with no significant changes in diameter, PDI, or ζ-potential ( p > 0.05, ANOVA). Accelerated stability tests (centrifugation, thermal stress up to 80 °C) confirmed robustness, with minimal changes in key parameters. The V.E 0:3 formulation (pure squalane) showed the highest vitamin E release (0.341 h -1 , Korsmeyer-Peppas model, R 2 = 0.993) and skin permeation (164.71 ± 10.06 μg cm -2 over 24 h, p < 0.05), significantly outperforming coconut oil-rich formulations (V.E 3:0:11.72 ± 12.41 μg cm -2 ). Steady-state flux (Jss) for V.E 0:3 was 35.1 ± 1.4 μg cm -2 h -1 , compared to 0.1 ± 0.2 μg cm -2 h -1 for V.E 3:0 ( p < 0.05). Squalane-based O/W nanoemulsions significantly enhance the stability and dermal delivery of vitamin E, with the V.E 0:3 formulation demonstrating superior release kinetics and skin permeation. These findings support the potential of squalane-based nanoemulsions for effective topical delivery in cosmetic applications, warranting further in vivo studies to confirm efficacy and safety.

Squalene (SQE) is a key triterpene used in pharmaceuticals, nutraceuticals and cosmetics. Although olive pomace (OP) is a sustainable source of SQE, conventional hexane extraction raises environmental and health concerns. This study investigates the potential of 2-methyltetrahydrofuran (2-MeTHF) as a greener alternative for SQE extraction and catalytic hydrogenation to squalane (SQA); a high-value compound in industrial applications. 2-MeTHF provided 83% SQE recovery from OP, which was further concentrated in deodorizer distillates during refining. SQE hydrogenation in 2-MeTHF significantly improved reaction efficiency at lower temperatures (60 °C, 3 bar H 2 , 0.5 mol % Pd/C), enabling full conversion within 1 h. This represents a major advantage over conventional industrial hydrogenation, which requires harsher conditions (200 °C, 4-30 bar H 2 ) and longer reaction times (6-7 h). In order to assess industrial feasibility, SQE from OP deodorizer distillates (6.8 wt %) was concentrated via saponification and molecular distillation (∼34 wt %), followed by flash chromatography (59 wt % purity, 85% recovery). However, residual impurities caused catalyst poisoning, lowering the SQA yield to 19.8%. This study highlights 2-MeTHF's potential for industrial-scale SQE valorization via integrated extraction and hydrogenation. Future efforts should focus on improving SQE purification from OP-DDs and enhancing catalyst recyclability.

Squalane, a highly stable derivative of squalene, has received attention for its potential application in dermatology and cosmetics due to its biocompatibility, moisturizing properties, and antioxidant activity. This study investigates the effects of squalane on UVA-induced oxidative stress, inflammation, deregulation of collagen metabolism, and some growth signaling pathways in human dermal fibroblasts (HDFs). It has been found that squalane at concentrations of 0.005-0.015% counteracted the UVA-induced inhibition of oxidative stress, collagen biosynthesis, prolidase activity, expression of the β1-integrin receptor, insulin-like growth factor-I receptor (IGFR), transforming growth factor-β (TGF-β), phosphorylated kinases ERK1/2, and increase in the expression of p38 kinase in HDFs. Moreover, squalane at the studied concentrations counteracted UVA-induced increase in the expression of NF-κB and COX-2 in HDFs, suggesting its anti-inflammatory activity. Interestingly, squalane augmented the UVA-induced expression of nuclear factor erythroid 2-related factor 2 (Nrf2). The functional significance of squalane activities was found in a model of wound healing in HDFs. Squalane at the studied concentrations stimulated fibroblast migration, facilitating the repair process following exposure of the cells to UVA radiation. These results demonstrate the ability of squalane to counteract UVA-induced cell damage and suggest its potential to support skin regeneration, highlighting its application in anti-aging, post-sun repair, and regenerative care formulations.

