Advances in Zoology and Botany 8(4): 358-368, 2020 http://www.hrpub.org DOI: 10.13189/azb.2020.080408 In-Vivo Study of Boswellia serrata for Modulating Immune System and Quenching Free Radicals Kavita Chahal 1,* , Megha Jha 2 1 Department of Botany, Government College Bichhua, Chhindwara, Madhya Pradesh, India 2 Department of Biotechnology, R&D, Pinnacle Biomedical Research Institute, Bhopal (M.P), India Received April 16, 2020; Revised May 13, 2020; Accepted June 16, 2020 Copyright©2020 by authors, all rights reserved. Authors agree that this article remains permanently open access under the terms of the Creative Commons Attribution License 4.0 International License Abstract In several diseased conditions like asthma, allergy, ageing, arthritis, cancer etc., there is a production of reactive nitrogen and oxygen species, as well as our immune system also gets harmed. In order to stop or quench these harmful free radicals, antioxidants, which are the first line of defense, are used. And the immune system can be modulated to work properly by using natural agents like medicinal plants, having antioxidant property. In this context, the present study was undertaken to investigate the immunomodulatory activity and free radical quenching ability of the Boswellia serrata Roxb. (Bs) in murine model. This herb is known to afford protection to human physiological system against diverse stressors. It was tested at three dose levels of 50mg /kg of mice body weight, 100mg /kg of mice body weight, and 150 mg /kg of mice body weight for five consecutive days. Alpha tocopherol (25 mg/ kg, of mice body weight) and Di-methyl Sulphoxide (35mg /kg of mice body weight) were used as the reference standards. The extent of protection against immunosuppression was evaluated after 9 days of respective drug administration, by measuring macrophage phagocytic activity. A statistically significant antioxidant and immunomodulatory activity were shown by the extract of Boswellia serrata as evident by its effect on the activity of non-enzyme antioxidant reduced glutathione (GSH), antioxidant enzyme glutathione peroxidase (GPx), the degree of lipid peroxidation, and increase in the number of peritoneal macrophages. Keywords Boswellia serrata, Antioxidant, Immunomodulatory, Glutathione Peroxidase, Lipid Peroxidation, Peritoneal Macrophages 1. Introduction In case of chronic inflammatory conditions, the immune system sometimes go out of the track and harm the host himself. Therefore, the modulation of immune responses becomes necessary. The immunological responsiveness of an organism can be increased by agents that can modulate the immune system by interfering with its regulatory mechanisms in a process called as immunomodulation [1-3]. Chronic inflammatory conditions also produce free radicals, which are unstable molecules, as a byproduct. In excessive amounts these free radicals are harmful for healthy tissues [4-6]. These radicals can be better scavenged by antioxidation, which a mechanism of stopping or quenching harmful free radicals. Hence, for treating an inflammatory condition immunomodulation can go hand in hand with antioxidant activity [7-9]. There is an increasing concern about use of synthetic immunomodulating agents and antioxidants which has increased researcher’s interest in finding out alternatives from natural sources [10-12]. As mentioned in Charaka Samhita [13], popularity of natural healthcare, side effects of synthetic drugs, better cultural acceptability, better compatibility with the human body and increased efficiency of plant derived drugs, prohibitive cost of allopathic drugs, and unavailability of allopathic drugs in remote areas, and a growing interest in preventing future health problems and a view to address specific health concerns, are the main reasons for the deviation of people towards plant-based medicines [14-16]. Boswellia serrata Roxb. belongs to Burseraceae family and commonly known as Salai, Frankincense, Gajabhakshya, Sallaki Guggul. Boswellia serrata Roxb., is a large branching tree found in India, the Middle East &Northern Africa. The bark contains a gummy oleo-resin [17-19]. Oils, terpenoids, sugars, and volatile oils are also present along with pentacyclic triterpene acids, i.e. -boswellic acid, 3-acetyl--boswellic acid, 11-keto--boswellic acid and 3-acetyl-11-keto--boswellic acid [20-22]. The gummy resin has been traditionally used in the Ayurvedic system of medicine as an anti-arthritic,