Bioactive insights into the essential oil composition and enzyme inhibitory effects of leaves of <i>Piper ridleyi</i> C.DC. (Piperaceae)

The <i>Piper</i> genus is widely distributed across tropical regions and consists mainly of aromatic shrubs and trees known for their high essential oil content. This study examined the chemical composition and biological properties of essential oil extracted from the leaves of <i>Piper ridleyi</i> C.DC. in Malaysia. Chromatographic analysis identified 23 chemical constituents, accounting for 99.7% of the total oil composition. The predominant constituents included β-asarone (30.2%), myristicin (22.0%), α-asarone (20.6%), and β-caryophyllene (9.2%). The biological activity of the essential oil was assessed through enzymatic assays, where its acetylcholinesterase inhibitory potential was determined using the Ellman method, tyrosinase inhibition was evaluated with mushroom tyrosinase, and its anti-inflammatory effects were tested using lipoxygenase enzymes. At a concentration of 1 mg/mL, the essential oil exhibited significant bioactivity, showing 76.5% ±0.22 inhibition of acetylcholinesterase, 60.8% ±0.32 inhibition of tyrosinase, and 65.5% ±0.23 inhibition of lipoxygenase. These results indicate that <i>P. ridleyi</i> essential oil could be a promising source of bioactive compounds with potential applications in neuroprotection, skincare, and inflammation control.