Biomedical subjects
Publications and source records attributed to Han-Dong Sun.
[structure: see text] A novel nortriterpene, micrandilactone A, was isolated from the medicinal plant Schisandra micrantha. This is the first example of an unusual, natural, highly oxidized cycloartane skeleton with a biosynthetically modified eight-membered ring D isolated from the family Schisandraceae.
A new ent-kaurane diterpenoid maoyecrystal F (1) and its acetonide derivative (2), together with seven known compounds, lasiodonin, maoyerabdosin, odonicin, enmenin, oridonin, beta-sitosterol and daucosterol, were isolated from the leaves of Isodon japonica.
Phytochemical investigation of the ethanol extract of the leaves of Ligustrum robustum, monitored by a bioassay involving the hemolysis of red blood cells induced by 2,2'-azo-bis(2-amidinopropane) dihydrochloride, led to the isolation of three new glycosides, ligurobustosides M (1), N (2), and O (3), along with 10 known ones, osmanthuside B (4), osmanthuside B6 (5), acteoside (6), ligupurpuroside A (7), ligupurpuroside B (8), ligurobustoside C (9), ligurobustoside E (10), ligurobustoside I (11), cosmosiin (12), and rhoifolin (13). The structures of the new compounds were elucidated by spectroscopic methods. Seven of the glycosides showed stronger antioxidant effects than the standard, trolox.
Bioassay-guided fractionation resulted in the isolation of four antifungal agents from the roots of Cudrania cochinchinensis. Two of these were new compounds, cudraxanthone S [1, 1,3,5,6-tetrahydroxy-2-(1,1-dimethyl-2-propenyl)xanthone] and cudraflavanone B (2, 2',4',5,7-tetrahydroxy-6-prenylflavanone). The remaining two compounds were known compounds, toxyloxanthone C (3) and wighteone (4). Among these compounds, 1, 3, and 4 exhibited antifungal activities against Cryptococcus neoformans, Aspergillusfumigatus, and A. nidulans (MICs = 2-8 microg/mL). Compounds 1 and 3 also showed antifungal activity against Candida glabrata (MICs = 4-8 microg/mL).
In a chemical study of taxonomically related Taxaceae plants of Yunnan Province, China, seven compounds, including a new amentoflavone biflavonoid, 2,3-dihydro-7,7' '-dimethoxyamentoflavone (1), were isolated from Amentotaxus yunnanensis, and 12 isolates were obtained from Torreya yunnanensis. From the latter plant, a new abietane diterpene, torreyayunnin (7), is reported for the first time. The known isolates from A. yunnanensis have been identified as sequoiaflavone (3), sotetsuflavone (4), 7,7' '-dimethoxyamentoflavone (5), lutein, beta-sitosterol, and sequoyitol. Amentoflavone (2), sotetsuflavone (4), sciadopitysin (6), 12-hydroxydehydroabietinol, meridinol, balanophonin, (+)-pinoresinol monomethyl ether, (+)-pinoresinol monomethyl ether glucoside, erythro-1-(4-hydroxy-3-methoxyphenyl)-2-[4-[2-formyl-(E)-vinyl]-2- methoxyphenoxy]propane-1,3-diol, threo-1-(4-hydroxy-3-methoxyphenyl)-2- [4-[2-formyl-(E)-vinyl]-2-methoxyphenoxy] propane-1,3-diol, and (E)-2-butenedioic acid were identified as known isolates from T. yunnanensis. The presence of the amentoflavone biflavonoids (1, 3-5) in A. yunnanensis supports its placement in the Taxaceae. The occurrence of the biflavonoid sotetsuflavone (4) in both A. yunnanensis and T. yunnanensis suggests that these two genera are closely related. The identification and structural elucidation of these isolates were based on spectral data analysis including 1D and 2D NMR.
Five new ent-kaurane diterpenoids, ludongnins F-J (1-5), along with 10 known compounds, guidongnins A-C (6-8), angustifolin (9), 6-epiangustifolin (10), sculponeatin J (11), gardenin D, 5,3',4'-trihydroxy-6,7,8-trimethoxyflavone, pedalitin, and quercetin, were isolated from the leaves of Isodon rubescens var. lushiensis. The structures of 1-5 were determined by spectroscopic analysis, as well as X-ray crystallographic analysis of 1. Compounds 1-11 were evaluated against K562 leukemia cells for their cytotoxic effects.
