Pimenta racemosa is a commonly known spice used in traditional medicine to treat several ailments. In this study, comprehensive phytochemical profiling of the essential oils and methanol extracts of P. racemosa leaves and stems was performed, alongside assessing their potential Helicobacter pylori inhibitory activity in vitro and in silico. The essential oils were chemically profiled via GC-MS. Moreover, the methanol extracts were profiled using HPLC-PDA-ESI-MS/MS. The antibacterial activity of the essential oils and methanol extracts against H. pylori was determined by adopting the micro-well dilution method. GC-MS analysis unveiled the presence of 21 constituents, where eugenol represented the major component (57.84%) and (59.76%) in both leaves and stems of essential oils, respectively. A total of 61 compounds were annotated in both leaves and stems of P. racemosa methanolic extracts displaying richness in phenolic compounds identified as (epi)catechin and (epi)gallocatechin monomers and proanthocyanidins, hydrolyzable tannin derivatives (gallotannins), flavonoids, and phenolic acids. The stem essential oil showed the most promising inhibitory effects on H. pylori, exhibiting an MIC value of 3.9 µg/mL, comparable to clarithromycin with an MIC value of 1.95 µg/mL. Additionally, in silico molecular modeling studies revealed that decanal, eugenol, terpineol, delta-cadinene, and amyl vinyl showed potential inhibitory activity on H. pylori urease as demonstrated by high-fitting scores indicating good binding to the active sites. These findings indicate that P. racemosa comprises valuable phytochemical constituents with promising therapeutic effects, particularly the stem, an economic agro-industrial waste.
Keywords: GC-MS; LC-MS; Pimenta racemosa; anti-Helicobacter pylori; drug discovery; health care; molecular modeling.