Abstract

ANTIOXIDANT-MEDIATED ANXIOLYTIC EFFECTS OF LACTOBACILLUS RHAMNOSUS GG: INSIGHTS INTO MICROBIOTAGUT- BRAIN AXIS MODULATION

*Elisabeth Mahaware, Dr. Rajesh Nagar, Dr. Sudhavengurlekar, Shikhar Rathore

Abstract

Background: Anxiety disorders are among the most prevalent neuropsychiatric conditions worldwide and are frequently associated with oxidative stress and dysregulation of the microbiota–gut–brain axis. Probiotics, particularly psychobiotic strains, have emerged as promising therapeutic agents capable of modulating emotional behavior and neurobiological functions. Lactobacillus rhamnosus GG (LGG) is a wellcharacterized probiotic strain known for its antioxidant, antiinflammatory, and gut-modulating properties. Objective: The present study aimed to evaluate the antioxidant and anxiolytic potential of Lactobacillus rhamnosus GG using in vitro antioxidant assays and in vivo behavioral and biochemical investigations in a stress-induced anxiety model. Methods: Antioxidant activity was assessed using DPPH, ABTS, nitric oxide, hydrogen peroxide, superoxide, and hydroxyl radicalscavenging assays. For in vivo evaluation, Wistar rats were divided into control, stress control, diazepam-treated, LGG low-dose, and LGG high-dose groups. Anxiety-like behavior was assessed using the Elevated Plus Maze (EPM), Open Field Test (OFT), and Light–Dark Box (LDB) paradigms. Oxidative stress biomarkers, including malondialdehyde (MDA), reduced glutathione (GSH), and superoxide dismutase (SOD), were estimated in brain tissue. Data were analyzed using one-way ANOVA followed by Tukey’s multiple comparison test.Results: LGG demonstrated concentration-dependent antioxidant activity in all in vitro assays. In behavioral studies, LGG significantly increased open-arm exploration in the EPM, enhanced locomotor and exploratory activity in the OFT, and increased time spent in the light chamber in the LDB test compared with the stress control group (p < 0.05). Furthermore, LGG significantly reduced MDA levels while restoring GSH and SOD activities, indicating attenuation of oxidative stress. The high-dose LGG group exhibited greater efficacy than the low-dose group and produced effects comparable to the standard drug diazepam. Conclusion: The findings suggest that Lactobacillus rhamnosus GG possesses significant antioxidant and anxiolytic-like properties. The observed effects may be mediated through modulation of oxidative stress and microbiota–gut–brain-axis signaling pathways. LGG may represent a promising psychobiotic candidate for the management of anxiety-related disorders, although further mechanistic and clinical studies are required to confirm its therapeutic potential.

Keywords: Lactobacillus rhamnosus GG, Anxiety, Psychobiotics, Gut–Brain Axis, Oxidative Stress, Antioxidant Activity, Elevated Plus Maze, Probiotics.