Phytochemical Profiling of Phragmites australis Leaf Extract and Its Nano-Structural Antioxidant, Antimicrobial, and Anticancer Activities

Abstract

AbstractFreshwater macrophytes have attracted interest as an alternative source of natural extracts and minerals for a variety of therapeutic uses. However, few studies have rigorously investigated the phytochemical components, properties, and potential biological benefits of Phragmites australis as an emergent macrophyte. This study investigates the phytochemical profile of aqueous Phragmites australis (PAE) leaves extract using chromatographic-mass spectrometry and free radical scavenging analysis. LC-QToF-MS/MS analysis in both positive and negative ionization revealed the existence of thirty and eleven bioactive compounds, respectively tentatively identified as alkaloids, flavonoids, indoles, glycosides, and quinolines from the extract. The polyphenolic content of the PAE was found to be 39.17 ± 0.65 mg GAE/g total phenol, while the flavonoids content was 19.85 ± 2.64 mg QE/g, and proanthocyanins content was 119.65 ± 1.70 CE/g. The PAE was utilized to synthesize silver nanoparticles (AgNPs) to evaluate its nano-structural formation efficiency, with the PAE displaying a greater ability to scavenge free radicals against ABTS, DPPH, and FRAP when compared with PA-AgNPs. Both PAE and PA-AgNPs were tested for their antimicrobial and anticancer activities and the results indicated that PA-AgNPs (MIC value range of 7.8–62.5 µg/mL) had excellent antimicrobial activity, compared to PAE. Moreover, the antiproliferative effect of PA-AgNPs on human cancer cells showed a higher cell-specific dose response and two-fold apoptotic induction with increased phosphorylation in the DNA ss-strand break post-treatment in MCF-7 than in A549 cells. These findings reveal the potential of the leaf extract of PA as a potent antioxidant source for many biological applications.