Research noteAntioxidant activity and γ-aminobutyric acid (GABA) producing ability of probiotic Lactobacillus plantarum DM5 isolated from Marcha of Sikkim

•Probiotic L plantarum DM5 isolated from Marcha displayed antioxidant properties.•L. plantarum DM5 has potential to protect oxidative damage mediated by reactive oxygen species.•L. plantarum DM5 showed resistance to hydrogen peroxide (1 mmol/L) for 8 h.•L. plantarum DM5 exhibited 20% inhibition rates of ascorbate autoxidation at 1010 CFU/ml.•L. plantarum DM5 has the ability to produce bioactive γ-aminobutyric acid (GABA).

A probiotic Lactobacillus plantarum DM5 isolated from fermented beverage Marcha of Sikkim displayed antioxidant properties. The antioxidant properties of L. plantarum DM5 were compared with L. plantarum NRRL B-4496 and Lactobacillus acidophilus NRRL B-4495. A concentration of 1010 CFU/ml of L. plantarum DM5 demonstrated the hydroxyl radical, superoxide anion radical and DPPH scavenging activities of 49%, 48%, and 55%, respectively and reducing activity of 149 μM (cysteine equivalents). Comparative analysis L. plantarum DM5 exhibited 38% and 20% higher hydroxyl radical, 31% and 22% higher superoxide anion radical, 43% and 33% higher DPPH scavenging activities than L. plantarum and L. acidophilus, respectively. Probiotic L. plantarum DM5 has the ability to produce bioactive γ-aminobutyric acid (GABA), a major inhibitory neurotransmitter in mammalian brain. It also possessed the ability to multiply in MRS medium containing abundant hydrogen peroxide (1 mM) and exhibited 20% inhibition rates of ascorbate autoxidation at 1010 CFU/ml. These findings suggested that L. plantarum DM5 has the potential to protect the oxidative damage mediated by the reactive oxygen species and can act as an antioxidative probiotic.