Zhi-g Yan

Flavonoids and their derivatives with β-amyloid aggregation inhibitory activity from the leaves and twigs of Pithecellobium clypearia Benth

To explore potential compounds with marked effect on Alzheimers disease (AD) in Pithecellobium clypearia Benth., nineteen compounds (1-19) were obtained, including two new flavonoid derivatives, named pithecellobiumol A (1) and pithecellobiumol B (2) and 17 flavonoids (3-19). Their structures were elucidated based on 1D and 2D-NMR spectra as well as HR-ESI-MS data. The absolute configurations of new compounds were assigned by comparing their experimental specific rotation or ECD curves with the calculated data. The inhibitory activity on Aβ aggregation was screened by ThT assay, and compounds 7 (70.7%), 9 (86.5%), 10 (88.4%), 15 (86.1%) and 16 (87.7%) showed outstanding inhibition rate at 20μM compared to the positive control, curcumin (65.64%). In addition, docking study was performed to initially examine possible molecular mechanisms. Considering the important role of oxidative stress in AD, all the isolated compounds were tested for their H2O2-induced damage in human neuronblastoma SH-SY5Y cells. Among them, compound 16 (91.0%) was the most potent candidate in the treatment of AD.

Network pharmacology-based screening of the active ingredients and potential targets of the genus of Pithecellobium marthae (Britton & Killip) Niezgoda & Nevl for application to Alzheimer’s disease

Abstract Alzheimer’s disease (AD) is a progressive neurodegenerative disorder associated with synaptic dysfunction, pathological accumulation of β-amyloid (Aβ), and neuronal loss. Given the prevalence of AD and the lack of effective long-term therapies, there is a pressing need to discover viable leads that can be developed into clinically approved drugs with disease-modifying effects. The analysis of current reported literatures confirms the importance of the plants of Pithecellobium genus as candidate against AD. Hence, it is necessary to identify selective anti-dementia agents from this genus. To explore potential compounds with marked effect on AD in Pithecellobium genus, a compound database based on the methods of network pharmacology prediction was established in this paper by constructing the compound-disease target network. The result showed that the most effective compound in the plants of this genus might be (7′R,8′R)-7′-methoxyl strebluslignanol, and the most potential target might be Macrophage colony-stimulating factor 1 receptor.

Investigation of chemical constituents of safflower and their tyrosinase inhibitory activity

Abstract Investigation on bioactive chemical constituents of safflower led to the isolation of 10 compounds from the aqueous extract, including a new alkaloid (1), a new glucopyranoside (2), and 8 known compounds (3–10). The structures of two new compounds were elucidated on the basis of extensive spectral analyses, including 1D, 2D-NMR and HRESIMS. Biological research on the isolates indicated that compounds 3, 4 and 9 remarkably inhibited tyrosinase with IC50 at 0.11, 0.20 and 0.11 mM, respectively, compared with the positive control arbutin (0.26 mM). To investigate the interaction between enzyme and isolated compounds, an in silico docking study was carried out. The research provided valuable experience for phytochemistry and biological investigation on safflower.

Racemic phenylpropanoids from the root barks of Ailanthus altissima (Mill.) Swingle with cytotoxicity against hepatoma cells

Four pairs of racemic phenylpropanoids (1a/1b-4a/4b), including five new compounds (1a/1b, 2a, 3a, and 4a) were obtained from the root barks of Ailanthus altissima (Mill.) Swingle. Their structures were determined by comprehensive spectroscopic analyses. The absolute configurations of the enantiomers were determined by comparison of the experimental ECD and OR with the calculated data. The antitumor activity of all isolates was evaluated against two human hepatoma carcinoma cells (HepG2 and Hep3B) in vitro. It was demonstrated that 1a/1b showed potent selective cytotoxicity against HepG2 cells. Additionally, 1a/1b could also induce apoptosis enantioselectively as demonstrated by Hoechst staining experiment.