Investigating Bioavailability of Curcumin and Piperine Combination in Comparison to Turmeric Rhizomes: An in vitro Study

Purpose

To assess the permeability of the test item (a combination of curcumin and piperine) and a reference item (dried and crushed turmeric rhizomes) using a combination of Caco-2 cell monolayer permeability assay and liquid chromatography-tandem mass spectrometry.

Methodology

In the Caco-2 cell assay, a transport buffer was prepared, and stock solutions of test and reference items were made. Caco-2 cells were cultured on transwell plates. Permeability assays were conducted for 2 and 6 hours, followed by post-experiment testing for assessing the monolayer integrity. LC-MS/MS (Liquid Chromatography with tandem mass spectrometry) analysis was performed to calculate apparent permeability of each item.

Results

The test item was undetectable at the end of 2 hours of permeability assay. Further, after 6 hours of permeability assay, the permeability of both test and reference item was found to be low.

Conclusion

The results showed that the curcumin and piperine combination had low permeability of curcumin in vitro as compared to the dried and crushed turmeric rhizomes. This could predict the low bioavailability of curcumin in vivo when co-administered with piperine.

Trace metals accumulation in Bacopa monnieri and their bioaccessibility

Bacopa monnieri is commonly known as "Brahmi" or "Water hyssop" and is a source of nootropic drugs. Aboveground parts of plant samples collected from peri-urban Indian areas were analysed for total trace metal concentrations. Subsequently, three samples with high concentrations of Cd and Pb were subjected to in vitro gastrointestinal digestion to assess the bioaccessibility of the trace metals in these plants. The total concentrations of trace metals on a dry weight basis were 1.3 to 6.7 mg·kg⁻¹ Cd, 1.5 to 22 mg·kg⁻¹ Pb, 36 to 237 mg·kg⁻¹ Cu, and 78 to 186 mg·kg⁻¹ Zn. The majority of Bacopa monnieri samples exceeded threshold limits of Cd, Pb, Cu, and Zn for use as raw medicinal plant material or direct consumption. Therefore, it is necessary to evaluate Bacopa monnieri collected in nature for their trace metal content prior to human consumption and preparation of herbal formulations.