Fourteen new limonoids, munronins A-N (1-14), and eight known limonoids (15-22) were isolated from the whole plants of Munronia henryi. The structures of the new compounds were elucidated by 2D NMR spectroscopy and mass spectrometry, and the structure of 8 was confirmed by single-crystal X-ray diffraction analysis. Compound 1 represents the first limonoid found with a novel 7-oxabicyclo[2.2.1]heptane moiety produced by incorporating C-11 and C-14 via an oxygen atom. All compounds were evaluated for their anti-tobacco mosaic virus (TMV) activity and in vitro cytotoxicity against the human cancer HL-60, SMMC-7721, A-549, MCF-7, and SW-480 cell lines. Among them, compounds 2, 8, 9, 10, 11, 12, 18, and 20 showed significant anti-TMV activity, with IC50 values in the range 19.6-44.4 mu g/mL. Compounds 1 and 18 exhibited cytotoxic effects for all five cancer cell lines, with IC50 values between 0.4 and 4.8 mu M.
National Natural Science Foundation of China 
; Youth Innovation Promotion Association, CAS 
; National Key Scientific Instrument Development Projects of China [2011YQ12003506]
; Scientific and Technological Planning Project of Guizhou [QKH-ZY 3015]
1.Key Lab Chem Nat Prod Guizhou Prov, Guiyang 550002, Peoples R China 2.Chinese Acad Sci, Guiyang 550002, Peoples R China 3.Guizhou Univ, Ctr Res & Dev Fine Chem, Guiyang 550025, Peoples R China 4.Chinese Acad Sci, Kunming Inst Bot, State Key Lab Phytochem & Plant Resources West, Kunming 650201, Yunnan, Peoples R China