Effects of Croton lechleri sap (Sangre de Drago) on AGEs formation, LDL oxidation and oxidative stress related to vascular diseases.

The sap of Croton lechleri Müll. Arg. (Euphorbiaceae) is well-known in South American traditional medicine. This research investigated its activity against glycation and oxidative stress (glycoxidation) to estimate its usefulness in ROS-related diseases. The activity of the sap on albumin glycation, LDL oxidation and ROS formation was detected. C. lechleri sap inhibited BSA glycation and exhibited a protective effect against LDL oxidation; at the concentration of 0.8 µg/mL, it extended the Lag phase of almost 60%. Furthermore, the sap was studied on cell viability and ROS production in HUVEC showing valuable free-radical scavenging activity. In detail, the sap (1.0 and 10.0 µg/mL) significantly decreased the baseline level and H2O2-induced ROS production in HUVEC. This research showed for the first time the ability of C. lechleri sap to decrease the albumin glycation, LDL oxidation and ROS formation in HUVEC, supporting its potential in vascular diseases.

α-Glucosidase and advanced glycation end products inhibition with Vernonia amygdalina root and leaf extracts: new data supporting the antidiabetic properties.

OBJECTIVE: This study aims to investigate antidiabetic activity of several Vernonia amygdalina extracts to study their potential use in medicine. METHODS: Aqueous and ethanol extracts were obtained by maceration and Soxhlet extraction from roots and leaves of V. amygdalina. The extracts were tested as inhibitors of α-glucosidase activity and of advanced glycation end products (AGEs) formation. Further, radical scavenging activity was examined detecting the oxygen radical absorbance capacity, while the potential cytotoxicity of extracts was estimated with MTT assay. KEY FINDINGS: In aqueous and ethanol extracts, several polyphenolic compounds were identified; in detail, (-)-catechin and luteolin were found in leaf extracts, while caffeic acid, chlorogenic acid and the terpenoid vernodalol were recognized in root extracts. Regarding antidiabetic activity, the aqueous root extracts efficiently inhibited α-glucosidase activity in a concentration-dependent manner (IC50 = 5.6 µg/ml and 39.8 µg/ml, respectively of macerated and Soxhlet extracts), whereas those obtained from leaves exhibited lower potency. Furthermore, AGEs formation was reduced by all V. amygdalina extracts starting from 10 µg/ml. CONCLUSIONS: The aqueous extracts of V. amygdalina roots obtained by maceration and Soxhlet extraction show remarkable anti-α-glucosidase activity, and all extracts have favourable antiglycation and antioxidant activities.