RESUMO
Ocotea fasciculata presents yangambin (YAN) and its isomer epi-yangambin (EPI-YAN) as major lignans, which are employed as the plant markers for quality control purposes and as potential pharmacological compounds. However, a gap between the pure isomers and safety and efficacy protocols is faced by the scientific community. In this context, this work aimed to report (i) a new and advantageous purifying process in a semi-preparative scale for YAN and EPI-YAN isolation from Ocotea fasciculata, and (ii) an in vitro cytotoxicity study to estimate, for the first time, the LD50 values of the isolated epimers, as well as the influence of albumin concentration in cell culture medium. The best condition for epimers isolation was achieved in normal-phase liquid chromatography. The lignan fraction (LF), previously obtained from the plant ethanolic extract, was purified yielding 17% and 29% of YAN and EPI-YAN, respectively. The in vitro study demonstrated that YAN and EPI-YAN were safe, and only at the highest concentration studied, a decrease on cell viability was observed. The estimated LD50 value was higher than 1612 mg/kg for both epimers. The LF, on the other hand, demonstrated an estimated LD50 of 422 mg/kg. Lignan cytotoxicity studies also evidenced that the higher cell viability was related to the higher concentration of fetal bovine serum as a source of albumin in medium. This is the first time the LD50 and safety of the isolated epimers were estimated, opening up great perspectives of success in in vivo studies.
Assuntos
Furanos , Lignanas , Ocotea , Extratos VegetaisRESUMO
Inga edulis is a fruit tree native from Central and South America. Different species of Inga have demonstrated high polyphenolic content and high antioxidant capacity. The oxidative stress significantly contributes to the development of several chronicle diseases, particularly age-related diseases. Therefore, photochemoprevention is an emerging interest in the use of naturally occurring antioxidants for their therapeutic use. A partial purification of the extract was carried out onto macroporous resin and the main components of I. edulis leaf extract and fraction were identified using UPLC-DAD-MS/MS as epicatechin, apigenin C-di-hexoside, myricetin-O-hexose-deoxyhexose, myricetin-O-deoxyhexose and vicenin-2, which was identified for the first time in I. edulis. Both extract and fraction presented high antioxidant capacity, the fraction exhibiting higher polyphenol and flavonoid contents and higher content of vicenin-2, suggesting that the fractioning process effectively resulted in the partial purification of the extract. The cytotoxicity and photostability were assessed in L929 fibroblast cells to evaluate whether I. edulis extract and fraction were suitable for topical application. The UVA and UVB irradiated extract and fraction did not decrease the antioxidant capacity and cell viability of L929 fibroblasts, demonstrating the photostability of the samples. The fractioning process successfully purified and enriched I. edulis extract, and both the extract and fraction are potential candidates to be safely incorporated in topical photochemopreventive formulations.
Assuntos
Antioxidantes/química , Antioxidantes/farmacologia , Fabaceae/química , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Animais , Antioxidantes/isolamento & purificação , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Frutas/química , Peroxidação de Lipídeos/efeitos dos fármacos , Camundongos , Extratos Vegetais/isolamento & purificação , Espectrometria de Massas em TandemRESUMO
Ultraviolet radiation (UVR) exposure causes various injurious effects to human skin by generating reactive oxygen species (ROS). Excessive ROS production can lead to oxidative stress which may damage cellular components like lipids and proteins and causing photoaging. The use of natural photochemopreventive agents with antioxidant properties is an important alternative to improve the effectiveness of sunscreens and reduce skin photodamage. A crude extract (CE) from the leaves of Arrabidaea chica underwent partition by a liquid-liquid method. The hexane fraction (FH), chloroform fraction (FC), and ethyl acetate fraction (FEA) were obtained. The antioxidant capacity of the CE, FH, FC, and FEA was studied in a cell-free system using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method and the xanthine/luminol/xanthine oxidase system. The FC had the best antioxidant activity. We also evaluated the photochemoprotective effect of A. chica in protecting L929 fibroblasts against UV-A- and UV-B-induced cell damage. A. chica inhibited the extended production of ROS up to 3h. Posttreatment with the CE and FC attenuated UV-induced cell damage through scavenging mechanisms, including the quenching of intracellular ROS and mitochondrial O2- and preventing lipid peroxidation. These results suggest that A. chica may be a promising non-sunscreen photoprotector that can improve the effectiveness of commercial sunscreens.