The Expert Panel for Cosmetic Ingredient Safety reviewed newly available studies since their original assessment in 1982, along with updated information regarding product types and concentrations of use, and confirmed that Squalane and Squalene are safe as cosmetic ingredients in the practices of use and concentration as described in this report.

Polyphenols have gained attractiveness as ingredients in cosmetic formulations as result of their ability to delay the aging process. However, different factors limit their use, including low solubility and poor skin permeability. In this sense, this study describes the potential of squalane to increase the polyphenols ex vivo skin penetration, incorporated into a water-in-oil emulsion. Polyphenols skin permeation followed the Fick's first law and, p-coumaric acid, vitexin, schaftoside and ferulic acid had the higher permeability coefficients (Kp = 6.0-8.0 × 10 -3 cm -2 h -1 ). Addition of squalane to phenolic compounds decreased the permeability coefficients (Kp = 4.1-5.9 × 10 -3 cm -2 h -1 ), indicating that squalane increased the retention of polyphenols in the skin. Gentisic acid, ferulic acid, and p-coumaric acid were the only compounds permeating from water-in-oil emulsion, in the first 8 h of study and, according Krosmeyer-Peppas model, its n value was > 1 indicating a high transport resistance from the formulation and throughout the skin. Results suggest squalane as an efficient vehicle to increase the dermal availability increasing phenolic compounds physiological functions, by enhancing the skin retention time where they should exert antiaging effect.

Ultraviolet A (UVA) radiation has been identified as a significant factor contributing to skin photoaging and skin diseases, operating through the excessive generation of reactive oxygen species (ROS) and the subsequent induction of DNA damage. Plant-derived antioxidants have demonstrated efficacy in mitigating UVA-induced damage; nevertheless, their instability limits their therapeutic potential. This study investigates the mechanisms of antioxidant and cytoprotective effects of squalane (Sq), a stable, plant-derived triterpene, in human dermal fibroblasts (HDFs) exposed to UVA radiation. Sq was administered at concentrations ranging from 0.005% to 0.015% prior to UVA exposure (10 J/cm 2 ). It has been found that Sq counteracted UVA-induced ROS formation, decreased the level of reduced thiol groups, activated apoptosis, and inhibited DNA biosynthesis. Immunofluorescence analysis revealed that Sq suppressed the UVA-induced expression of p53, caspase-3, caspase-9, and PARP, while restoring the activity of the pro-survival p-Akt/mTOR pathway. The findings indicate that Sq exerts protective effects on UVA-induced fibroblast damage through a combination of antioxidant and anti-apoptotic mechanisms.

This critical review describes the squalene-ozone (SqOz) reaction, or squalene ozonolysis. Ambient ozone penetrates indoors and drives indoor air chemistry. Squalene, a component of human skin oil, contains six carbon-carbon double bonds and is very reactive with ozone. Bioeffluents from people contribute to indoor air chemistry and affect the indoor air quality, resulting in exposures because people spend the majority of their time indoors. The SqOz reaction proceeds through various formation pathways and produces compounds that include aldehydes, ketones, carboxylic acids, and dicarbonyl species, which have a range of volatilities. In this critical review of SqOz chemistry, information on the mechanism of reaction, reaction probability, rate constants, and reaction kinetics are compiled. Characterizations of SqOz reaction products have been done in laboratory experiments and real-world settings. The effect of multiple environmental parameters (ozone concentration, air exchange rate (AER), temperature, and relative humidity (RH)) in indoor settings are summarized. This critical review concludes by identifying the paucity of available exposure, health, and toxicological data for known reaction products. Key knowledge gaps about SqOz reactions leading to indoor exposures and adverse health outcomes are provided as well as an outlook on where the field is headed.

