IL6 and acne: As for the inflammatory factors, as shown in Supplementary Figures 4B–G, the expression of IL-1β (6.627 ± 0.473 and 6.667 ± 0.611), IL-6 (7.067 ± 1.589 and 7.033 ± 0.710), and TNF-α (7.433 ± 1.358 and 6.267 ± 0.569) in the IAA group and indole group was significantly decreased than that of their counterparts (11.300 ± 1.153, 13.530 ± 0.982, and 11.470 ± 1.626, respectively) in the acne group (p < 0.05).