Phytochemicals as modulators of M1-M2 macrophages in inflammation

// Uzma Saqib 1 , Sutripta Sarkar 2 , Kyoungho Suk 3 , Owais Mohammad 4 , Mirza S. Baig 5 and Rajkumar Savai 6, 7 1 Discipline of Chemistry, School of Basic Sciences, Indian Institute of Technology (IIT) Indore, MP, India 2 PostGraduate Department of Food & Nutrition, BRSN College (affiliated to WBSU), Kolkata, WB, India 3 Department of Pharmacology, Kyungpook National University School of Medicine, Joong-gu Daegu, South Korea 4 Interdisciplinary Biotechnology Unit, Aligarh Muslim University (AMU), Aligarh, UP, India 5 Discipline of Biosciences and Biomedical Engineering (BSBE), Indian Institute of Technology (IIT), Indore, MP, India 6 Department of Internal Medicine, Universities of Giessen and Marburg Lung Center (UGMLC), member of the German Center for Lung Research (DZL), Justus Liebig University, Giessen 35392, Germany 7 Max Planck Institute for Heart and Lung Research, Department of Lung Development and Remodeling, Member of the DZL, Bad Nauheim, Germany Correspondence to: Mirza S. Baig, email: msb@iiti.ac.in Rajkumar Savai email: rajkumar.savai@mpi-bn.mpg.de Keywords: Anti-inflammatory cytokines; inflammation; M1–M2 macrophages; natural compounds; pro-inflammatory cytokines Received: December 21, 2017      Accepted: February 25, 2018      Published: April 03, 2018 ABSTRACT Macrophages are critical mediators of the innate immune response against foreign pathogens, including bacteria, physical stress, and injury. Therefore, these cells play a key role in the “inflammatory pathway” which in turn can lead to an array of diseases and disorders such as autoimmune neuropathies and myocarditis, inflammatory bowel disease, atherosclerosis, sepsis, arthritis, diabetes, and angiogenesis. Recently, more studies have focused on the macrophages inflammatory diseases since the discovery of the two subtypes of macrophages, which are differentiated on the basis of their phenotype and distinct gene expression pattern. Of these, M1 macrophages are pro-inflammatory and responsible for inflammatory signaling, while M2 are anti-inflammatory macrophages that participate in the resolution of the inflammatory process, M2 macrophages produce anti-inflammatory cytokines, thereby contributing to tissue healing. Many studies have shown the role of these two subtypes in the inflammatory pathway, and their emergence appears to decide the fate of inflammatory signaling and disease progression. As a next step in directing the pro-inflammatory response toward the anti-inflammatory type after an insult by a foreign pathogen (e. g., bacterial lipopolysaccharide), investigators have identified many natural compounds that have the potential to modulate M1 to M2 macrophages. In this review, we provide a focused discussion of advances in the identification of natural therapeutic molecules with anti-inflammatory properties that modulate the phenotype of macrophages from M1 to M2.