The skin is the largest organ in the integumentary system, protecting against various external threats, including ultraviolet exposure, heat, infections, dehydration and mechanical injuries. Skin disorders can arise from various causes, including allergic reactions or breaches in the skin barrier, which allow microorganisms or chemicals to penetrate the sweat ducts. These conditions encompass a wide range of issues, including acne, xerosis (dry skin), fungal infections, atopic dermatitis (eczema) and psoriasis. Collectively, these ailments affect a significant portion of the global population, impacting approximately one-third of people worldwide. Additionally, oxidative stress induced by ageing and prolonged exposure to ultraviolet rays can manifest in visible alterations such as pigmentation, wrinkling and dehydration. Recent investigations have underscored the potential of natural antioxidant compounds in safeguarding skin health and combating ageing-related changes. Tocotrienols, a subgroup of vitamin E, have garnered significant attention owing to their antioxidant and anti-inflammatory properties. Significant amounts of tocotrienols can be found in rice bran, olive, oats and hazelnuts. Similarly, squalene, predominantly sourced from fish liver oils such as those from sharks, has been used as an emollient in cosmetic formulations. This article offers a comprehensive review of existing literature elucidating the dermatological benefits associated with tocotrienols and squalene, emphasising their roles as antioxidants, anti-inflammatories, skin barrier protection and facilitators of wound healing. Moreover, it sheds light on contemporary research findings suggesting these compounds' therapeutic promise in managing and ameliorating various skin conditions.

Squalene is a triterpene that is an intermediate in the cholesterol biosynthesis pathway. It was so named because of its occurrence in shark liver oil, which contains large quantities and is considered its richest source. However, it is widely distributed in nature, with reasonable amounts found in olive oil, palm oil, wheat-germ oil, amaranth oil, and rice bran oil. Squalene, the main component of skin surface polyunsaturated lipids, shows some advantages for the skin as an emollient and antioxidant, and for hydration and its antitumor activities. It is also used as a material in topically applied vehicles such as lipid emulsions and nanostructured lipid carriers (NLCs). Substances related to squalene, including beta-carotene, coenzyme Q10 (ubiquinone) and vitamins A, E, and K, are also included in this review article to introduce their benefits to skin physiology. We summarize investigations performed in previous reports from both in vitro and in vivo models.

Since skin moisturization may be achieved by both actives and chosen carrier, plant stem cells, squalene and natural alkyl polyglucoside emulsifier may be potential components of contemporary cosmetic products. The aim of the study was in vivo evaluation of the skin irritation potential and the efficacy of Alpine Rose stem cells incorporated into li-posomes and olive oil squalene as ingredients of moisturizing creams, with respect to the novel emulsifier used for creams’ stabilization. With the employment of noninvasive skin biophysical measurements, skin hydration (EC), transepi-dermal water loss (TEWL), erythema index (EI) and viscoelas-ticity were measured on 76 healthy volunteers. In the first phase, skin irritation after a 24-hour occlusion and the long-term efficacy of creams (a 21-day study) on healthy skin were evaluated. Phase II of the study focused on the cream efficacy assessment after a 6-day treatment of sodium lauryl sulfate-irritated skin. After a 24-hour occlusion, there were no significant changes in the EI for any tested sample. In the second phase of the study, the EI was not significantly altered for the cream containing squalene, while the application of all active samples resulted in a significant reduction of TEWL. In both phases of the study an EC increase was recorded, espe-cially for the squalene-containing cream. Due to the lack of skin irritation and skin barrier impairment along with the marked hydration effect, it could be said that the in-vestigated actives incorporated into alkyl polyglucoside emulsi-fier-stabilized creams may be safely applied as ingredients for "tailor-made" cosmetic moisturizers intended for normal and dry skin care, whereas olive oil squalene could be used for the treatment of irritated or sensitive skin as well. [Projekat Ministarstva nauke Republike Srbije, br. TR34031]

