IRD, UMR DIADE (IRD/UM2), BP 64501, 34394 Montpellier, France.
Ann Bot. 2012 Aug;110(3):595-613. doi: 10.1093/aob/mcs119. Epub 2012 Jun 13.
The phenolic composition of Coffea leaves has barely been studied, and therefore this study conducts the first detailed survey, focusing on mangiferin and hydroxycinnamic acid esters (HCEs).
Using HPLC, including a new technique allowing quantification of feruloylquinic acid together with mangiferin, and histochemical methods, mangiferin content and tissue localization were compared in leaves and fruits of C. pseudozanguebariae, C. arabica and C. canephora. The HCE and mangiferin content of leaves was evaluated for 23 species native to Africa or Madagascar. Using various statistical methods, data were assessed in relation to distribution, ecology, phylogeny and use.
Seven of the 23 species accumulated mangiferin in their leaves. Mangiferin leaf-accumulating species also contain mangiferin in the fruits, but only in the outer (sporophytic) parts. In both leaves and fruit, mangiferin accumulation decreases with ageing. A relationship between mangiferin accumulation and UV levels is posited, owing to localization with photosynthetic tissues, and systematic distribution in high altitude clades and species with high altitude representatives. Analyses of mangiferin and HCE content showed that there are significant differences between species, and that samples can be grouped into species, with few exceptions. These data also provide independent support for various Coffea lineages, as proposed by molecular phylogenetic analyses. Sampling of the hybrids C. arabica and C. heterocalyx cf. indicates that mangiferin and HCE accumulation may be under independent parental influence.
This survey of the phenolic composition in Coffea leaves shows that mangiferin and HCE accumulation corresponds to lineage recognition and species delimitation, respectively. Knowledge of the spectrum of phenolic accumulation within species and populations could be of considerable significance for adaptation to specific environments. The potential health benefits of coffee-leaf tea, and beverages and masticatory products made from the fleshy parts of Coffea fruits, are supported by our phenolic quantification.
咖啡叶的酚类成分几乎没有被研究过，因此本研究首次进行了详细调查，重点关注芒果苷和羟基肉桂酸酯（HCEs）。
使用 HPLC，包括一种新的技术，允许定量测定阿魏酰奎宁酸和芒果苷，并结合组织化学方法，比较了 C. pseudozanguebariae、C. arabica 和 C. canephora 的叶片和果实中芒果苷的含量和组织定位。评估了 23 种原产于非洲或马达加斯加的叶类和果实类咖啡的 HCE 和芒果苷含量。使用各种统计方法，评估了数据与分布、生态、系统发育和用途的关系。
23 种中有 7 种在叶片中积累了芒果苷。在叶片中积累芒果苷的物种，其果实中也含有芒果苷，但仅在外部（孢子体）部分。在叶片和果实中，芒果苷的积累随着年龄的增长而减少。由于与光合作用组织的定位以及在高海拔分支和具有高海拔代表的物种中的系统分布，推测芒果苷的积累与 UV 水平有关。分析芒果苷和 HCE 含量表明，不同物种之间存在显著差异，并且可以根据物种分组，除了少数例外。这些数据还为各种咖啡谱系提供了独立的支持，如分子系统发育分析所提出的那样。对 C. arabica 和 C. heterocalyx cf. 的杂种进行采样表明，芒果苷和 HCE 的积累可能受独立亲本的影响。
本研究对咖啡叶中酚类成分的调查表明，芒果苷和 HCE 的积累分别对应于谱系识别和物种划分。了解特定物种和种群中酚类积累的范围，对于适应特定环境可能具有重要意义。咖啡叶茶、果肉饮料和咀嚼产品的潜在健康益处得到了我们酚类定量的支持。
