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Our present study investigated the anti-diabetic activity and potential mechanism of β-ecdysterone (β-EC) derived from Cyanotis arachnoidea . In vitro , β-EC exhibited a promising effect on increasing GLUT4 translocation by 1.6 folds and glucose uptake by 1.75 folds in L6 cells. In vivo , KK-Ay mice’s body weight, blood glucose levels and other related blood–lipid indexes can be significantly reduced with β-EC treatment. For the mechanism study, we have found that β-EC exhibited a significant protective effect on insulin resistance (IR) in L6 and HepG2 cells through increasing expressions of IRβ, p-Akt, p-IRS-1 and increasing the expressions of GLUT4 and GLUT2. The phosphorylation of Akt, IRS-1 and the expression of IRβ, GLUT4 and GLUT2 in the liver and skeletal muscle in KK-Ay mice were also significantly ameliorated after 4-weeks treatment with β-EC. According to our present findings, we could conclude that β-EC possessed the potential anti-diabetic effects through activating IRS-1/AKT/GLUT4 and IRS-1/AKT/GLUT2 pathways. [ABSTRACT FROM AUTHOR]

Bioassay-guided phytochemical investigation of the EtOAc fraction (ST-EtOAc) from the roots of Sophora tonkinensis resulted in the isolation of a new compound 6a R ,11a R -1-hydroxy-4-isoprenyl-maackiain ( 1 ), along with 12 known compounds ( 2 – 13 ). The structure of the new compound was established by 1D and 2D NMR, MS data and circular dichroism analysis. Polyprenylated flavonoids 6 – 9 and 11 – 13 increased GLUT-4 translocation by the range of 1.35–2.75 folds. Sophoranone (8 ) exerted the strongest activity with 2.75 folds GLUT-4 translocation enhancement at the concentration of 10 μM. This is the first report of the GLUT-4 translocation activity of the plant Sophora tonkinensis . [ABSTRACT FROM AUTHOR]

Sustainable stereocomplex-type polylactide (SC-PLA) has been recognized as a potential substitute for some traditional engineering plastics, however its widespread application still faces several hurdles primarily related to poor melt processability (i.e., the unfavorable melt memory effect in SC crystallization as well as the low melt strength) and insufficient fracture toughness. To overcome these hurdles, an equimolar poly(l -lactide)/poly(d -lactide) (PLLA/PDLA) blend toughened with poly(ethylene -co- vinyl acetate) (EVA) has been chosen as a model system and a facile strategy has been devised by incorporating trace amounts (i.e., 0.5 wt%) of epoxy-functionalized oligo(styrene-acrylic) (ESA) into the PLLA/PDLA/elastomer blends through direct melt-blending at 200 °C. Such a one-pot blending not only facilitates the stereocomplexation between PLLA and PDLA chains but also permits the highly efficient reaction between terminal hydroxyl groups of some enantiomeric PLAs and epoxy groups of ESA before their stereocomplexation. This results in the in situ generation of large amounts of long-chain-branched PLA- graft -ESA copolymer in the SC-PLA matrix. Very impressively, the generation of this PLA- graft -ESA copolymer gives rise to a substantial improvement in the melt memory effect of the SC-PLA matrix. This copolymer behaves as a compatibilizer to stabilize regular PLLA/PDLA chain clusters in blend melts and hence to stimulate the exclusive formation of SC crystallites in melt-processed blend products. In addition, long PLA branches endow the matrix with a considerably enhanced melt viscosity owing to the increased interchain entanglement density. Consequently, highly stereocomplexed SC-PLA/EVA products with exceptional impact toughness and heat resistance as well as robust mechanical strength have been prepared by injection molding. More notably, this strategy can be generalized to various SC-PLA-based blends, irrespective of whether the elastomers have reactive groups. Overall, these exciting findings illustrate a promising avenue toward the design and applications of high-performance SC-PLA-based materials with excellent melt-processability via the generation of unique graft copolymers having long PLLA and PDLA branches. [Display omitted] • SC-PLA/elastomer blends with markedly enhanced melt processability are designed. • Long-chain-branched copolymers are in-situ generated during melt-blending with ESA. • The chain branching induces drastically enhanced melt memory effect and melt strength. • The blends have been injection-molded into super-tough and heat-resistant products. • Our strategy can be generalized to various SC-PLA-based blends. [ABSTRACT FROM AUTHOR]

