Shu-Lin Peng

Stimuli-induced gel–sol transition of multi-sensitive supramolecular β-cyclodextrin grafted alginate/ferrocene modified pluronic hydrogel

This paper studies a kind of biocompatible hydrogel composed of alginate-g-β-cyclodextrin (Alg-β-CD) and ferrocene-terminated pluronic F127 (F127-Fc), which showed gel–sol phase transformations in response to temperature, oxidizing agents, and glucose because of the reversible association–dissociation of Fc-β-CD inclusions and F127 micelles.

Semi-permeable nanocapsules of konjac glucomannan-chitosan for enzyme immobilization.

Carboxymethyl konjac glucomannan-chitosan (CKGM-CS) nanocapsules, spontaneously prepared under very mild conditions by electrostatic complexation, were used for immobilizing L-asparaginase. The matrix has semi-permeability to allow the substrate and product to pass through and to keep L-asparaginase in the matrix to prevent leaking. The cell-like hydrogel matrix was prepared in aqueous system without organic solvents and reagents. The process of the preparation does not denature the enzyme and the activity of the immobilized and native enzyme is very similar. The activity, stability, and characters of the enzyme-loaded nanocapsules were studied. The results indicated the immobilized enzyme has better stability and activity in contrast to the native enzyme. These studies may supply a new material for the immobilization of pH and temperature-sensitive enzyme.

Self-assembly hollow nanosphere for enzyme encapsulation

This paper studies a kind of self-assembled hollow nanosphere for L-asparaginase encapsulation, and it was found that the hollow spheres not only enable a high loading of enzyme, but also show semi-permeability which could prevent the enzyme from leaving while allowing substrates and products to pass through to maintain the enzyme activity, and the encapsulated L-asparaginase showed significantly higher stability.

Chemical constituents from the aerial parts of Artemisia minor.

Four new compounds including three bicoumarins, arteminorins A-C (1-3), and one neolignan, arteminorin D (4), together with 31 known ones were isolated from the aerial parts of Artemisia minor. Their structures were established on the basis of spectroscopic data and comparison with those of the related known compounds. Ethyl caffeate (27) showed in vitro cytotoxicity against the HepG2 cancer cell line. Arteminorin C (3) and luteolin (19) showed inhibitory activity on xanthine oxidase (XOD), and caffeic acid (28) exhibited inhibitory activity on protein tyrosine phosphatase 1B (PTP1B).

Selective extraction of berberine from Cortex Phellodendri using polydopamine-coated magnetic nanoparticles

A new extraction agent featuring dopamine self-polymerized on magnetic Fe3 O4 nanoparticles has been successfully synthesized and evaluated for the SPE of berberine from the extract of the traditional Chinese medicinal plant, Cortex Phellodendri. The nanoparticles prepared possessed a core-shell structure and showed super-paramagnetism. It was found that these polydopamine-coated nanoparticles exhibited strong and selective adsorption for berberine. Among the chemical components present in C. Phellodendri, only berberine was adsorbed by the nanoparticles and extracted by a following SPE procedure. Various conditions such as the amount of polydopamine-coated nanoparticles, desorption solvent, desorption time and equilibrium time were optimized for the SPE of berberine. The purity of berberine extracted from C. Phellodendri was determined to be as high as 91.3% compared with that of 9.5% in the extract. The established SPE protocol combined advantages of highly selective enrichment with easy magnetic separation, and proved to be a facile efficient procedure for the isolation of berberine. Further, the prepared polydopamine-coated magnetic nanoparticles could be reused for multiple times, reducing operational cost. The applicability and reliability of the developed SPE method were demonstrated by isolating berberine from three different C. Phellodendri extracts. Recoveries of 85.4-111.2% were obtained with relative standard deviations ranging from 0.27-2.05%.

Minor iridoids from the roots of Valeriana wallichii

Four new iridoids, valeriotetrates B and C (1 and 2), 8-methylvalepotriate (3), and 1,5-dihydroxy-3,8-epoxyvalechlorine A (4), together with three known iridoids, were isolated from the roots of Valeriana wallichii. The structures of the new compounds were elucidated by analysis of 1D and 2D NMR and HRESIMS data. Compound 4 is an unusual iridoid bearing a C-10 chloro group and an oxo bridge connecting C-3 and C-8, resulting in a rigid skeleton.

A New Dimeric Iridal Triterpenoid from Belamcanda chinensis with Significant Molluscicide Activity

An unprecedented dimeric triterpenoid, designated dibelamcandal A, with a six-membered ring linking two iridal type triterpenoid nuclei, was isolated from the rhizome of Belamcanda chinensis. Its structure was determined by extensive spectroscopic measurements, including IR, ESI-MS, HR-ESI-MS, and 1D and 2D NMR. It demonstrated significant molluscicide activity against Pomacea canaliculata.

Two new triterpenoid saponins from Gymnema sylvestre

Two new oleanane-type triterpenoid saponins, gymnemoside-W1 and W2, together with seven known compounds were isolated from the leaves of Gymnema sylvestre R. Br. By means of spectral and chemical analysis, the structures of the new compounds were elucidated as 16 beta-hydroxyl olean-12-en-3-O-[beta-D-glucopyranosyl (1-->6)-beta-D-glucopyranosyl]-28-O-beta-D-glucopyranoside(1) and 16 beta,21 beta,28-trihydroxyl-olean-12-ene-3-O-glucoronopyranoside (2). The EtOH/H(2)O extracts of this plant were shown to be able to inhibit glucose absorption in rats.

Encapsulation studies and selective membrane permeability properties of self-assembly hollow nanospheres

This paper presents a kind of self-assembled hollow nanosphere for enzyme encapsulation. The enzyme molecules were encapsulated in hollow spheres directly in aqueous solution through the self-assembly of rod-coil Alg-g-PEG and α-CDs complexes. These Alg-g-PEG/α-CD hollow spheres showed semi-permeability which could prevent big enzyme molecules from leaving while allowing small substrates and products to pass through to maintain the enzyme activity. The permeability properties of Alg-g-PEG/α-CD hollow nanospheres were investigated by encapsulating different probes. The results showed that the molar mass cutoff (MMCO) of these hollow nanospheres was between 20 and 40 kDa. The encapsulation capability of Alg-g-PEG/α-CD hollow nanospheres was also investigated, the results indicated a maximal values for L-asparaginase encapsulation. Furthermore, the encapsulation behavior for L-asparaginase showed PEG graft density (GD) dependence.

Chemical constituents from Cimicifuga foetida

From the rhizoma of Cimicifuga foetida L. (Ranunculaceae) a new chromone, 6′-hydroxylangelicain (18), has been isolated together with 20 known compounds. The structure of 18 has been elucidated on the basis of spectroscopic and chemical evidence.