Abstract

Despite the various reports on the toxicity of clove oil and its major component eugenol, systematic evaluations on the safety of polyphenolic extracts of clove buds have not been reported. Considering the health beneficial pharmacological effects and recent use of clove polyphenols as dietary supplements, the present study investigated the safety of a standardized polyphenolic extract of clove buds (Clovinol), as assessed by oral acute (5 g/kg b.wt. for 14 days) and subchronic (0.25, 0.5 and 1 g/kg b.wt. for 90 days) toxicity studies on Wistar rats and mutagenicity studies employing Salmonella typhimurium strains. Administration of Clovinol did not result in any toxicologically significant changes in clinical/behavioural observations, ophthalmic examinations, body weights, organ weights, feed consumption, urinalysis, hematology and clinical biochemistry parameters when compared to the untreated control group of animals, indicating the no observed-adverse-effect level (NOAEL) as 1000 mg/kg b.wt./day, the highest dose tested. Terminal necropsy did not reveal any treatment-related histopathology changes. Clovinol did not show genotoxicity when tested on TA-98, TA-100 and TA-102 with or without metabolic activation, rather exhibited significant antimutagenic potential against the known mutagens, sodium azide, NPD and tobacco as well as against 2-acetamidoflourene, which needed metabolic activation for mutagenicity.

Abstract

Microalgae are increasingly being utilized as food ingredients for a variety of applications, including as sources of protein, egg and dairy substitutes, and cooking oils. The dietary safety of a new structuring fat produced using a heterotrophic fermentation process by a strain of Prototheca moriformis was evaluated in a 13-week dietary toxicity study and compared with kokum fat, a structuring fat of similar composition used in the food industry and derived from Garcinia indica seeds. The algal structuring fat was evaluated for its genotoxic potential using both in vitro and in vivo assays. No treatment-related adverse events occurred in rats consuming algal structuring fat or kokum fat in the 13-week study, no treatment-related effects were reported for body weight, food consumption, urinalysis, hematology, clinical chemistry, gross pathology, organ weights, or histopathology. While statistically significant effects occurred in some parameters, none were dose-related or considered adverse. Overall, the NOAELs for the algal structuring fat and the kokum fat were 100 000 ppm, the highest concentrations tested. The algal structuring fat was not mutagenic in the bacterial reverse mutation assay in the Salmonella typhimurium or Escherichia coli strains tested and was not clastogenic in the in vivo mouse bone marrow chromosome aberration assay.