Plant-mediated green synthesis of metal-based nanoparticles for dermopharmaceutical and cosmetic applications.

The skin is the primordial barrier that protects the human body against environmental factors. Due to the arise of dermatological pathologies, the development of efficient delivery systems for topical applications has received increased interest. The highest challenge consists of increasing the penetration of the active ingredients through the skin barrier, alongside to the need of obtaining enough skin retention to achieve therapeutic concentrations. Metals, specially noble metals, have been used for years to treat and prevent health issues, among them dermatological disorders. Nanoparticles have been extensively used for topical applications given their advantages, namely by enhancing solubility of apolar drugs, the possibility of controlled release, the higher stability and the capability to target specific areas and delivery of high concentrations of active ingredients. In order to take advantage of the before mentioned unique properties of nanoparticles and the biological activities of metals, various metal-based nanoparticles (MNPs) have been synthesized in the past few years, such as silver (AgNPs), gold (AuNPs), zinc (ZnNPs), zinc oxide (ZnONPs), copper (CuNPs) and copper oxide (CuONPs) nanoparticles. These MNPs are flexible structures that allow the control of physical characteristics, with enhanced surface properties, which provides a high applicability in dermopharmacy and cosmetics. The conventional methods for synthesizing nanoparticles (physical and chemical approaches) are associated with major drawbacks, being the most concerning the high cost (in resources, energy, time and space) and human/environmental toxicity. Hence, the need to develop an alternative synthesis pathway was imposed, giving rise to the green synthesis methodology. In general, green synthesis consist of using biological sources (plants, bacteria or fungi) to synthesize ecological benign, non-hazard and biocompatible nanoparticles. With the development of green synthesis, starting materials have been used more frequently, among them plants. Plant-mediated green synthesis of nanoparticles is based on the use of plant extracts to synthesize nanoparticles, and their outstanding advantages have paved the way for exciting developments on nanoparticle synthesis to the detriment of complex and toxicity-associated chemical and physical synthesis. MNPs produced by plant-mediated synthesis also demonstrate notorious biological activities, i.e., anticancer, antioxidant, anti-inflammatory, antimicrobial, wound healing and antiaging activities. However, safety assessment of phyto MNPs (phyto-MNPs) holds significant importance due to the lack of toxicological studies and the conception issues that some of the available studies show. In general, current studies suggest the biocompatibility and safety of phyto-MNPs, together with significantly improved and relevant biological activities towards dermopharmaceutical and cosmetic applications. Against this backdrop, there is still a long way to run until the application of phyto-MNPs in the medical, pharmaceutical and cosmetic fields, but studies so far show a very high potential towards their clinical translation for dermopharmaceutical and cosmetics applications. This review focuses on phyto-MNPs synthesized resorting to various plant extracts, including their production, characterization and the biological activities that support their topical application for dermopharmaceutical and cosmetic purposes.

Antioxidant, Anti-Inflammatory, and Analgesic Activities of Agrimonia eupatoria L. Infusion.

Agrimony (Agrimonia eupatoria L.) (Ae) is used in traditional medicine to treat inflammatory and oxidative related diseases. Therefore, this study focuses on the anti-inflammatory and analgesic potential of Ae infusion (AeI). Phenolic compounds characterization was achieved by HPLC-PDA-ESI/MS n . To evaluate antioxidant potential, 2,2-diphenyl-1-picrylhydrazyl (DPPH), superoxide anion, hydroxyl radical, and SNAP assays were used. In vitro anti-inflammatory activity of AeI was investigated in LPS-stimulated macrophages by measuring the NO production. In vivo anti-inflammatory activity was validated using the mouse carrageenan-induced paw edema model. Peripheral and central analgesic potential was evaluated using the acetic acid-induced writhing and hot-plate tests, respectively, as well as the formalin assay to assess both activities. The safety profile was disclosed in vitro and in vivo, using MTT and hematoxylin assays, respectively. Vitexin, quercetin O-galloyl-hexoside, and kaempferol O-acetyl-hexosyl-rhamnoside were referred to in this species for the first time. AeI and mainly AePF (Ae polyphenolic fraction) showed a significant antiradical activity against all tested radicals. Both AeI and AePF decreased NO levels in vitro, AePF being more active than AeI. In vivo anti-inflammatory and analgesic activities were verified for both samples at concentrations devoid of toxicity. Agrimony infusion and, mainly, AePF are potential sources of antiradical and anti-inflammatory polyphenols.