Combretum mucronatum Schumach. & Thonn. is a medicinal plant widely used in West African traditional medicine for wound healing and the treatment of helminth infections. The present study aimed at a phytochemical characterization of a hydroalcoholic leaf extract of this plant and the identification of the anthelmintic compounds by bioassay-guided fractionation. An EtOH-H2O (1:1) extract from defatted leaves was partitioned between EtOAc and H2O. Further fractionation was performed by fast centrifugal partition chromatography, RP18-MPLC and HPLC. Epicatechin (1), oligomeric proanthocyanidins (OPC) 2 to 10 (mainly procyanidins) and flavonoids 11 to 13 were identified as main components of the extract. The hydroalcoholic extract, fractions and purified compounds were tested in vitro for their anthelmintic activity using the model nematode Caenorhabditis elegans. The bioassay-guided fractionation led to the identification of OPCs as the active compounds with a dose-dependent anthelmintic activity ranging from 1 to 1000 μM. Using OPC-clusters with a defined degree of polymerization (DP) revealed that a DP ≥ 3 is necessary for an anthelmintic activity, whereas a DP > 4 does not lead to a further increased inhibitory effect against the helminths. In summary, the findings rationalize the traditional use of C. mucronatum and provide further insight into the anthelmintic activity of condensed tannins.
Combretum mucronatum Schumach. & Thonn.是一种药用植物,在西非传统医学中被广泛用于伤口愈合和治疗蠕虫感染。本研究旨在对该植物的
水醇叶
提取物进行植物
化学鉴定,并通过
生物测定指导分馏法鉴定抗蠕虫化合物。脱脂叶片的 EtOH-
H2O (1:1)
提取物在 EtOAc 和 之间分配。通过快速离心分离层析、RP18-MPLC 和 HPLC 进行了进一步分馏。
表儿茶素(1)、低聚
原花青素(OPC)2 至 10(主要是
原花青素)和
黄酮类化合物 11 至 13 被鉴定为
提取物的主要成分。利用模式线虫秀丽隐杆线虫对
水醇
提取物、馏分和纯化化合物的驱虫活性进行了体外测试。
生物测定指导下的分馏结果表明,OPCs 是活性化合物,具有 1 至 1000 μM 的剂量依赖性驱虫活性。使用具有确定聚合度(DP)的 OPC 簇发现,DP ≥ 3 是抗蠕虫活性的必要条件,而 DP > 4 不会进一步增加对蠕虫的抑制作用。总之,这些发现合理解释了 C. mucronatum 的传统用途,并进一步揭示了缩合
单宁的驱虫活性。