Argutalactone, an unprecedented sesquiterpenoid lactone with a 6/5/7 tricyclic system from Incarvillea arguta

Argutalactone (1), a novel sesquiterpenoid lactone featuring an unprecedented 6/5/7 rigid skeleton, was isolated from the roots of Incarvillea arguta. The structure and relative configuration of 1 were established by extensive analysis of spectroscopic data. The absolute configuration of 1 was determined as 2R,5S,10R,12S based on the analysis of biogenetical transformation, comparison of the optical rotation with literature data, and comparison of the experimental circular dichroism spectrum with the calculated electronic circular dichroism spectra.

Sesquiterpene lactones from Inula hookeri

Four new sesquiterpene lactones, (1 S,5 R,6 S,7 S,8 R,9 R,10 S,11 S)-6-acetoxy-9-hydroxy-4-oxo-pseudoguai-2(3)-en-12,8-olide, (1 S,2 R,5 R,6 S,7 R,8 S,10 R)-6-acetoxy-2-ethoxy-4-oxo-pseudoguai-11(13)-en-12,8-olide, (1 S,2 R,5 R,6 S,7 R,8 S,10 R)-6-acetoxy-2-hydroxy-4-oxo-pseudoguai-11(13)-en-12,8-olide, and 14-acetoxy-1 β,5 α,7 αH-4 β-hydroxy-guai-9(10),11(13)-dien-12,8 α-olide, along with 26 known sesquiterpene lactones, were isolated from the whole plants of Inula hookeri C. B. Clarke. Their structures were established based on spectroscopic methods including HRESIMS, 1D and 2D NMR, and CD techniques. All compounds were evaluated for their cytotoxic activities against HepG2, HeLa, PC-3, and MGC-803 cell lines by CCK-8 assay. Some of the isolates, especiallly pseudoguaianolides and guaianolides, exhibited significant cytotoxicities against these four examined cell lines.

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.

Cyclopenicillone, a unique cyclopentenone from the cultures of Penicillium decumbens

Cyclopenicillone (1), possessing a unique 2,5-dimethylcyclopent-2-enone carbon skeleton, has been isolated from the cultures broth of the fungus Penicillium decumbens. The structure and absolute configuration of 1 were elucidated using a combination of NMR spectroscopy, CD data and computational approaches. Cyclopenicillone (1) demonstrated a dose-dependent (10-100 μM) inhibition against LPS-induced NO production in RAW264.7 macrophages.

Mono- and sesquiterpenoids, flavonoids, lignans, and other miscellaneous compounds of Abies georgei

A systematic phytochemical investigation of the aerial parts of Abies georgei yielded nine new and 72 known compounds, including four monoterpenes, four sesquiterpenes, 25 flavonones, 14 lignans, and 34 other chemical constituents. The new compounds included two monoterpenes (1 and 2), two sesquiterpenes (3 and 4), three flavonones (5, 6, and 7), and two other components (8 and 9). Their chemical structures were established on the basis of various spectroscopic data. All the isolates were tested for antitumor and anti-inflammatory activities. The new compound 9,4'-dihydroxy-5,7-dimethoxy-8-methylchalcone (7) demonstrated a moderate antiproliferative effect on QGY-7703 tumor cells (IC (50)  = 17.6 µg/mL). The known compound isoferulaldehyde (67) exhibited the strongest inhibitory activity against lipopolysaccharide (LPS)-induced NO production in RAW 264.7 macrophages (IC (50) = 19.0 µg/mL). Abies georgei may be a significant source of beneficial pharmaceutical compounds.

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.

Heterocyclic compounds and aromatic diglycosides from Bretschneidera sinensis

Two new heterocyclic compounds, bretschneiderazines A and B (1, 2), three new aromatic diglycosides, bretschneiderosides A-C (3-5), and three known aromatic diglycosides, 6-8, were isolated from Bretschneidera sinensis. The structure of bretschneiderazine A (1) was confirmed by single-crystal X-ray diffraction analysis. Bretschneiderazine A (1) showed moderate activity against the NCI-H446 cell line.

Terpenoids from Daphne aurantiaca and their potential anti-inflammatory activity

Phytochemical examination of the methanolic extract from the stem bark of Daphne aurantiaca led to the isolation of six new sesquiterpenoids, dauca-3,11-dien-2alpha,15-diol (1), 3-oxoguai-4-ene-11,12-diol (2), 4alpha,5alpha,8alpha,11alphaH-3-oxoguai-1(10)-en-12,8-olide-7alpha-diol (3), 4alpha,5alpha,8alpha,11betaH-3-oxoguai-1(10)-en-12,8-olide-7beta-diol (4), 4alpha,5betaH-guai-9,7(11)-dien-12,8-olide-1alpha,8alpha-diol (5), 4alpha,5alphaH-guai-9,7(11)-dien-12,8-olide-1alpha,8alpha-diol (6), and a new diterpenoid, 12-O-benzoylphorbol 13-nonanoate (7), together with 10 known terpenoids. All compounds were tested for inhibitory activity against LPS-induced NO production in RAW 264.7 macrophages. Compounds 7, 8, 9, 10, and 11 showed potent inhibitory activities against NO production with IC(50) values of 0.01, 0.01, 0.06, 0.07, and 0.03 microM, respectively.

Iridoids and lignans from Valeriana jatamansi

Thirteen new iridoids including seven iridolactones, jatamanins A-M (1-13), and a new lignan, (+)-9'-isovaleroxylariciresinol (14), together with seven known iridoids and 13 lignans were obtained from whole plants of Valeriana jatamansi. Structures of the new compounds were determined by spectroscopic and crystallographic methods, and the absolute configuration of compound 1 was assigned by application of the modified Mosher method. Jatamanins H (8) and I (9) are iridolactones with an unusual C-8-C-11 oxygen bridge, forming a cage-like structure. (+)-9'-Isovaleroxylariciresinol (14) showed significant in vitro cytotoxicity against PC-3M and HCT-8 cell lines, with IC(50) values of 8.1 and 5.3 microM, respectively.

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.

Polyacetylenes from Bupleurum longiradiatum

Eight new polyacetylenes (1-8) and six known polyacetylenes were isolated from the entire parts of Bupleurum longiradiatum, a poisonous plant. The structures of the new compounds were determined by spectroscopic data interpretation. The absolute configuration of the known compound bupleurotoxin (9) was established by the modified Mosher's method. All isolates were also tested for their cytotoxicity against a human leukemia cell line (HL-60).

Chemical constituents of Dracocephalum forrestii

A systematic phytochemical examination of the whole plant Dracocephalum forrestii led to the isolation of 4 new and 65 known chemical constituents. By detailed 1D and 2D NMR spectroscopic analyses, the new compounds were identified as 4-hydroxy-3-methoxyphenylethanol 8- O-[(6- O-syringoyl)- beta- D-glucopyranoside] (1), 3,4,5-trimethoxyphenylethanol beta- D-glucopyranoside ( 2), 4- O-[ beta- D-glucopyranosyl-(1 --> 3)- alpha- L-rhamnopyranosyl]phenylethylcinnamamide (3), and 9''- O- N-butyl lithospermate (4). The new isolates were evaluated for inhibitory activities against LPS-induced NO production in RAW 264.7 macrophages. Compound 2 revealed a moderate effect without any cytotoxicity under the assayed concentrations.