Uncaria tomentosa (Willd.) D.C. (Rubiaceae), commonly known as "Uña de Gato" or "Cat's Claw", is a tropical vine from the rainforest used in traditional medicine and spread through Central and South America, including Costa Rica. There is an increasing demand for medicinal extracts with biological activity attributed mainly to oxindole alkaloids (OA), where the ratio between tetracyclic (TOA) and pentacyclic oxindole alkaloids (POA) determines its feasibility for medicinal applications. The ratio is affected by distinct factors including the dynamics of environmental conditions during seasons. The purpose of the study was to assess the seasonality effect in oxindole alkaloids content in relation to plant organs from U. tomentosa grown in the Caribbean region of Costa Rica. Young leaves followed by mature leaves presented the highest amount of total OA during seasons; for these, isoryncophylline, pteropodine and isomitraphylline, were the predominant OA. The POA/TOA ratio of both leaf materials was nearly 1:1 (3.2 mg g-1: 3.1 mg g-1). Bark and root material showed a pentacyclic chemotype in all seasons with a ratio of 6:1 (6.7 mg g-1: 1.3 mg g-1) with pteropodine and isomitraphylline as the predominant POA. The POA content presented seasonality with a significant increase from rainy to dry season in young leaves, bark and roots. In contrast, TOA amount remained virtually unchanged in all plant parts. Humidity and temperature between the studied seasons were constant except for precipitation, reflecting that differences of water content had an effect in the POA amounts. Further studies of abiotic factors, like water stress, could explain the variation of POA content due to seasonality.

中文翻译：

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季节性对哥斯达黎加加勒比地区绒毛钩藤不同器官羟吲哚生物碱组成的影响

Uncaria tomentosa (Willd.) DC (Rubiaceae)，俗称“Uña de Gato”或“猫爪”，是一种来自热带雨林的热带藤本植物，用于传统医学，分布于中美洲和南美洲，包括哥斯达黎加。对具有生物活性的药用提取物的需求不断增加，主要归因于羟吲哚生物碱 (OA)，其中四环 (TOA) 和五环羟吲哚生物碱 (POA) 之间的比例决定了其药用可行性。该比率受不同因素的影响，包括季节期间环境条件的动态变化。该研究的目的是评估与生长在哥斯达黎加加勒比地区的毛绒花植物器官相关的羟吲哚生物碱含量的季节性影响。年轻叶其次是成熟叶在季节中的总OA含量最高；对于这些，异烟碱、蝶豆碱和异米曲茶碱是主要的 OA。两种叶子材料的 POA/TOA 比率接近 1:1（3.2 mg g-1: 3.1 mg g-1）。树皮和根材料在所有季节都显示出五环化学型，比例为 6:1（6.7 mg g-1: 1.3 mg g-1），其中以蝶豆碱和异烟碱为主要 POA。POA 含量呈现季节性，幼叶、树皮和根从雨季到旱季显着增加。相比之下，所有植物部位的 TOA 量几乎保持不变。除了降水外，研究季节之间的湿度和温度是恒定的，这反映了水含量的差异对 POA 量有影响。进一步研究非生物因素，