Metabolomic profiling of Piper sarmentosum Roxb. Extracts reveals potent xanthine oxidase inhibition and...

Piper sarmentosum (Psar) is widely used in traditional medicine across Vietnam, Thailand, and Malaysia to treat joint pain, inflammation, and digestive ailments. In Vietnam, Psar is commonly used to relieve symptoms associated with gout. Despite its broad ethnomedical applications, the plant has not been comprehensively studied for its anti-gout properties, particularly xanthine oxidase (XO) inhibition.

This study aimed to scientifically validate the traditional use of Piper sarmentosum for gout management by evaluating its antioxidant, anti-inflammatory, and XO inhibitory activities. It further aimed to identify key bioactive compounds through LC/MS-based metabolomic profiling and bioassay-guided isolation.

Psar aerial part were extracted using solvents of varying polarity (50 % ethanol, 96 % ethanol, hexane, ethyl acetate, methanol), and fractionated. Antioxidant capacity was evaluated via DPPH, ABTS, FRAP, H₂O₂, and NO scavenging assays. Anti-inflammatory activity was assessed in vitro using LPS-induced RAW264.7 macrophages (NO, TNF-α, IL-6 assays) and in vivo using a carrageenan-induced paw edema mouse model. XO inhibition was determined via spectrophotometric assays. LC/MS-GNPS molecular networking was employed for metabolomic profiling, and seven bioactive compounds were isolated and characterized using NMR spectroscopy.

The ethyl acetate fraction (PLEA) exhibited the strongest XO inhibition (IC₅₀ value of 13.90 ± 0.82 μg/mL) and antioxidant activity. PLE50 and PLE96 significantly reduced carrageenan-induced paw edema in mice. Among the seven isolated compounds, chrysin displayed outstanding XO inhibition (IC₅₀ value of 2.05 ± 0.04 μM), outperforming allopurinol (IC₅₀ = 4.80 ± 0.11 μM), along with notable NO and TNF-α inhibition. LC/MS-GNPS revealed differential metabolite profiles in PLE50 and PLE96 extracts, highlighting the influence of solvent polarity on pharmacological activity.

This is the first study to validate the traditional use of Piper sarmentosum for gout using modern metabolomic and pharmacological approaches. The results support its ethnopharmacological role as a natural XO inhibitor and anti-inflammatory agent. Chrysin, in particular, emerges as a promising lead compound. Further studies using monosodium urate-induced gout models and clinical validation are warranted.