Xike Xu

Acylated Iridoids with Cytotoxicity from Valeriana jatamansi

Thirteen new acylated iridoids, jatamanvaltrates A-M (1-13), together with nine known valepotriates (14-22), were isolated from the whole plants of Valeriana jatamansi (syn. Valeriana wallichii). The structures of these new compounds were assigned by detailed interpretation of spectroscopic data. Jatamanvaltrates D (4) and H (9) are the first examples of naturally occurring valepotriates containing an o-hydroxybenzoyloxy moiety at C-10. All isolated compounds were tested for their cytotoxicity against lung adenocarcinoma (A549), metastatic prostate cancer (PC-3M), colon cancer (HCT-8), and hepatoma (Bel7402) cell lines.

Ainsliadimer A, a new sesquiterpene lactone dimer with an unusual carbon skeleton from Ainsliaea macrocephala.

A phytochemical investigation of Ainsliaea macrocephala led to the isolation of a new dimeric sesquiterpene lactone, ainsliadimer A (1). The structure of 1 was elucidated by spectroscopic analysis, and confirmed by single crystal X-ray diffraction. Ainsliadimer A represents an unusual carbon skeleton with a cyclopentane system connecting the two monomeric sesquiterpene lactone units. This unique molecule exerted potent inhibitory activity against the production of nitric oxide in RAW264.7 stimulated by LPS.

Chemical constituents of Crinum asiaticum L. var. sinicum Baker and their cytotoxic activities.

A phytochemical investigation of the bulbs of Crinum asiaticum L. var. sinicum Baker resulted in the isolation of two new alkaloids, asiaticumines A and B (1 and 2, resp.), together with 21 known compounds, including nine alkaloids, four amides, five phenolic compounds, and three flavonoids. All 23 compounds were isolated for the first time from Crinum asiaticum L. var. sinicum Baker. Their structures were elucidated by spectroscopic methods. In addition, ten alkaloids, 1–10, were evaluated for their cytotoxic activities against human tumor cell lines A549, LOVO, HL‐60, and 6T‐CEM. Compounds 3, 4, and 7–10 selectively showed remarkable inhibition against one or more of the tested cell lines.

Revision of the structures of 1,5-dihydroxy-3,8-epoxyvalechlorine, volvaltrate B, and valeriotetrate C from Valeriana jatamansi and V. officinalis.

The structures of 1,5-dihydroxy-3,8-epoxyvalechlorine (1a) and volvaltrate B (6a), two new chlorinated iridoids isolated from Valeriana jatamansi and V. officinalis, respectively, were originally assigned on the basis of spectroscopic methods. Reinvestigation using X-ray analysis and chemical transformation revealed that the original assignment of H-7 in 1a and OH-8 in 6a should be inverted and that the structures should be revised to 1 and 6, respectively. Correspondingly, the structure of valeriotetrate C (7a) should be revised to 7. Volvaltrate B (6) showed cytotoxic activity against the lung adenocarcinoma (A549), metastatic prostate cancer (PC-3M), colon cancer (HCT-8), and hepatoma (Bel7402) cell lines, with IC50 values of 8.5, 2.0, 3.2, and 6.1 μM, respectively.

Characterization of chlorinated valepotriates from Valeriana jatamansi

HPLC-PDA-MS and TLC analysis were used to look for minor cytotoxic chlorinated valepotriates from whole plants of Valeriana jatamansi (syn. Valeriana wallichii DC.). This resulted in isolation of 15 chlorinated valepotriates, designated as chlorovaltrates A-O, together with six known analogues, (1S,3R,5R,7S,8S,9S)-3,8-epoxy-1,5-dihydroxyvalechlorine, volvaltrate B, chlorovaltrate, rupesin B, (1S,3R,5R,7S,8S,9S)-3,8-epoxy-1-O-ethyl-5-hydroxyvalechlorine, and (1R,3R,5R,7S,8S,9S)-3,8-epoxy-1-O-ethyl-5-hydroxyvalechlorine. Their structures were elucidated by spectroscopic methods including homo- and heteronuclear two-dimensional NMR experiments. Chlorovaltrates K-N, chlorovaltrate and rupesin B showed moderate cytotoxicity against lung adenocarcinoma (A 549), metastatic prostate cancer (PC-3M), colon cancer (HCT-8) and hepatoma (Bel 7402) cell lines with IC₅₀ values of 0.89-9.76 μM.

