Departamento de Produtos Naturais e Alimentos, Faculdade de Farmácia, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro (UFRJ), Rio De Janeiro, RJ, 21941-902, Brazil.
Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, DIPEQ, Rua Pacheco Leão 915, Rio De Janeiro, RJ, 22460-030, Brazil.
J Plant Res. 2021 Jan;134(1):127-139. doi: 10.1007/s10265-020-01246-4. Epub 2021 Jan 6.
The Swartzia species are commonly known as bloodwood due to the red exudate released from the stem after injury. This exudate has aroused great interest, and an integrative study is essential to describe it in detail. Thus, this work aimed to identify the red exudate's secreting-site in S. flaemingii and S. langsdorffii, and determine if it is a latex or a resin. Samples of the stem bark and the secondary xylem were prepared for histological analysis. Fresh exudates were dissolved in deuterated methanol and analyzed by H-NMR; other samples were resuspended in MeOH:HO (9:1), partitioned with organic solvents and analyzed by direct infusion mass spectrometry. Total phenolic and total flavonoid contents were determined spectrophotometrically, and antioxidant capacity was determined using ferric reducing antioxidant power assay. The results showed that the exudate is a red latex produced by articulated laticifers located among the phloem cells. The latex is composed of sucrose, catechin glucosides, chlorophyll derivatives, and hederagenin-type saponins. Both samples of S. flaemingii and S. langsdorffii presented high amounts of phenolics and flavonoids, as well as a strong antioxidant capacity. The anatomical study showed that the secreting-site of the Swartzia red exudates were laticifers. This finding allows us to exclude other substances such as resin or oleoresin, generally produced by secretory cavities or ducts. Furthermore, since laticifers are rare in Fabaceae, this finding is significant, and represents an essential taxonomic feature. The showy red color is due to the large amounts of flavonoids. This latex probably has a protective role against microorganisms and photodamage. The bioactive potential of this exudate inspires further studies, which may boost the economic importance of Swartzia.
斯沃特济亚（Swartzia）树种通常被称为血木，因为其茎干受伤后会渗出红色分泌物。这种分泌物引起了人们的极大兴趣，对其进行综合研究对于详细描述它至关重要。因此，本工作旨在确定血木树种——斯沃特济亚弗拉明吉（S. flaemingii）和斯沃特济亚朗斯多夫（S. langsdorffii）中红色分泌物的分泌部位，并确定它是乳胶还是树脂。为此，我们对茎皮和次生木质部进行了组织学分析。采集新鲜分泌物用氘代甲醇溶解后进行 H-NMR 分析；其它样本则用 MeOH:HO（9:1）重悬，用有机溶剂萃取后用直接进样质谱分析。总酚和总类黄酮含量通过分光光度法测定，铁还原抗氧化能力测定法用于测定抗氧化能力。结果表明，该分泌物是由韧皮部细胞之间的节状乳汁管产生的红色乳胶。乳胶由蔗糖、儿茶素葡萄糖苷、叶绿素衍生物和齐墩果酸型皂苷组成。斯沃特济亚弗拉明吉和斯沃特济亚朗斯多夫的两种样本均含有大量的酚类物质和类黄酮，以及很强的抗氧化能力。解剖学研究表明，斯沃特济亚红色分泌物的分泌部位是乳汁管。这一发现排除了树脂或松脂等一般由分泌腔或导管产生的其它物质。此外，由于乳汁管在豆科植物中较为罕见，因此这一发现具有重要意义，代表了一个重要的分类特征。显眼的红色是由于大量的类黄酮。这种乳胶可能具有保护作用，可防止微生物和光损伤。这种分泌物的生物活性潜力激发了进一步的研究，这可能会提高斯沃特济亚的经济重要性。
