•Five new C19-diterpenoid alkaloids were isolated from the aerial part of Aconitum carmichaeli.•Carmichaenine A (1) and E (5) are featured with an 8-O-benzoyl substitution.•Carmichaenine C (3) and D (4) are featured with a 14-O-benzoyl substitution.•Carmichaenine B (2) and E (5) are featured with a OH substitution at C-10.Five new aconitine-type C19-diterpenoid alkaloids, namely, carmichaenine A–E (1–5), and six known diterpenoid alkaloids, namely, 14-benzoylneoline (6), neoline (7), 10-hydroxyneoline (8), neolinine (9), songoramine (10), and songorine (11), were isolated from the aerial parts of Aconitum carmichaeli. Their structures were determined by extensive spectroscopic methods, especially 2D NMR analyses. Compounds 8 and 9 were isolated for the first time from A. carmichaeli.

Three hitherto unknown taxane diterpenoids, namely baccatin VIII (1), baccatin IX (2), and baccatin X (3), along with 10 known analogues were isolated from an ethanolic extract of the twigs and leaves of Taxus yunnanensis. The new structures were characterized based on extensive spectroscopic analysis. Compounds 1 and 2 were tested for their in vitro cytotoxicity against five human tumor cell lines, and 1 exhibited inhibitory effects on HL-60 and MCF-7, with IC50 values of 3.44 and 9.67 μM, respectively.

•Three structurally unusual alkaloids were isolated from Daphniphyllum longeracemosum.•Their structures were determined by extensive spectroscopic analysis.•Hybridaphniphyllines A and B represent a hitherto unknown class of natural product hybrids.•Hybridaphniphyllines A and B were possibly generated via Diels–Alder cycloaddition.Two Daphniphyllum alkaloid and iridoid hybrids with the hitherto unknown decacyclic fused skeletons, hybridaphniphyllines A and B, along with one diamino Daphniphyllum alkaloid, daphnicyclidin I, were isolated from dried stems and leaves of Daphniphyllum longeracemosum. Their structures were elucidated on the basis of extensive spectroscopic analysis, and the absolute configuration of daphnicyclidin I was deduced by the CD exciton chirality method. A biogenetic pathway for 1 and 2 involving natural Diels–Alder cycloaddition is proposed.Two Daphniphyllum alkaloid and iridoid hybrids, hybridaphniphyllines A (1) and B (2), along with one diamino Daphniphyllum alkaloid, daphnicyclidin I, were isolated from Daphniphyllum longeracemosum. Natural Diels–Alder cycloaddition is suggested in the biogenetic pathway to 1 and 2.

Six eudesmane-type sesquiterpene lactones, named chlorantholides A–F, were isolated from the ethanol extract of Chloranthus elatior (Chloranthaceae) together with 12 known compounds. Their structures were elucidated on the basis of extensive spectroscopic analysis, and their absolute configurations were studied by the CD exciton chirality method. The structure of a recently reported eudesmanolide from Chloranthus anhuiensis: 8β-hydroxy-1-oxoeudesma-3,7(11)-dien-12,8-olide, was also revised as 8β-hydroxy-2-oxoeudesma-3,7(11)-dien-12,8-olide (chlorantholide D).Graphical abstractSix eudesmane sesquiterpene lactones, chlorantholides A–F (1–6), were isolated from Chloranthus elatior. The structure of an eudesmanolide from C. anhuiensis: 8β-hydroxy-1-oxoeudesma-3,7(11)-dien-12,8-olide (4a), was revised as 8β-hydroxy-2-oxoeudesma-3,7(11)-dien-12,8-olide (chlorantholide D, 4).Highlights► Six eudesmane sesquiterpene lactones were isolated from Chloranthus elatior. ► The structure of an eudesmanolide was revised. ► The HMBC and ROESY correlations of hydroxy proton signals were applied for structure elucidation. ► The CD exciton chirality method was employed to determine absolute configuration.

Phytochemical study on the ethanol extract of the aerial parts of Carpesium abrotanoides led to the isolation of two new sesquiterpene lactones, carabrolactone A (1) and carabrolactone B (2). Their structures were elucidated on the basis of extensive spectroscopic analysis.