Sesquiterpenoids from Tussilago farfara and their inhibitory effects on nitric oxide production.

Tussilagone (TSL) and its allied sesquiterpenoids were considered as the main active principles of the flower buds of Tussilago farfara, which has been widely used in China as an antitussive herbal medicine. Six new bisabolane-type sesquiterpenoids, tussfararins A-F (1-6), along with 12 known sesquiterpenoids, were isolated from the flower buds of T. farfara. Structures of the new compounds were elucidated by extensive spectroscopic analysis. The biological analysis showed that compounds 1, 3, 6, and 7 inhibited nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells with IC50 values of 13.6-24.4 µM.

Kadcotriones A-C: tricyclic triterpenoids from Kadsura coccinea.

Three new triterpenoids, kadcotriones A-C (1-3), together with the biogenetically related lanostane-type triterpenoid (4), were isolated from Kadsura coccinea. Compound 1 features a 12,14ß-dimethyl 6/6/6-fused tricyclic skeleton, while 2 and 3 are characterized by a 6/6/5-ring system. Their structures were determined by NMR and electronic circular dichroism spectroscopic methods. Compounds 2 and 4 exhibited anti-HIV-1 activities with EC50 values of 30.29 and 54.81 µM, respectively.

Cytotoxic indole alkaloids from Tabernaemontana divaricata.

Five new vobasinyl-ibogan-type bisindole alkaloids, tabernaricatines A-E (1-5), two new monomers, tabernaricatines F and G (6 and 7), and 24 known indole alkaloids were isolated from the aerial parts of Tabernaemontana divaricata. Alkaloids 1 and 2 are the first vobasinyl-ibogan-type alkaloids possessing a six-membered ring via an ether linkage between C-17 and C-21. All compounds except for 3 were evaluated for their cytotoxicity against five human cancer cell lines; conophylline showed significant bioactivity against HL-60, SMMC-7721, A-549, MCF-7, and SW480 cells with IC50 values of 0.17, 0.35, 0.21, 1.02, and 1.49 µM, respectively.

Triterpenoids and steroids with cytotoxic activity from Emmenopterys henryi.

Two new ursane-type triterpenoids, 3ß,19α,23-trihydroxyurs-12-en-24-al-28-oic acid (1) and 3ß,19α,24-trihydroxy-23-norurs-12-en-28-oic acid (2), two new pregnane derivatives, 3ß,12ß-dihydroxy-5α-pregnane-14,16-dien-20-one (9) and 12ß-hydroxy-5α-pregnane-14,16-dien-3,20-dione (10), and eight known compounds were isolated from the twigs and leaves of Emmenopterys henryi. The structures of the new compounds were elucidated on the basis of extensive spectroscopic analysis, including 1D and 2D NMR experiments. Compounds 4, 11, and 12 showed cytotoxicity against HL-60, SMMC-7721, A-549, MCF-7, and SW-480 cell lines with IC50 values in the range of 3.11-20.12 µM.

Diterpenoids from the twigs and leaves of Fokienia hodginsii.

Five new isopimarane diterpenoids, fokihodgins A-E (1-5), four new labdane diterpenoids, fokihodgins F-I (6-9), and one new icetexane diterpenoid, fokihodgin J (10), as well as 18 known diterpenoids were isolated from Fokienia hodginsii. The structures of the new compounds were determined on the basis of their spectroscopic analysis, and the absolute configurations of 1 and 6 were established by X-ray crystallographic analysis. Compound 9 showed moderate cytotoxicity against HL-60 and SMMC-7721 cell lines, with IC50 values of 9.10 and 7.50 µM, respectively.

Cytotoxic limonoids from Melia azedarach.

Five new compounds (1-5), including two limonoids, one triterpenoid, one steroid, and one sesquiterpenoid, along with nine known limonoids (6-14), were isolated from the bark of Melia azedarach. The structures of the new compounds were elucidated by 2D NMR spectroscopy and mass spectrometry. The isolated compounds as well as three acetylated derivatives of 9 were evaluated for their cytotoxicities against five human tumor cell lines (HL-60, SMMC-7721, A-549, MCF-7, and SW480) by an MTT assay. Seven limonoids (1, 6, 7, 8, 9, 9b, and 9c) showed significant inhibitory activities against tested cell lines with IC50 values ranging from 0.003 to 0.555 µM, and their preliminary structure-activity relationships are also discussed.

Kadcoccitones A and B, two new 6/6/5/5-fused tetracyclic triterpenoids from Kadsura coccinea.

A pair of new triterpenoid epimers, kadcoccitones A (1) and B (2), together with a new biogenetically related compound kadcoccitone C (3), were isolated from Kadsura coccinea. The epimers featured an unprecedented carbon skeleton with a 6/6/5/5-fused tetracyclic ring system unit and a C(9) side chain. Their structures were determined by spectroscopic data, ECD calculation, and single-crystal X-ray diffraction. Compounds 1 and 3 showed anti-HIV-1 activity with an EC(50) value of 47.91 and 32.66 µg/mL, respectively.

