Neuroprotective Effect of 3′,4′-Dihydroxyphenylglycol in Type-1-like Diabetic Rats-Influence of the Hydroxytyrosol/3′,4′-dihydroxyphenylglycol Ratio

The aim of this study was to assess the possible neuroprotective effect of 3',4'-dihydroxyphenylglycol (DHPG), a polyphenol from extra virgin olive oil (EVOO), in an experimental model of diabetes and whether this effect is modified by the presence of another EVOO polyphenol, hydroxytyrosol (HT). The neuroprotective effect was assessed in a hypoxia-reoxygenation model in brain slices and by quantifying retinal nerve cells. The animals were distributed as follows: (1) normoglycemic rats (NDR), (2) diabetic rats (DR), (3) DR treated with HT (5 mg/kg/day p.o.), (4) DR treated with DHPG (0.5 mg/kg/day), or (5) with 1 mg/kg/day, (6) DR treated with HT plus DHPG 0.5 mg/kg/day, or (7) HT plus 1 mg/kg/day p.o. DHPG. Diabetic animals presented higher levels of oxidative stress variables and lower numbers of neuronal cells in retinal tissue. The administration of DHPG or HT reduced most of the oxidative stress variables and brain lactate dehydrogenase efflux (LDH) as an indirect index of cellular death and also reduced the loss of retinal cells. The association of DHPG+HT in the same proportions, as found in EVOO, improved the neuroprotective and antioxidant effects of both polyphenols.

Automated summary

This study aimed to evaluate the neuroprotective effect of a polyphenol called 3',4'-dihydroxyphenylglycol (DHPG) from olive oil in a diabetes model, and whether another polyphenol called hydroxytyrosol (HT) could modify this effect. The results showed that both DHPG and HT could reduce oxidative stress, improve cell survival, and reduce retinal cell loss. The combined use of DHPG and HT had a better effect.