Investigating phenolic acids’ potential in anti-wrinkle treatments presents a promising direction in skincare research. Phenolic acids' antioxidant, anti-inflammatory, MMP-inhibitory capabilities, coupled with their ability to penetrate the skin and offer photoprotective effects, make them standout candidates for the development of cutting-edge anti-aging skincare solutions (Zduńska et al., 2018).
Chromatographic analysis has revealed that propolis extract is a rich source of a broad spectrum of phenolic compounds, including notable acids such as caffeic, ferulic, p-coumaric acid, and CAPE. Significantly, the extract boasted 4,715.49 µg/g of ferulic acid, surpassing the 3,000 µg/g found in whole bran (Matilla et al., 2005), and contained 1,627.50 µg/g of caffeic acid, which is notably higher than the 175–875 µg/g found in coffee (Higdon & Frei, 2006; Clifford 1997). This broad spectrum and high content of phenolic compounds highlight propolis extract's substantial potential for varied activities in skin care.
In vitro studies on phenolic acid polymer extract (PAPE) demonstrated its regulatory effects on several inflammation and tissue remodeling biomarkers. For instance, in the HDF3CGF system, reductions in monocyte chemoattractant protein 1 (MCP-1), vascular cell adhesion molecule 1 (VCAM-1), intracellular cell adhesion molecule 1 (ICAM-1), and matrix metalloproteinase 1 (MMP-1) suggest a significant anti-inflammatory impact and a possible improvement in skin structure and function, as evidenced by the increase in collagen III levels and sulforhodamine B (SRB) activity, which indicates enhanced matrix synthesis or stabilization and potential benefits for cellular growth and viability. The decreased activity of tissue inhibitors of metalloproteinase (TIMP) 1 and 2 further supports the idea of PAPE influencing tissue repair processes.
Similarly, findings from the KF3CT system showed that PAPE could decrease inflammatory markers like MCP-1, ICAM-1, and interleukin 8 (IL-8), along with MMP-9, indicating a pronounced anti-inflammatory and anti-degradative effect on the extracellular matrix. The reduction in PAI-I activity points to a modulation of proteolytic activity, aiding in maintaining extracellular matrix integrity. An increase in SRB activity suggests a role in promoting keratinocyte proliferation, essential for skin regeneration. These results align with studies confirming the anti-inflammatory properties of various propolis extracts and phenolic acids (Šuran et al., 2021).
The in vitro findings correspond with the clinical observations, where PAPE achieved a statistically significant dose-dependent reduction in wrinkles in the crow’s feet area, demonstrating dose-dependent effects of 25% and 34%.
The effectiveness of PAPE can be compared to other known anti-wrinkle compounds, such as topical retinoids and bakuchiol. Tretinoin is the topical retinoid with the strongest clinical evidence and a gold standard of antiaging activity (Milosheska and Roškar, 2022). After 8 weeks of a 0.02% tretinoin regimen, there was an average of 11% reduction in wrinkle area (Fu et al., 2010). In a study with double conjugated retinoids, wrinkles were significantly reduced by 14.3% at 4 weeks, 23.8% at 8 weeks, and 33.3% at 12 weeks (Mazur et al., 2017). A comparative study of the effects of retinol and retinoic acid reported a reduction of 27.93% in wrinkles in the eye area after 4 weeks of 0.1% retinol treatment and 38.74% after 12 weeks of treatment (Kong et al., 2015). In a study conducted to determine the effectiveness and effect rate of retinol concentrations ranging from 1500 IU to 6600 IU, it was found that after 24 weeks of treatment with different concentrations, there was a 30% improvement on average in the area of crow's feet among those using the 6600 IU dosage and a 21% improvement among those using the 1500 IU dosage of retinol (Jang et al., 2022). Retinoids are known to reduce signs of aging effectively but can cause skin irritation (Szymański et al., 2020), ocular discomfort, and dry eyes when used around the eyes (Ng et al., 2016). For this reason, researchers are extensively studying safer alternatives. Bakuchiol is a natural compound that has been shown to have anti-aging effects comparable to retinol. In fact, a study reported a statistically significant decrease of 11% in wrinkles after 12 weeks of bakuchiol application (Chaudhuri & Bojanowski, 2014). This compound functions as an anti-aging agent through gene expression regulation similar to retinol (Chaudhuri & Bojanowski, 2014).
Our results show that PAPE is comparable in effectiveness to topical retinoids and bakuchiol: wrinkles were reduced by 34% after using face cream with 3% PAPE for only 4 weeks and 25% when using 1.5% PAPE.
The exploration into natural bioactive compounds for combating the signs of skin aging, particularly through the lens of chronic inflammation, marks a pivotal advancement in dermatological research and cosmetic innovation. PAPE is a complex mixture of reproducible phenolic compound content (Radic et al., 2020), but recent proteomic analysis has demonstrated it contains proteins as well, adding another layer to its efficacy (Šuran et al., 2023). This discovery suggests that protein or peptide activity could further contribute to its anti-aging effects, opening new avenues for further research.
Most importantly, shows a favorable safety profile with no reported negative side effects, making it suitable for both sensitive and non-sensitive skin types as a tolerable and gentle anti-aging solution. This approach not only illuminates a path for visibly reducing skin roughness and wrinkles but also aligns with a deeper understanding of skin aging as a process intricately tied to chronic inflammatory mechanisms and meets the growing consumer demand for effective and gentle products.