Phenolic profiles and antioxidant activities of free, esterified and bound phenolic compounds in walnut kernel

HPLC fingerprinting-based multivariate analysis of chemical components in Tetrastigma Hemsleyanum Diels et Gilg: Correlation to their antioxidant and neuraminidase inhibition activities

Tetrastigma Hemsleyanum Diels & Gilg (TDG) has attracted growing attention in China; however, there were few studies on its bioactive components. Herein, the characteristic chemical components and dual antioxidant and neuraminidase inhibitory activities of fifteen batches of TDG from different places of origin and their relevance were investigated. The HPLC fingerprint was first established and the marker components were identified by using UPLC-Q-TOF-MS/MS. Catechin-5-O-β-d-glucopyranoside, tartaric acid, (1R, 2R, 4S)-2-hydroxy-1, 8-cineole-β-d-glucopyranoside, and phlorizin were identified for the first time. The result of multivariate statistical analysis indicated that multiple components have a significant contribution to the classification of TDG, such as chlorogenic acid, saccharumoside C/D, robinin, procyanidin B₂, rutin, isoquercitrin, etc. Then, the antioxidant and neuraminidase inhibitory activities of fifteen batches of TDG were measured. The result of grey relationship analysis showed that the contents of rutin, isoquercitrin, kaempferol-3-rutinoside, and astragalin were positively correlated with these two activities with correlation coefficients more than 0.8. The quantitative analysis of these four bioactive compounds was performed by using HPLC-DAD. The recovery rate of the method varied from 98.02% to 100.21%, the RSD values of precision, stability and repeatability were between 1.32-3.15 %, and the R value of the linear equation was above 0.9990. To sum up, this study is valuable in the quality control of TDG.

Exploration of the Wound Healing Potential of Thermoplastic Polyurethane Electrospun Membrane Incorporated with Phenolic Acids in Spenceria ramalana Trimen

Wound healing process is usually accompanied by infection and the wound dressing loaded with antibiotics is usually used to treat skin wound. However, the intensive use of antibiotics may lead to development of resistance and the antibiotic resistance has become a major global problem. Finding new wound dressing with sustained antibacterial property to overcome the problem of resistance is one of clinical challenge. In this work, phenolic acids in Spenceria ramalana Trimen and sliver nanoparticle incorporated thermoplastic polyurethane nanofibrous membrane (TPU/AgNPs/TPA) are fabricated via electrospinning. The TPU/AgNPs/TPA membrane exhibits excellent physicochemical properties with uniform morphology, good mechanical capacity, and appropriate hydrophilia providing suitable environment for wound healing. Moreover, the TPU/AgNPs/TPA membrane shows mild antioxidant property and exhibits continuous antibacterial activity against Staphylococcus aureus and Escherichia coli especially against drug-resistant E. coli. The antibacterial efficiency is as high as 99% lasting for 36 h. Furthermore, the TPU/AgNPs/TPA membrane used as wound dressing can accelerate wound healing through downregulating TNF-α and IL-1β and upregulating vascular endothelial growth factor and epidermal growth factor. Therefore, the TPU/AgNPs/TPA membrane presented in this work with good antibacterial activity is an excellent wound dressing and has great potential in wound healing applications to overcome the problem of resistance.