Safety evaluation of pectin-derived acidic oligosaccharides (pAOS): genotoxicity and sub-chronic studies.

Pectin-derived acidic oligosaccharides (pAOS) are non-digestible carbohydrates to be used in infant formulae and medical nutrition. To support its safety, the genotoxic potential of pAOS was evaluated. pAOS was not mutagenic in the Ames test. Positive results were obtained in the chromosome aberration test only at highly cytotoxic concentrations. The effects obtained in the mouse lymphoma test were equivocal; pAOS was not mutagenic in vivo. A sub-chronic dietary study, preceded by 4-week parental and in utero exposure phase, investigated general safety. Administration of pAOS did not affect parental health nor pup characteristics. No effects specific for acidic oligosaccharides were observed in the subsequent sub-chronic study. Slight diffuse hyperplasia of epithelial layer of the urinary bladder was noted to result from concurrently elevated urinary sodium, due to high sodium in pAOS, and elevated urinary pH. This phenomenon was confirmed in a mechanistic (sub-chronic) study. In contrast, in rats fed pAOS in combination with NH(4)Cl, an acidifying agent, the induced low urinary pH completely prevented the development of urothelial hyperplasia. Hyperplasia induced by this mechanism in rats is considered not relevant to man. Based on the current knowledge we consider pAOS safe for human consumption under its intended use.

A sub-chronic (13 weeks) oral toxicity study in rats and an in vitro genotoxicity study with Korean pine nut oil (PinnoThin TG).

In this paper a sub-chronic (13 weeks) toxicity study in rats and an in vitro genotoxicity study with Korean pine (Pinus koraiensis Siebold & Zucc.) nut oil, KPNO (PinnoThin) are described. Both studies were performed in compliance with GLP, and in line with OECD guidelines applicable. In the sub-chronic toxicity study, no clinical signs, abnormalities in functional observation tests or ophthalmologic examinations or changes in body weight or food intake were noted at any of the doses of KPNO tested. Various changes in clinical biochemistry parameters were noted. Whilst these changes were not consistent in both sexes, and neither associated with any histopathological changes, nor dose-related, these were not considered to be toxicologically relevant. No toxicologically significant changes were noted in haematological parameters. There were a few histopathological observations such as a periportal vacuolation of the liver in all dose groups including the control, and renal tubular mineralisation in most females of the high dose group but also in all control female rats. These findings can be considered to be due to the high fat content of the diets, and are not related to the treatment with KPNO. Based on these findings a No Observable Adverse Effect Level (NOAEL) of 15% has been established for KPNO. This NOAEL corresponded to a mean of 8866 and 10,242 mg KPNO/kg bw/day for males and females, respectively. This dose level was the highest achievable oral dose for KPNO in rats. The in vitro reverse mutation test (Ames test), showed no significant dose-related increase in the number of revertants in two independently repeated mutation assays. The negative and strain-specific positive control values were within the laboratory historical control data ranges indicating that the test conditions were adequate and that the metabolic activation system functioned properly. Based on these results it has been concluded that KPNO is not mutagenic in the Escherichia coli and Salmonella typhimurium reverse mutation assays. In conclusion, KPNO can be considered to be non-genotoxic in the AMES test. A NOAEL of 8866 and 10,242 mg KPNO/kg bw/day has been established for male and female rats, respectively. For both sexes, the NOAEL was achieved at the highest dose tested.

Toxins of cyanobacteria.

Blue-green algae are found in lakes, ponds, rivers and brackish waters throughout the world. In case of excessive growth such as bloom formation, these bacteria can produce inherent toxins in quantities causing toxicity in mammals, including humans. These cyanotoxins include cyclic peptides and alkaloids. Among the cyclic peptides are the microcystins and the nodularins. The alkaloids include anatoxin-a, anatoxin-a(S), cylindrospermopsin, saxitoxins (STXs), aplysiatoxins and lyngbyatoxin. Both biological and chemical methods are used to determine cyanotoxins. Bioassays and biochemical assays are nonspecific, so they can only be used as screening methods. HPLC has some good prospects. For the subsequent detection of these toxins different detectors may be used, ranging from simple UV-spectrometry via fluorescence detection to various types of MS. The main problem in the determination of cyanobacterial toxins is the lack of reference materials of all relevant toxins. In general, toxicity data on cyanotoxins are rather scarce. A majority of toxicity data are known to be of microcystin-LR. For nodularins, data from a few animal studies are available. For the alkaloids, limited toxicity data exist for anatoxin-a, cylindrospermopsin and STX. Risk assessment for acute exposure could be relevant for some types of exposure. Nevertheless, no acute reference doses have formally been derived thus far. For STX(s), many countries have established tolerance levels in bivalves, but these limits were set in view of STX(s) as biotoxins, accumulating in marine shellfish. Official regulations for other cyanotoxins have not been established, although some (provisional) guideline values have been derived for microcystins in drinking water by WHO and several countries.