The first paper says Purple sweet potato color reduced hepatic inflammation through raising NAD+.
The second paper says age related reduction of NAD+ allows NF-kB activation and NLRP3 activation.
"The Inhibitory Effects of Purple Sweet Potato Color on Hepatic Inflammation Is Associated with Restoration of
NAD⁺ Levels and Attenuation of NLRP3 Inflammasome Activation in High-Fat-Diet-Treated Mice."
https://www.ncbi.nlm...pubmed/28786950
T"he origin of NF-κB activation was related to the age-dependent Bmal1/Clock/RORα/Rev-Erbα loop disruption, which lowers NAD(+) levels, reducing the SIRT1 deacetylase ability to inactivate NF-κB. Consequently, NF-κB binding to DNA increases, raising the formation of proinflammatory mediators and inducing mitochondrial impairment. The cycle is then closed with the subsequent NLRP3 inflammasome activation. "
https://www.ncbi.nlm...pubmed/26681113