Sequential extraction of oxindole alkaloids from Uncaria tomentosa leaves by green pressurized solvents

Botelho, José Rafael S.; Gaspar, Marisa C.; Sousa, Hermínio J.C. de; Braga, Mara E.M.

http://hdl.handle.net/10400.8/14470

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Authors

Botelho, José Rafael S.

Gaspar, Marisa C.

Sousa, Hermínio J.C. de

Braga, Mara E.M.

Abstract(s)

Uncaria tomentosa (Cat’s Claw) is a woody climbing vine known for its therapeutic effects, which have been validated in clinical trials. The leaves, often discarded in traditional uses, contain high quantities and a wide variety of oxindole alkaloids, such as rhynchophylline (Rhy), isomytraphylline (Imyt), or mitraphylline (Myt), with Myt typically being the major alkaloid found in extracts of this species. In this study, sequential extraction in two steps was employed to recover oxindole alkaloids. In the first step, pressurized liquid acetone was used, extracting approximately 17 % of the raw material mass, with no detectable alkaloids in the extract. In the second step, CO2-expanded liquid ethanol (25 % w/w) was used under varying temperature, pressure, and solvent density conditions. Extracts enriched with the oxindole alkaloids Rhy, Imyt, and Myt were obtained from the 2nd step extraction, with ratios ranging from 39:61 to 62:38 (Rhy:Myt + Imyt). These extracts demonstrated significant inhibition of lipoxygenase (up to 95 %) and acetylcholinesterase, indicating potential anti-inflammatory and neurological applications. Moreover, these effects were positively correlated with the proportion of Rhy relative to Myt + Imyt. Based on the alkaloid content and the observed potential bioactivities, optimized parameters, robustness and process stability were assessed using deterministic and stochastic statistical methods to maximise Rhy and minimise Imyt and Myt. Finally, this study presents the development and optimization of a robust process to obtain extracts with anti-inflammatory and neurological potential, adding value to U. tomentosa leaves and promoting the sustainable use of this plant as a raw material.

Description

Article number - 134679

Keywords

Anti-inflammatory Bayesian optimization Oxindole alkaloid Pressurized fluid extraction Process optimization Uncaria tomentosa (cat’s claw) leaves

URI

http://hdl.handle.net/10400.8/14470

Citation

José Rafael S. Botelho, Marisa C. Gaspar, Hermínio J.C. de Sousa, Mara E.M. Braga, Sequential extraction of oxindole alkaloids from Uncaria tomentosa leaves by green pressurized solvents, Separation and Purification Technology, Volume 378, Part 2, 2025, 134679, ISSN 1383-5866, https://doi.org/10.1016/j.seppur.2025.134679.