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This study aimed to investigate the effect of metal ions on the degradation of phytosterols in oils. The oil was heated at 180 °C for 1 h with/without addition of Fe 3 + , Fe 2 + , Cu 2 + , Mn 2 + , Zn 2 + , Na + , Al 3 + and Mg 2 + . Variations of β-sitosterol, stigmasterol, campesterol, brassicasterol and their degradation products were confirmed by the GC–MS analysis. In general, the increase of the metal ion concentration resulted in more phytosterol degradation, and the ability of metal ions following decreasing order: Fe 3 + > Fe 2 + > Mn 2 + ≥ Cu 2 + ≥ Zn 2 + > Na + ≥ Mg 2 + > Al 3 + . Metal ions significantly induced phytosterol autoxidation on C5, C6 and C7 on Ring B of steroid nucleus at even a low concentration, and induced dehydration on the C3 hydroxyl to form dienes and trienes at high concentration. The metal ions in oils are accounted for increasing phytosterol degradation, which decreases food nutritional quality and gives rise to the formation of undesirable compounds. [ABSTRACT FROM AUTHOR]

Ethnopharmacological relevance Osmanthus fragrans var. thunbergii ( O. fragrans ) flower has been consumed as folk medicine for thousands of years. O. fragrans flower extract is a well-characterized phenylethanoid glycoside-rich extract, which has been used as a natural anti-oxidant. The aim of this study was to evaluate the safety of O. fragrans flower phenylethanoid glycoside-rich extract (OFFE). Materials and methods The OFFE was extracted by 80% (v/v) aqueous ethanol with 0.01% sodium isoascorbate (w/v) from the O. fragrans flower and purified on HPD300 resins. The total phenylethanoid glycosides content and individual phenylethanoid glycosides was determined by photocolorimetric method and reversed phase UPLC respectively. An acute oral toxicity study, reverse mutation test, bone marrow cell micronucleus test, and sperm abnormality test as well as a 90-day oral toxicity study were performed on experimental animals. Results The total content of phenylethanoid glycosides in OFFE was 73.4 g acteoside equivalent per 100 g of extract, include acteoside (52.5 g per 100 g of extract), salidroside (13.8 g per 100 g of extract), and isoacteoside (2.6 g per 100 g of extract) and so on. No acute lethal effect at the maximal tested OFFE dose of 10 g/kg body weight (bw) in either rats or mice was observed, suggesting that OFFE can be considered nontoxic. No evidence for mutagenicity was detected in any of the three mutagenic tests. Administration at levels of 0.50, 1.00, and 2.00 g/kg bw to rats for 90 days failed to induce any significant hematological, clinical, chemical, or histopathological changes. The no-observed adverse-effect-level for OFFE was >2.00 g/kg bw for the study on subchronic toxicity. Conclusion The results showed that consuming OFFE has no adverse effects and poses no health risk in the acute oral toxicity study, subchronic oral toxicity study, and in the micronucleus test, which may provide supportive evidence for the safety of OFFE powder that has been used in medicine as well as in functional foods, and dietary supplements. [ABSTRACT FROM AUTHOR]