Insights into antibacterial mechanism of Apocynum Venetum L. fiber: Evolution of bioactive natural substances in bast during chemical degumming process

Abstract

There is an increasing interest in the study of biomass-derived cellulosic fiber. Apocynum venetum L. (A. venetum) is considered as a promising source for functional fiber. The antibacterial activity of textiles made from A. venetum fibers has been validated by fabrics testing, but the underlying antibacterial mechanism is still obscure. Here, a hypothesis of transformation and deposition was presented to explain the mechanism of antibacterial activity of A. venetum technical fiber. An in vitro experiment was designed and performed to simulate the chemical reaction pathway of antibacterial substances in the bast of A. venetum undergoing chemical degumming process. Chemical compositions and antibacterial properties of polyphenols and A. venetum bast, before and after the process were measured and analyzed. Results showed that water-soluble polyphenols became insoluble after alkaline degumming treatment at high temperature. MALDI-TOF spectrometry analysis also revealed the formation of oligomers from quercetin. Structural consistency between the insoluble product and A. venetum fiber was confirmed by second derivative infrared (SD-IR) and Raman spectroscopy. While, the resulting derivatives had significant antibacterial activity toward the assayed microorganisms in broth dilution tests. This investigation of transformation behavior of polyphenols provided new insights into material basis of A. venetum fiber for antibacterial property.