Phytochemical Profiling of Mint and Basil Extracts and Their Association with Wastewater Biofilm-Associated Structures
Bidisha Sengupta, Olabisi Ogunlewe, Nkeiruka Angela Aziekwu, Ken Fiffick, Robert Friedfeld, Cephus Bess-Grunewald, Perla Tovar, Philip Baker, Thanh Tien Dao, Kylie Robertson, Michael Janusa, Paul Kim
Source record
Source: Crossref
Published: Oct 23, 2026
DOI: 10.3390/molecules31213836
Open original source ↗Source abstract
Microbial biofilms in treated wastewater are a concern for water reuse because microorganisms can remain associated with surfaces after treatment. This study examined the flavonoid composition of methanolic extracts of peppermint (Mentha × piperita), spearmint (Mentha spicata), chocolate mint (Mentha × piperita f. citrata ‘Chocolate’), and basil (Ocimum basilicum) and investigated their association with Bacillus thuringiensis biofilms formed on silicon wafers in treated wastewater supplemented with Luria–Bertani (LB) broth. The final concentration of each plant extract was 0.3% (v/v). Ultra-performance liquid chromatography coupled with high-resolution tandem mass spectrometry (UPLC–HRMS/MS) was used to identify and quantify selected flavonoids. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) were used to examine surface morphology, bacterial-cell dimensions, and elemental composition. The extracts showed distinct phytochemical profiles. Luteolin-7-O-rutinoside was the major quantified flavonoid in the three mint extracts, whereas basil contained predominantly kaempferol-3-O-rutinoside and kaempferol-3-O-glucoside. SEM images showed differences in surface-associated structures among untreated, methanol-control, and plant-extract-treated samples. The longitudinal dimensions of selected dispersed bacterial cells also varied among the treatments. Thickness measurements were obtained for the untreated and methanol-control samples, while scattered, poorly defined structures in representative plant-extract-treated samples did not permit reliable thickness measurements. EDX analysis showed variation in the relative elemental composition of selected surface regions, with differences observed among treatments and between the two wastewater conditions. These findings provide a chemical and surface-characterization profile of the tested plant extracts and their association with B. thuringiensis biofilm-associated structures.
Evidence graph
No public relationships recorded yet.
Integrity note: This page is a factual metadata record created by deterministic ingestion. It is not a claim that the work moves a mathematical frontier or has been independently verified.