Biomedical subjects
Publications and source records attributed to Rong-Tao Li.
Human cathepsin K, matrix metalloproteinase 9, and alpha(V)beta(3) integrin are the key regulators in osteoclast-mediated bone resorption. In this paper, we found natural inhibitors 1-10 for them by enzyme inhibition assays. Inhibitors 1-7, 8-9, and 10 are novel inhibitors of human cathepsin K, matrix metalloproteinase 9, and alpha(V)beta(3), respectively.
[structure: see text] Two novel nortriterpenoid compounds, sphenadilactones A (1) and B (2), have been isolated from the leaves and stems of Schisandrasphenanthera. The structural elucidation of 1 and 2 was accomplished by extensive NMR analysis. The relative stereochemistry of 1 was established by single-crystal X-ray crystallography. Both compounds were tested for their cytotoxicities against K562, A549, and HT-29, and compound 1 was further tested for its anti-HIV-1 activity.
Rubriflordilactones A (1) and B (2), two novel highly unsaturated rearranged bisnortriterpenoids possessing a biosynthetically modified aromatic D-ring, were isolated from the leaves and stems of Schisandra rubriflora. Their structures were established on the basis of extensive spectroscopic methods, including two-dimensional NMR techniques, and confirmed by X-ray crystallographic analysis. Compound 1 showed weak anti-HIV-1 activity, and compound 2 exhibited an EC50 value of 9.75 microg/mL (SI=12.39) against HIV-1 replication with low cytotoxicity.
Six new ent-labdane diterpenoids, 3-O-beta-D-glucopyranosyl-14,19-dideoxyandrographolide (1), 14-deoxy-17-hydroxyandrographolide (2), 19-O-[beta-D-apiofuranosyl(1-->2)-beta-D-glucopyranoyl]-3,14-dideoxyandrographolide (3), 3-O-beta-d-glucopyranosylandrographolide (4), 12S-hydroxyandrographolide (5), and andrographatoside (6), together with 17 known analogues, were isolated from the aerial parts of Andrographis paniculata. The structures of 1-6 were determined by spectroscopic data analysis. All compounds isolated were evaluated for their inhibitory activity against several bacterial and fungal strains.
A new trinorcycloartane triterpenoid, lancifodilactone H (1), and a new A ring-secocycloartane triterpenoid, lancifoic acid A (2), together with a known compound, nigranoic acid (3), were isolated from the leaves and stems of Schisandra lancifolia. Their structures were elucidated by spectroscopic data analysis. Compound 1 features a biosynthetically modified seven-membered lactone ring, which was confirmed by single-crystal X-ray diffraction. Compounds 1-3 exhibited weak anti-HIV-1 activity in vitro.
Six new nortriterpenoids, lancifodilactones I-N (1-6), as well as nine known ones, were isolated from the leaves and stems of Schisandra lancifolia. Their structures were elucidated on the basis of spectroscopic methods including 2D NMR analysis, and the structures of compounds 1 and 4 were further confirmed by single-crystal X-ray crystallography. In addition, all new compounds were tested for anti-HIV-1 activity.
[structure: see text] Two novel triterpene dilactones with an unprecedented rearranged hexacyclic skeleton, kadlongilactones A (1) and B (2), have been isolated from the leaves and stems of Kadsura longipedunculata Finet et Gagnep (Schisandraceae). Their structures were established by comprehensive 1D and 2D NMR spectroscopic analysis, coupled with single-crystal X-ray crystallographic diffraction. Compounds 1 and 2 exerted significant inhibitory effects against human tumor K562 cells with IC(50) = 1.40 and 1.71 microg/mL, respectively.
Two new highly oxygenated nortriterpenoids with a unique norcycloartane skeleton, micrandilactones B and C, were isolated from Schisandra micrantha; micrandilactone C exhibited an EC50 value of 7.71 microg/mL (SI > 25.94) against HIV-1 replication with minimal cytotoxicity, and the potent anti-HIV-1 activity and unique structural features of make it a promising lead for therapeutic development of a new generation of anti-HIV drug.
[structure: see text]. Lancifodilactone G (1), a novel, highly oxygenated nortriterpenoid featuring a partial enol structure and a spirocyclic moiety, was isolated from the medicinal plant Schisandra lancifolia. Its structure and stereochemistry were determined from extensive one- and two-dimensional NMR and mass spectral data, coupled with single-crystal X-ray analysis. Compound 1 exerted minimal cytotoxicity against C8166 cells (CC50 > 200 microg/mL) and showed anti-HIV activity with EC50 = 95.47 +/- 14.19 microg/mL and a selectivity index in the range of 1.82-2.46.
Four new, highly oxygenated nortriterpenoids with unique schisanartane skeletons, micrandilactones D-G (1-4), have been isolated from the leaves and stems of Schisandra micrantha, and their structures have been elucidated on the basis of extensive spectral studies. The postulated biogenetic sequences of sixteen highly oxygenated nortriterpenoids and bisnortriterpenoids with new skeletons from three Schisandra species are discussed and have been compared from a chemotaxonomic standpoint.
