Bioactive volatile compounds in indigenous LAB extracts and the anticancer activity of their fermented milk against WiDr and MCF-7 cells

Fermented milk is recognized as a functional food with potential anticancer benefits, especially when produced using probiotic lactic acid bacteria (LAB). This study focused on two indigenous Indonesian LAB strains, Lactiplantibacillus plantarum IIA-1A5 and Lactobacillus acidophilus IIA-2B4. Volatile compounds were identified in the bacterial extracts prior to their use as starter cultures, using gas chromatography–mass spectrometry (GC–MS). A total of 83 volatile compounds were detected, including several previously associated with anticancer properties. Principal component analysis (PCA) showed distinct volatile profiles for each strain, with L. plantarum IIA-1A5 extract exhibiting a higher abundance of bioactive compounds. Subsequently, the two strains were used to ferment milk at a 10% inoculation level. The resulting fermented milk met the Indonesian National Standard (SNI) for yogurt, indicating its suitability for human consumption. Anticancer activity was evaluated using MTT assays on WiDr (colorectal cancer) and MCF-7 (breast cancer) cell lines. The fermented milk samples exhibited dose-dependent inhibition of cell viability. IC₅₀ values ranged from 28.55 to 32.99 µg/mL for WiDr cells and 24.98 to 69.00 µg/mL for MCF-7 cells, with L. plantarum IIA-1A5 showing slightly stronger cytotoxic effects. These results suggest that fermented milk made with bioactive compound-producing probiotics can serve as a functional food with potential anticancer effects. The presence of volatile bioactives in the LAB extracts supports the role of strain-specific metabolites in enhancing the health benefits of probiotic dairy products.