Silicon’s Influence on Polyphenol and Flavonoid Profiles in Pea (Pisum sativum L.) under Cadmium Exposure in Hydroponics: A Study of Metabolomics, Extraction Efficacy, and Antimicrobial Properties of Extracts

The current study aimed to investigate the impact of
silicon (Si)
supplementation in the form of Na2SiO3 on the
metabolome of peas under normal conditions and following exposure
to cadmium (Cd) stress. Si is known for its ability to enhance stress
tolerance in various plant species, including the mitigation of heavy
metal toxicity. Cd, a significant contaminant, poses risks to both
human health and the environment. The study focused on analyzing the
levels of bioactive compounds in different plant parts, including
the shoot, root, and pod, to understand the influence of Si supplementation
on their biosynthesis. Metabolomic analysis of pea samples was conducted
using a targeted HPLC/MS approach, enabling the identification of
15 metabolites comprising 9 flavonoids and 6 phenolic acids. Among
the detected compounds, flavonoids, such as flavon and quercetin,
along with phenolic acids, including chlorogenic acid and salicylic
acid, were found in significant quantities. The study compared Si
supplementation at concentrations of 1 and 2 mM, as well as Cd stress
conditions, to evaluate their effects on the metabolomic profile.
Additionally, the study explored the extraction efficiency of three
different methods: accelerated solvent extraction (ASE), supercritical
fluid extraction (SFE), and maceration (MAC). The results revealed
that SFE was the most efficient method for extracting polyphenolic
compounds from the pea samples. Moreover, the study investigated the
stability of polyphenolic compounds under different pH conditions,
ranging from 4.0 to 6.0, providing insights into the influence of
the pH on the extraction and stability of bioactive compounds.