[structures: see text] Lancifodilactone F (1), possessing an unprecedented rearranged pentanortriterpenoid backbone derived from cycloartane, was isolated from the leaves and stems of Schisandra lancifolia (Rehd. et Wils) A. C. Smith. Its structure was established by comprehensive NMR and MS spectroscopic analysis, coupled with single-crystal X-ray experiment. Compound 1 exerted minimal cytotoxicity against C8166 cells (CC50 > 200 microg/mL) and showed anti-HIV activity with EC50 = 20.69 +/- 3.31 microg/mL and a selectivity index > 6.62.
Investigation on the anthelminthic bioactive compounds of the ethanol extract of Tadehagi triquetrum resulted in the isolation of three new prenylated isoflavones, triquetrumones A (1), B (2), and C (3), and one new prenylated biisoflavanone, (R)-triquetrumone D (4), along with 16 known compounds, cyclokievitone (5), yukovanol (6), aromadendrin (7), kaempferol (8), astragalin (9), 2-O-methyl-l-chiro-inositol (10), galactitol (11), p-hydroxycinnamic acid (12), ursolic acid (13), betulinic acid (14), beta-sitosterol (15), daucosterol (16), stigmasterol (17), stigmasta-5,22-dien-3-O-beta-d-glucopyranoside (18), saccharose (19), and docosanoic acid (20). The structures of 1-4 were elucidated on the basis of spectroscopic and spectrometric methods. Compounds 1-3 displayed mild anthelminthic bioactivity, and compound 3 showed a significant binding ability to the estrogen receptor.
Nine new diterpenoids, albopilosins B-J (1-9), together with six known analogues, albopilosin A (10), macrocalyxin C (11), rabdokunmin C (12), excisanin (13), amethystonoic acid (14), and coetsanoic acid (15), were isolated from the aerial parts of Isodon albopilosus. The structures of 1-9 were established using spectroscopic methods including extensive 1D and 2D NMR analysis. The diterpenoids isolated were evaluated for their inhibitory activities against HepG2 (hepatoma) cells. Compounds 7 and 13 were the most active, with both having IC(50) values of <15 microM.
Two new compounds, rubescensins Q and R (1 and 2), and a new acetonide derivative (3) of lasiodonin, together with thirteen known analogues, oridonin (4), ponicidin (5), wikstroemioidin B (6), lasiodonin (7), lasiokaurin (8), enmenol (9), 1-O-beta-D-glucopyranosyl-enmenol (10), trichokaurin (11), the acetonide of maoyecrystal F (12), rabdoternins A-D (13-16), have been isolated from Isodon rubescens var. taihangensis. The structures of the new compounds were elucidated on the basis of spectroscopic methods, especially the 2D NMR spectral analysis. Compound 3 exhibited cytotoxicity against K562, Bcap37, CA, CNE, BIU87, BGC823, and HeLa cell lines.
Reinvestigation of the aerial parts of Isodon melissoides has afforded two new ent-diterpenoids, melissoidesins V (1) and W (2), together with five known ones, glabcensin W (3), melissoidesin C (4), melissoidesin A (5), melissoidesin B (6) and melissoidesin D (7), one new ionone derivative 3alpha,4alpha-isopropyliden-beta-ionol (8), as well as three analogues, 3-hydroxy-4-oxo-beta-ionol (9), megastigma-7-en-3,5,6,9-tetraol (10) and blumenol A (11), and three phenolic compounds salicylic acid (12), syringic acid (13) and cirsiliol (14). The new structures were elucidated on the basis of spectroscopic techniques, especially the 2D-NMR spectral analysis.
Both coriatone (1). a novel highly oxygenated picrotoxane-type sesquiterpene, and corianlactone (2). with an unprecedented sesquiterpene basic skeleton, named coriane, were isolated from Coriaria nepalensis Wall. The structures of 1 and 2 were determined by analysis of their two-dimensional NMR data, and the structure of 2 was confirmed by X-ray analysis. Compounds 1 and 2 showed no remarkable inhibitory activity toward K(562) cells. They are cytotoxic with IC(50) > 50 microg/mL (cis-platinim: IC(50) = 0.49 microg/mL).
Three new ent-kaurene diterpenoids, oreskaurins A-C (1-3), together with ten known ent-kaurene diterpenoids, enmenin monoacetate (4), effusanin E (5), adenolin B (6), maoecrystal G (7), enmelol (8), trichokaurin (9), sodoponin (10), trichorabdal A (11), nodosin (12), enmein (13), and a flavonoid, vitexin (14), were isolated from Isodon oresbius. Their structures were determined by spectroscopic means. Compound 12 showed inhibitory activity toward K562 cells with IC(50)=1.43 microg/ml.
Four new nortriterpenes, lancifodilactones B-E (1-4), were isolated from the leaves and stems of Schisandra lancifolia. Their structures were determined by analysis of 1D and 2D NMR spectroscopic data. These compounds are members of a new highly oxygenated cycloartane skeletal class with a biosynthetically modified eight-membered ring D.