Characterization and cytotoxic activity on glial cells of alkaloid-enriched extracts from pods of the plants Prosopis flexuosa and Prosopis nigra (Fabaceae)

Authors: CHOLICH, LUCIANA - National University Of The Northeast Argentina; PISTAN, MARIA - National University Of The Northeast Argentina; TORRES, ANA - National University Of The Northeast Argentina; ORTEGA, HUGO - National University Of The Northeast Argentina; Gardner, Dale; BUSTILLO, SOLEDAD - National University Of The Northeast Argentina

Submitted to: Revista De Biologa Tropical
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/18/2020
Publication Date: 11/18/2020
Citation: Cholich, L.A., Pistan, M.E., Torres, A.M., Ortega, H.H., Gardner, D.R., Bustillo, S. 2020. Characterization and cytotoxic activity on glial cells of alkaloid-enriched extracts from pods of the plants Prosopis flexuosa and Prosopis nigra (Fabaceae). Revista De Biologa Tropical. 69(1): 197-206. https://doi:10.15517/RBT.V69I1.43515.
DOI: https://doi.org/10.15517/RBT.V69I1.43515

Interpretive Summary: The seed pods from many species of Prosopis plants are known to be a potential source of protein for livestock. However, prolonged ingestion of some pods appears to produce toxic neurological symptoms in some livestock. Some species of Prosopis may contain potential toxic alkaloids. In this study, the alkaloid enriched extract from the pods of two species of Prosopis were tested for cytotoxic effects using a developed cell culture model. In addition, the alkaloid content of the two extracts was assessed using high performance liquid chromatography and mass spectrometry to identify the major alkaloids present. The extract from pods of P. flexuosa were found to be significantly more cytotoxic that from P. nigra and this was correlated to the fact that P. flexuosa contained two major alkaloids, juliprosine and juliprosopine as P. nigra did not contain these alkaloids.

Technical Abstract: Introduction: Prosopis spp. pods have shown to be a potential source of protein and energy in livestock. However, prolonged ingestion of some of these species produces neurological symptoms in ruminants. Objective: In the present study, the alkaloid content and the in vitro neurotoxic activity of alkaloid enriched extracts from P. flexuosa and P. nigra pods were determined in order to elucidate the mechanism of animal poisoning caused by these species. Methods: The main alkaloids present in both extracts were analysed by high performance liquid chromatography-high resolution mass spectrometry (HPLC-HRMS). The cytotoxic activity of Prosopis alkaloid enriched-extracts in primary mixed glial cell culture was assessed by phase contrast microscopy and using neutral red, and lactate dehydrogenase (LDH) activity assays. Results: Juliprosine and juliprosopine were identified in P. flexuosa pods, while the absence of these alkaloids in P. nigra was confirmed. Both extracts (5-30 µg/mL) induced in a dose dependent manner, morphological alterations, such as swelling, enlargement and detachment from the culture surface. Consistent with this, decrease in cell viability and release of LDH 48 hours after exposure, revealed that P. flexuosa pods was significantly more cytotoxic than P. nigra. Conclusions: In P. flexuosa pods, juliprosine and juliprosopine alkaloids were identified for the first time. Moreover, the present study suggests that the cytotoxic effect displayed by both extracts is due to its alkaloid content. However, the presence of piperidine alkaloids in P. flexuosa could explain the greater cytotoxicity on glial cells with respect to P. nigra that was not shown to contain these alkaloids.