This study evaluated Apis mellifera brood fat extracts as a sustainable alternative to beeswax for anti-inflammatory topical delivery, including their formulation into nanostructured lipid carriers (NLCs). Brood fat was extracted using acetone, ethyl acetate (EA), and hexane, and the resulting extracts were characterized for fatty acid composition and physicochemical properties. Safety was assessed using the hen's egg chorioallantoic membrane test and cytotoxicity testing in RAW 264.7 macrophages. Anti-inflammatory activity was assessed by inhibition of lipopolysaccharide-induced interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) production. The most suitable extract was formulated into NLCs using sugar squalane as liquid lipid, and the effects of lipid ratio and preparation method were investigated. The results showed that the ethyl acetate extract had the highest yield. Compared with beeswax, all fat extracts exhibited a favorable oleic acid-rich fatty acid profile with comparable crystallinity and thermal behavior, while showing significantly enhanced anti-inflammatory activity ( p < 0.05). All extracts and their NLCs were non-irritating and non-cytotoxic. Ethyl acetate extract-based NLCs exhibited favorable particle sizes (72.1 ± 0.3 nm) and narrow polydispersity (0.14 ± 0.00), with high-pressure homogenization producing smaller particles compared to probe sonication without affecting IL-6 or TNF-α inhibition. Therefore, A. mellifera brood fat extract is a sustainable anti-inflammatory lipid source with strong potential as an alternative to beeswax in topical nano-formulations.

Glucans, structural polysaccharides in the yeast cell wall, are known for their biological and immunomodulatory capacities, helping in prevention and management of infections. Herpes simplex virus type 1 (HSVI) is a prevalent infection that causes great comorbidity and is challenging to treat due to the adverse effects of standard antiviral drugs like acyclovir. This study assessed the potential of yeast glucans extracted from two different origins - a steviol-glycoside producing strain and a wild-type strain- to circumvent HSVI infection, either in vitro and ex vivo. Treatment with glucans in keratinocytes and macrophages in vitro reduced cell infection similarly to acyclovir. However, unlike acyclovir, glucans demonstrated an immunostimulatory effect, increasing the production of IL-1β, TNF-α and IL-6. Additionally, both glucans were formulated with squalane for skin application. This formulation improved glucans penetration in the skin, restored skin structure and reduced the cytopathic effect of HSVI infection. In summary, this study highlights yeast glucans as a natural therapeutic alternative for HSVI treatment, offering an option with an excellent safety profile. Moreover, using glucans from industrial side-streams promotes a sustainable approach, contributing to the circular economy.

Atopic dermatitis (AD) is a chronic, inflammatory skin condition characterized by eczema lesions and dry, itchy skin. Recent guidelines for the management of AD emphasize the importance of using moisturizers in the management of AD. This study is a double-blind clinical trial to determine the effectiveness of moisturizers containing anti-inflammatory ingredients compared with moisturizers without anti-inflammatory ingredients for skin hydration in mild to moderate adult AD patients for 14 days at the Dermatology and Venereology Outpatient Clinic at Dr. Soetomo General Academic Hospital. There was a significant difference ( p < 0.05) at the baseline and day 14 skin hydration values in the experiment group with anti-inflammatory ingredients (35.97 ± 6.04-66.06 ± 15.84) and the control group without anti-inflammatory ingredients (40.74 ± 10.94-56.12 ± 8.34). After comparison, there was a significant difference ( p < 0.05) in the skin hydration value between the experiment group and the control group on the 14th day. There was also a significant difference in the improvement of skin hydration outcomes between both groups ( p < 0.05). The severity of the disease using Scoring Atopic Dermatitis (SCORAD) showed a significant difference ( p < 0.05) between the experiment group and the control group after 2 weeks of intervention. The addition of anti-inflammatory ingredients in the moisturizer, namely, shea butter, bacterial lysate, allantoin, bisabolol, Phragmites kharka extract, Poria cocos , and Mirabilis jalapa in a moisturizer containing occlusive (dimethicone), humectants (glycerin, saccharide, butylene glycol, and hyaluronic acid), and emollient (shea butter and squalane) was shown to be significantly better in improving skin hydration in patients with mild to moderate AD.

