Supramolecular nanoparticle loaded with bilirubin enhances cartilage protection and alleviates osteoarthritis via modulating oxidative stress and inflammatory responses.

Osteoarthritis (OA) is a chronic inflammation that gradually leads to cartilage degradation. Prolonged chondrocyte oxidative stress contributes to the development of diseases, including chondrocyte apoptosis, cartilage matrix degradation, and aggravation of articular cartilage damage. Bilirubin (BR) possesses strong antioxidant properties by scavenging reactive oxygen species (ROS) and potent protection effects against inflammation. However, its insolubility and short half-life limit its clinical use. Therefore, we developed a supramolecular system of ε-polylysine (EPL) conjugated by ß-cyclodextrin (ß-CD) on the side chain, and bilirubin was loaded via host-guest interactions, which resulted in the self-assemble of this system into bilirubin-loaded polylysine-ß-cyclodextrin nanoparticle (PB) with improving solubility while reducing toxicity and prolonging medication action time. To explore PB's potential pharmacological mechanisms on OA, we established in vitro and in vivo OA models. PB exerted ROS-scavenging proficiency and anti-apoptotic effects on rat chondrocytes by activating the Nrf2-HO-1/GPX4 signaling pathway. Additionally, PB reprogrammed the cartilage microenvironment by regulating the NF-κB signaling pathway to maintain chondrocyte function. Animal experiments further confirmed that PB had excellent scavenging ability for ROS and inflammatory factors related to charge adsorption with cartilage as well as long retention ability. Together, this work suggests that PB has superior protective abilities with beneficial effects on OA, indicating its great potential for intervention therapy targeting chondrocytes.

Evaluation Procoagulant Activity and Mechanism of Astragalin.

Astragalin, isolated from flowers of Rosa chinensis Jacq., is a kind of flavonoid, with anti-inflammatory, antioxidant, antiviral, analgesic, antibacterial, antiallergic, and antihepatotoxic effects. However, no studieson the procoagulant effect of astragalin have been reported. This study aimed to investigate the procoagulant activity of astragalin and its mechanism. Its procoagulant effect was investigated by activated partial thromboplastin time (APTT), thrombin time (TT), prothrombin time (PT), and fibrinogen (FIB) in vitro, and a rat model established by heparin sodium was used to evaluate the mechanism for the procoagulant effect in vivo. The results showed that astragalin had good procoagulant effects compared with the control group in vitro. Compared with the model group in vivo, astragalin could shorten the coagulation time and significantly increase the number of platelets. Meanwhile, astragalin could significantly reduce the effectual time of PT and APTT and increase the content of FIB. The contents of 6-keto-PGF1α and eNOS significantly decreased. Astragalin could increase whole blood viscosity (WBV), plasma viscosity (PV), erythrocyte sedimentation rate (ESR) and packedcell volume (PCV). All of the above revealed that astragalin had good procoagulant effects by promoting the intrinsic and extrinsic coagulation system.

Chemical constituents and coagulation activity of Syringa oblata Lindl flowers.

The leaves and bark of Syringa oblata Lindl are used as folk medicine which has heat-clearing, detoxifying, dampness-removing and jaundice-relieving effects. There are many studies about leaves of S. oblata because of its abundant resource, however, less reports about the components of S. oblata flowers. The previous studies on S. oblate flowers were mainly focused on the volatile components and its traditional pharmacological activity. Thus, this study aimed to investigate the nonvolatile chemical constituents and the coagulation activity of S. oblate flowers. The chemical constituents of S. oblate flowers were isolated with various column chromatographies and coagulation activity of the major constituents was investigated by assaying the activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT) and fibrinogen (FIB) on plasma of rabbit in vitro. Fifteen known compounds (namely compound 1-15) were isolated from S. oblata flowers. Compound 6, 10, 11 and 14 were isolated from Syringa genus for the first time. Compound 1, 2, 4, 5, 8 and 9 were isolated from the plant for the first time. The results of coagulation activity showed that water part of S. oblate flowers, lauric acid and kaempferol-rutinose significantly shorten PT (P < 0.001), TT (P < 0.001) and APTT (P < 0.001) compared with blank group, thus revealed that water extract of S. oblate flowers, lauric acid and kaempferol-rutinose possessed the procoagulant activity, but the effects were not better than that of Yunnan Baiyao as positive control.