New ent-cleistanthanes and ent-pimaras diterpenoids with potential cytotoxicity from Phyllanthus franchetianus H. Lév.

Abstract

Seven diterpenoids including five ent-cleistanthanes (1, 2, 4–6) and two ent-pimaranes (3, 7) were isolated for the first time from the aerial part of Phyllanthus franchetianus H. Lév. Their structures were elucidated on the basis of the extensive spectroscopic analyses, single-crystal X-ray diffraction and ECD analysis. Phyllanthanes A-C (1–3) are new compounds. Notably, the ent-cleistanthanes 1 and 4–5 exhibited moderate cytotoxicity against five human cancer (HL-60, A549, HepG2, MDA-MB-231, SW480) (IC₅₀ = 5.01–32.41 μM) and one normal BEAS-2B (IC₅₀ = 20.45–24.33 μM) cell lines.