Pre-clinical safety assessment of biotechnologically produced lacto-N-tetraose (LNT).

Lacto-N-tetraose (LNT) is a human milk oligosaccharide with average concentrations ranging from 0.74 to 1.07 g/L in breastmilk, depending on the lactation stage. In this study, the preclinical safety of LNT produced by the Escherichia coli K-12 E2083 production strain was assessed. LNT was negative in both the bacterial reverse mutation assay and the in vitro micronucleus assay, demonstrating the absence of genotoxic potential for this substance. In the OECD 408 guideline compliant 90-day oral toxicity study rat, LNT did not induce any adverse effects in any treatment group up to and including the highest dose tested, and no LOAEL could be determined. Therefore, the no-observed-adverse effect level (NOAEL) is set at the highest dose level tested, i.e. a dietary level of 5 % (w/w), corresponding to ≥2856 mg/kg bw/day and ≥3253 mg/kg bw/day for males and females, respectively. This might be an underestimation of the NOAEL, caused by the range of dose levels tested. The results obtained in the current study are in good agreement with available data generated using other biotechnologically produced LNT batches and therefore support its safe use as a food ingredient.

Black pepper constituent piperine: genotoxicity studies in vitro and in vivo.

Piperine is responsible for the hot taste of black pepper. Publications on genotoxicity of piperine are reported: negative Ames Tests and one in vitro micronucleus test (MNT). In vivo tests were mainly negative. In the majority of the data the administered dose levels did not follow the dose selection requirements of regulatory guidelines of having dose levels up to the maximum tolerated dose (MTD). The only oral high dose studies were a positive in vivo MNT in mice in contrast to a negative in vivo chromosome aberration test in rats. Thus, conflicting results in genotoxicity testing are published. To investigate this further, we administered piperine to mice up to the MTD and determined micronuclei-frequency. Piperine reduces core body temperature and interferes with blood cells both being known to result in irrelevant positive in vivo MNTs. Therefore we added mechanistic endpoints: core body temperature, haematology, erythropoietin level, and organ weights. Additionally an in vitro MNT in Chinese hamster ovary cells was performed. Piperine was negative in the in vitro MNT. It caused significant reduction of core body temperature, decrease of white blood cells and spleen weights but no increase in the micronucleus-frequency. Thus, in our studies piperine was not genotoxic.