In this paper, we complement our previous study on the antiproliferative activity of Calea fruticosa (Asteraceae) by isolating the compounds apigenin-4',7-dimethyl ether (1), budlein A (2), quercetin (3), and cichoriin (4) from the plant's aerial parts. The antiproliferative activity of these compounds was evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method against human tumor cell lines. Compound 3 displayed moderate antiproliferative activity in three cell lines (HCT-116, PC-3, and SF-295, with cell growth inhibition values of 72.97, 74.55, and 68.94%) and high antiproliferative activity (90.86%) in the HL-60 cell line. The in vitro sun protection factor (SPF) of the extracts and compound 4, with and without sunscreen, was determined by a spectrophotometric method. The ethanol extract exhibited the highest SPF (9.67) at a concentration of 0.100 mg/mL, while compound 4, isolated from this extract, showed a SPF of 13.79 at the same concentration. A relative increased efficacy of SPF was observed for the extracts and compound 4 when sunscreen was also used. Compound 4 has not been reported previously from any species within the genus Calea. Compounds 1-4 were obtained from this species for the first time.

Recebido em 17/09/2018; aceito em 24/01/2019; publicado na web em 13/03/2019 Although Quercetin absorbs in the UVA/UVB electromagnetic region, it is limited for applications as a UV filter due to its low lipophilicity and capacity to penetrate the epidermis. In order to overcome this limitation, we synthetized and evaluated the photo protective properties of a derivative obtained from Quercetin. The derivative was prepared by alkylation of Quercetin with iodoethane and characterized by IR and NMR spectroscopy. The in vitro Solar Protection Factor was determined by the Mansur method and the cytotoxicity was evaluated using hepatocellular cell (Hep G2) cells. Finally, Quercetin and the corresponding derivative were incorporated in nanoemulsions. Nanoemulsions with particles sizes between 53 and 73 nm were obtained, and polydispersity indexes were around 0.1, indicating good homogeneity of the nanoemulsion particles. The cell viability study for the Quercetin derivative indicated a very low cytotoxicity profile. The chemical modification of Quercetin resulted in a promising compound with improved properties desirable for skin penetration and incorporation into sunscreen formulations.

Ultraviolet solar radiation can generate free radicals that damage skin and cause skin lesions or skin cancer. Sunscreens are a protective measure against the effects of solar radiation that protects the skin by absorbing or reflecting solar rays. Ideally, the sunscreen should protect the skin against UVB (290-320 nm) and UVA (320-400 nm) rays, be photostable and non-toxic. This work describes a preliminary study on the SPF of a benzophenone and a lactone derivative. The synthesized compounds were characterized by spectroscopic techniques, submitted to cell viability assays against MTT and SPF determined in vitro by UV/VIS spectroscopy measurements. The spectroscopic data was in agreement with the proposed structures of the compounds studied. The SPF was proportional to concentration, and in one case, the sun protection factor was lower at higher concentrations. The benzophenone derivatives were evaluated for toxicity by a cell viability study, and found to be non-cytotoxic at the tested concentrations.