Yu-Xin Yan

Three new triterpenoids containing four-membered ring from the fruiting body of Ganoderma sinense.

Methyl ganosinensate A (1), ganosinensic acid A (1a), and ganosinensic acid B (2), three new triterpenoids with an unusual four-membered ring skeleton produced by a bond across C-1 to C-11, were isolated from the fruiting body of Ganoderma sinense . Their structures were established on the basis of extensive spectroscopic methods, including 1D and 2D NMR techniques, and methyl ganosinensate A was confirmed by X-ray crystallographic analysis.

Four New Polycyclic Meroterpenoids from Ganoderma cochlear

Four pairs of new polycyclic-meroterpenoid enantiomers, ganocins A-C (1-3) possessing a spiro[4,5]decane ring system, along with ganocin D (4) with an eight-membered ring, were isolated from the fruiting bodies of Ganoderma cochlear. Their structures were determined by spectroscopic data and X-ray diffraction crystallography. Their anti-AChE activities were evaluated, and a possible biogenetic pathway was also proposed.

Pregnane alkaloids from Pachysandra axillaris

Nine new pregnane alkaloids, pachysamines J-R (1-9), together with seven known ones, were isolated from Pachysandra axillaris. The chemical structures of the new alkaloids were elucidated by spectroscopic methods. All the compounds were evaluated for their inhibitory activities against HL-60, SMMC-7721, A-549, SK-BR-3, and PANC-1 cell lines. Compound 15 possessed moderate activities against A-549, SK-BR-3, and PANC-1 cells, with the IC(50) values of 11.17, 4.17, and 10.76 microM, respectively. Besides, compound 11 showed cytotoxicities against A-549 cell, with the IC(50) values as 24.94 microM.

Cytotoxic triterpenoid alkaloids from Buxus microphylla.

Five new triterpenoid alkaloids, buxmicrophyllines E-I (1-5), and six known ones (6-11) were isolated from the leaves and stems of Buxus microphylla. The structures of compounds 1-5 were elucidated by NMR and MS spectroscopic analysis, and the relative stereochemistry of 5 was determined by single-crystal X-ray crystallography. Compounds 3 and 9 were cytotoxic against HepG2 cells, with IC(50) values of 0.89 and 0.78 microM, and compounds 2, 3, 7, 8, and 9 were cytotoxic against K562 cells, with IC(50) values of 2.95, 4.44, 1.70, 5.61, and 0.37 microM, respectively.

Cytotoxic Triterpenoids from Azadirachta indica

Two new tirucallane triterpenoids, 24,25-epoxy-3 β-hydroxy-20-oxo-7-tirucallene (1) and 22,23;24,25-diepoxy-3 β-hydroxy-7-tirucallene (2), and a new tetranortriterpenoid, 4 α-hydroperoxy-6- O-acetylnimbandiol (3), along with eight known compounds, were isolated from the branches and leaves of Azadirachta indica. Their structures were elucidated through spectroscopic and chemical methods. The cytotoxic assay showed that the abundant constituent nimbolide (8) had obvious cytotoxic activities against HL-60, SMMC7721, A549, MCF-7, and SW-480 cell lines, with IC₅₀ values of 0.8 ± 0.1, 2.2 ± 0.2, 1.9 ± 1.3, 4.5 ± 1.1, and 2.3 ± 0.1 µM, respectively.

Cytotoxic Steroids from Sarcococca saligna

Two new C₂₁-steroidal esters, sarsaligates A(1) and B(2), and two new steroidal alkaloids, sarsaligenines A(3) and B(4), together with four known compounds (sarcovagine, sarcorucinine, dimethylamino-3 β-pregnane-20-one, and β-sitosterol 5- 8, respectively), were isolated from the leaves and stems of Sarcococca saligna. The structures of compounds 1-4 were elucidated by NMR and MS spectroscopic analysis. Of the compounds tested, 5 and 6 were the most cytotoxic against the cell lines K562, SK-BR-3, and PANC-1, with IC₅₀ values in the range of 2.25-5.00 µM, while 3 and 4 selectively inhibited HL-60 cells with IC₅₀ values of 2.87 and 3.61 µM, respectively. Compounds 3-6 therefore deserve further evaluation of their cytotoxic potentials.

Identification and Antifeedant Activities of Limonoids from Azadirachta indica

Four new limonoids, azadiraindins A–D (1–4, resp.), together with seven known analogs, were isolated from the MeOH extract of Azadirachta indica. The structures of 1–4 were elucidated by NMR and MS spectroscopic analyses, and the relative configuration of 1 was determined by single‐crystal X‐ray crystallography. The compounds isolated in comparatively large amount were evaluated for their antifeedant activities against Plutella xylostella; the antifeedant rate of 10 was 90.6% and the corrected mortality of 8 was 79.2%.

Triterpenoid alkaloids from Buxus microphylla.

Two new triterpenoid alkaloids, buxmicrophyllines J and K (1 and 2, resp.), together with four analogues, 3–6, were isolated from the leaves and stems of Buxus microphylla. The structures of the new compounds were elucidated by NMR and MS spectroscopic analyses. The partial assignments of the NMR spectra of 3 were also revised. Compounds 1 and 3–6 were evaluated for their growth inhibitory activity against human cell lines HL‐60, SMMC‐7721, A‐549, SK‐BR‐3, and PANC‐1. Compound 6 showed significant cytotoxicity against HL‐60, SK‐BR‐3, and PANC‐1 cell lines, with IC50 values of 6.46, 19.61, and 28.57 μM, respectively.

New triterpenoids from the kernels of Azadirachta indica

Three new limonoids (1–3) and a new intact triterpenoid (4), along with three known constituents (5–7), were isolated from the dried kernels (after extracting azadirachtin) of Azadirachta indica. The structures of the new compounds 1-benzoyl-3-deacetyl-1-detigloyl salannin (1), 7-tigloyl-12-oxo vilasini (2), azadiralactone (3) and azadirahemiacetal (4) were elucidated by means of spectroscopic analysis. The cytotoxities of these isolated constituents were assayed.Graphical abstract

Triterpenoid alkaloid derivatives from Buxus rugulosa

Four new triterpenoid alkaloid derivatives, buxrugulines A–D (1–4), together with four known ones (5–8), were isolated from the leaves and stems of Buxus rugulosa. The structures of compounds 1–4 were elucidated by NMR and MS spectroscopic analysis. All compounds were assayed for their cytotoxicities against HL-60, SMMC-7721, A549, MCF-7, and SW480 cells lines.