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Percorrer por autor "Corso, Luan Barichello"

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  • Green extraction of artemisinin from Artemisia annua L. and evaluation of the antimalarial activity
    Publication . Corso, Luan Barichello; Martins, Mónia; Pinho, Simão; Ferreira, Olga; Zuber, André
    Malaria remains one of the greatest global public health challenges, affecting millions of people, especially in tropical and subtropical regions. One of the main obstacles to treating the disease is the low water solubility of antimalarial compounds, which compromises their bioavailability. In this work, terpenes are proposed as alternative solvents and pharmaceutical excipients for processing and formulating these drugs, aiming for higher sustainability and safety in line with green chemistry principles. First, the COSMO-RS model was used to investigate approximately 8000 systems that combine solvents from different classes with antimalarial drugs (artemisinin, quinine, quinidine, tetracycline, artemether, dapsone, and pyrimethamine). Focusing on artemisinin and the evaluated terpene candidates, thymol and its mixtures with α-pinene, β-pinene, γ-terpinene, and p-cymene showed the greatest potential, and were selected as solvents to extract artemisinin from the plant Artemisia annua L. Heat extractions with magnetic stirring were performed using a carousel system under the conditions: 50 °C, 600 rpm, 1 hour, and 1:10 solid-liquid ratio. Besides artemisinin (ART), dihydroartemisinic acid (DHAA) was also identified in significant amounts. The extraction yields using conventional solvents were 1.15 mg ART/gplant and 5.53 mg DHAA/gplant for water and 7.11 mg ART/gplant and 9.42 mg DHAA/gplant for ethanol. Higher global yields were obtained using pure terpenes (α-pinene and β-pinene), and all the equimolar thymol mixtures. The highest values were 10.43 mg ART/gplant for the thymol:α-pinene mixture and 11.86 mg DHAA/gplant for α-pinene. These values are consistent with the maximum amount available in the plant (11.2 ± 0.8 mg ART/gplant, 13.4 ± 1.0 mg DHAA/gplant), obtained by performing five consecutive extraction cycles with an Accelerated Solvent Extractor (100 °C, 5 min, 1:10 S/L ratio). A selected set of extracts (water, dichloromethane, ethanol, p-cymene, γ-terpinene, α-pinene, β-pinene) was subject to in vitro antimalarial activity assays against Plasmodium falciparum (strain 3D7-GFP). All extracts obtained with terpenes were proven to be significant inhibitors, with IC50 values ranging from 5.19 nM (γ-terpinene) to 8.17 nM (α-pinene), close to the value of the standard artemisinin (IC50 = 4.20 nM). Terpenes maintained high activity, highlighting them and reinforcing their predictions as a green alternative for the extraction and formulation of antimalarial compounds.
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