Five new ent-kaurane diterpenoids, enanderianins K-O (1-5), and one new ent-abietane diterpenoid, enanderianin P (6), together with five known ent-kaurane diterpenoids, rabdocoetsin A (7), rabdocoetsin B (8), rabdocoetsin D (9), megathyrin A (10), megathyrin B (11) were isolated from the aerial parts of Isodon enanderianus. Their structures were determined by spectral means. Some diterpenoids were tested for their cytotoxicity against the human tumor K562 cells. Compounds 1, 2, 6, 8, 9 showed significant inhibitory activities against K562 cells with IC50 values ranging from 0.13 to 0.87 microg/mL.
Two novel octanortriterpenoids, micranoic acids A (1) and B (2), along with three known compounds, kadsuric acid (3), 3beta-hydroxy-lanost-9(11),24(25)-dien-26-oic acid (4) and schizandronic acid (5), were isolated from the leaves and stems of Schisandra micrantha. The structures of 1 and 2 were determined by 1D and 2D NMR spectroscopic analysis. Micranoic acids A and B represent a new group of triterpenes in which the entire C-17 side chain has lost. This is the first report of octanortriterpenoids isolated from the family Schisandraceae.
Four new ent-kaurane diterpenoids lushanrubescensins F-I (1-4), together with 11 known ones, lasiodonin (5), oridonin (6), ponicidin (7), isodonoiol (8), isodonal (9), rabdosin B (10), rabdoternins A and B (11 and 12), enmenol (13), epinodosin (14), and inflexusin (15), were isolated from Isodon rubescens var. lushanensis, and the structures were elucidated by spectroscopic analysis. The inhibitory effect against the K562, Bcap37, BGC823, BIU87, CA, CNE, and Hela cell lines of compounds 3 and 5-10 were evaluated.
Three new 11beta,16beta-epoxy-ent-kauranoids melissoidesins I-K (1-3) and one new ent-abietanoid melissoidesin L (4) were obtained from the aerial parts of Isodon melissoides (BENTHAM) H. HARA, their structures were established on the basis of the spectral methods, especially two dimensional (2D) NMR spectroscopy.
We have previously reported that ponicidin (PND), isolated from Rabdosia ternifolia, potentiates the cell-killing activity of antiherpes prodrugs acyclovir (ACV) and ganciclovir (GCV) in human cancer cells expressing herpes simplex virus thymidine kinase (HSV-TK). To extend these in vitro results to in vivo situations, HSV-TK-expressing HeLa cells were injected into nude mice. The in vivo growth of TK(+) HeLa cells was significantly inhibited by coadministration of PND and ACV, or of PND and GCV, compared with single use of ACV or GCV in spite of lower doses of 1 or 0.25 mg/mouse, respectively. These results indicate that there is a good correlation between this in vivo efficacy and previously reported in vitro efficacy. Because of the insufficiency of incorporation of genes into tumors, bystander cell killing has attracted special interest. In the present study, we determined the ability of PND to potentiate the bystander effects of ACV and GCV in both in vitro and in vivo systems. In vitro combined use of PND with ACV or GCV rendered tumor cells more sensitive to the prodrugs, demonstrating a 1.8- to 97-fold or 2.8- to 26-fold reduction in IC(50) compared with ACV or GCV only, respectively, in 1 to 20% of HSV-TK(+) cells. In the in vivo experiments using nude mice injected with 3 or 10% HSV-TK(+) cells, tumor volume was lower in mice treated with a combination of PND and ACV/GCV than in those treated with ACV or GCV only. No toxicity of PND was seen in mice even at a dose 10-fold higher than that used in the in vivo experiments. These novel strategies could provide benefit to ablative cancer gene therapy by making it feasible to use toxic GCV at lower doses and relatively nontoxic ACV.
Four ent-kauranoids, 6-epiangustifolin and enanderinanins F-H, as well as 11 known ent-kaurane diterpenoids, macrocalin B, xerophilusin A, trichorabdal A, trichorabdal B, effusin, angustifolin, longikaurin D, longikaurin F, enanderinanin B, xerophilusin G and shikokianin were isolated from the aerial parts of Isodon enanderianus. The new diterpenoids were identified as 6-epiangustifolin (11alpha-hydroxy-6alpha-methoxy-6,19-epoxy-6,7-seco-ent-kaur-16-en-15-one-7,20-olide), enanderinanin F (19-acetoxy-6,20:6,11beta-diepoxy-6,7-seco-ent-kaur-16-en-15-one-1beta,7-olide), enanderinanin G (1beta,6beta,7beta-trihydroxy-19-acetoxy-16beta-methoxymethyl-7alpha,20-epoxy-ent-kaur-15-one) and enanderinanin H (6beta,7beta,14beta-trihydroxy-1alpha,11beta-acetonide-7alpha,20-epoxy-ent-kaur-16-en-15-one), respectively, on the basis of spectral data, especially by 2D NMR techniques. 6-Epiangustifolin showed significant cytotoxic activity against K562 cell.
