Evaluation of the in vitro anti-inflammatory and cytotoxic potential of ethanolic and aqueous extracts of Origanum syriacum and Salvia lanigera leaves.

In this study, the chemical compositions of the ethanolic and aqueous extracts of the leaves of Origanum syriacum and Salvia lanigera were identified based on GC-MS spectrometric analyses. The in vitro anti-inflammatory potential of the different extracts was evaluated by determining the membrane stabilization of human red blood cells and the percent inhibition of the COX1/2, 5LOX, and sPLA2-V enzymes. Both ethanolic extracts showed maximum membrane stabilization (≤ 91%, at 100 µg/mL) compared to the aqueous extracts (≤ 45%) and the reference drug diclofenac sodium (90.75%). The membrane-stabilizing effects of the ethanolic extracts could be directly correlated to their anti-inflammatory activity. While both ethanolic fractions strongly inhibited the 5LOX and COX-1 enzymes at 100 µg/mL, only the O. syriacum ethanolic extract selectively inhibited sPLA2-V (99.35%, at 50 µg/mL). The differences in the pharmacological efficiencies of the different extracts could be attributed to the variation in their chemical compositions particularly the content of oxygenated monoterpenoids. Additionally, none of the ethanolic extracts demonstrated cytotoxicity to human colorectal cancer cell lines (HCT-116 and Lovo), even at the highest concentration tested (200 µg/mL). The safe profiles of these extracts towards the tested cell lines may be due to the absence of the toxic phthalic acid ester substances. Collectively, these findings clearly suggest that the studied ethanolic extracts of O. syriacum and S. lanigera can be considered interesting candidates for the treatment of human inflammatory diseases related to oxidative stress and microbial infections.

A novel bactericidal homodimeric PLA2 group-I from Walterinnesia aegyptia venom.

A novel non-toxic phospholipase A2 was purified to homogeneity in a single chromatography step from the venom of Walterinnesia aegyptia, a monotypic elapid snake caught in Saudi Arabia, and its antimicrobial and hemolytic properties were evaluated as well. This enzyme, namely WaPLA2, is a homodimer with an estimated molecular mass of 30 kDa, and its NH2-terminal sequence exhibits a significant degree of similarity with PLA2 group-I. At optimal pH (8.5) and temperature (45 °C), the purified PLA2 exhibited a specific activity of 2100 U/mg, and it requires bile salts and Ca2+ for its activity. However, other cations such as Cd2+ and Hg2+ diminished the enzyme activity remarkably, thereby suggesting that the catalytic site arrangement has an exclusive structure for Ca2+ binding. Furthermore, WaPLA2 maintained almost 100% and 60% of its full activity in a pH range of 6.0-10 after 24 h incubation or after 60 min treatment at 70 °C, respectively. In the biological activity assays, WaPLA2 displayed potent indirectly hemolytic and antimicrobial activities that were strongly correlated. These promising findings encourage further in-depth research to understand the molecular mechanism of WaPLA2's antimicrobial properties for its possible use as a potential therapeutic lead molecule for treating infections.

High-fat diet stimulates the gut pathogenic microbiota and maintains hepatic injury in antibiotic-treated rats.

The gut and the liver are closely linked to each other, as changes in the gut microbiota can play a significant role in the development of many liver diseases. Gut bacteria respond rapidly to changes in diet and thus can affect the liver through their metabolites. The impact of a high lipid diet on the liver in the presence of an altered gut flora modulated by ampicillin was investigated. The study was performed on 30 male Western albino rats randomly divided into 3 groups: control (phosphate buffered saline treated), group II (ampicillin 50 mg/kg for three weeks to induce microbiota alterations and fed on standard diet) and group III (same dose of ampicillin and fed on a lipid rich diet). Stool samples were collected for qualitative determination of bacteria. Serum hepato-specific markers, in addition to Glutathione (GSH), Lipid peroxidase (MDA), Glutathione-S- transferase(GST), and vitamin C in liver tissues, were measured. Altered gut microbiota significantly increased the level of the hepato-specific marker MDA and reduced the GST, GSH and vitamin C levels. However, animals fed a lipid rich diet displayed a more significant shift in hepatic markers and antioxidants. Moreover, a new switch in composition of the gut bacteria was observed by feeding the lipid rich diet. Our study showed that bacterial overgrowth in the gut can be associated with liver dysfunction and that a high lipid diet can promote the overgrowth of some liver damaging microflora during antibiotic treatment.