Science
Pancreatic cancer is one of the trickiest and deadliest cancers around. It’s sneaky; most people don’t even know they have it until it’s advanced, which makes it hard to treat in time. Globally, it’s on the rise, and sadly, fewer than 1 in 10 people survive five years after diagnosis.
Why is it so tough?
Because it spreads fast, resists many treatments like surgery and chemotherapy, and rarely shows early signs. That’s why scientists are searching for new ways to combat it, and they’re particularly interested in the potential of nature’s medicine cabinet.
One promising lead? Stevia is the plant used to sweeten your tea. Early studies suggest that its leaves may contain compounds that combat cancer cells. However, the challenge is determining exactly which parts do the heavy lifting.
It turns out that stevia isn’t just a guilt-free sugar substitute; it might also be a stealthy cancer fighter. Researchers at Hiroshima University discovered that when stevia leaves are fermented with a special bacterium found on banana leaves (Lactobacillus plantarum SN13T), the extract becomes a powerful weapon against pancreatic cancer cells.
The fermentation process transforms stevia’s natural compounds into bioactive metabolites, such as chlorogenic acid methyl ester (CAME), which are significantly more potent.
Corresponding author Masanori Sugiyama, professor in the Department of Probiotic Science for Preventive Medicine, Graduate School of Biomedical and Health Sciences, said, “To enhance the pharmacological efficacy of natural plant extracts, microbial biotransformation has emerged as an effective strategy.”
Imagine testing over 1,300 friendly bacteria strains from everyday plants, fruits, veggies, flowers, and even herbs. That’s precisely what Sugiyama’s team did!
Their goal was to determine how these bacteria, known as lactic acid bacteria (LAB), could enhance the potency of herbal extracts. They compared regular (non-fermented) plant extracts and lab-fermented extracts.
By examining the differences, they hoped to identify which compounds become more active after fermentation, thereby enhancing the effectiveness of herbal medicines against cancer.
Researchers took stevia leaf extract and fermented it using a plant-derived bacterium called Lactobacillus plantarum SN13T, a strain found initially on banana leaves. The result? A supercharged version of stevia known as FSLE (Fermented Stevia Leaf Extract).
To test its cancer-fighting properties, they compared FSLE to regular, non-fermented stevia extract by applying both to PANC-1 cells, a standard laboratory model for pancreatic cancer, and HEK-293 cells, healthy human kidney cells used to assess safety.
All cells were obtained from well-established commercial lines, ensuring consistency and reliability in the results. This study aimed to determine whether fermentation enhances the effectiveness of stevia in killing cancer cells without harming healthy ones. Spoiler: it did.
“Our findings indicate that FSLE demonstrates significantly greater cytotoxicity than the non-fermented extract at equivalent concentrations, suggesting that the fermentation process enhances the bioactivity of the extract,” Sugiyama said. “Notably, FSLE exhibited lower toxicity toward the HEK-293 cells, with minimal inhibition observed even at the highest concentration tested.”
Researchers discovered that CAME is the main anticancer ingredient. When stevia is fermented, the amount of chlorogenic acid decreases significantly, approximately six times less, as bacteria break it down. This change likely occurred due to the presence of special enzymes in the bacteria.
The result? CAME is more potent than chlorogenic acid at killing cancer cells (specifically, pancreatic cancer cells) and triggering their death
The team next wants to study the effects in a mouse model to understand better the effectiveness of various dosages across a whole-body system.
“The present study has substantially enhanced our understanding of the mechanism of action of the Lactobacillus plantarum SN13T strain in the fermentation of herbal extracts, while also offering a valuable research perspective on the potential application of probiotics as natural anti-tumor agents,” Danshiitsoodol said.
Journal Reference:
- Rentao Zhang, Narandalai Danshiitsoodol, Masafumi Noda et al. Stevia Leaf Extract Fermented with Plant-Derived Lactobacillus plantarum SN13T Displays Anticancer Activity to Pancreatic Cancer PANC-1 Cell Line. International Journal of Molecular Sciences. DOI: 10.3390/ijms26094186