Red onion wastes (ROW) are valuable sources of bioactive metabolites with promising antimicrobial effects. Methicillin-resistant Staphylococcus aureus (MRSA) infections are a growing risk in hospitals and communities. This study aims to investigate the in vitro and in vivo antibiofilm activities of the acidified ethanolic extract of red onion scales (RO-T) and its fractions against an MRSA vaginal colonization model. The RO-T extract, as well as its anthocyanin-rich fraction (RO-P) and flavonoid-rich fraction (RO-S), recorded a promising antibacterial activity against highly virulent strains of bacteria (MRSA, Acinetobacter baumannii, Escherichia coli and Pseudomonas aeruginosa). RO-S showed the highest antibacterial activity (MBC of 0.33 ± 0.11 mg/mL) against MRSA USA300 and significantly eradicated its biofilm formation with an IC₅₀ of 0.003. Using a rat model, in vivo assessment on all samples, which were formulated as a hydrogel, revealed a significant reduction of MRSA bacterial load recovered from an infected vagina compared to that of the negative control group (NCG). RO-T extract and vancomycin groups recorded the highest antibacterial activity with a bacterial load 2.998 and 3.358 logs lower than the NCG, respectively. The histopathological investigation confirmed our findings. RO-T and RO-S were standardized for their quercetin content. Finally, ROW offers a new potent antibiofilm agent mostly due to its high quercetin content.

Alpinia katsumadai Hayata (Zingiberaceae) is an edible seed valued in traditional medicine for its remarkable therapeutic properties. The seed serves as a fragrant culinary spice, adding a unique flavor to various foods. In this study, three approaches were employed to elucidate seed metabolome including UHPLC-MS/MS-based molecular networking, HS-SPME/GC–MS, and post-silylation GC–MS. A total of 82 secondary metabolites spanning diverse chemical classes were annotated, including the report of two newly annotated catechin-guibourtinidol derivatives and deoxy phloretin-3’-C-hexoside for the first time in Alpinia genus, alongside the first hypothesis of calyxins’ class mass fragmentation pattern. HS-SPME/GC–MS analysis led to the detection of 30 aroma determinants dominated by sesquiterpenes (55.1%) and monoterpenes (36.8%). Daucene and α-phellandrene were detected at 274.41 µg/g and 161.25 µg/g, respectively, and to likely account for seed aroma. GC–MS post-silylation dissected 48 metabolites, revealing the abundance of sugars, arylheptanoids, and flavonoids, with sucrose as major sugar (23.81 mg/g), and cardamonin, as major flavonoid. Such comprehensive phytochemical mapping provides critical insights into A. katsumadai seed metabolome, offering novel evidence for its health-promoting and culinary qualities.