Context: Piper aduncum L. (Piperaceae) produces an essential oil (dillapiole) with great exploitative potential and it has proven effects against traditional cultures of phytopathogens, such as fungi, bacteria and mollusks, as well as analgesic action with low levels of toxicity. Objective: This study investigated the in vivo anti-inflammatory activity of dillapiole. Furthermore, in order to elucidate its structure-anti-inflammatory activity relationship (SAR), semisynthetic analogues were proposed by using the molecular simplification strategy. Materials and methods: Dillapiole and safrole were isolated and purified using column chromatography. The semisynthetic analogues were obtained by using simple organic reactions, such as catalytic reduction and isomerization. All the analogues were purified by column chromatography and characterized by ¹H and ¹³C NMR. The anti-inflammatory activities of dillapiole and its analogues were studied in carrageenan-induced rat paw edema model. Results: Dillapiole and di-hydrodillapiole significantly (p<0.05) inhibited rat paw edema. All the other substances tested, including safrole, were less powerful inhibitors with activities inferior to that of indomethacin. Discussion and conclusion: These findings showed that dillapiole and di-hydrodillapiole have moderate anti-phlogistic properties, indicating that they can be used as prototypes for newer anti-inflammatory compounds. Structure-activity relationship studies revealed that the benzodioxole ring is important for biological activity as well as the alkyl groups in the side chain and the methoxy groups in the aromatic ring.

The excessive exposure to ultraviolet (UV) radiation is the main cause of skin cancer, the most commonly diagnosed cancer in the world. In this context, the development of innovative and more effective sunscreens, with bioactive compounds like caffeine, displaying antioxidant and anticancer potential, is required. This research work assessed in vitro and in vivo the efficacy and safety of topical sunscreen formulations containing caffeine as an adjuvant of the UV filters. Sunscreens were prepared with 2.5% w/w caffeine or in the absence of this compound. In order to evaluate the safety of these formulations, stratum corneum hydration, skin barrier and colorimetry were assessed in vivo in healthy subjects before and after skin treatment with the samples. The efficacy of the sunscreens was assessed in vitro, using PMMA plates and a spectrophotometer equipped with an integrating sphere; and in vivo by the determination of the sun protection factor (SPF). None of the formulations caused erythema or impaired the skin barrier function. The in vitro functional characterization showed higher SPF values for the caffeine formulation. The in vivo studies also confirmed the higher SPF value of the formulation combining caffeine with the filters, compared to the caffeine-free sample. This improvement contributed to an increase of, approximately, 25% in the in vivo anti-UVB protection. In conclusion, caffeine was well tolerated by the skin and increased the photoprotective activity, being a new alternative adjuvant in sunscreens formulation.

Lipinski`s Rule for central nervous system drugs (RoCNS), reported in 1999, predicts that poor absorption or permeation is more likely when there are more than three hydrogen bond donors (HBD), seven hydrogen bond acceptors (HBA), molecular weight (MW) is greater than 400 Da and CLog P is greater than five. The objective of this work was to evaluate the applicability of RoCNS for drugs approved from 1985 to 2014. Calculated physicochemical properties of central nervous system (CNS) drugs were compared to parameters established by the rule. From 1985 to 1999, 48 drugs were introduced for clinical therapy and 31% unsuited the RoCNS (among which six drugs did not fit within the determined CLog P, four the MW, four the HDA and two the HBD). From 2000 to 2014, 38 drugs were introduced and 32% violated RoCNS parameters (among which eight drugs did not fit within the determined MW, four the HBD, two the HBA and one the CLog P). These findings suggest that even though drugs introduced to the market after RoCNS publication showed a tendency to apply the rule, the application of the rule is similar for both periods. Examining the applicability of the RoCNS, it may serve as a guide for medicinal chemists designing future CNS-active small molecules.