Lemon grass (Cymbopogon citratus (D.C) Stapf) polyphenols protect human umbilical vein endothelial cell (HUVECs) from oxidative damage induced by high glucose, hydrogen peroxide and oxidised low-density lipoprotein

Design and formulation of a topical hydrogel integrating lemongrass-loaded nanosponges with an enhanced antifungal effect: in vitro/in vivo evaluation

Lemongrass oil (LGO) is a volatile oil extracted from the leaves of Cymbopogon citratus that has become one of the most important natural oils in the pharmaceutical industry because of its diverse pharmacologic and clinical effects. However, LGO suffers from low aqueous solubility, which could lead to a reduced effect. Moreover, the instability of its major active constituent, citral, could lead to volatilization, reaction with other formulation ingredients, and consequently, skin irritation. To surmount these problems, this research aims to formulate lemongrass-loaded ethyl cellulose nanosponges with a topical hydrogel with an enhanced antifungal effect and decreased irritation. The minimal inhibitory concentration and minimal fungicidal concentration of LGO against Candida albicans strain ATC 100231, determined using the broth macrodilution method, were found to be 2 and 8 μL/mL, respectively. The emulsion solvent evaporation technique was used for the preparation of the nanosponges. The nanosponge dispersions were then integrated into carbopol hydrogels (0.4%). Nine formulations were prepared based on a 32 full factorial design employing the ethyl cellulose:polyvinyl alcohol ratio and stirring rate as independent variables. The prepared formulations were evaluated for particle size, citral content, and in vitro release. Results revealed that all the nanosponge dispersions were nanosized, with satisfactory citral content and sustained release profiles. Statistical analysis revealed that both ethyl cellulose:polyvinyl alcohol ratio and stirring rate have significant effects on particle size and percentage released after 6 hours; however, the effect of the stirring rate was more prominent on both responses. The selected hydrogel formulation, F9, was subjected to surface morphological investigations, using scanning and transmission electron microscopy, where results showed that the nanosponges possess a spherical uniform shape with a spongy structure, the integrity of which was not affected by integration into the hydrogel. Furthermore, the selected formulation, F9, was tested for skin irritation and antifungal activity against C. albicans, where results confirmed the nonirritancy and the effective antifungal activity of the prepared hydrogel.

Cytoprotective effect of short-term pretreatment with proanthocyanidin on human gingival fibroblasts exposed to harsh environmental conditions

Our previous study showed that exposing mouse fibroblasts to proanthocyanidin (PA) for only 1 min accelerated cell proliferation in a concentration-dependent manner. In this study, exposing human gingival fibroblasts (HGFs) to PA for 1 min similarly accelerated the proliferative response of the cells. Besides the accelerated proliferative response, PA showed a cytoprotective effect on HGFs exposed to harsh environmental conditions; short-term exposure of HGFs in the mitotic phase to pure water or physiological saline resulted in a lower recovery of viable cells. Pretreatment and concomitant treatment with PA improved the low recovery of cells exposed to pure water or physiological saline. In addition, HGFs exposed to PA for 1 min proliferated well even after being cultured in serum-free medium. In 100% confluent HGFs, being cultured in serum-free medium resulted in a high intracellular reactive oxygen species (ROS) level, but pretreatment with PA prevented the cells from increasing intracellular ROS. Thus, the results suggest that a short-term PA treatment exerts cytoprotective effects on HGFs exposed to harsh environmental conditions by improving the intracellular oxidative stress response.

Effect of Baechu Kimchi Added Ecklonia cava Extracts on High Glucose-induced Oxidative Stress in Human Umbilical Vein Endothelial Cells

Endothelial cell dysfunction is considered to be a major cause of vascular complications in diabetes. In the present study, we investigated the protective effect of a baechu kimchi added Ecklonia cava extract (BKE) against high glucose induced oxidative damage in human umbilical vein endothelial cells (HUVECs). Treatment with a high concentration of glucose (30 mM) induced cytotoxicity, whereas treatment with BKE protected HUVECs from high glucose induced damage; by restoring cell viability. In addition, BKE reduced lipid peroxidation, intracellular reactive oxygen species and nitric oxide levels in a dose dependent manner. Treatment with high glucose concentrations also induced the overexpression of inducible nitric oxide synthase, cyclooxygenase-2 and NF-κB proteins in HUVECs, but BKE treatment significantly reduced the overexpression of these proteins. These findings indicate that BKE may be a valuable treatment against high glucose-induced oxidative stress HUVECs.

Detoxifying effect of fermented black ginseng on H2O2-induced oxidative stress in HepG2 cells

Fermented black ginseng (FBG) is prepared by repeated steaming and drying processes with fresh ginseng followed by fermentation with Saccharomyces cerevisiae. It has recently been shown to have several bioactivities. FBG contains crude saponin (1,440 µg/ml), ginsenoside Rg2 (2.86 µg/ml), ginsenoside Rg3 (24.52 µg/ml), ginsenoside Rh1 (12.64 µg/ml), ginsenoside Rh2 (0.63 µg/ml) and ginsenoside Rf (1.32 µg/ml). The present study investigated the antioxidant defense properties of FBG against hydrogen peroxide (H2O2)-mediated oxidative stress in HepG2 human hepatocellular carcinoma cells. The increased production of reactive oxygen species (ROS) induced by H2O2 was attenuated in a dose-dependent manner when the cells were pre-treated with FBG (10-50 µg/ml). FBG induced both the expression and activity of antioxidant enzymes, such as superoxide dismutase, catalase and glutathione peroxidase in the H2O2-treated HepG2 cells. The inhibitory effects of FBG on the phosphorylation of upstream mitogen-activated protein kinases (MAPKs), such as c-Jun N-terminal kinase, extracellular signal-regulated kinase and p38 were also observed. Overall, our results demonstrate that FBG protects HepG2 cells from oxidative stress through the induction of antioxidant enzyme activity and the inhibition of MAPK pathways.