Aucoumea klaineana Pierre (Okoume) tannins were extracted by an artisanal maceration method in the presence of acetone/water used as solvent. The tannins obtained from the sapwood and heartwood and characterized by Maldi-ToF and FTIR did not present any differences regarding their type of oligomers. Tannins were more abundant in sapwood than in heartwood, but in both of them, fisetinidin and gallocatechin were the main monomers of condensed tannin. A low content of trihydroxyflavan monomer was identified, whereas non-glycosylated condensed tannins up to seven oligomers were found in high content in Okoume. These results, which revealed for the first time the chemical structure of Okoume condensed tannins showed the presence of a glycosylated condensed tannin series up to six carbohydrate residues attached to 2xgallocatechin-1xcatechin flavonoids.

中文翻译：

---

来自加蓬天然森林的 Aucoumea klaineana Pierre (Okoume) 边材和心材浓缩单宁的 Maldi-ToF 分析和 FTIR 表征

Aucoumea klaineana Pierre (Okoume) 单宁是在丙酮/水作为溶剂存在下通过手工浸渍法提取的。从边材和心材获得并通过 Maldi-ToF 和 FTIR 表征的单宁在其低聚物类型方面没有任何差异。单宁在边材中比心材中更丰富，但在两者中，非瑟替尼和没食子儿茶素是缩合单宁的主要单体。确定了低含量的三羟基黄烷单体，而在 Okoume 中发现了高达 7 个寡聚体的非糖基化缩合单宁。这些结果首次揭示了 Okoume 缩合单宁的化学结构，表明存在糖基化缩合单宁系列，多达 6 个碳水化合物残基与 2x 没食子儿茶素-1x 儿茶素类黄酮相连。