Abstract Polylactide (PLA), a promising biodegradable and renewable polymer, finds many applications, particularly, used as biodegradable fiber in textile industry. The key is to improve its heat resistance. In this work, small amount of poly (D-lactide) (PDLA) was added firstly into poly (L-lactide) (PLLA) matrix to form stereocomplex polylactide (SC-PLA), which has much better heat resistance than that of PLLA matrix. Then two melting temperatures were adopted for fiber spinning, the one (210 °C) is far below the melting temperature of SC-PLA (i.e., 220–230 °C), and the other (225 °C) is close to the melting temperature of SC-PLA. The boiling water shrinkage and tensile strength of PLLA/PDLA fibers were investigated as function of PDLA content. It was found, the boiling water shrinkage could be largely reduced to as low as 5.6% and a satisfactory tensile strength (628 MPa) is achieved for fibers spun at 225 °C, compared with fibers spun at 210 °C (7.5% and 500 MPa, respectively), as the PDLA content is 3 wt%. SEM observation suggests a formation of nanofibrillar like SC-PLA structure as spun at 225 °C, while only spherical SC-PLA particles as spun at 210 °C. DSC result indicates that adding PDLA could largely enhance the crystallization rate of PLLA, but almost a constant crystallinity and SC-PLA content were observed for both spun fibers, disregarding the spinning temperatures. Herman's orientation parameters of spun fiber were obtained from 2D-WAXD, which suggests that fiber spun at 225 °C has higher orientation than that of fiber spun at 210 °C. Thus it can be concluded that the formation of nanofibrillar like SC-PLA and enhanced orientation degree contribute mainly to the improved heat resistance and tensile strength. This work presents a feasible and effective way to fabricate all-PLA-based fibers with the outstanding heat resistance by adding a small amount of PDLA and using a suitable spinning temperature. Graphical abstract Image 1 Highlights • The influence of spinning temperature on the orientation and properties of PLLA/PDLA fibers was depicted in detail. • A critical PDLA content of increasing PLLA/PDLA fibers' heat resistant and mechanical property was revealed.. • All-PLA-based fiber with outstanding heat resistance was manufactured by melt spinning process. [ABSTRACT FROM AUTHOR]

Abstract As the most promising bio-derived and biodegradable polymers with tremendous application potential, the practical application of poly(l -lactide) (PLLA) has been severely restricted by its inherent brittleness. Unfortunately, blending with various rubbers can substantially enhance the toughness of PLLA, but usually causes a significant deterioration in mechanical strength and modulus. In this work, taking novel PLLA/core-shell rubber (CSR) blends as an example, we describe a facile and robust strategy to obtain good stiffness-toughness balance by promoting the networking of CSR particles within PLLA matrix with the aid of stereocomplex (SC) crystallites. To do this, small amounts (5–20 wt%) of poly(d -lactide) (PDLA) were incorporated into the blends through simple melt-blending. The results demonstrate that the CSR particles can be uniformly dispersed in PLLA matrix due to the good interfacial compatibility, but the stereocomplex (SC) crystallites formed between the incorporated PDLA and PLLA matrix chains induces the organization of the CSR particles into a network-like structure in the matrix. Compared with the well-dispersed structure, the network-like structure can endow the PLLA/CSR blends with dramatically enhanced impact toughness, without compromising their mechanical strength and modulus, indicating a marvelous balance between the stiffness and toughness. Furthermore, the elongation at break of the blends is also enhanced greatly. These interesting findings suggest that the formation of SC crystallites could provide a promising avenue for fabricating CSR particles toughened PLLA blends with balanced stiffness-toughness. Graphical abstract Image 1 Highlights • A promising strategy to induce the networking of CSR particles in PLLA/CSR blends has been reported. • The CSR particles can be organized into a network-like structure in PLLA matrix under the drive of SC crystallites. • The SC crystallites is formed during melt mixing of the blends with small amounts of PDLA. • The formation of the network structure can significantly enhance the toughening efficiency. • The obtained PLLA/CSR/PDLA blends exhibit a balanced stiffness and toughness. [ABSTRACT FROM AUTHOR]

