Nordihydroguaiaretic acid (NDGA) and α-mangostin inhibit the growth of Mycobacterium tuberculosis by inducing autophagy

Tuberculosis (TB) remains as a global health problem. The prevalence of this infection is related to the association with other diseases, such as HIV, neglect treatment and misuse of antibiotics. Hence, the identification of new drugs is required to eradicate TB. Possible alternatives to existing antibiotics include pure compounds extracted from medicinal plants, which are an important source of antimicrobial agents. The aim of this study was to evaluate the effect of nordihydroguaiaretic acid (NDGA) and α-mangostin on Mycobacterium tuberculosis growth and bacterial survival in infected macrophages derived from the human THP-1 cell line and monocytes. Our results show that both compounds directly inhibit M. tuberculosis growth in liquid medium with Minimal Inhibitory Concentrations (MIC) of 250 and 62 μg/mL respectively, likely through preventing bacterial replication. In addition, NDGA and α-mangostin were able to induce autophagy in human cells at lower concentrations (7 and 6 μg/mL, respectively) and contributed to the elimination of intracellular bacteria. NDGA and α-mangostin could be candidates for coadjuvant therapy in cases of drug-resistant TB, and their ability to enhance the immune response by promoting autophagy might contribute to TB treatment.