Melodinines M-U, cytotoxic alkaloids from Melodinus suaveolens.

Nine new alkaloids, melodinines M-U (1-9), and 11 known alkaloids were isolated from Melodinus suaveolens. The new structures were elucidated by extensive NMR and mass spectroscopic analyses and comparison to known compounds. All compounds were evaluated for their cytotoxicity against five human cancer cell lines. Compounds 6, 11, and 16 showed significant cytotoxicity.

Phenols with anti-HIV activity from Daphne acutiloba.

The present paper describes the study of the phytochemical properties and anti-HIV activity of the phenolic isolates of the plateau medicinal plant Daphne acutiloba Rehd. (Thymelaeceae). Two new lignans named daphnenin (1) and daphnetone (2), along with 11 known ones, were isolated, and their structures were elucidated by 1D and 2DNMR spectroscopy aswell as HR­ESI­MS. In the anti-HIV activity study, daphnenin (1) and caffeic acid n-octadecyl ester (13) showed definite anti-HIVactivity with EC(50) values of 0.39 and 0.16 µg/mL, respectively.

Daphnane-type diterpene esters with cytotoxic and anti-HIV-1 activities from Daphne acutiloba Rehd.

Seven previously unreported daphnane-type diterpene esters named acutilobins A-G, together with 12 known ones, were isolated from EtOAc extract of Daphne acutiloba Rehd. Their structures were elucidated based on the spectroscopic data. The cytotoxic and anti-HIV-1 activities of these daphnane-type diterpene esters were evaluated through bioassays. Fourteen of these isolates exhibited definite cytotoxic activities against the five human tumor cell lines HL-60, SMMC-7721, A-549, MCF-7, and SW480. Additionally, anti-HIV-1 activities were observed in 13 daphnane-type diterpene esters, among which acutilobins A-G exhibited significant anti-HIV-1 activities with EC50 below 1.5 nM and SI over 10,000. Particularly, genkwanineVIII showed the strongest activity with EC50 0.17 nM and SI 187,010.

One new pregnane glycoside from the seeds of cultivated Brucea javanica.

A new pregnane glycoside, named (20R)-O-(3)-ß-D-glucopyranosyl-(1→2)-α-L-arabinopyranosyl-pregn-5-en-3ß,20-diol (1), and seven known compounds, brusatol (2), bruceine B (3), bruceine D (4), yadanziolide A (5), bruceine E (6), yadanzioside G (7), and yadanzioside B (8), were isolated from the cultivated dry seeds of Brucea javanica. The structure of 1 was elucidated on the basis of 1D- and 2D-NMR spectroscopic analyses. Their inhibitory effects on tumor cells were also tested. Compound 1 was slightly active against HL-60, SMMC-7721, A-549, and MCF-7 tumor cells. Compounds 2 and 3 demonstrated significant inhibitory activities against all tested cells. These results indicate that cultivated B. javanica could replace the wild plant as an antitumor plant resource.

Five new diarylpropan-1-ols from Combretum yunnanense.

Five new 1,3-diarylpropan-1-ols, combretol A-E (1- 5), together with one known coumarin (6) and ten known triterpenes (7-16), were isolated from Combretum yunnanense. Their structures were determined by spectroscopic investigation, including ¹H and ¹³C NMR, NOESY, HSQC, HMBC, and HRESIMS analyses. This is the first report on the occurrence of 1,3-diarylpropan-1-ols and coumarin in the Combretum genus including C. yunnanense. Also, to the best of our knowledge, 1,3-diarylpropan-1-ols are rare in nature.

Neoclerodane diterpenoids from Scutellaria barbata.

Eight new neoclerodane diterpenoids (1- 8), scutebatas H-O, together with eight known compounds, have been isolated from the whole plant of Scutellaria barbata D. Don. Their structures were elucidated on the basis of spectroscopic studies. In vitro cytotoxicity of selected compounds against cancer cell lines HL-60, SMMC-7721, A-549, MCF-7, and SW480 was evaluated. Compounds 5, 6, 7 showed moderate cytotoxicities against several human cancer cell lines, with IC50 values ranging from 12.6-31.4 µM. In addition, compound 1 showed selective cytotoxicity against MCF-7.

New chalcone and dimeric chalcones with 1,4-p-benzoquinone residue from Combretum yunnanense.

New chalcone and dimeric chalcones with 1,4- P-benzoquinone residue, combrequinone A (1), combrequinone B (2), and combrequinone C (3), along with three known compounds (4-6), were isolated from the ethanolic extract of the stems and leaves of Combretum yunnanense, and their structures were determined by spectroscopic analysis. Compounds 1-3 were evaluated for in vitro cytotoxicity against five human cancer cell lines: HL-60, SMMC-7721, A-549, MCF-7, and SW480. Compounds 1, 2 and 3 were found to be most potent against HL-60 acute leukemia cells, with IC50 values of 4.63, 4.07, and 1.26 µM, respectively.