Antioxidant and cytotoxic activities of alkaloids extracted from inermis nopals of Algerian Opuntia ficus-indica (L).

The prickly pear (Opuntia ficus-indica L.) is not only prized for its fruit but also for its cladode which contains many bioactive compounds of health interest such as alkaloids. The present study aims to characterize the alkaloids of young inermis cladodes (nopals) of Algerian Opuntia ficus-indica, and to evaluate their in vitro antioxidant and cytotoxic activities. The alkaloid extraction yield was remarkably low (0.59%). The GC-MS analysis demonstrated the presence of seventeen alkaloids such as Neronin and Glucobrassicin. Assessment of alkaloid antioxidant activity showed a significant DPPH scavenging capacity, a medium reducing power and a weak inhibition of β-carotene bleaching. The nopal alkaloids had no cytotoxic effect on the viability of the hepatic cancer cell line HepG2, or even after inhibition of CYP enzymes. However, their presence can significantly induce the overproduction of reactive species and lead to the loss of mitochondrial membrane potential ∆ψm. The purification of these alkaloids, the rational choice of the doses and the understanding of their pharmacological mechanism are obviously one of the key steps to identify the overall therapeutic potential of these nopals.