Safety evaluation of certain food additives - ipcs inchem

PHYTOSTEROLS, PHYTOSTANOLS AND THEIR ESTERS 129
phytosterols or phytosterol esters at any dose level did not show an effect on uterine
weight (Baker et al., 1999).
The hormonal activity of the pure substances -sitosterol, stigmasterol and
their purified chlorine dioxide oxidation products was assessed in vitro and in vivo.
Neither the parent compounds nor the oxidation products showed relevant activity
in the estrogen receptor binding assay in vitro. In the androgen receptor binding
assay, the phytosterols and their oxidation products showed a small but measurable
activity. -Sitosterol, stigmasterol and their oxidation products were inactive in the
28-day masculinization assay with mosquitofish at concentrations up to 100 μg/l
(van den Heuvel et al., 2006).
2.3 Toxicological studies: Phytostanol–phytosterol mixtures
A submission was made to the Committee, consisting of toxicity studies on
mixtures of unesterified phytosterols and phytostanols. In 2000, the technical manufacturing
process changed from solvent extraction to vacuum distillation, which
resulted in a change in composition. Mixtures of phytosterols and phytostanols
derived from solvent extraction (MPSS-SE), which were used for toxicity studies,
consisted of about 40– 55% -sitosterol, 16–31% -sitostanol, 11–15% campesterol
and 2–11% campestanol. A mixture derived from vacuum distillation (MPSS–VD)
between 2000 and 2003 and used for a repeated-dose toxicity study contained
63.5% -sitosterol, 21.7% -sitostanol, 6.5% campesterol and 2.8% campestanol.
If not indicated otherwise, studies discussed in this section were done with these
mixtures, which were derived from tall oil. Data provided by the sponsor show that
mixtures obtained from vacuum distillation after 2003 contain higher percentages
of -sitosterol (approximately 73%).
2.3.1 Short-term studies of toxicity
Both MPSS-SE and MPSS-VD have been investigated in 90-day oral toxicity
studies. In a dietary toxicity study with Crl:CD Sprague-Dawley rats performed in
compliance with USFDA GLP regulations, 0, 1.25, 2.5 or 5% MPSS-SE in the diet,
equal to 0, 1.0, 2.0 and 4.2 g test material/kg bw per day for males and 0, 1.2, 2.4
and 4.8 g test material/kg bw per day for females (mean intakes over the study
period), were administered to 20 animals per group and sex for at least 91 days.
Four additional animals per sex and group were used for toxicokinetic studies
(analysis of test material in serum and determination of total cholesterol and
triglycerides during the treatment period). Body weights and food consumption
were measured and clinical observations were made during the treatment
period. Investigations comprised ophthalmological examinations, haematology and
serum chemistry evaluation, urinalysis, sperm analysis and determination of
vitamins A, D, E and K and -carotene in serum. After treatment, all animals were
necropsied. Organ weights were determined, and organs (all tissues of control and
high-dose animals) were examined histopathologically. No treatment-related effects
regarding body weights, haematology, urinalysis or clinical chemistry parameters
or in histopathological investigations were observed. Serum levels of “total
phytosterols” (sum of -sitosterol, -sitostanol, campesterol and campestanol) were
increased during the study about 2- to 3-fold, but did not show clear dose