IN VITRO AND IN VIVO EVALUATION OF ANTIMICROBIAL AND ANTIOXIDANT POTENTIAL OF STEVIA EXTRACT.

BACKGROUND: The current trend globally is the utilization of natural products as therapeutic agents given its minimum side effects. The leaves of Stevia contain several active ingredient compounds such as rebaudioside. Stevia extract have been used for many purposes. Active oxygen radicals can induce base modifications, DNA breakage, and intracellular protein crosslink's. This study was done to evaluate the potential of stevia extract as antibacterial and antioxidants actions. MATERIALS AND METHODS: Antibacterial activity of different extracts of stevia was tested in vitro against different species of bacteria and hepato-protective efficacy was testes in rats injected with CCl4 as hepatotoxic. RESULTS: Acetone extract exhibited antibacterial activity against selected five bacteria species. The acetone extract suppressed the elevation of serum ALT (p <0.05) and AST (p <0.001) activities induced by CCl4. Animals given stevia extract showed prevention against deleterious effects of CCl4 by lowering lipid peroxidation and enhancement of antioxidant activities as SOD and CAT. The protection trial is better than treatment trial. Total phenolic content of aqueous and acetone extracts were found 30 mg and 85 mg gallic /gm extract respectively. While the total flavonoids were 40 mg and 80 mg quercetin/g respectively. The GC-MS analysis showed that monoterpene and indole are the main components. Aqueous extract don't show any antibacterial activity against the tested strains. The antioxidant properties were attributable to its phenolic content to scavenge free radicals. CONCLUSION: Acetone extract possess a potent antimicrobial and activity against deleterious effect of CCl4-caused liver damage.

Impact of aqueous doash extract on urinary mutagenicity in rats exposed to heterocyclic amines.

Doash (Origanum majorana) is an herbaceous plant found commonly in Saudi Arabia. It is used as a food flavor and a folk remedy to treat a number of diseases. The 2-amino-3-methylimidazo[4,5-f] quinoline (IQ) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) are the most abundant of the heterocyclic amine carcinogens present in cooked food. In the present study, the potential of doash tea to influence carcinogen metabolism was investigated indirectly using heterocyclic amines as model mutagens, IQ and PhIP. Results obtained showed that doash tea had no influence on body weight in both the studies. Rats were treated with different doses of IQ (1, 3, 5 and 10 mg/kg) or PhIP (1, 5, 10 and 20 mg/kg). The selected dosage was 5 mg/kg for both heterocyclic amines. Results obtained revealed that rats treated with doash tea and given a single dose of the heterocyclic amines, whether for 1 day (short-term) or for 1 month (long term), showed a statistically significant decrease in their excretion of indirect mutagens (IQ or PhIP). Following treatment of the rats with a single oral dose of IQ or PhIP, the highest mutagenic activity determined in the presence of an activation system was excreted in the urine after 24 h, with much lower levels of mutagencity being excreted during subsequent elimination from the body. No mutagenicity was observed in the absence of an activation system that is direct-acting mutagenicity using (IQ and PhIP). Statistical analysis revealed that, in comparison with the control group, the aqueous doash extract significantly reduced the mutagenic response after 24 h. It was concluded that doash extract significantly decreased the excretion of mutagens in comparison with the control group (water only).

Evaluation of the in vitro antimutagenic effect of Doash tea aqueous extracts.

Human carcinogens are formed mainly due to the lifestyle and diet that is followed. It is well known that dietary factors play a crucial role in the aetiology of human cancer. The new attractions of drug discovery using natural products remain an important issue in the current herbal medicine research. The present study aimed to evaluate the antimutagenic activity of the water extracts of Doash leaves against several known mutagens, both direct- and indirect-acting, belonging to different chemical classes. These classes are heterocyclic amines (HAs), polycyclic aromatic hydrocarbons and nitrosamines. The antimutagenic activity will be determined in Salmonella/microsomal system (Ames) using strains of Salmonella Typhimurium. Four Salmonella bacterial strains (TA98, TA97, TA100 and TA1530) were used in the present study. Results obtained showed that Doash extract possesses powerful antimutagenic properties, which impair the deleterious effects of various chemicals used in this study. One possible mechanism involved in this protection is the inhibition of the metabolic activation of chemical carcinogens to their reactive metabolites. We also suggest that the health benefits of Doash could be derived from the additive and synergistic combinations of the various phytochemicals present in Doash leaves. Other studies should also be conducted to determine the active components of Doash leaves, including macronutrients, micronutrients and other phytochemicals. Clinical studies should be performed before any claims that Doash consumption offers chemoprotection against cancer can be made.

Assessment of the antimutagenic effect of Doash tea extract fractions.

Origanum majorana L (Doash) is one of the traditional remedy that is used as a tea and to treat ailments, in the Kingdom of Saudi Arabia. The present study has attempted to evaluate the inhibitory action of Doash fractions on the bioactivation of selected food mutagens and direct-acting mutagens. Four Sallmonella bacterial strains (TA98, TA97, TA100 and TA1530) were used in the present study. These strains contain different mutations in the histidine operon, allowing the bacteria to detect different types of mutation. The two strains (TA98 and TA97) are capable of detecting frameshift mutations, while TA100 and TA1530 are able to detect base-pair substitutions. The liver homogenate and other subcellular fractions were prepared. Identification of Doash fractions was conducted using the high-performance liquid chromatography/mass spectrometry system. The results of the present study demonstrated that the Doash tea fraction components have the ability to reduce the in vitro mutagencity of several promutagens, which were employed in this study. Fraction No. 5 (with the highest content of solid) was the most potent inhibitor of the mutagenicity of all promutagens employed in this study. The antimutagenic effect of Doash tea extract, and its various fractions, was pronounced, indicating that the metabolism of cytochrome P450 1A2 isozyme is likely to be inhibited.