Emerging natural product based alternative therapeutics for tuberculosis

Tuberculosis (TB) has inflicted mankind throughout much of the known human history. In the last hundred years, remarkable scientific and clinical progress has helped in better control of this disease worldwide. Discovery of BCG vaccine in 1921, and antitubercular drugs in 1940s marked an important advancement towards controlling this disease. Many more components essential to fighting, even eradicating, an infectious disease have since been discovered and yet today, this treatable, preventable disease is still one of the leading infectious killer on our planet. Poor efficacy of BCG vaccine, inadequate diagnosis, emergence of drug resistance, prolonged treatment duration leading to non-compliance, ability of the pathogen to undergo latency, and adverse drug reactions associated with anti-TB regimens are some of the major hurdles and challenges we face today in achieving an effective control of this disease. These factors underscore the need for better understanding of the host pathogen interactions, leading to cutting edge research over the past few decades that has uncovered some of the underlying mechanisms at the heart of Mycobacterium tuberculosis pathogenesis, though many interactions likely still await discovery. This chapter first briefly reviews the recent groundbreaking research discoveries that has led to bridging the knowledge gap towards better understanding the mechanisms and associated pathological and immunological events that occur during different outcomes of the disease. We further summarize significant progress in the discovery, development and evaluation of new natural product-based prevention and treatment options that have shown promising results in recent times. We also discuss potential alternative herbal medicine-based approaches that could help in designing resilient TB control strategies in the future.