Areca alkaloids measured from buccal cells using DART-MS serve as accurate biomarkers for areca nut chewing

Background Areca nut (AN) chewing is carcinogenic and biomarkers reflecting it are urgently needed to determine the effectiveness of emergent cessation programs. Buccal cells (BCs) may serve as an ideal matrix to measure such biomarkers; however, their utility for this purpose is unknown. Direct analysis in real time-mass spectrometry (DART-MS) is a sensitive technique that analyzes materials in the open air and requires minimal/no sample preparation. We utilized DART-MS to analyze BCs to test the usefulness of this method in measuring areca alkaloids as biomarkers for AN chewing. Methods We applied DART-MS in positive-ion mode to quantitate over time human BCs: (a) exposed ex vivo to betel quid extracts (BQE) consisting of young AN, Piper betle L. leaf, slaked lime, and tobacco; and (b) obtained from seven chewers before and after BQ chewing. Quantification was performed by normalizing DART-MS alkaloid signal intensities to cholesterol intensities. Results Signals for areca alkaloids arecoline and arecaidine-guvacoline were detected in BCs exposed ex vivo to BQE up to 7 days (the last day tested) after exposure and in BCs from chewers up to 3 days (the last day tested) post chewing. Discussion The presence of alkaloid signals in BQ-exposed BCs verified BCs as a valid matrix and DART-MS as a suitable technique to measure biomarkers for AN chewing and provided reliable information on AN chewing timing. Conclusion DART-MS analyses of BCs can be used to accurately determine areca alkaloids as AN chewing biomarkers up to 3 days post chewing and possibly longer.