Impact of phenolic-rich olive leaf extract on blood pressure, plasma lipids and inflammatory markers: a randomised controlled trial

Purpose Dietary polyphenols have been demonstrated to favourably modify a number of cardiovascular risk markers such as blood pressure (BP), endothelial function and plasma lipids. We conducted a randomised, double-blind, controlled, crossover trial to investigate the effects of a phenolic-rich olive leaf extract (OLE) on BP and a number of associated vascular and metabolic measures. Methods A total of 60 pre-hypertensive [systolic blood pressure (SBP): 121–140 mmHg; diastolic blood pressure (DBP): 81–90 mmHg] males [mean age 45 (±SD 12.7 years, BMI 26.7 (±3.21) kg/m2] consumed either OLE (136 mg oleuropein; 6 mg hydroxytyrosol) or a polyphenol-free control daily for 6 weeks before switching to the alternate arm after a 4-week washout. Results Daytime [−3.95 (±SD 11.48) mmHg, p = 0.027] and 24-h SBP [−3.33 (±SD 10.81) mmHg, p = 0.045] and daytime and 24-h DBP [−3.00 (±SD 8.54) mmHg, p = 0.025; −2.42 (±SD 7.61) mmHg, p = 0.039] were all significantly lower following OLE intake, relative to the control. Reductions in plasma total cholesterol [−0.32 (±SD 0.70) mmol/L, p = 0.002], LDL cholesterol [−0.19 (±SD 0.56) mmol/L, p = 0.017] and triglycerides [−0.18 (±SD 0.48), p = 0.008] were also induced by OLE compared to control, whilst a reduction in interleukin-8 [−0.63 (±SD 1.13) pg/ml; p = 0.026] was also detected. Other markers of inflammation, vascular function and glucose metabolism were not affected. Conclusion Our data support previous research, suggesting that OLE intake engenders hypotensive and lipid-lowering effects in vivo

Changes in Total and Individual Crocetin Esters upon in Vitro Gastrointestinal Digestion of Saffron Aqueous Extracts

Changes that may be expected in crocetin esters (crocins) upon digestion were examined in saffron aqueous extracts for the first time. Chemical characterization of total and individual crocins and other bioactive compounds was achieved by UV–vis spectrophotometry, RP-HPLC-DAD, and LC-ESI-MS. Antioxidant activity was evaluated using in vitro assays and the comet assay. The observed loss for both total and <i>trans</i>-crocins was higher in saffron (∼50%) than in gardenia extracts (∼30%), which were also examined for comparison. Loss was lower than that reported for hydrophobic carotenoids. <i>cis</i>-Isomers were less affected, leading to the hypothesis that <i>trans</i>/<i>cis</i> isomerization may occur in parallel to degradation reactions. Monitoring changes in the extracts at oral, gastric, or intestinal phases, separately, verified this view pointing out the critical effect of pH, temperature, and duration of process but not of digestive enzymes. No isomerization and less degradation (<20% loss) was evidenced when pure <i>trans</i>-crocetin (di-β-d-gentiobiosyl) ester was subjected to gastric or intestinal conditions

Cellular Transport and Bioactivity of a Major Saffron Apocarotenoid, Picrocrocin (4-(β‑d‑Glucopyranosyloxy)-2,6,6-trimethyl-1-cyclohexene-1-carboxaldehyde)

The cellular transport and bioactivity of the second major saffron apocarotenoid, picrocrocin, was examined in parallel to that of the major group, crocetin sugar esters, in aqueous extracts. The transport of pure picrocrocin was investigated in comparison to that of other saffron apocarotenoids, <i>trans</i>-crocetin (di-β-d-gentiobiosyl) ester and crocetin using the Caco-2 cell model coupled with an in vitro digestion procedure. RP-HPLC-DAD was employed to quantify the bioaccessible and bioavailable amounts of individual apocarotenoids. Picrocrocin and crocetin sugar esters though highly bioaccessible (75% and 60%, respectively) were transported at minute quantities (0.2% and 0.5%, respectively; 10-fold lower than crocetin). Picrocrocin did not protect against oxidant-induced DNA damage in U937, human monocytic blood cells at the concentration investigated, however, it reduced the proliferation of human adenocarcinoma and hepatocarcinoma cells. Our findings may be useful for the requirements of food legislation regarding saffron preparations, in which both apocarotenoid groups coexist

Comparison of Prooxidant-antioxidant Balance Method with Crocin Method for Determination of total Prooxidant-antioxidant Capacity

Objective(s)Comparison of prooxidant-antioxidant balance (PAB) assay with crocin assay.Materials and MethodsTwenty eight serum samples were chosen, PAB and the total antioxidant capacity were measured by PABassay and crocin, respectively, and the correlation of both assays, along with their correlation with otherclinical and biochemical parameters, were determined.ResultsA significant negative correlation was established between PAB assay and crocin assay. Also a significantnegative correlation was established between PAB and uric acid and creatinine.ConclusionThe results showed that by increasing the total antioxidant capacity, which is showed by crocin, the PABshifts in favor of antioxidants, which is showed by PAB assay. Now, it could be considered that the PAB,along with other risk factors, might help in the prediction of the risk for cardiovascular events; and furtherresearch could clarify whether by application of PAB assay and appropriate interventions for correctingoxidative stress, progression of the cardiovascular disease could be reduced.Keywords: Crocin, Oxidative stress, Prooxidant-antioxidant balance assa