Dr. Annette Gabaldón, Biology

The objective of this study is to determine whether metabolites generated through probiotic fermentation of dietary hempseed (Cannabis sativa L.) exert anti-cancer effects. Specifically, we will culture human colorectal carcinoma cells Caco-2 in growth media supplemented with hempseed fermentation supernatant and test for alterations in cell viability, proliferation, and energy metabolism.

Previously, we investigated the ability of two lactic acid-producing probiotics (L. plantarum and L. fermentum) to ferment whole hempseed. Our question of interest was whether hempseed could serve as a prebiotic to support probiotic growth and metabolism. In results that will be reported at the 2019 ICR Conference, we discovered that both probiotic organisms grow very well in media prepared with 5% hempseed powder(HS-5).

From colony forming unit (CFU) assays, we observed the characteristic phases of a bacterial growth curve (i.e., lag, log, stationary). From pH measurements of the fermentation media, we observed significant acidification, indicative of acidic secondary metabolite synthesis. Acidic metabolites yielded from carbohydrate fermentation include lactic acid and short-chain fatty acids (SCFAs), notably acetate, butyrate, and propionate. These SCFAs provide protective effects against colorectal cancer. 

If hempseed fermentation is found to yield high levels of SCFAs, then perhaps this nutrient-rich seed can be developed as a novel dietary anti-cancer therapeutic. We are finalizing SCFA and lactic acid analysis on the HS-5 fermented samples and if this new proposal is funded, we will grow Caco-2 cells in a cell culture system and test for anti-cancer activity using HS-5 fermentation samples that were collected in the study described.

In the event that chemical analyses of the HS-5 fermentation media show low SCFA levels, the Caco-2 study is still worth pursuing because the HS-5 fermented media is expected to be complex. Whole hempseed is a rich nutrient that is high in protein, lipid, digestible and indigestible carbohydrate, vitamins, and phytochemicals.

The HS-5 fermented product that we have generated may also contain protein fermentation metabolites and there is much interest in identifying bioactive fermentation peptides related to human health. In a second study, we are proposing to investigate the role of CB receptors in modulating the viability, proliferation, and cellular energy metabolism of cultured colon cancer cells.