Biomedical subjects

Xiao-Dong Luo

Publications and source records attributed to Xiao-Dong Luo.

10 recordsLinked to original sources

PubMed2006

New antioxidant phenolic glycosides from Walsura yunnanensis.

Four new polyphenolic glycosides (1-4) were isolated from the BuOH extract of the bark of Walsura yunnanenis C. Y. Wu. These compounds comprise two lignans, i.e., the 9-O-alpha-L-arabinopyranosides 1 and 2 of (-)-isolariciresinol and of (+)-5-methoxyisolariciresinol, respectively, and the two phenolic glycosides 3,4,5-trimethoxyphenyl 2-O-(alpha-L-fucopyranosyl)-beta-D-glucopyranoside (3) and 3,5-dihydroxyphenyl 6-O-(4-hydroxy-3,5-dimethoxybenzoyl)-beta-D-glucopyranoside (walsuraside; 4). In addition, three known compounds, 3,4,5-trimethoxyphenyl beta-D-glucopyranoside, asperglaucide, and butyl alpha-D-fructofuranoside were identified. Their structures were elucidated spectroscopically and by chemical transformation (hydrolysis). The new compounds 1, 2, and 4 displayed significant antioxidant activities, with IC(50) values in the range of ca. 42 to 49 microg/ml.

Antioxidants↗

PubMed2005

Compound representatives of a new type of triterpenoid from Aglaia odorata.

[structure: see text] A novel triterpenoid, 21,25-cyclodammar-20(22)-ene-3beta,24alpha-diol, has been isolated from Aglaia odorata. Its structure was elucidated on the basis of 1D- and 2D-NMR and MS spectra and then confirmed by X-ray diffraction. It represents a new type of natural five-membered-ring triterpenoid, named cyclodammarane. Its possible biopathway was that squalene-2,3;22,23-diepioxide was directly cyclized to form 24,25-epoxydammar-20(21)-en-3-ol, followed by protonation of the remaining 24,25-epoxide and the cation attacking 21(20) methylene to generate the E ring.

Aglaia↗

PubMed2005

Quinones from Chirita eburnea.

Five new quinone derivatives, (R)-7-hydroxy-alpha-dunnione (1), (R)-8-hydroxy-alpha-dunnione (2), (R)-7,8-dihydroxy-alpha-dunnione (3), (R)-7-methoxy-6,8-dihydroxy-alpha-dunnione (4), and 1,7-dihydroxy-2-hydroxymethylanthraquinone (5), along with seven known compounds, were isolated from Chirita eburnea. All structures were elucidated by spectroscopic techniques (NMR, MS, UV, and IR). The EtOAc fraction of the EtOH extract and compounds 3 and 4 showed free radical (DPPH) scavenging activity, with IC50 values of 101.7 +/- 5.2 microg/mL, 124.82 +/- 8.4 microM, and 45.72 +/- 3.6 microM, respectively, compared with 86.91 +/-6.8 microM for ascorbate.

Algorithms↗

PubMed2005

A new diterpenoid and active stilbenes from Pinus armandii heartwood.

8(17),13-Labdadien-16,14-olid-18-oic acid (1), a new diterpenoid, has been isolated from the heartwood of Pinus armandii Francher, along with seven known diterpenoids (2-8) and four known stilbenes (9-12). Their structures have been elucidated by spectral evidence. (E)-3-Hydroxy-5-methoxystilbene (9) showed significant inhibition against white-rot fungi.

Diterpenes↗

PubMed2004

Constituents of Carapa guianensis Aubl. (Meliaceae).

Nine compounds were isolated from the EtOH extraction of the twig of Carapa guianensis Aubl. On the basis of spectroscopic methods, their structures were elucidated as 1,3-di-benzene carbon amine-2-octadecylic acid-glyceride (1), hexacosanoic acid-2,3-dihydroxy-glyceride (2), ursolic acid (3), naringenin (4), scopoletin (5), 3,4-dihydroxymethylbenzoate (6), 2,6-dihydroxymethylbenzoate (7), tetratriacontanoic acid (8), triacontanoic acid (9) respectively. Among them 1 was new, 2 was firstly isolated from nature, and 3-9 were obtained from this plant for the first time.