A new stilbene, gnetifolin M (1), was isolated from the lianas of Gnetum montanum, together with seven known compounds, resveratrol (2), gnetol (3), 4', 5,7-trihydroxy-3'-methoxyflavone, beta-sitosterol, daucosterol, ursolic acid, and tetracosanoic acid. The structure of 1 was determined to be 2-(5'-methoxy-3'-hydroxyphenyl)-4-hydroxybenzofuran on the basis of spectroscopic evidence.
Eight new abietane diterpenoids, coleon U 11-acetate (1), 16-acetoxycoleon U 11-acetate (2), and xanthanthusins F-K (3-8), together with five known analogues, coleon U (9), 16-O-acetylcoleon C (10), coleon U-quinone (11), 8alpha,9alpha-epoxycoleon U-quinone (12), and xanthanthusin E (13), were isolated from the aerial parts of Coleus xanthanthus. The structures of 1-8 were elucidated on the basis of spectral methods. Compounds 1, 5, and 11-13 were evaluated for their cytotoxicity against K562 human leukemia cells.
Four new ent-kaurane diterpenoids, laxiflorins J-M (1-4), along with maoecrystal A (5) and maoecrystal P (6), were isolated from the leaves of Isodon eriocalyx var. laxiflora. Their structures were determined by spectroscopic analyses. All the compounds were assayed for their cytotoxic effects on human tumor K562, A549, and T24 cell lines. Compounds 1 and 6 showed significant inhibitory effects on human tumor K562 and T24 cells, with IC(50) values less than 0.5 microg/mL. Compound 3 also demonstrated cytotoxic activities against all three types of human tumor cells, with IC(50) values in the range of 1-25 microg/mL.
Eleven new diterpenoids, adenanthins B-L (1-11), together with five known analogues, calcicolin B (12), adenanthin (13), weisiensin A (14), nervosanin (15), and forrestin C (16), were isolated from the aerial parts of Isodon adenantha. The structures of 1-11 were elucidated on the basis of spectral methods, as well as the X-ray crystallographic analysis of 11. Compounds 2, 5, and 14 showed significant inhibitory activities against K562 cells, with IC(50) values less than 4.0 microg/mL, respectively.
Four new 11(15-->1)-abeotaxoids with an opened oxetane ring system, taxuyunnanines S, T, U and V (1 - 4) were isolated from the bark of Taxus yunnanensis. Taxuyunnanine S (1), is the most hydroxylated abeotaxoid discovered to date from Taxus species. The structures were determined by spectroscopic means including 1D and 2D NMR experiments.
Three new ent-kaurane diterpenoids laxiflorin E (1), laxiflorin H (6) and laxiflorin I (8) were isolated from the leaves of Isodon eriocalyx var. laxiflora, along with nine known diterpenoids, eriocalyxin A (2), laxiflorin C (3), laxiflorin D (4), laxiflorin A (5), maoecrystal S (7), maoecrystal Q (9), eriocalyxin B (10), maoecrystal C (11) and enmelol (12). The structures of the new compounds were determined by spectroscopic methods. Compounds 1-5 are 6,7-seco-ent-kaurane-7,20-olide diterpenoids, and 6-12 belong to 7,20-epoxy-ent-kauranoids. The spectral data of enmelol (12) are reported here for the first time. Ten of these compounds were tested for their cytotoxicity toward K562 and T24 human tumor cells. Compounds 1, 3 and 10 showed significant inhibitory effects on K562 cells with IC50 values 0.077, 0.569 and 0.373 microg/mL, and compounds 1 and 10 also demonstrated significant inhibitory activities toward T24 cells with IC50 values 0.709 and 0.087 microg/mL. Compounds 8 and 11 also displayed inhibitory effect on both two kinds of cells with IC 50 value less than 6.5 microg/mL.