There is a growing need for research of photoprotective molecules from natural sources. Flavonoids have shown significant absorption in ultraviolet A (UVA), ultraviolet B (UVB) region, due to their chemical structure with conjugated double bonds, and may be used as ingredients in cosmetics formulations for skin protection. This systematic review reports what has been researched over the past decade on flavonoid and photoprotective activity, as well as some mechanisms of action by which these metabolites act. The search was conducted in three databases (Science Direct, PubMed and Scopus) using the descriptors “flavonoid”, “photoprotection” and “sunscreen” combined, published between January 2006 and January 2016. Twenty-two articles were selected and 17 flavonoids were cited. The data reviewed here indicate that flavonoids are potential in the fight against UVA and UVB radiation and which may be used as adjuvants in photoprotective formulations. Key words: Ultraviolet (UV), induced damage, natural products, flavonoids photoprotective activity, ultraviolet radiation.

Metal–organic frameworks (MOFs) are also known as porous coordination polymers. This kind of material is constructed with inorganic nodes (metal ions or clusters) with organic linkers and has emerged as a promising class of materials with several unique properties. Well-known applications of MOFs include their use as gas storage and in separation, catalysis, carbon dioxide capture, sensing, slender film gadgets, photodynamic therapy, malignancy biomarkers, treatment, and biomedical imaging. Over the past 15 years, an increasing amount of research has been directed to MOFs due to their advanced applications in fuel cells, supercapacitors, catalytic conversions, and drug delivery systems. Various synthesis methods have been proposed to achieve MOFs with nanometric size and increased surface area, controlled surface topology, and chemical activity for industrial use. In this context, the pharmaceutical industry has been watching the accelerated development of these materials with great attention. Thus, the objective of this work is to study the synthesis, characterization, and toxicity of MOFs as potential technological excipients for the development of drug carriers. This work highlights the use of MOFs not only as delivery systems (DDSs) but also in advanced diagnostics and therapies, such as photodynamic therapy and targeted delivery to tumors. Bibliometric analyses showed a growing interest in the topic, emphasizing its contemporary relevance.

The monoterpenes are the main constituents of most essential oils and p‐cymene is a monoterpene commonly found in various species of aromatic herbs, which has been reported for anti‐inflammatory, antinociceptive, and antimicrobial activities. However, there is no report concerning its pharmacological activity on the vascular smooth muscle. The aim of current work was to investigate the effects of p‐cymene in isolated rat aorta and also study its mechanism of action. In this work, we show that p‐cymene has a relaxant effect, in a dose‐dependent way, on the vascular smooth muscle, regardless of the presence of the endothelium. Using a nonselective potassium channel blocker, the CsCl, the relaxant effect of p‐cymene was attenuated. In the presence of more selective potassium channels blockers, such as TEA or 4‐AP, no change in the relaxant effect of p‐cymene was evidenced, indicating that BK_Ca and K_V channels are not involved in that relaxant effect. However, in the presence of glibenclamide or BaCl₂, K_ATP and K_ir blockers, respectively, the relaxant effect of p‐cymene was attenuated. The data presented indicate that p‐cymene has a relaxing effect on rat aorta, regardless of the endothelium, but with the participation of the K_ATP and K_ir channels.

Background: Cnidoscolus quercifolius is a Brazilian medicinal plant often found in the Caatinga biome. Previous studies have described several pharmacological properties for this plant, including antiproliferative effect. However, there are still few pharmacological and phytochemical reports involving this plant. Objective: In this report, it was described the cytotoxic effect of extract and fractions obtained from the leaves of C. quercifolius. It was also reported for the first time the identification of two flavonoids in this species. Materials and Methods: Ethanol extract (EE) and fractions hexane, chloroform-Fr, ethyl acetate (AcOEt-Fr) and methanol (MeOH-Fr) were evaluated against prostate (PC3 and PC3-M) and breast (MCF-7) cancer cell lines. A preliminary phytochemical analysis was performed by thin layer chromatographic, while the content of total phenolic compounds and flavonoids was determined by colorimetric assays. EE and bioactive fraction (AcOEt-Fr) were selected for analysis by high-performance liquid chromatography-diode-array detector (HPLC-DAD). Results: Phytochemical analysis revealed that the samples were positive for the presence of several classes of secondary metabolites, mainly phenolic derivatives and flavonoids. EE and AcOEt-Fr presented the highest phenolic and flavonoid content. HPLC-DAD analysis of EE and AcOEt-Fr allowed the identification of two flavonoids (rutin and apigenin) not yet described for this species. Concerning the cytotoxicity evaluation, only AcOEt-Fr demonstrated a strong cytotoxic effect against all cell lines, presenting the half maximal inhibitory concentration values between 15.75 and 46.97 μg/ml. Conclusion: The results suggest that flavonoids may play an important role in the cytotoxic effect observed for this species. In addition, this report contributed to the phytochemical knowledge of the species through the identification and quantification of flavonoids. Abbreviations used: AcOEt-Fr: Ethyl acetate fraction; CHCl₃-Fr: Chloroform fraction; EE: Ethanol extract; Hex-Fr: Hexane fraction; IC₅₀: Half maximal inhibitory concentration; MeOH-Fr: Methanol fraction; TLC: Thin layer chromatography; UV: Ultraviolet.

Respiratory diseases are responsible for significant morbidity and mortality in worldwide. One of most important respiratory disease is asthma, which the current treatment is based on use of β2‑agonists combined to inhaled corticosteroids. However, in recent years, many in vitro studies have attempted to validate the use of aromatic medicinal plants and its chemical compounds, such as monoterpenes, as potential therapeutically alternatives. In this work it was demonstrated that three different monoterpenes (carvacrol, citronellal and p-cymene) has relaxant effect in guinea-pig trachea, somehow showing different profile regarding epithelium presence, potency and efficacy. Key words: Monoterpenes, carvacrol, p-cymene, citronellal, guinea-pig trachea, relaxant effect.