Search

The overproduction of free radicals and oxygen reactive species is suspected to be implicated in a wide range of metabolic reactions that can have pernicious consequences in the development of a variety of human diseases. Botanical extracts are sources of antioxidants that counteract both free radicals and oxygen reactive species. The processing conditions used in the botanical extraction may influence the antioxidant composition; therefore, different extracts from the same plant may have different antioxidant properties. To illustrate this fact, we conducted a study using three commercial rosemary (Rosmarinus officinalis L.) leaf extracts. The three extracts were standardized to contain, respectively, 20% carnosic acid, 40% ursolic acid, or 20% rosmarinic acid. They were evaluated for their total (hydrophilic + lipophilic) antioxidant effects on oxygen radical absorbance capacity (ORAC), their ferric reducing/antioxidant power (FRAP), and their capacity to inhibit Cu(2+)-induced low-density lipoprotein (LDL) oxidation ex vivo. The ursolic acid extract showed the lowest antioxidant capacity on all models. The rosmarinic acid extract had an antioxidant capacity 1.5 times higher on ORAC and four times higher on FRAP than the carnosic acid extract. However, the carnosic acid extract was better than the rosmarinic acid extract in inhibiting the oxidation of LDL ex vivo. These results encourage conducting further studies to evaluate the carnosic acid and rosmarinic acid extracts in vivo. Our study offers an example of the importance of the extraction procedures, on which depends the nature of the antioxidant composition, and highlights interest to proceed with in vitro/ex vivo assay selection for the evaluation of the antioxidant properties of botanical extracts.

Fenugreek ( Trigonella foenum-graecum L.) has properties which are hypolipidemic, hypocholesterolemic, hypoglycemic, insulinotropic, and antioxidant. These properties are related to the control of the Metabolic Syndrome, a disorder of carbohydrate and lipid metabolism which increases the risk of diabetes and cardiovascular disease. The purpose of this study was to evaluate the effect of fenugreek extract (Hydroxylean®, Naturex) containing 25% of 4-hydroxyisoleucine (4-OH-Ile, isomer 2 S,3 R,4 S) and 15.7% of trigonelline on peroxisome proliferator-activated receptor alpha (PPARα) transcriptional activity and Cu2+-induced low-density lipoprotein (LDL) oxidation in vitro. The activation of PPARα is linked to controlling lipidemia, cholesterolemia and glycemia, all associated with diabetes and cardiovascular disease. Also, the inhibition of LDL oxidation reduces the risk of stroke. 1,000 μg/mL of fenugreek extract showed a 31.2% activation of PPARα as compared with the positive control, 100 μM of fenofibrate. Fenugreek extract also inhibited LDL oxidation induced by Cu2+ at concentrations higher than 5 μg/mL (P2+-induced LDL oxidation in vitro for fenugreek extract rich in 4-OH-Ile and trigonelline. The findings support the current evidence on fenugreek's capacity to control the Metabolic Syndrome.