Bladder cancer is one of the most prevalent malignancies worldwide, with high recurrence rates and significant morbidity and mortality. This has led to increased interest in exploring natural bioactive compounds as potential complementary or alternative therapeutic agents for bladder cancer management. Stingless bee honey (SBH), a unique type of honey produced by meliponine bees, has gained attention due to its rich composition of phenolic compounds, flavonoids, organic acids, and antibacterial properties. Unlike honey from Apis mellifera, SBH has been reported to possess higher antioxidant and antimicrobial activity. Previous studies have demonstrated that various types of honey exhibit anti-proliferative, pro-apoptotic, and cytotoxic effects on different cancer cell lines, yet the specific impact of SBH on bladder cancer remains largely unexplored. This study aims to investigate the anti-proliferative effects of SBH on bladder cancer cell lines. Understanding the underlying mechanisms of SBH’s effects on bladder cancer cells may pave the way for further studies on its use in integrative oncology.

The T24 bladder cancer cell line was obtained from a certified cell repository and cultured in Dulbecco’s Modified Eagle Medium (DMEM) or RPMI-1640, supplemented with 10% fetal bovine serum (FBS), 1% penicillin-streptomycin (100 U/mL penicillin and 100 µg/mL streptomycin), and maintained at 37°C in a humidified atmosphere with 5% CO₂. The cells were subcultured upon reaching 80–90% confluency and were seeded in 96-well plates at a density of approximately 5 × 10⁴ cells per well for the MTT assay. Stingless bee honey (SBH) was diluted in a serum-free culture medium and sterilized using a 0.22 µm filter before treatment. Cells were treated with varying concentrations of SBH, ranging from 3.125 to 100 ppm and incubated for 24, 48, and 72 hours to assess the dose- and time-dependent effects on cell viability and proliferation. A dose-response curve was generated to determine the IC₅₀ value (the concentration of SBH required to inhibit 50% of cell viability).

The results demonstrated a dose- and time-dependent reduction in cell viability following SBH treatment. At 24 hours, a moderate decrease in cell viability was observed, particularly at higher SBH concentrations (≥25 ppm), whereas lower concentrations (≤12.5 ppm) exhibited minimal inhibitory effects. After 48 hours of treatment, a significant reduction in cell viability was noted across a wider range of SBH concentrations, with 50 ppm and 100 ppm showing marked cytotoxicity (p < 0.05). By 72 hours, the inhibitory effect was most pronounced, with cell viability dropping below 50% at concentrations ≥25 ppm, indicating sustained cytotoxic effects over time.

The findings from this study demonstrate that stingless bee honey (SBH) exerts a significant dose- and time-dependent anti-proliferative effect on T24 bladder cancer cells, as evidenced by reduced cell viability in response to increasing SBH concentrations and prolonged exposure times. The observed cytotoxicity, particularly at ≥25 ppm, suggests that SBH contains bioactive compounds capable of inhibiting cancer cell growth, potentially through mechanisms such as oxidative stress induction, apoptosis, and metabolic disruption. Similarly, stingless bee honey has been reported to contain higher levels of phenolic acids, flavonoids, and organic acids, which contribute to its potent antioxidant and anticancer properties (Khalil et al., 2012). The cytotoxicity observed in our study aligns with previous reports, where prolonged honey exposure led to enhanced apoptosis and cell cycle arrest in different cancer models (Ahmed & Othman, 2013).

The findings support the potential use of stingless bee honey as a natural anti-cancer agent against bladder cancer, with dose- and time-dependent cytotoxic effects observed in T24 cells. Further research, including in vivo studies and mechanistic analyses, is required to confirm these effects and assess the bioavailability and therapeutic applicability of SBH in cancer treatment.

Khalil, M. I., Sulaiman, S. A., & Gan, S. H. (2012). High 5-hydroxymethylfurfural concentrations are found in Malaysian honey samples stored for more than one year. Food and Chemical Toxicology, 50(11), 3190-3196.
Ahmed, S., & Othman, N. H. (2013). The anti-cancer effects of Tualang honey in modulating breast cancer cell lines: An in vitro study. BMC Complementary and Alternative Medicine, 13(1), 129.