A new bufadienolide with cytotoxic activity from the Chinese traditional drug Ch'an Su.

AIM: To study the bufadienolides in the Chinese traditional drug "Ch'an Su" and their cytotoxic activity. METHOD: Various chromatographic techniques were used to isolate the constituents, and their structures were elucidated through physical and spectroscopic data. RESULTS: Twenty compounds were isolated, and eighteen were evaluated in vitro for their cytotoxic activity against A-549 and K-562 cells. CONCLUSION: Compound 1 (bufalin 3ß-acrylic ester) was a new bufadienolide and exhibited the most potent activity against the two tumor cell lines with IC50 values of 7.16 and 6.83 nmol · L(-1). The relationships between structure and activity are discussed.

Diarylheptanoids and phenylphenalenones from Musa itinerans fruits.

Two diarylheptanoids, musaitinerins A and B, one heterodimeric phenylphenalenone musaitinerone and four known phenylphenalenones, identified as 4-hydroxy-2-methoxy-9-phenyl-1H-phenalen-1-one, musanolone E, hydroxyanigorufone and irenolone were isolated from the fruits of Musa itinerans Cheesm. Their structures were elucidated using spectroscopic analyses. The antimicrobial activity of these compounds was evaluated against Escherichia coli, Staphylococcus aureus and Candida albicans; the cytotoxic activity of these compounds was also evaluated against human erythromyeloblastoid leukemia (K562) and human alveolar carcinoma epithelial (A549) cell lines, respectively. Musaitinerone and musanolone E exhibited weak effects against the A549 cell line, as compared with adriamycin. However, these two compounds did not exhibit any growth inhibition against K562 cells, S. aureus, E. coli or C. albicans. The other compounds were inactive against all of the tested cell lines and microorganisms, even at concentrations as high as 50 µM.

Sarmentosumols A to F, new mono- and dimeric alkenylphenols from Piper sarmentosum.

Two new mono- and four new dimeric alkenylphenols, namely sarmentosumols A to F (1-6), were isolated from the aerial parts of Piper sarmentosum. The structures of these compounds were determined through a detailed analysis of NMR and MS data. Their antimicrobial activity against Escherichia coli, Staphyloccocus aureus, and Candida albicans, and their cytotoxic activity against human myeloid leukemia (K562) and human lung adenocarcinoma (A549) cell lines were also evaluated. Except for sarmentosumol A (1), whose MIC on S. aureus was reported to be 7.0 µg/mL, none of the other newly discovered compounds exhibited antimicrobial property. The studied compounds did not possess any cytotoxic property.

Nudibaccatumone, a trimer comprising a phenylpropanoid and two sesquiterpene moieties from Piper nudibaccatum.

A new complex natural product with a C39 skeleton, named nudibaccatumone, and the known sesquiterpenes (+)-spathulenol, (-)-4ß,10α-aromadendranediol, and ent-T-muurolol, as well as the phenylpropanoid hydroxychavicol, were isolated from the aerial parts of Piper nudibaccatum. The structure and absolute configuration of nudibaccatumone were elucidated using spectroscopic methods and ECD calculations. A 1,8-Michael addition reaction and an intermolecular, inverse electron demand Diels-Alder reaction are proposed as the key steps in the biosynthesis of nudibaccatumone.

[Study on chemical constituents of Euphorbia helioscopia and their antitumor activities].

OBJECTIVE: To investigate the chemical constituents of Euphorbia helioscopia and their antitumor activities. METHODS: Normal phase silica gel, RP-18 silica gel and Sephadex LH-20 column chromatographies combined with recrystallization were used to isolate and purify the constituents. Their structures were identifided by spectroscopic methods, including 1H-NMR, 13C-NMR, ESI-MS and EI-MS. And the antitumor activities of some of chemical constituents in vitro were detected by sulphorhodamine B protein staining. RESULTS: Nine compounds were isolated and their structures were identified as euphohelioscopin A (1), euphoscopin (2), 9, 19-cyclolanost-23E-ene-3, 25-diol (3), euphoscopin C (4), euphornin A (5), euphoheliosnoid A (6), ent-kaurane-3-oxo-16beta, 17-diol (7), 9, 19-cyclolanost-25-ene-3beta, 22-diol (8) and helioscopinolide A(9) Compound 9 showed effect on inhibiting the cell proliferations of MCF-7 cell line. CONCLUSION: Compounds 3, 7, 8 and 9 are obtained from this plant for the first time, and compound 9 shows the potential antitumor activity.

