The Toxicity Profile of Hydrolyzed Aqueous Olive Pulp Extract

Abstract

The toxicity profile of HIDROX (Hydrolyzed Aqueous Olive Pulp Extract; OPE) was characterized in a series of toxicology studies. A limit dosage of 2000 mg/kg produced no toxicity in mice (acute oral NOAEL: 2000 mg/kg). In rats, an acute oral NOAEL of 2000 mg/kg was established, based on reductions in weight gains in both sexes at 5000 mg/kg. Reduced gains in female rats at 1500 and 2000 mg/kg were not significantly different from control values. Daily oral dosages of 1000, 1500 and 2000 mg/kg/day for 90 days produced small decreases in body weight gains at 2000 mg/kg/day in the male rats and in all groups of female rats. Feed consumption was comparable to controls. There were no adverse clinical, hematologic, biochemical, organ weight or gross necropsy effects. Focal, minimal or mild hyperplasia of the mucosal squamous epithelium of the limiting ridge of the forestomach occurred in some rats at 2000 mg/kg/day; this change was attributed to local irritation by repeated intubation of large volumes of viscous, granular dosing suspension. A NOAEL of 2000 mg/kg/day was established for the 90-day study, based on the lack of significant adverse effects. Toxicokinetic data indicated that hydroxytyrosol (HT, the major component of OPE) was rapidly absorbed. Mean concentrations were measurable through 1 to 4 hours (t(last)) at 1000 and 1500 mg/kg/day and through 8 hours at 2000 mg/kg/day. Dosages of OPE ranging from 500 to 2000 mg/kg/day did not adversely affect any of the mating, fertility, delivery or litter parameters investigated in an oral rat dosage-range reproduction study. Adverse effects were also absent in a rat developmental toxicity study in which pregnant dams were treated with 1000, 1500 or 2000 mg/kg/day on days 6 through 20 of gestation. Plasma levels for pregnant and lactating rats were comparable to non-pregnant rats; minimal levels crossed the placenta. Quantifiable levels were not identified in maternal milk or plasma from nursing pups. A bacterial reverse mutation and a CHO chromosome aberration assay revealed evidence of mutagenic activity at high dosages with S9 metabolic activation. However, three rat micronucleus evaluations performed after single and repeated (28-day) dosages of up to 2000 mg/kg/day and dosages of 5000 mg/kg/day for 29 days resulted in negative findings; therefore, OPE was not considered to be mutagenic in this in vivo assay.

Investigations into the genotoxic potential of olive extracts

“…These results are consistent with those for pure HT which did not induce reverse mutations in bacteria (Ames test), either in the absence or presence of metabolic activation (rat liver S9), using plate incorporation or pre-incubation methodology, at concentrations up to 5 L per plate. However, positive results with HIDROX in TA98 and TA100 had been reported by Christian et al [12], although in a subsequent paper from the same group [13] the responses with HIDROX in these strains were reported as equivocal.…”

“…Whole blood cultures will be rich in catalase, but high concentrations of the test chemical could saturate the antioxidant capability, and the surplus hydrogen peroxide could be sufficient to be clastogenic in the absence of S9 as was shown in the experiments of Long et al [15] with CHO cells. It should be noted, however, that induction of chromosomal aberrations by HIDROX was seen in the presence of S9 [12], and therefore is not easily explained by hydrogen peroxide formation as discussed above. This is also more surprising since the HT content was low.…”

“…Negative results were obtained at higher plasma levels of HT with Hydroxytyrosol 15% SD (4-week study) and with two batches of H40 (acute studies). Furthermore Christian et al [12] also obtained negative MN results with HIDROX both in an acute study and also when incorporated as a satellite phase within a 90-day rat toxicity study.…”

“…In the Ames test, positive results in TA98 and TA100 were reported by Christian et al [12], but in a subsequent paper from the same group [13] the responses with HIDROX in these strains were reported as equivocal. Christian et al [12] also investigated micronucleus induction by HIDROX in an acute study, and also when incorporated as a satellite phase within a 90-day rat toxicity study, and reported negative results in both cases.…”

Potential use of olive mill wastewater in the preparation of functional beverages: A review

“…No mortality was noted in any of the treatment groups, suggesting that the LD50 of the extract is greater than 2000 mg/kg (Christian et al, 2004). Sprague-Dawley male rats (n = 6) were administered a single gavage dose of 2000 mg hydroxytyrosol/kg.…”