Olive oil and its main phenolic micronutrient (oleuropein) prevent inflammation-induced bone loss in the ovariectomised rat

Abstract

The present study was designed to evaluate the effect of olive oil and its main polyphenol (oleuropein) in ovariectomised rats with or without inflammation. Rats (6 months old) were ovariectomised or sham-operated as control. Ovariectomised rats were separated into three groups receiving different diets for 3 months: a control diet with 25 g peanut oil and 25 g rapeseed oil/kg (OVX), the control diet with 50 g olive oil/kg or the control diet with 0·15 g oleuropein/kg. The sham-operated group was given the same control diet as OVX. Inflammation was induced 3 weeks before the end of the experiment by subcutaneous injections of talc (magnesium silicate) in one-half of each group. The sucess of ovariectomy was verified at necropsy by the atrophy of uterine horns. Inflammation, oleuropein or olive oil intakes did not have any uterotrophic activity, as they had had no effect on uterus weight. The plasma concentration of a-1-acid glycoprotein (an indicator of inflammation) was increased in OVX rats with inflammation. With regard to bone variables, osteopenia in OVX was exacerbated by inflammation, as shown by a decrease in metaphyseal and total femoral mineral density. Both oleuropein and olive oil prevented this bone loss in OVX rats with inflammation. At necropsy, oleuropein and olive oil consumption had had no effect on plasma osteocalcin concentrations (marker of bone formation) or on urinary deoxypyridinoline excretion (marker of bone resorption). In conclusion, oleuropein and olive-oil feeding can prevent inflammation-induced osteopenia in OVX rats.

Dietary fat intake and the risk of osteoporotic fractures in the elderly

“…Furthermore, animal studies have shown that virgin olive oil prevents inflammation-induced bone loss (Puel et al, 2004), thus providing a potential mechanistic support to our findings. The reduced risk of fractures associated with high HDL-cholesterol level is consistent with the protection observed for MUFA, because a high MUFA intake, typical of the Mediterranean food pattern, has been repeatedly shown to increase HDL levels (Mensink and Katan, 1992;Mensink et al, 2003;Esposito et al, 2004).…”

Localization of the noncovalent binding site between amyloid-β-peptide and oleuropein using electrospray ionization FT-ICR mass spectrometry

“…Digestion with trypsin yielded the four expected A␤ fragments: [1][2][3][4][5], [6 -16], [17][18][19][20][21][22][23][24][25][26][27][28], and [29 -40] following cleavage after arginine (R) or lysine (K) residues (Table 2), as well as partially cleaved fragments ( Table 3). The soft ESI ionization also enabled the detection of noncovalent interactions between sequential and nonsequential fragments.…”

“…Noncovalent interactions of peptide fragments with OE, added before digestion, were detected for the [17][18][19][20][21][22][23][24][25][26][27][28] fragment of A␤ (Figure 2) and the partially cleaved peptide fragments [6 -28] and [6 -40]. In addition, noncovalent complexes of OE with the [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] fragment, derived from the chymotryptic activity of the enzyme, was also detected.…”

“…When OE was added into already digested A␤ samples with trypsin ( Similarly, ESI-MS analysis of the A␤-OE Glu-C digest yielded signals corresponding to the expected A␤ fragments [4 -11], [12][13][14][15][16][17][18][19][20][21][22], and [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40] following cleavage at the carboxy-terminus of glutamic acid (E) residues (Table 2), and the noncovalent complexes between OE and the [4 -11] and [12][13][14][15][16][17][18][19][20][21][22] A␤ Glu-C fragments ( Figure 3). Interactions between OE and the partially cleaved peptide fragments [4 -40] and (Table 4) When OE was added into already digested A␤ samples with Glu-C (Table 4), ESI signals corresponded to ...…”

“…Moreover, OE and its metabolites have been shown to be potent against contemporary diseases, such as HIV [20,21] and osteoporosis [22,23]. Interestingly, in vitro [24] and epidemiological [25] studies demonstrated the positive impact of polyphenols on the onset of age-related disorders, such as dementia [26,27].…”