Abstract The aim of this work was to determine the total phenolic content and evaluate the antioxidant, antibacterial, photoprotective and cytotoxic properties of corn silk ethanol extract prepared from corn silk that was air-dried at room temperature. Corn silk ethanol extract has a high content of phenolic compounds. The concentrations of ethanol extract required to produce 50% of maximal effect (EC50) in DPPH and ABTS radical scavenging assays were 489.0 and 166.1 µg/mL respectively, indicating low activity when compared to the positive control. The ethanolic extract of corn silk showed antibacterial activity, mainly on Gram-positive bacteria. The in vitro sun protection factor (SPF) of the ethanolic extract of corn silk incorporated into sunscreen UVA-UVB 5% gel with Pemulen TR-1® was evaluated for the first time. A relative increase in SPF efficacy was observed for the extract when the sunscreen was incorporated. The ethanolic extract of corn silk and the gel were considered non-cytotoxic. The corn silk ethanolic extract was characterized using ultra performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC-QTOF-MS/MS). Eleven compounds including flavonoids, coumaric acid derivatives, terpenoid, hydroxycinnamic acid derivative and quinic acid derivative were suggested based on their accurate mass and MS/MS spectra.

Due to the increase of bacterial resistance, the search for new antibiotics is necessary and the medicinal plants represent its most important source. The aim of this study was to evaluate the antibacterial property of extract and fractions from Protium spruceanum leaves, against pathogenic bacteria. By means of diffusion and microdilution assays, the crude extract was active against the nine bacteria tested being the hydromethanolic fraction the most active. During phytochemical procedures, procyanidin (1) and catechin (2) were identified as the main antibacterial constituents of this fraction. In silico results obtained using PASSonline tool indicated 1 and 2 as having good potential to interact with different targets of currently used antibiotics. These results no indicated potential to none DNA effect and indicated the cell wall as mainly target. Electrophoresis result supported that had no DNA damage. Cell wall damage was confirmed by propidium iodide test that showed increased membrane permeability and by cell surface deformations observed in scanning electronic microscopy. The in vitro assays together with the in silico prediction results establish the potential of P. spruceanum as source of antibacterial compounds that acts on important bacterial targets. These results contribute to the development of natural substances against pathogenic bacteria and to discovery of new antibiotics.

ABSTRACT The excessive sun exposure, coupled with lack of sun protection represents one of the biggest risks to the occurrence of skin cancer and photoaging. Recent strategies for photoprotection have included the incorporation of natural antioxidant and anti-inflammatory compounds, into sunscreens, and the oral administration of natural antioxidant extracts. In this work, we use Brazilian red propolis extract because its antioxidant and anti-inflammatory activities. The aim of this work was to evaluate the sun protection factor and antioxidant activity of different hydroalcoholic extracts of red propolis (70% and 75%) prepared from lyophilized red propolis at room and high temperatures. The sun protection factor in vitro was determined by a spectrophotometric method developed by Mansur. The hydroalcoholic extracts of red propolis incorporated with Filter UVA-UVB 5% Gel Permulem TR-1 presented absorption in the UVB region. Also, the in vitro capacity of the hydroalcoholic extracts of red propolis to increase photoprotective activity of Filter UVA-UVB 5% Gel was evaluated. The hydroalcoholic extracts of red propolis incorporated presented higher values of sun protection factor and showed synergism in the photoprotective activity of Filter UVA-UVB 5% Gel Permulem TR-1. The antioxidant activity and sun protection factor are correlated with total phenolics content of the extracts and the hydroalcoholic extract of red propolis 75% at room temperature was choosen. The formulation developed with Filter UVA-UVB 5% Gel Permulem TR-1 with this hydroalcoholic extract of red propolis showed safe to be applied on the skin according HET-CAM test. Suggests indication of hydroalcoholic extract of red propolis (75% – room temperature) associated to photoprotective formulations for use in photoprotective products.