In vitro antioxidant, antitumor and leishmanicidal activity of riparin A, an analog of the Amazon alkamides from Aniba riparia (Lauraceae)

ABSTRACT Aniba riparia (Lauraceae) is an important medicinal plant found in the Amazon region and presents alkaloids of the type alkamide known as riparins. Riparin A is structurally represented as the fundamental core of all Amazon riparins. This work aimed to assess the in vitro antioxidant, antitumor and antileishmanial effects of riparin A. Riparin A presented weak antioxidant capacity by tecniques of DPPH• (EC50 of 296.2 μg mL-1) and ABTS•+ (EC50 of 450.1 μg mL-1), showed moderate activity against colon carcinoma (HCT-116: IC50 of 21.7 μg mL-1) and leishmanicidal activity on promastigotes of L. amazonensis (IC50 of 307.0 ± 79.6, 193.7 ± 44.3 and 81.8 ± 11.2 μg mL-1, respectively, after 24, 48 and 72 h of incubation). Then, in addition to its structural simplicity, riparin A revealed promising biological activities and remarkable in vitro leishmanicidal action, an important result in epidemiological point of view to control leishmaniasis in Brazil, including in the Amazon region.

摘要 河生阿尼巴木（Aniba riparia，樟科Lauraceae）是分布于亚马逊流域的重要药用植物，其所含生物碱属于烷酰胺类（alkamide），被命名为里帕林类（riparins）。里帕林A（Riparin A）的结构是所有亚马逊来源里帕林类生物碱的核心骨架。本研究旨在评估里帕林A的体外抗氧化、抗肿瘤及抗利什曼原虫活性。通过DPPH自由基（DPPH•）与ABTS自由基阳离子（ABTS•+）检测技术分析结果显示，里帕林A的抗氧化能力较弱，其半数有效浓度（EC₅₀）分别为296.2 μg·mL⁻¹和450.1 μg·mL⁻¹；对结肠癌细胞（HCT-116）表现出中等强度的抗肿瘤活性，半数抑制浓度（IC₅₀）为21.7 μg·mL⁻¹；对亚马逊利什曼原虫（L. amazonensis）前鞭毛体具有杀利什曼原虫活性，分别在培养24、48和72小时后，其半数抑制浓度依次为307.0±79.6、193.7±44.3和81.8±11.2 μg·mL⁻¹。综上，里帕林A不仅结构简洁，还展现出良好的生物活性与显著的体外杀利什曼原虫作用；从流行病学角度而言，这一结果对于巴西（包括亚马逊流域）的利什曼病防控具有重要意义。