Extracts and components of Taxodium ascendens Brongn, an excellent afforestation tree, have exhibited several activities, including antibacterial activity and inhibitory activity on carbonic anhydrase II. However, the anti-hepatocellular carcinoma (anti-HCC) activity of extracts from the leaves of T. ascendens (TALE) remains unclear. In the present study, six diterpenoid compounds were isolated from a TALE extract. Here, the pro-apoptotic activities and the molecular mechanisms of TALE and the compounds 1 – 6 on HepG2 and Hep3B HCC cells were evaluated. Results show that the TALE and compounds 1 – 6 were able to induce apoptosis in the HepG2 and Hep3B HCC cells, particularly ferruginol ( 3 ). Mechanistically, the application of TALE and ferruginol ( 3 ) resulted in a significant decrease in mitochondria membrane potential, which was coupled with an increase in the Bax/Bcl-2 ratio and caspase-3/-9 activity. In vivo experiments showed that oral administration of TALE inhibited the proliferation of transplanted H22 cells in Kunming mice. However, TALE toxicity in KM mice was undetectable. The study provides strong evidence for the anti-HCC capacity of TALE. [ABSTRACT FROM AUTHOR]

Despite of its enormous application potential as a prominent engineering bioplastic, the processing of the stereocomplex-type polylactide (SC-PLA) formed from poly(l -lactide)/poly(d -lactide) (PLLA/PDLA) blends into useful products remains challenging. Recently, low-temperature sintering has emerged as a feasible and promising processing technology towards transparent highly-crystalline SC-PLA products. During the sintering of SC-PLA nascent powder, the interfaces between adjacent particles could be bound together through SC crystallization of interdiffused PLLA and PDLA chains across the interfaces. However, the massive generation of the interface-localized SC crystallites is significantly impaired by the insufficient chain interdiffusion resulting from the rapid SC crystallization. In this work, miscible poly(methyl methacrylate) (PMMA) is adopted to substantially promote the chain interdiffusion by fundamentally diminishing the SC crystallization rate. Intriguingly, we find that the crystallization of PLLA/PDLA chains is greatly decelerated with the incorporation of PMMA and thus more enantiomeric PLA chains could interdiffuse through the interfaces before their crystallization. Moreover, the PMMA is also favorable for the particle wetting of the densified nascent powders, which makes it easier for the enantiomeric chains to interdiffuse across the interfaces. The promoted chain interdiffusion leads to an evident increase in the number of the newly-generated SC crystallites and resulting interfacial weld strength. Consequently, the sintered SC-PLA products possessing superior thermomechanical properties and markedly enhanced hydrolytic resistance have been fabricated by incorporating 9 wt% PMMA, without compromising transparency. These findings could bode well for the industrial fabrication and applications of SC-PLA products. Image 1 • PMMA has been used to improve the low-temperature sintering of SC-PLA nascent powder. • The PMMA can promotes the interdiffusion of PLLA/PDLA chains across the particle interfaces. • Both the decelerated crystallization and enhanced particle wetting contribute to the promotion of the chain interdiffusion. • Sufficient amounts of interface-localized SC crystallites are generated to achieve mechanically robust interfaces. • The obtained SC-PLA products have superior thermomechanical properties, transparency, and hydrolytic stability. [ABSTRACT FROM AUTHOR]