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 mu g/mL; roots: ICso = 9.95 mu g/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.