Bisindole Alkaloids with Neural Anti-inflammatory Activity from Gelsemium elegans

Three new trace bisindole alkaloids geleganimines A and B (1, 2) and geleganamide (3) were isolated from the aerial parts of Gelsemium elegans. Their structures were elucidated by spectroscopy, particularly from their carbon–proton coupling constants, and electronic circular dichroism. Compounds 1–3 are the first bisindole alkaloids discovered from the genus Gelsemium. Geleganimine B exhibited anti-inflammatory activity indirectly by suppressing lipopolysaccharide-induced pro-inflammatory factors in BV2 microglial cells with an IC50 value of 10.2 μM. These findings confirm the importance of bioactive trace components in medicinal plant research.