Kennedy D O, Haskell C F, Wesnes K A, Scholey A B
Human Cognitive Neuroscience Unit, Division of Psychology, Northumbria University, Newcastle upon Tyne, NE1 8ST, United Kingdom.
Pharmacol Biochem Behav. 2004 Nov;79(3):401-11. doi: 10.1016/j.pbb.2004.07.014.
Extracts from the plant guarana (Paullinia cupana) feature as putatively stimulating ingredients in a number of foods, drinks and dietary/herbal supplements. To date, little research in humans has examined the potential psychoactive effects of these extracts. Extracts of Panax ginseng, which are often sold in combination with guarana, contain similar potentially active components, and have been shown to modulate cognitive performance. In this double-blind, counterbalanced, placebo-controlled study, the cognitive and mood effects of separate single doses of: 75 mg of a dried ethanolic extract of guarana (approx 12% caffeine), 200 mg of Panax ginseng (G115), and their combination (75 mg/200 mg), were assessed in 28 healthy young (18-24) participants. On each day of the study (separated by a 7-day washout), cognitive performance and subjective mood were assessed pre-dose and at 1, 2.5, 4 and 6 h post-dose using the Cognitive Drug Research computerised assessment battery, Serial subtraction tasks and Bond-Lader mood scales. In comparison to placebo, all three treatments resulted in improved task performance throughout the day. In the case of guarana, improvements were seen across 'attention' tasks (but with some evidence of reduced accuracy), and on a sentence verification task. While also increasing the speed of attention task performance, both ginseng and the ginseng/guarana combination also enhanced the speed of memory task performance, with little evidence of modulated accuracy. Guarana and the combination, and to a lesser extent ginseng, also led to significant improvements in serial subtraction task performance. These results provide the first demonstration in humans of the psychoactive effects of guarana, and confirmation of the psychoactive properties of ginseng. Given the low caffeine content (9 mg) of this dose of guarana extract, the effects are unlikely to be attributable to its caffeine content.
植物瓜拉那（Paullinia cupana）的提取物在许多食品、饮料和膳食/草药补充剂中作为假定的刺激性成分。迄今为止，针对这些提取物对人体潜在的精神活性作用的研究很少。人参（Panax ginseng）提取物常与瓜拉那联合销售，含有类似的潜在活性成分，并且已被证明可调节认知表现。在这项双盲、平衡、安慰剂对照研究中，对28名健康的年轻（18 - 24岁）参与者评估了单独单剂量的75毫克瓜拉那干乙醇提取物（约含12%咖啡因）、200毫克人参（G115）及其组合（75毫克/200毫克）的认知和情绪影响。在研究的每一天（间隔7天洗脱期），使用认知药物研究计算机评估电池、连续减法任务和邦德 - 莱德情绪量表在给药前以及给药后1、2.5、4和6小时评估认知表现和主观情绪。与安慰剂相比，所有三种治疗在一整天内均使任务表现得到改善。就瓜拉那而言，在“注意力”任务中观察到改善（但有一些准确性降低的迹象），以及在句子验证任务中。人参和人参/瓜拉那组合在提高注意力任务表现速度的同时，还提高了记忆任务表现的速度，几乎没有准确性受到调节的迹象。瓜拉那及其组合，以及程度较轻的人参，也使连续减法任务表现有显著改善。这些结果首次在人体中证明了瓜拉那的精神活性作用，并证实了人参的精神活性特性。鉴于该剂量瓜拉那提取物的咖啡因含量较低（9毫克），这些作用不太可能归因于其咖啡因含量。
