Chemical Composition and Anti-Inflammatory Activity of Essential Oils from Piper betle Leaves Growing in Vietnam

Piper betle commonly called betel, is a medicinally important plant used traditionally for the treatment of inflammatory conditions, gastrointestinal disorders, hepatic diseases, and microbial infections. Piper betle leaves are particularly rich in essential oil with numerous bioactive constituents. This study aimed to investigate the chemical composition and anti-inflammatory activity of essential oils (EOs) from Piper betle leaves. The EOs were extracted via steam distillation from fresh and dried leaves collected at three distinct time points in 2022 (January, May, and September). The chemical profile of the EOs were determined by gas chromatography-mass spectrometry (GC-MS). The anti-inflammatory activity of the EOs was evaluated by the inhibition of lipopolysaccharide (LPS)-stimulated nitric oxide (NO) production in murine RAW 264.7 macrophage cells. GC-MS analysis identified chavibetol and eugenol acetate as major EO components, with varying numbers of compounds detected across samples and collection periods. Chemical profiling consistently revealed significant differences between fresh and dried leaf EOs, as well as notable variations across collection times. Phenylpropanoids (44.56 – 84.14%) and hydrocarbon sesquiterpenes (6.86–39.71%) were the dominant compound classes in all EOs. Regarding anti-inflammatory activity, the January fresh EO exhibited the highest potency with IC50 value of 26.33 ± 1.51 µg/mL), followed by the September fresh EO (IC50 = 35.71 ± 2.05 µg/mL). These findings highlight the variability in Piper betle EO composition based on drying and collection time, underscoring their potential as a natural source of anti-inflammatory agents.