In vivo and in vitro neuroprotective effects of the pentane soluble compounds from Lepidium meyenii (Maca).

摘要

The neuroprotective activity of extract of the plant Lepidium meyenii Maca was studied using in vivo and in vitro experimental models. The pentane extract obtained by continuous liquid-liquid extraction, was chemically characterized and administered intravenously to rats prior to and following middle cerebral artery occlusion produced with two models of focal cerebral infarction. While infarct volumes were decreased for the lower dose, higher doses increased infarct volumes compared to controls, indicating two types of activity. In vitro experiments were performed on crayfish neurons and rat neuroblastoma cells. Cells in well plates were pretreated with vehicle, the pentane extract, isolated macamides (natural alkamides and possible active principles) or synthesized alkamides (with structures based on the natural alkamides), and then were subjected to H2O2 as a neurotoxic agent. Cell viability was determined microscopically and chemically. A significant neuroprotective effect was demonstrated by the pentane extract and purified alkamides. In other in vitro experiments, cells were pretreated with O-2050 [a high affinity silent CB 1 (cannabinoid) receptor antagonist], and later exposed to the treatments mentioned above. Anandamide and tetrahydrocannabinol (THC) were used as cannabinoid controls. O-2050 significantly blocked the neuroprotective effects of the pentane extract and alkamides as well as the effects of anandamide and THC. The pentane extract and the alkamide designated MCP-33 which significantly reversed the deleterious effects of O-2050 on the cells. Finally, when the tested compounds were evaluated for antioxidant activity using the ABTS method with trolox as a positive control, none of the compounds evaluated (pentane extract, alkamide MCP-33, anandamide and THC) showed any antioxidant effects. These results suggest the potential application of alkamides, which represent part of the active principles of Maca, as neuroprotectants. The mechanism of action appears to involve the endocannabinoid system.