Fig. 7. Potential of NAD⁺ modulation on pathogenic growth.

a Viable intracellular bacterial count of M. tuberculosis was determined as CFUs in samples treated with molecules 8, 9, and 10. Significant reduction in CFU was observed in 8 and 9 treated cells at 24 and 48 h post-infection compared to the untreated infected controls (*P < 0.05, **P < 0.01). b Growth inhibition assay to calculate IC₅₀ value of small molecules 8, 9, and 10 from non-linear regression analysis of graph plotted between percent growth inhibition and log concentrations of molecules on graph pad prism 6. Parasite morphology was observed by evaluating Giemsa-stained blood smears under light microscope. Scale bar represents 2 µm. c Effect of small molecules 8, 9, and 10 on cell viability measured by MTT assay. RAW cells were treated with increasing concentrations (1.5–25 µM) of molecules for 48 h. Results show no significant change in cell viability suggesting that the molecules are not toxic in nature. d NAD⁺ levels in erythrocytes treated with 1 µM and 5 µM of small molecules without parasite infection. NAD⁺ level of control erythrocytes was considered as 100%. Significance of Difference in values was calculated using unpaired t-test with Welch’s correction (*P < 0.05, **P < 0.01). e Model explaining role of NAD⁺ metabolism in pathogenesis of malaria and tuberculosis. Pathogen modulates host NAD⁺ homeostasis for its growth and survival. Targeting this modulation of host NAD⁺ levels could restrict pathogen growth and aid in development of novel drugs.