Trigonosins A-F, daphnane diterpenoids from Trigonostemon thyrsoideum.

Phytochemical study of the roots of Trigonostemon thyrsoideum led to the isolation of four new oxygenated daphnane-type diterpenoids, trigonosins A-D (1-4), and two new modified daphnanes, trigonosins E and F (5 and 6). The structures and relative configurations were elucidated on the basis of extensive spectroscopic analysis, including 1D and 2D NMR experiments. All compounds isolated were evaluated for their cytotoxicity against HL-60, A549, and MCF-7 human cancer cell lines.

Palhinine A, a novel alkaloid from Palhinhaea cernua.

Palhinine A, a novel C(16)N-type Lycopodium alkaloid with a unique 5/6/6/9 tetracyclic ring system, was isolated from the whole plant of Palhinhaea cernua L. (Lycopodiaceae). Its structure was elucidated by spectroscopic methods, and the absolute configuration was determined by single-crystal X-ray diffraction analysis using the Flack parameter. Palhinine A is reported as the first example of Lycopodium alkaloids of which C-16 is fused to a new ring through a C-16-C-4 lingkage.

Pyrrolidinoindoline alkaloids from Selaginella moellendorfii.

Eight new pyrrolidinoindoline alkaloids (1-8) were isolated from the whole plant of Selaginella moellendorfii. Their structures were determined by mass spectrometry, 1D and 2D NMR spectroscopy, and chemical interconversions. These alkaloids have a 3-carboxybut-2-enyl group at C-3a and two methyl groups at N-8. The possible biogenetic route from selaginellic acid (1) to neoselaginellic acid (6) was postulated and chemically mimicked. Tautomerization between 6 and 6a was observed. Selected compounds were evaluated for antibacterial, cytotoxic, and acetylcholinesterase inhibitory activities.

Structure elucidation and biomimetic synthesis of hostasinine A, a new benzylphenethylamine alkaloid from Hosta plantaginea.

Hostasinine A (1), a benzylphenethylamine alkaloid with an unprecedented skeleton featuring a C-4-C-6 linkage and a nitrone moiety, was isolated from Hosta plantaginea. Its structure was established on the basis of spectroscopic data, and was further confirmed by single-crystal X-ray diffraction. The alkaloid was postulated biogenetically from haemanthidine via N-oxidation and aza-aldol-type condensation and was synthesized biomimetically. The inhibitory activities of 1 on acetylcholinesterase (AChE) and two tumor cell lines (K562 and A549) were also evaluated.

Benzylphenethylamine alkaloids from Hosta plantaginea with inhibitory activity against tobacco mosaic virus and acetylcholinesterase.

Five new benzylphenethylamine alkaloids, hostasine (1), 8-demethoxyhostasine, 8-demethoxy-10-O-methylhostasine, 10-O-methylhostasine, and 9-O-demethyl-7-O-methyllycorenine, along with 12 known compounds, were isolated from Hosta plantaginea by bioassay-guided fractionation. The structures of the new alkaloids were established by means of extensive spectroscopic methods, and the relative configuration of 1 was further confirmed by single-crystal X-ray diffraction. 7-Deoxy-trans-dihydronarciclasine (IC(50) = 1.80 microM), a known alkaloid, showed strong activity against tobacco mosaic virus by the half-leaf method. Some of these alkaloids were also evaluated for their inhibitory activity against acetylcholinesterase. 8-Demethoxy-10-O-methylhostasine was found to possess significant activity, with an IC(50) of 2.32 microM.

Trijugin-type limonoids from the leaves of Cipadessa cinerascens.

Four new trijugin-type limonoids, cipatrijugins A-D (1-4), together with the known cipadesin A (5), were isolated from the leaves of Cipadessa cinerascens, and their structures were elucidated on the basis of spectroscopic and computational methods. The ability of compounds 1-5 to inhibit the growth of the A549 and K562 tumor cell lines was evaluated.