Anti-Inflammatory and Antioxidant Effects of Carvacrol on N-Methyl-N'-Nitro-N-Nitrosoguanidine (MNNG) Induced Gastric Carcinogenesis in Wistar Rats.

Carvacrol is a dietary polyphenol from Lamiaceae plants that has been shown to possess a wide range of biological activities including antioxidant and antitumor effects. This study aimed to investigate its anti-inflammatory and antioxidant effects on N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) induced gastric carcinogenesis in Wistar rats. Forty-nine rats were randomly assigned to four treatment and three control groups. Over 60 days, MNNG (200 mg/kg BW) was orally applied to animals of groups 1-5 while the rats in groups 2-5 also received different doses of carvacrol (10, 25, 50, and 100 mg/kg BW, respectively) until the end of the experiment. Group 6 rats were treated with 100 mg/kg BW carvacrol and no MNNG whereas group 7 was the control group without any treatment. After the euthanasia of all rats, the inflammatory cytokines and oxidative stress parameters were assessed in the blood and tissues. The expression of caspase 9, Bax, and Bcl-2 proteins in the stomach tissues were investigated through histopathological examinations. Statistically significant differences were observed in the body weight, oxidative stress, and inflammation parameters of groups 1 to 6 compared to group 7 (p ≤ 0.001). Animals in MNNG groups 2 and 3 treated with the low dose carvacrol (10 and 25 mg/kg BW) showed significantly reduced oxidative stress, inflammation, and apoptotic effect compared to animals of the MNNG groups receiving increased doses of carvacrol (50 and 100 mg/kg BW) or no carvacrol. Rats exposed to MNNG exhibited gastric cancer cells in several areas. In the MNNG group receiving 100 mg/kg BW carvacrol, the inflammatory cell infiltration was observed in gastric mucosal and submucosal areas whereas MNNG rats supplemented with 10 and 25 mg/kg BW carvacrol showed no pathological alterations of the gastric cells. The results of this study indicate that significant antioxidant and anti-inflammatory effects induced by carvacrol at doses of 10 and 25 mg/kg BW interfered with gastric carcinogenesis induced by MNNG in Wistar rats as well as provide hepatoprotection. However, high doses of carvacrol (50 and 100 mg/kg BW) increased oxidative stress, inflammation, and apoptosis.

Preparation and evaluation of novel functional fermented dairy products containing propolis and cinnamon.

Novel functional food products might be an easy accessible and eligible approach to help reduce the risk of severe viral infections including SARS-CoV-2. Hence a product containing probiotics, propolis and cinnamon was developed and interferences of the ingredients were characterized. Yogurts were prepared using starter cultures with propolis (0.03%) and cinnamon in various concentrations (0.3%, 1%, and 2.5%). Bifidobacterium animalis ssp. lactis, Lactobacillus acidophilus, Streptococcus thermophilus, and Lactobacillus delbrueckii subsp. bulgaricus were used as microorganisms for yogurt production. Chemical analysis revealed a decline of fat matter in the presence of propolis and/or cinnamon. Propolis had statistically significant suppressive effects on Bifidobacterium animalis ssp. lactis as well as on Lactobacillus delbrueckii subsp. bulgaricus numbers (p < 0.05). These effects were diminished in the presence of increasing cinnamon concentrations. For Lactobacillus acidophilus a statistically significant reducing effect on the number of colonies was observed in all products investigated. Nevertheless all samples met the standard of recommended level of ≥ 106 viable cells/g of a product. Propolis showed an inverse effect on Streptococcus thermophilus by increasing its colony numbers in yogurts. The probiotic yogurt samples containing propolis (0.03%) and cinnamon (2.5%) gained the highest number of points in the sensory evaluation compared to control.

Effects of carvacrol on human fibroblast (WS-1) and gastric adenocarcinoma (AGS) cells in vitro and on Wistar rats in vivo.

Carvacrol is a natural phenolic compound found in essential oils of Lamiaceae species. In the present study, an attempt has been made to elucidate the mechanism behind the anti-cancer potential of carvacrol on human gastric adenocarcinomas (AGS) by comparing its effects on cancer cells AGS to those on normal human fibroblast (WS-1) cells, in vitro. Cytotoxicity, reactive oxygen species (ROS) generation, glutathione (GSH) levels, genotoxicity, and apoptotic effects of carvacrol (0-600 µM) were studied in both cell lines. Additionally, the effect of high dose carvacrol (100 mg/kg BW) on the oxidative status was investigated in vivo. For this purpose, carvacrol was administered orally to male Wistar rats over a period of 60 days. Rats were weighed regularly. At the end of the experiment, rats were euthanized. Blood and stomach tissues were collected for biochemical and pathological examinations. The in vitro results showed significant differences in cell viability of AGS compared to WS-1 cells exposed to carvacrol. Also the extent of ROS generation, GSH reduction and DNA damage differed significantly between the cell lines studied (P ≤ 0.001). The differences observed were statistically significant at all concentrations applied (P ≤ 0.001). The results found in AGS cells were mirrored in the pathohistological findings obtained from animals of the in vivo experimental group. Changes in body weight, and oxidative stress index for plasma and stomach tissues of animals in this group were found to differ statistically significant from those found in the control group of Wistar rats (P ≤ 0.001). The data obtained from our present study uncovered that carvacrol has the potential to cause toxic effects in both, AGS and WS-1 cells but more effectively in cancer cells than in normal cells. The carvacrol-mediated responses observed in the in vitro and in vivo experiments presented suggest a double-edged pro-oxidative effect. Via this mechanism carvacrol induced cytotoxicity, apoptosis, and DNA damage in a dose-dependent manner in both cancer and normal cells and these activities were higher in cancer cells than those of normal cells.