Raw materials suitable for a sustainable society have attracted interest in the cosmetics industry. We focused on rice bran as a sustainable material and evaluated the gelation behavior of paraffin extracted from rice bran (rice paraffin) against liquid paraffin, squalane, jojoba oil, and silicone oil. In addition, the frictional properties of the prepared organogel on an artificial skin surface were evaluated using a sinusoidal motion friction evaluation system. Rice paraffin solidified all oils even at the lowest wax concentration of 5 wt%. The hardness and kinetic friction coefficient μ k increased with an increase in the wax composition. The hardness and μ k of organogels solidified with rice paraffin were smaller than those of gels solidified with petroleum-derived paraffin. These differences are caused by the smaller carbon amount of rice paraffin. The friction parameters depended on the type of oil: the μ k of RLG composed of rice and liquid paraffin was greater than that of the other three oils (R, L, and G denote rice paraffin, liquid paraffin, and gel, respectively). These findings promote the development of lipsticks and cleansing gels consisting of sustainable development goal-responsive raw materials.

In this study, we determined partition (K sc/m ) and diffusion (D sc ) coefficients of five different polycyclic aromatic hydrocarbons (PAH) migrating from squalane into and through the stratum corneum (s.c.) layer of the skin. Carcinogenic PAH have previously been detected in numerous polymer-based consumer products, especially those dyed with carbon black. Upon dermal contact with these products, PAH may penetrate into and through the viable layers of the skin by passing the s.c. and thus may become bioavailable. Squalane, a frequent ingredient in cosmetics, has also been used as a polymer surrogate matrix in previous studies. K sc/m and D sc are relevant parameters for risk assessment because they allow estimating the potential of a substance to become bioavailable upon dermal exposure. We developed an analytical method involving incubation of pigskin with naphthalene, anthracene, pyrene, benzo[a]pyrene and dibenzo[a,h]pyrene in Franz diffusion cell assays under quasi-infinite dose conditions. PAH were subsequently quantified within individual s.c. layers by gas chromatography coupled to tandem mass spectrometry. The resulting PAH depth profiles in the s.c. were fitted to a solution of Fick's second law of diffusion, yielding K sc/m and D sc . The decadic logarithm logK sc/m ranged from -0.43 to +0.69 and showed a trend to higher values for PAH with higher molecular masses. D sc , on the other hand, was similar for the four higher molecular mass PAH but about 4.6-fold lower than for naphthalene. Moreover, our data suggests that the s.c./viable epidermis boundary layer represents the most relevant barrier for the skin penetration of higher molecular mass PAH. Finally, we empirically derived a mathematical description of the concentration depth profiles that better fits our data. We correlated the resulting parameters to substance specific constants such as the logarithmic octanol-water partition coefficient logP, K sc/m and the removal rate at the s.c./viable epidermis boundary layer.

In the present study, the mesomorphic phase and internal structure of sucrose fatty acid ester (S1670) with cetyl alcohol mixed in different proportions was studied and assessed, within common emulsion system of cosmetics and pharmaceuticals. To characterize the system's colloidal structure the following physicochemical techniques were used: polarization microscopy, small- and wide-angle X-ray scattering (SAXS and WAXS), differential scanning calorimetry (DSC), continual and oscillatory rheology and cryogenic scanning electron microscopy (cryo-SEM). Ultimately, it was well established that there was a predominant and stable α-crystalline gel structure, formed with sucrose fatty acid ester (S1670) and cetyl alcohol, in the pseudo quarter-phase system (including squalane and aqua). In addition, the optimum ratio for α-crystalline gel formation was found to be around 61.50:38.50 (S1670 to Cetyl alcohol). Moreover, as it deviates from the critical point within a controllable range, although identical α-gel (α-form hydrated crystal) continues to exist, yet the strength and proportion in whole sample decrease with the expansion of deviation. The decent stability (which was derived from the dismatch between the lipophilic chains and the intensive hydration of -OH from S1670) and the agreeable rheological properties of the above α-gel suggest wide application in cosmetics and pharmacy in the future.