ANTI-INFLAMMATORY ACTIVITY OF PIPER LONGUM METHANOLIC EXTRACT IN LPS-STIMULATED RAW 264.7 MACROPHAGES

Abstract

Piper longum L. is traditionally recognized for its broad therapeutic applications;
however, its cellular anti-inflammatory mechanisms remain insufficiently characterized. The
present study investigated the anti-inflammatory potential of the methanolic stem extract of
Piper longum in lipopolysaccharide (LPS)-stimulated RAW 264.7 murine macrophages. The
extract exhibited a clear concentration-dependent suppression of key inflammatory enzymes,
including cyclooxygenase (COX), lipoxygenase (LOX), myeloperoxidase (MPO), and
inducible nitric oxide synthase (iNOS). Maximum inhibition was observed at 100 μg/mL, with
IC50 values of 110 μg/mL (COX), 107.49 μg/mL (LOX), and 99.26 μg/mL (iNOS), indicating
substantial enzyme inhibitory potency. Furthermore, intracellular nitrite levels were
significantly reduced from 792.00 μg in the LPS control to 492.03 μg at 100 μg/mL,
confirming effective suppression of nitric oxide production. These findings demonstrate that
the methanolic stem extract of Piper longum attenuates LPS-induced inflammatory responses
through multitarget modulation of enzymatic pathways, supporting its potential as a natural
antiinflammatory therapeutic candidate.