Antioxidant Capacity and Antimutagenic Potential ofMurraya koenigii

It is well known that the intake of antioxidants with increased consumption of fruits and vegetables and medicinal herbs contributes towards reduced risk of certain diseases including cancers. This study aims to evaluate the broad-spectrum antioxidant and antimutagenic activities as well as to elucidate phytochemical profile of an Indian medicinal plantMurraya koenigii(curry) leaves. Leaves of the plant were successively fractionated in various organic solvents. Benzene fraction demonstrated the highest phenolic content followed by petroleum ether. The benzene fraction showed maximum antioxidant activity in all tested assays, namely, phosphomolybdenum, 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical, ferric reducing antioxidant power (FRAP) and cupric reducing antioxidant capacity (CUPRAC) assays. Based on the promising broad-spectrum antioxidant activity, benzene fraction was further evaluated for antimutagenic activity and showed a dose-dependent antimutagenic response in AmesSalmonellamutagenicity assay. It inhibited 72–86% mutagenicity induced by sodium azide, methyl methanesulfonate, benzo(a)pyrene, and 2-aminoflourene at the maximum tested concentration (100 μg/mL) inSalmonella typhimuriumtester strains. At least 21 compounds were detected by GC/MS. The findings clearly demonstrated that phenolic-rich benzene fraction has promising broad-spectrum antioxidant and antimutagenic property and needs further evaluation to exploit its therapeutic potential.

Effect of Mammalian Tissues on Mutagenicity of Several N-Nitroso Compounds1

Supernatant fractions from different organs of rat and beef origin were tested for their effect on the mutagenic activity of N-methyl-N′-nitro-N-Nitrosoguanidine (MNNG), using Salmonella typhimurium tester strain (TA 1535). At equal protein concentrations their effects were quite different. Both beef and rat liver supernatant fluids (1.7 – 3.4 mg of protein per plate) completely inhibited the mutagenic action of MNNG (5 μg per 0.1 ml of cell culture) while that of the heart showed partial inactivation. Under similar conditions, beef kidney and rat seminal vesicle fractions had no effect on MNNG-induced mutagenesis. The antimutagenic property of the liver supernatant fluid was unaffected by mild heat treatment (70°C for 30 min) but completely destroyed by boiling for 10 min. Liver supernatant fluids also had a lethal effect on the tester strain. The antibacterial agent was separated from the antimutagenic property by dialysis. The dialyzate fraction had no lethal effect, but still remained active in inhibiting mutagenesis. To test whether the action of liver supernatatnt fluid was specific for MNNG alone, several other carcinogens belonging to the N-nitroso groups, methyl methane sulfonate (MMS), ethyl methane sulfonate (EMS) and l-nitrosopyrrolidine (NO-Pyr), were tested. Among various tissue fractions tested only the liver supernatant fluids drastically reduced the mutagenic activity of MMS (500 μg/plate), EMS (104 μg/plate) and NO-Pyr (104 μM/plate).