Chemical constituents from the aerial parts of Musella lasiocarpa

Phytochemical investigation of the aerial parts of the monotypic plant, Musella lasiocarpa, led to the isolation of four rare bicyclic diarylheptanoids, musellarins B-E (2–5), two new phenylphenalenones, 2-methoxy-9-(3′,4′-dihydroxyphenyl)-1Hphenalen-1-one (9), 2-methoxy-9-(3′-methoxy-4′-hydroxyphenyl)-1H-phenalen-1-one (10), a new acenaphtylene derivative, trans-(1S,2S)-3-(4′-methoxyphenyl)-acenaphthene-1,2-diol (13), and two new sucrose esters, 1,2′,3′,4′,6′-O-pentaacetyl-3-O-trans-pcoumaroylsucrose (16), 1,2′,3′,4′,6′-O-pentaacetyl-3-O-cis-p-coumaroylsucrose (17), together with nine known compounds. In addition, (4E,6E)-1-(3′,4′-dihydroxyphenyl)-7-(4″-hydroxyphenyl)-hepta-4,6-dien-3-one (15) was isolated for the first time from a natural source. The structures of new compounds were elucidated by analysis of their spectroscopic data. Compounds 2, 6, 8–10, 12, and 14 were cytotoxic toward several of the human tumor cell lines (HL-60, SMMC-7721, A-549, MCF-7, and SW480). Of these, the new compound 9 was the most potent one, with IC50 values of 5.8, 10.3, 6.3, 3.3, and 2.3 µM, respectively.