Immunomodulatory activity of isolated phenanthrene and dihydrophenanthrene derivatives (coelotrinins A-L) from Coelogyne trinervis

Twelve previously undescribed compounds, named coelotrinins A-L (1–12), comprising eight dihydrophenanthrene derivatives (1, 4–5, and 7–11), two phenanthrene derivatives (2–3), and two phenanthrene-dihydrophenanthrene derivatives (6 and 12), along with twenty-one known compounds (13–33), were isolated from the pseudobulbs of Coelogyne trinervis. The structures were elucidated via spectroscopic data analysis, and their configurations were determined by optical rotation values and by comparing experimental and calculated electronic circular dichroism curves. Among these compounds, four compounds (1, 16, 23, and 24) showed immunomodulatory effects by inhibiting LPS-induced TNF-α production in THP-1 monocytes. Only coelotrinin A (1) exhibited an immunomodulatory effect with suppression on human peripheral blood mononuclear cells isolated from patients with multiple sclerosis.