Chlorogenic acid is a phytochemical that belongs to the hydroxycinnamate group of polyphenols. Chlorogenic acid is an ester of caffeic acid and quinic acid. As with caffeic acid, chlorogenic acid is an intermediate in the synthesis of lignin and therefore is present in all plants. However, some plants contain higher concentrations of chlorogenic acid than others. Coffee, blueberries, kiwi fruit, plums, cherries and apples are good sources of chlorogenic acid, but most fruits contain some chlorogenic acid. Evidence suggests that chlorogenic acid may be the most abundant polyphenol in fruit. Polyphenols including hydroxycinnamates have been shown to possess anti-anxiety effects in animals and humans. A number of studies have investigated the effects of chlorogenic acid on mood. For example, in one study, mice were subjected to experimental stress and this induced anxiety in the animals. However, administration of chlorogenic acid was effective at attenuating the anxious behaviour.
In another study, chlorogenic acid from extracts of the herb Artemisia capillaris (oriental wormwood) were administered to mice. The mice were exposed to experimental stress and this induced behavioural changes that were indicative of mood changes, particularly depression. However, administration of chlorogenic acid was able to attenuate these effects and normalise the behaviour of the mice, suggesting that chlorogenic acid may have normalised the mood of the mice. In humans, chlorogenic acid from coffee has also been shown to possess mood elevating effects. For example, one group of researchers administered a coffee rich in chlorogenic acid to a group of elderly and healthy individuals. The results of the study showed that the chlorogenic acid rich coffee was able to improve mood significantly. The authors demonstrated that this effect was not due to the caffeine in the coffee. Researchers have also suggested that chlorogenic acid could decrease neurodegeneration, and therefore may protect cognitive function.
Chlorogenic acid may possess neuroprotective effects. In one study, mice were administered the drug scopolamine in order to reduce their acetylcholine levels. This negatively affected the ability of the mice to memorise routes through a maize. However, administration of chlorogenic acid was able to attenuate the detrimental effects of the scopolamine, suggesting that chlorogenic acid possesses memory enhancing effects. The researchers concluded that chlorogenic acid inhibited the acetylcholine degradation enzyme acetylcholinesterase in parts of the brain in a dose dependent manner, and this raised brain levels of acetylcholine. The chlorogenic acid also significantly decrease oxidative stress in the brains of the mice, in a dose dependent manner. The authors concluded that chlorogenic acid possesses significant neuroprotective effects in mice. Coffee is a good dietary source of chlorogenic acid.
It is unclear how chlorogenic acid may reduce anxiety, but an antioxidant mechanism could exist, and this may be common to all phytochemical antioxidants. Administration of the drug flumazenil is able to inhibit the anti-anxiety effects of chlorogenic acid. As flumazenil is able to inhibit activation of the benzodiazepine receptor, this suggests that the mechanism of action of chlorogenic acid may be through activation of this receptor. However, chlorogenic acid is an effective antioxidant that is bioavailable in animals and humans, and a general antioxidant effect could also explain the anti-anxiety effects. Oxidative stress has been implicated in the pathogenesis of a number of forms of anxiety including panic disorders and obsessive compulsive disorder and high levels of oxidative stress have been shown to be present in animals experiencing experimentally induced anxiety. Therefore the antioxidant function of chlorogenic acid may contribute towards the anti-anxiety effects of the phytochemical.
Eat Well, Stay Healthy, Protect Yourself
RdB
