Prevention of UVB radiation-induced oxidative stress in mice by topical administration of Azadirachta indica(neem) extract

Neem tree (Azadirachta indica A. Juss. fam. Meliaceae) has been extensively employed to combat diverse pathologies. Moreover, it has been described that its leaf extract present anticarcinogenic action. Thus, the neem extract (NE) chemical and antioxidant properties was evaluated, and also, the capacity of two dermatological formulations incorporated with neem extract (F1 and F2) to avoid oxidative UVB-induced skin injury in hairless mice. NE constituents were investigated and free radical scavenging ability were determined by different methods in vitro. Skin from mice treated with F1 and F2 and submitted to UVB radiation were tested for different parameters of inflammation and oxidative injury. Results show that the NE polyphenol and flavonoid content were 135.30 and 37.12mg/g, respectively. High performance liquid chromatography (HPLC) results demonstrated the existence of azarachtin, rutin, ursolic acid and tannic acid. NE presented scavenging ability by ABTS radical, ferric-reducing antioxidant power (FRAP), inhibition of lipid peroxidation and iron chelation. In vivo, it was observed that mice treated with F1 and F2 showed amelioration of the inflammation by reducing UVB induced skin edema. However, only samples from animals treated with F1 had lower neutrophil recruitment (measured by myeloperoxidase activity), and returning the oxidative status to baseline levels in parameters such as reduced glutathione level, ferric reducing ability (FRAP), and scavenging of free radical (ABTS). Concluding, NE demonstrated a good antioxidant property in vitro, and the data suggest the use of NE added F1 to prevent skin damage caused by UVB irradiation.(AU)

Properties of extruded xanthan-starch-clay nanocomposite films

The aim of this work was to manufacture the biodegradable nanocomposite films by extrusion from different combinations of cassava starch, xanthan gum and nanoclays (sodium montmorillonite - MMT- Na) and to characterize them according to their microstructure, optical, mechanical and barrier properties. Films were manufactured from nine starch/xanthan/nanoclay combinations, containing glycerol as plasticizer. Scanning electron microscopy (SEM) of the starch-xanthan extruded films showed reticulated surface and smooth interior, indicating that the gum was mostly concentrated on the surface of the films, while starch/xanthan/nanoclays films showed a more homogeneous surface, suggesting that the introduction of nanoclays provided a better biopolymeric interaction. In general, nanoclays addition (2.5 - 5.0, w percent) generated more transparent and resistant films, with lower water vapor permeabilities and lower water sorption capacities and xanthan gum addition improved the elongation ofa starch films.