Natural Products from Pithecellobium clypearia

Anti-influenza effect and action mechanisms of the chemical constituent gallocatechin-7-gallate from Pithecellobium clypearia Benth.[Pubmed: 29802302]

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Enantiomeric lignans with anti-β-amyloid aggregation activity from the twigs and leaves of Pithecellobium clypearia Benth.[Pubmed: 29477125]

To develop potential agents for slowing the progression of Alzheimer's disease, two pairs of new enantiomeric lignans, including a couple of rarely 8',9'-dinor-3',7-epoxy-8,4'-oxyneolignanes named (7S, 8S)- and (7R, 8R)-pithecellobiumin A (1a/1b) and a pair of 2',9'-epoxy-arylnaphthalenes named (7R, 8R, 8'R)- and (7S, 8S, 8'S)-pithecellobiumin B (2a/2b) were separated by chiral high performance liquid chromatography (HPLC). Their planar structures were elucidated by spectroscopic data analyses. The absolute configurations were determined by comparing of experimental and calculated electronic circular dichroism (ECD). The inhibitory activity on Aβ aggregation of all optical pure compounds was tested by ThT assay. Interestingly, enantiomeric inhibitors 1a (62.1%) and 1b (81.6%) exhibited different degrees of anti-Aβ aggregation activity. However, 2a (65.4%) and 2b (68.4%) showed similar inhibition rate. The different inhibition profiles were explained by molecular dynamics and docking simulation studies.

Flavonoids and their derivatives with β-amyloid aggregation inhibitory activity from the leaves and twigs of Pithecellobium clypearia Benth.[Pubmed: 28988761]

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Pharmacokinetic study of gallocatechin-7-gallate from Pithecellobium clypearia Benth. in rats.[Pubmed: 26904400]

The pharmacokinetic profile of gallocatechin-7-gallate (J10688) was studied in rats after intravenous administration. Male and female Sprague-Dawley (SD) rats received 1, 3, and 10 mg/kg (i.v.) of J10688 and plasma drug concentrations were determined by a high performance liquid chromatography-mass spectrometry (LC-MS) method. The pharmacokinetic software Data Analysis System (Version 3.0) was used to calculate the pharmacokinetic parameters. For different i.v. doses of J10688, the mean peak plasma concentration (C 0) values ranged from 11.26 to 50.82 mg/L, and mean area under the concentration-time curve (AUC0-t ) values ranged from 1.75 to 11.80 (mg·h/L). J10688 lacked dose-dependent pharmacokinetic properties within doses between 1 and 10 mg/kg, based on the power model. The method developed in this study was sensitive, precise, and stable. The pharmacokinetic properties of J10688 in SD rats were shown to have rapid distribution and clearance values. These pharmacokinetic results may contribute to an improved understanding of the pharmacological actions of J10688.

Studies on the bioactive flavonoids isolated from Pithecellobium clypearia Benth.[Pubmed: 24727419]

One new flavonoid named (2R,3R)-7-O-galloylplumbocatechin A (1) and three known flavonoids, (-)-5,3',4',5'-tetrahydroxyflavan-7-gallate (2), (+)-3,5,3',4',5'-penta-hydroxyflavan-7-gallate (3), and (-)-7,4'-di-O-galloyltricetiflavan (4), were isolated from Pithecellobium clypearia Benth. Their structures were elucidated based on spectroscopic analysis, including homonuclear and heteronuclear correlation NMR (HSQC and HMBC) experiments. In vitro assays, compounds 1 and 2 showed moderate inhibitory effects against influenza H1N1 virus neuraminidase (NA). Compounds 1-4 were all found to inhibit the expression of proinflammatory cytokines IL-6 or MCP-1 induced by influenza H1N1 virus in human A549 lung carcinoma cells.