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Eight new complex flavanones with a novel linkage, cryptoyunnanones A-H (1-8), together with four known α-pyrones, were isolated from the leaves and twigs of Cryptocarya yunnanensis. The structures of 1-8 including their absolute configurations were characterized by spectroscopic data analysis and single-crystal X-ray crystallography. Plausible biosynthetic pathways for the formation of compounds 1-8 were proposed. Compounds 1-4 exhibited cytotoxicity against HCT-116, MDA-MB-231, and PC-3 cancer cells with IC50 values from 6.4 to 9.1 μM.

Eight new complex flavanones with a novel linkage, cryptoyunnanones A-H (

Nine new cedrelone limonoids, namely, walsuranolide B (1), 11β-hydroxy-23-O-methylwalsuranolide (2), yunnanolide A (3), yunnanol A (4), 11β-hydroxyisowalsuranolide (5), 11β-hydroxy-1,2-dihydroisowalsuranolide (6), 1α,11β-dihydroxy-1,2-dihydroisowalsuranolide (7), 11β-hydroxy-1α-methoxy-1,2-dihydroisowalsuranolide (8), and yunnanolide B (9), together with a new cycloartane triterpenoid, (24S*,25R*)-cycloartane-3β,24,25,26-tetrol (10), were isolated from the leaves and twigs of Walsura yunnanensis. Their structures were elucidated on the basis of spectroscopic analysis and by comparison with literature data. Compounds 3 and 5 exhibited potent cytotoxicity against five human tumor cell lines with IC50 values in the range 2.2-4.2 μM.

Nine new alkaloids of the koumine (1–4), humantenine (5–7), and yohimbane (8, 9) types as well as 12 known analogues were isolated from the leaves and vine stems of Gelsemium elegans. Compound 1 is the first N-4-demethyl alkaloid of the koumine type, compound 7 is the first nor-humantenine alkaloid, and compounds 8 and 9 are the first N-1-oxide and the first seco-E-ring alkaloids, respectively, of the yohimbane type. Compounds 1 and 7 exhibited moderate cytotoxicity against five human tumor cell lines with IC50 values in the range 4.6–9.3 μM.

Three new norlimonoids, toonaciliatins A (1), F (6), and G (7), four new limonoids, toonaciliatins B-E (2-5), and five known compounds, 5alpha,6beta,8alpha-trihydroxy-28-norisotoonafolin (8), toonaciliatins H (9) and I (10), febrifugin (11), and khayasin T (12), were isolated from the leaves and stems of Toona ciliata. Compounds 1-3 have an unusual 1-en-3-one system with a 1,11-oxygen bridge, limonoids 11 and 12 have a mexicanolide-type structural frame, and others are typical A,B-seco- (4, 5, 9, and 10) or B-seco-29-nor- (3, 6, 7, and 8) limonoids. Toonaciliatins H (9) and I (10) were obtained for the first time as natural products. The structures were established by extensive spectroscopic methods, particularly 1D and 2D NMR techniques.

Three new alkaloids, gelsebanine (1), 14alpha-hydroxyelegansamine (2), and 14alpha-hydroxygelsamydine (3), and a new extraction artifact , gelsebamine (4), together with 12 known alkaloids, were isolated from the stems and leaves of Gelsemium elegans. The structures of 1-4 were determined by spectroscopic methods, especially 2D NMR techniques. Compounds 1-4 were evaluated for cytotoxic activity against four tumor cell lines, and gelsebamine (4) selectively inhibited the A-549 human lung adenocarcinoma cell line.