Artemisia lactiflora Extracts Prevent Inflammatory Responses of Human Macrophages Stimulated with Charcoal Pyrolysis Smoke

Artemisia lactiflora, a Chinese-origin plant, has been reported to have unique phytochemicals responsible for its medicinal properties. The growth of the agricultural industry emits air pollution, which has adverse effects on health. There are limited scientific reports on the biological activities of A. lactiflora. Studies on its activities and mechanisms may provide insight into its use in medicinal purposes to treat those health problems and conditions. In this study, leaves of A. lactiflora were extracted and fractioned with solvents of different polarities. Total phenolics, total flavonoids DPPH(•) scavenging, ABTS(•+) scavenging, and cytotoxicity of A. lactiflora were assessed. Anti-inflammatory activities were evaluated by pre-treating macrophages with extract or fractions then induced inflammatory response by coconut shell pyrolysis smoke. Inflammatory responses were assessed by measuring pro-inflammatory genes expression and pro-inflammatory cytokines secretion. Among all extract and fractions of A. lactiflora, butanol fraction has the highest phenolic, flavonoid, and DPPH(•) scavenging activity. All extract and fractions significantly down-regulated pro-inflammatory genes expression (RelA, TNF, IL6) and decreased pro-inflammatory cytokines secretion (TNF-α, IL-6), p < 0.0001, compared with pyrolysis smoke-induced macrophages. The ethyl acetate fraction showed the highest anti-inflammatory activity in decreasing pro-inflammatory cytokines secretion. These results may prove the anti-inflammatory activities of A. lactiflora through the inhibition of the NF-κB-dependent pathway. Taken together, this study first reported the anti-inflammatory activities of A. lactiflora. Thus, the plant can be used to prevent and treat inflammatory responses caused by highly oxidative pyrolysis smoke released from the re-utilization of agro-industrial leftovers.