Danshen, the dried root of Salvia miltiorrhiza (Lamiaceae), is one of the most popular traditional herbal medicines commonly used in China. Recently, danshen has been used as a health-promoting functional tea to prevent diseases by strengthening the human immunity in China. To search for secondary metabolites with immune-modulating activity, a phytochemical investigation was carried out on the roots of S. miltiorrhiza, which led to the isolation of 6 new diterpenoids (1–4, 16, and 20) along with 20 known diterpenoids. The structures and absolute configurations of these new compounds were elucidated on the basis of spectroscopic analysis, X-ray diffraction analysis, calculated optical rotation, and calculated electronic circular dichroism spectra. Among these isolates, compounds 3, 17, 19, and 23 promoted the proliferation of HMy2.CIR, exhibiting a protective effect on lymphocytes at the concentration from 2.50 to 40 μM, whereas compounds 2, 7, 8, 10, 14, 18, 22, and 25 inhibited the cell proliferation in a concentration-dependent manner.Keywords: diterpenoids; human B lymphoblastoid cells; immune-modulating activity; Salvia miltiorrhiza;

Aphapolin A, a nemoralisin-type diterpenoid possessing a unique 4/5-fused-ring system that is unprecedented in previously reported nemoralisin diterpenoid, and aphapolin B, a novel nemoralisin-type diterpenoid derivative containing a benzofuran moiety, along with a new natural product were isolated from Aphanamixis polystachya (Wall.) R. Parker. Their structures and absolute configurations were elucidated by spectroscopy data, X-ray crystallography diffraction analysis, and electronic circular dichroism calculations. Plausible biosynthetic pathways of aphapolins A and B were also delineated.

Two new triterpenoids, spirochensilides A (1) and B (2) were isolated from Abies chensiensis. Comprehensive spectroscopic analysis revealed that 1 and 2 are the first example of triterpenoids possessing a unique 8,10-cyclo-9,10-seco and methyl-rearranged carbon skeleton. The single crystal X-ray diffraction analyses and computational methods allowed the absolute configuration assignments of the two compounds. A plausible biogenetic pathway of spirochensilide A (1) is also proposed.

•Compounds 1–4 were rarely reported trinorsesquiterpenoids.•The structure of a previously reported trinorsesquiterpenoid was revised to compound 2.•The absolute configuration of compounds 1–3 was determined.•Compound 2 showed significant antiproliferative activities.Four trinorsesquiterpenoids (1–4) were isolated from the roots of Inula racemosa and the structures of two new compounds, (4R,5S,10S)-5-hydroxy-11,12,13-trinoreudesm-6-en-8-one (1) and (4R,5R,10R)-4,15-epoxy-11,12,13-trinoreudesman-8-one (3), were elucidated by extensive spectroscopic analysis. Furthermore, the structure of compound 2a should be revised as (4R,5R,10S)-5-hydroxy-11,12,13-trinoreudesm-6-en-8-one (2) and compound 2 showed antiproliferative activity against A549, HepG2, and HT1080 cell lines with IC50 values of 3.71, 5.94, and 3.95 μg/mL, respectively.