Two new iridoids from roots of Patrinia scabra Bunge

Two new iridoids 1,3-dimethyloxy-7-hydroxymethyl-4-(3-methyl-butyryloxymethyl)-1-hydrocyclopenta-4,7-diene[c]pyran-6-one (1) and 1,3-dimethyloxy-7-hydroxymethyl-4-methyloxymethyl-1-hydrocyclopenta-4,7-diene[c]pyran-6-one (2) were isolated from the roots of Patrinia scabra Bunge. The structure elucidation of the isolated compounds was based primarily on HRESIMS, EIMS, IR, UV, 1D- and 2D-NMR analyses, including COSY, HMQC, HMBC and NOESY correlations, as well as X-ray crystallographic analysis.

Carpedilactones A–D, Four New Isomeric Sesquiterpene Lactone Dimers with Potent Cytotoxicity from Carpesium faberi

Four new isomeric sesquiterpene lactone dimers, carpedilactones A-D (1-4), were isolated from the acetonic extract of Carpesium faberi. Among them, 1-3 are the first three 2,4-linked exo-Diels-Alder adducts between a eudesmanolide dienophile and a guaianolide diene. The absolute configurations of 1-4 were unambiguously established by Cu Kα X-ray crystallographic analyses. Compounds 1-4 exhibited potent cytotoxicities against human leukemia (CCRF-CEM) cells with IC50 value of 0.14, 0.32, 0.35, and 0.16 μM, respectively.

New Sesquiterpenoids from Ainsliaea macrocephala and Their Nitric Oxide Inhibitory Activity

Investigation of the ethanol extract of the whole plant of Ainsliaea macrocephala led to the isolation of five new sesquiterpenoids, namely ainsliadimer C (1), ainsliadimer D (2), ainsliaolide B (3), ainsliatone B (4), and ainsliaolide C (5), together with seventeen known sesquiterpenes and sesquiterpene glycosides (6- 22). Their structures were elucidated by spectroscopic methods. The relative stereochemistry of ainsliadimers C (1) and D (2) were further confirmed by single crystal X-ray diffraction analysis. Total extract of A. macrocephala and compounds 1- 22 were tested for inhibitory activity against the production of nitric oxide in RAW 264.7 cells stimulated by LPS, as well as for cytotoxicity against RAW 264.7 macrophages. Of all samples tested, purified compounds 4, 7, and 12 strongly inhibited the production of nitric oxide with IC50 values of 8.78, 2.50, and 7.11 µM, and simultaneously showed low cytotoxicity against RAW 264.7 macrophages.

A New Furostanol Saponin from Asparagus cochinchinensis

A new furostanol saponin, (25S)-26-O-β-d-glucopyranosyl-5β-furost-20(22)-en-3β, 15β,26-triol-3-O-[α-l-rhamnopyranosyl-(1–4)]-β-d-glucopyranoside, namely, aspacochioside D (1) were isolated from Asparagus cochinchinensis (Lour.) Merr, along with three known saponins, aspacochioside C (2), (25S)-5β-spirostan-3β-yl-O-[O-α-l-rhamnopyranosyl-(1–4)]-β-d-glucopyranoside (3), and pseudoprotoneodioscin (4). The structure of 1 was elucidated on the basis of chemical reactions and spectral analysis (IR, GC, ESI-MS, 1H-NMR, 13C-NMR, DEPT, HMBC, HMQC and NOESY). The antiproliferative effects of 1–4 were evaluated in a cytotoxicity assay against the human tumor cell line, A549. Compound 2 (Aspacochioside C) exhibited moderate cytotoxicity against A-549, with an IC50 value of 3.87 μg/mL.

Diterpenoid lanceolatins A–G from Cephalotaxus lanceolata and their anti-inflammatory and anti-tumor activities

Seven new diterpenoids lanceolatins, A–G (1–7), together with five known diterpenoids (8–12), were isolated from the branches and leaves of Cephalotaxus lanceolata. The structures of the new diterpenoids were elucidated based on spectroscopic analysis, including 1D, 2D NMR, and HR-ESI-MS. Single crystal X-ray diffraction (CuKα radiation) was employed to confirm the structure of lanceolatin G (7), and its absolute configuration was finally established. Compound 12 showed significant inhibition against human tumor cell lines HCT116 and HepG2 with IC50 values of 0.17 and 0.63 μg mL−1, respectively, whereas compounds 3–5 can inhibit nitric oxide (NO) release in LPS-induced RAW264.7 macrophages with IC50 values of 8.72, 10.79, and 12.73 μM, respectively.