Nitrogen-containing bibenzyls from Pleione bulbocodioides: Absolute configurations and biological activities

Four new pyrrolidone substituted bibenzyls, dusuanlansins A–D (1–4) were isolated from the pseudo bulbs of Pleione bulbocodioides, along with 19 known compounds (5–23). Compounds 1–4 are two pairs of epimers of pyrrolidone substituted bibenzyls, which were separated successfully by a Chiralcel OD-RH C18 column. Their absolute configurations were elucidated by calculated ECD. Biological investigations showed that compounds 5 and 7 exhibited potent anti-inflammatory activities on LPS-stimulated NO production in BV-2 microglial cells, with IC50 values of 2.46 and 3.14 μM, respectively.

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