In vitro and in silico approaches to appraise Polygonum maritimum L. as a source of innovative products with anti-ageing potential

Different Polygonum species have in vitro neuroprotective properties and are traditionally used for their anti-ageing benefits. In this context this work explored for the first time P. maritimum (sea knotgrass) as a potential source of natural products with industrial application as cognitive enhancers with anti-ageing potential. For that purpose methanol and dichloromethane extracts were prepared from leaves and roots of that species and evaluated for in vitro neuroprotective effects through the inhibition on acetyl- (AChE) and butyrylcholinesterase (BuChE), protection against hydrogen peroxide (H2O2)-induced cytoxicity on neuroblastoma cells and lipopolysaccharide (LPS)-induced neuroinflammation on microglia cells. The extracts were chemically characterized by ultra-high-pressure liquid chromatography (UHPLC) coupled to tandem mass spectrometry (MS/MS) and docking studies were performed on the identified compounds. Methanol extracts had the highest activity in AChE (leaves: IC50 = 0.27 mg/mL; roots: IC50 = 0.17 mg/mL) and BuChE (leaves: IC50 = 0.62 mg/mL; roots: IC50 = 0.61 mg/mL) inhibition, as well as reduction of nitric oxide (NO) production in LPS-treated microglia (leaves: IC50 = 4.17 μg/mL; roots: IC50 = 9.95 μg/mL). Methanol extracts prevented oxidative stress-induced cytotoxicity in SH-SY5Y cells when applied simultaneously with H2O2, whereas cells pre-treated with the dichloromethane extracts had increased viability. Fifteen flavonoids were identified and showed favorable binding energies to AChE and BuChE binding pockets. These data suggests P. maritimum as a promising source of natural products and/or molecules with cognitive enhancement and anti-ageing properties.