Phytochemical Characterization and Anti-Proliferative Effects of SpentTea Dust Bioactive Compounds against Hep-G2 and MCF-7 Cell Lines

Introduction: Tea (Camellia sinensis L., family Theaceae) is a widely consumed, low-cost beverage valued for its rich aroma, cultural significance, and various health benefits. However, the value of processed Tea Dust (TD) residues in terms of nutritional, bioactive, and functional properties is not well characterized. This study aimed to evaluate the nutritional and bioactive compounds in processed tea dust residues. It included samples with sugar and with both milk and sugar. The study also assessed their antioxidant and anti-cancer properties. Methods: Standardized protocols were implemented to assess nutritional components (carbohydrates, proteins, and minerals) and bioactive compounds (phenolics, flavonoids, and alkaloids, including theobromine, theophylline, and caffeine) using HPLC and GC-MS. The anticancer activity of these compounds was tested against Hep-G2 and MCF-7 cell lines in vitro. Results: The data reveal that carbohydrate and protein retention were significantly good in the processed TD residue. The C16:0 was the major fatty acid across all samples (40-45 µmol%), followed by about 20 µmol% of oleic acid (C18:1) and linoleic acid (C18:2). Processed samples with sugar for 15 minutes had the highest gallic acid (313.88 mg/100 g) and rutin (59.54 mg/100 g) content. Theobromine content increased with prolonged extraction and sugar addition but decreased with milk addition. Added sugar also maximised total phenolics and flavonoids extraction. These bioactives showed promising antioxidant and anticancer properties. Discussion: The spent tea dust biomass was proven to be rich in nutritional and nutraceutical activities. In addition, the extracts of spent biomass possess bioactive metabolites and good anti-cancer activity against Hep-G2 and MCF-7 cell lines. Hence, the tea dust spent residue (with and without sugar processing) could be used for various commercial-scale industrial applications. Conclusions: These research findings support the reuse of TD residue possessing a quality profile of nutritional, phenolic, flavonoid, and antioxidant activities exhibiting a very good anticancer activity. Hence, it could be