Antiaging and smoothness-improving properties of farnesol-based facial masks on rat skin exposed to ultraviolet B

Enhanced skin neocollagenesis through the transdermal delivery of poly-L-lactic acid microparticles by using a needle-free supersonic atomizer

In this study, a spindle-type nozzle was designed to accelerate poly-L-lactic acid (PLLA) microparticles to supersonic velocities for the transdermal delivery of these microparticles to rats. This approach is needle- and pain-free and enhances skin collagen regeneration. The addition of PLLA microparticles at a concentration of 2 mg/mL did not hinder the growth of 3 T3 fibroblasts and Raw264.7 macrophages. The TNF-α assay revealed no obvious inflammation effect of PLLA microparticles at a concentration of 1 mg/mL. A time-lapse recording revealed that after being cocultured with PLLA microparticles for 24 h, Raw264.7 macrophages gradually approached and surrounded the PLLA microparticles. When 3 T3 fibroblasts were cocultured with Raw264.7 macrophages, which were stimulated using PLLA microparticles, collagen synthesis was increased by approximately 60 % compared with that in samples without PLLA microparticles. In vivo animal experiments indicated that after the transdermal delivery of 10 shots of PLLA microparticles through the supersonic atomizer, no obvious changes or damage to the back skin of Sprague-Dawley rats was observed. More importantly, numerous PLLA microparticles penetrated the rat epidermis into the dermal layer. We found macrophages and fibroblasts present close to the PLLA microparticles. Moreover, only mild or no inflammation reaction was observed. Masson staining revealed that after 6-week implantation, 6 % and 12 % of PLLA microparticles significantly stimulated collagen regeneration in 6-week-old and 32-week-old rats. In addition, picrosirius red staining revealed a significant increase in collagen regeneration, especially for type III collagen, following the 6-week implantation of PLLA microparticles. In summary, this study demonstrated an easy, pain-free, nondestructive approach for introducing PLLA microparticles into the dermal layer by using a supersonic atomizer to stimulate collagen regeneration in vivo.

Therapeutic Efficacy of Sesquiterpene Farnesol in Treatment of Cutibacterium acnes-Induced Dermal Disorders

Acne vulgaris is a highly prevalent skin disorder requiring treatment and management by dermatologists. Antibiotics such as clindamycin are commonly used to treat acne vulgaris. However, from both medical and public health perspectives, the development of alternative remedies has become essential due to the increase in antibiotic resistance. Topical therapy is useful as a single or combined treatment for mild and moderate acne and is often employed as maintenance therapy. Thus, the current study investigated the anti-inflammatory, antibacterial, and restorative effects of sesquiterpene farnesol on acne vulgaris induced by Cutibacterium acnes (C. acnes) in vitro and in a rat model. The minimum inhibitory concentration (MIC) of farnesol against C. acnes was 0.14 mM, and the IC50 of 24 h exposure to farnesol in HaCaT keratinocytes was approximately 1.4 mM. Moreover, 0.8 mM farnesol exhibited the strongest effects in terms of the alleviation of inflammatory responses and abscesses and necrotic tissue repair in C.acnes-induced acne lesions; 0.4 mM farnesol and clindamycin gel also exerted similar actions after a two-time treatment. By contrast, nearly doubling the tissue repair scores, 0.4 mM farnesol displayed great anti-inflammatory and the strongest reparative actions after a four-time treatment, followed by 0.8 mM farnesol and a commercial gel. Approximately 2-10-fold decreases in interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α, found by Western blot analysis, were predominantly consistent with the histopathological findings and tissue repair scores. The basal hydroxypropyl methylcellulose (HPMC) gel did not exert anti-inflammatory or reparative effects on rat acne lesions. Our results suggest that the topical application of a gel containing farnesol is a promising alternative remedy for acne vulgaris.

Farnesol-Loaded Liposomes Protect the Epidermis and Dermis from PM2.5-Induced Cutaneous Injury

Particulate matter with aerodynamic diameter ≤2.5 μm (PM2.5) increases oxidative stress through free radical generation and incomplete volatilization. In addition to affecting the respiratory system, PM2.5 causes aging- and inflammation-related damage to skin. Farnesol (Farn), a natural benzyl semiterpene, possesses anti-inflammatory, antioxidative, and antibacterial properties. However, because of its poor water solubility and cytotoxicity at high concentrations, the biomedical applications of Farn have been limited. This study examined the deleterious effects of PM2.5 on the epidermis and dermis. In addition, Farn-encapsulated liposomes (Lipo-Farn) and gelatin/HA/xanthan gel containing Lipo-Farn were prepared and applied in vivo to repair and alleviate PM2.5-induced damage and inflammation in skin. The prepared Lipo-Farn was 342 ± 90 nm in diameter with an encapsulation rate of 69%; the encapsulation significantly reduced the cytotoxicity of Farn. Lipo-Farn exhibited a slow-release rate of 35% after 192 h of incubation. The half-maximal inhibitory concentration of PM2.5 was approximately 850 μg/mL, and ≥400 μg/mL PM2.5 significantly increased IL-6 production in skin fibroblasts. Severe impairment in the epidermis and hair follicles and moderate impairment in the dermis were found in the groups treated with post-PM2.5 and continuous subcutaneous injection of PM2.5. Acute and chronic inflammation was observed in the skin in both experimental categories in vivo. Treatment with 4 mM Lipo-Farn largely repaired PM2.5-induced injury in the epidermis and dermis, restored injured hair follicles, and alleviated acute and chronic inflammation induced by PM2.5 in rat skin. In addition, treatment with 4 mM pure Farn and 2 mM Lipo-Farn exerted moderate reparative and anti-inflammatory effects on impaired skin. The findings of the current study indicate the therapeutic and protective effects of Lipo-Farn against various injuries caused by PM2.5 in the pilosebaceous units, epidermis, and dermis of skin.

Farnesol-Containing Macromolecular Systems for Antibiofilm Strategies

Farnesol is a natural sesquiterpenoid and an interesting quorum-sensing molecule. Its insolubility in water is the biggest obstacle to its application for bacterial biofilm treatments since it compromises the bioavailability. Recently, an increasing interest in farnesol encapsulation or loading in polymeric materials may be noted due to the prolonged action of the active macromolecular systems. In this short review, we present an overview of methods leading to improved interactions between farnesol and microbial biofilms.