Chemical Phenomena↗

PubMed2003

Insect antifeedants from Munronia henryi: structure of munroniamide.

A novel A,B-seco-tetranortriterpenoid lactam, named munroniamide (1), along with three known ceramides (2-4), was isolated from the methanolic extract of the whole bodies of Munronia henryi. The structure of 1 was established using spectroscopic methods. Compound 2 exhibited significant antifeeding activity, and 1 exhibited moderate activity, whereas 3 and 4 showed negative activity against Pieris brassicae L.

Animals↗

PubMed2003

Bioactive novel polyphenols from the fruit of Manilkara zapota (Sapodilla).

Activity-guided fractionation of a methanol extract from the fruit of Manilkara zapota cv. Tikal resulted in the isolation of two new antioxidants, methyl 4-O-galloylchlorogenate (1) and 4-O-galloylchlorogenic acid (2), along with eight known polyphenolic antioxidants, namely, methyl chlorogenate (3), dihydromyricetin (4), quercitrin (5), myricitrin (6), (+)-catechin (7), (-)-epicatechin (8), (+)-gallocatechin (9), and gallic acid (10). Of the 10 polyphenols, 1 showed the highest antioxidant activity (IC(50) = 12.9 microM) in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free-radical assay and displayed cytotoxicity in the HCT-116 and SW-480 human colon cancer cell lines with IC(50) values of 190 and 160 microM, respectively. Compound 2 showed high antioxidant activity (IC(50) = 23.5 microM) in the DPPH free-radical assay and displayed cytotoxicity in the HCT-116 and SW-480 human colon cancer cell lines with IC(50) values of 154 and 134 microM, respectively.

Antioxidants↗

PubMed2003

The chemical constituents of Munronia henryi.

Six compounds were isolated from the MeOH extract of the whole bodies of Munronia henryi. Their structures were elucidated as sitosterol-3-O-12',13'-epoxy-9'-oxo-(10'E)-octadecenoate (1), alpha-D-glucopyranosyl-6'-O-hexadecanoate (2), 4alpha,7alpha-aromodendranediol (3), 2beta,3beta,4beta-trihydroxypregnan-16-one (4), 4-O-alpha-D-psicofuranos-alpha-D-glucopyranose (5), and glyceryl-1-tetracosanoicate (6) on the basis of spectroscopic methods. Among them 1 was a new sterol carrying an octadecenoyl; 2 and 6 were isolated for the first time from a natural source.

Meliaceae↗

PubMed2002

Polyphenolic antioxidants from the fruits of Chrysophyllum cainito L. (Star Apple).

Chrysophyllum cainito L. (Sapotaceae), known commonly as star apple or caimito, is a tropical tree that bears edible fruits. The fruits are grown commercially in certain tropical and subtropical areas, such as southern Florida. In this study, the fresh fruits were extracted with methanol and partitioned with hexane and ethyl acetate sequentially. The ethyl acetate soluble fraction displayed high antioxidant activity in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay (IC50 = 22 microg/mL). Activity-guided fractionation of the ethyl acetate soluble fraction was performed to identify the antioxidant constituents. Nine known polyphenolic antioxidants, (+)-catechin (1), (-)-epicatechin (2), (+)-gallocatechin (3), (-)-epigallocatechin (4), quercetin (5), quercitrin (6), isoquercitrin (7), myricitrin (8), and gallic acid, have been identified from the fruits. Of these nine antioxidants, 2 is present in the highest concentration in star apple fruits (7.3 mg/kg fresh weight), and 5 showed the highest antioxidant activity (IC50 = 40 microM) in the DPPH assay.

Antioxidants↗

PubMed2002

Monoterpenoid derivatives from Paeonia delavayi.

Three new monoterpene glycosides, 4-O-ethylpaeoniflorin (1), 6'-O-benzoyl-4''-hydroxy-3"-methoxy-paeoniflorin (2), 6'-O-benzoylalbiflorin (3), and a new monoterpenoid, 9-hydroxy-paeonilactone-A (4) were isolated from the root cortex of Paeonia delavayi. Their structures were elucidated on the basis of spectral methods.

Glycosides↗