Protective effect of C. sativa leaf extract against UV mediated-DNA damage in a human keratinocyte cell line.

Toxic effects of ultraviolet (UV) radiation on skin include protein and lipid oxidation, and DNA damage. The latter is known to play a major role in photocarcinogenesis and photoaging. Many plant extracts and natural compounds are emerging as photoprotective agents. Castanea sativa leaf extract is able to scavenge several reactive species that have been associated to UV-induced oxidative stress. The aim of this work was to analyze the protective effect of C. sativa extract (ECS) at different concentrations (0.001, 0.01, 0.05 and 0.1 µg/mL) against the UV mediated-DNA damage in a human keratinocyte cell line (HaCaT). For this purpose, the cytokinesis-block micronucleus assay was used. Elucidation of the protective mechanism was undertaken regarding UV absorption, influence on (1)O2 mediated effects or NRF2 activation. ECS presented a concentration-dependent protective effect against UV-mediated DNA damage in HaCaT cells. The maximum protection afforded (66.4%) was achieved with the concentration of 0.1 µg/mL. This effect was found to be related to a direct antioxidant effect (involving (1)O2) rather than activation of the endogenous antioxidant response coordinated by NRF2. Electrochemical studies showed that the good antioxidant capacity of the ECS can be ascribed to the presence of a pool of different phenolic antioxidants. No genotoxic or phototoxic effects were observed after incubation of HaCaT cells with ECS (up to 0.1 µg/mL). Taken together these results reinforce the putative application of this plant extract in the prevention/minimization of UV deleterious effects on skin.

Oxygen and nitrogen reactive species are effectively scavenged by Eucalyptus globulus leaf water extract.

Eucalyptus globulus Labill. (Family Myrtaceae) is a plant of Australian origin, with a reported therapeutic use in airway inflammatory diseases. Considering that reactive oxygen species (ROS) and reactive nitrogen species (RNS) have been implicated in the pathogenesis of airway inflammatory diseases such as asthma and chronic obstructive pulmonary disease, an effective scavenging activity against these reactive species may contribute for the therapeutic effect of this plant. In the present study, a water extract of E. globulus leaves was evaluated for its putative in vitro scavenging effects on ROS (HO(*), O(2)(*-), ROO(*), and H(2)O(2)) and RNS ((*)NO and ONOO(-)) and on 2,2-diphenyl-1-picrylhydrazyl radical (DPPH). Qualitative and quantitative analyses of the extract's phenolic composition were also performed. The Eucalyptus leaf water extract presented a remarkable capacity to scavenge all the reactive species tested, with all the 50% inhibitory concentrations being found at the mug/mL level. Phytochemical analysis showed the presence of polyphenols such as flavonoids (rutin and quercitrin) and phenolic acids (chlorogenic acid and ellagic acid), which may be partially responsible for the observed antioxidant activity. These observations provide further support, beyond the well-known antibacterial and antiviral activities of the Eucalyptus plant, for its reported use in traditional medicine such as in the treatment of airway inflammatory diseases, considering the important role of ROS and RNS in the inflammatory process, although further studies are needed to prove the bioavailability of the antioxidants/antibacterial compounds of the extract as well as the ability of the active compounds to reach specific tissues and to act in them.

Moisturizing effect of oleogel/hydrogel mixtures.

The aim of this study was to obtain new vehicles for topical formulations based on the mixture of hydrogels (aqueous systems) with oleogels (lipophilic systems). Several formulations were prepared using different oleogels mixed with polyacrylic acid hydrogel without addition of other ingredients. The moisturizing effect of the bigels was assessed along with the hydrogel and oleogels used in their preparation by carrying out an in vivo study with 14 healthy volunteers. Corneometer measurements were taken each hour during a five-hour period after product's application. Stability tests (storage at 20 and 40 degrees C for six months) and mechanical characterization were also carried out. Stability tests showed no modifications of the textural properties and appearance over a six-month period at 20 degrees C. At accelerated conditions, modifications of colour and textural properties were detected after six months' storage. While retaining the mechanical and sensory properties of the hydrogel, the bigels showed simultaneously an enhanced moisturizing effect, making them promising candidates for topical formulations.

Protective effect of Castanea sativa and Quercus robur leaf extracts against oxygen and nitrogen reactive species.

Topical natural antioxidants are a useful strategy for the prevention of photoaging and oxidative stress mediated skin diseases. In view of this underlying principle, the screening of natural plant extracts with scavenging activity for pro-oxidant reactive species is a primary requirement for the development of new topical antioxidant formulations. In the present study, an ethanol:water (7:3) extract from Castanea sativa leaves and a ethanol:water (2:3) extract from Quercus robur leaves were evaluated for their putative in vitro scavenging effects on reactive oxygen species (ROS) namely superoxide radical (O(2)(-)), hydroxyl radical (HO()), peroxyl radical (ROO()), hydrogen peroxide (H(2)O(2)) and singlet oxygen ((1)O(2)) as well as on reactive nitrogen species (RNS) namely nitric oxide (()NO) and peroxynitrite (ONOO(-)). The extracts presented a high potency to scavenge the tested reactive species, all the IC(50)s being found at the microg/mL level. IC(50)s (mean+/-SE) for the ROS O(2)(-),HO(),H(2)O(2) and (1)O(2) were 13.6+/-1.8; 216+/-4; 410+/-8; 12.3+/-0.7 microug/mL, respectively, for C. sativa, and 11.0+/-0.5; 285+/-22; 251+/-32; 7.90+/-0.56 microg/mL, respectively, for Q. robur. The ORAC values obtained for ROO() were 1.24+/-0.13 for C. sativa and 1.09+/-0.06 for Q. robur. The IC(50)s (mean+/-SE) for ()NO and ONOO(-) were 3.10+/-0.14 and 1.49+/-0.10 microg/mL, respectively, for C. sativa and 3.13+/-0.11 and 0.95+/-0.02 microg/mL, respectively, for Q. robur. The content of total phenolics for C. sativa and Q. robur were 284+/-9 and 346+/-4 mg of gallic acid equivalents (GAE)/g of lyophilized extract respectively. The observed effects might be of relevance considering the putative interest of these extracts as topical antioxidants.