Centella asiatica is a perennial plant used in Ayurvedic and traditional medicine. It is thought to enhance cognitive functions and wound healing. Clinical studies have suggested modest benefits in a few cognitive functions with Centella asiatica; however, a meta-analysis of clinical trials failed to show cognitive benefits. Laboratory studies have shown that Centella asiatica reduced oxidative stress and neuronal death, but these have not been confirmed in humans. Centella asiatica is generally considered to be safe with mild side effects, but a few cases of liver toxicity have been reported.
Centella asiatica has been tested in numerous clinical trials, though all of the studies were small. Our search identified:
Small clinical trials have shown potential benefit for a few cognitive functions with Centella asiatica treatment [1]; however, a meta-analysis of eleven randomized controlled trials testing Centella asiatica reported no significant differences between Centella asiatica treatment and placebo on any cognitive functions [2]. In an exploratory clinical study of patients with post-stroke vascular cognitive impairment, treatment with a Centella asiatica extract did not improve overall cognitive functions compared to that observed in the control group that received folic acid treatment [3]. However, delayed recall memory was significantly improved in patients treated with Centella asiatica compared to those given folic acid. No differences were seen in other cognitive functions, including executive function, naming, attention, language, abstraction, or orientation. A small, short-term, phase I trial reported that Centella asiatica may increase blood levels of choline, which would theoretically support the synthesis of the brain chemical, acetylcholine, that is important for learning and memory [4].
In preclinical models of Alzheimer’s disease, extracts of Centella asiatica decreased biological markers of the disease (beta-amyloid levels) and oxidative stress [5; 6], prevented the shrinkage of neuronal processes [7], and protected against beta-amyloid-associated toxicity and behavioral abnormalities [8; 9; 10]. In preclinical models of cognitive impairment, Centella asiatica treatment significantly restored cognitive performance, decreased brain cell death, increased antioxidant defense, and reversed mitochondrial deficits [7; 11; 12; 13; 14; 15; 16; 17]. There are many components to Centella asiatica, of which asiatic acid has been the most studied in preclinical models. Asiatic acid does cross the blood-brain-barrier? and produces antioxidant and other protective effects [18; 19], though these findings have not been confirmed in humans.
No studies have reported whether Centella asiatica can improve cognitive function or slow decline in people with dementia. One small short-term phase I study in people with mild dementia reported that Centella asiatica extract increased gene expression of NRF2, a master regulator of antioxidant and anti-inflammatory functions [20]. In preclinical models of Alzheimer’s disease, extracts of Centella asiatica restored cognitive impairments, reduced biological markers of Alzheimer’s disease, protected against toxicity from beta-amyloid, reduced oxidative stress, and prevented the shrinkage of neuronal processes [5; 6; 7; 8; 9; 10; 18].
In a meta-analysis of eleven randomized controlled trials testing the effects of Centella asiatica on cognitive function, no adverse effects were reported in any studies that tested it alone [2]. In combination therapies, side effects were comparable to or lower than those for placebo and included gastrointestinal discomfort, flatulence, nausea, headache, decreased appetite, sedation, and rash. Other studies have reported gastrointestinal symptoms, constipation, abdominal bloating, drowsiness, and itchiness [3; 4; 21; 22].
There has been a report of three women who developed jaundice and hepatitis after taking Centella asiatica for 20-60 days [23]. They improved after discontinuation and treatment with a bile acid. It is unclear whether the liver toxicity is associated with a specific brand, preparation, or dose. People with liver disease should not take Centella asiatica.
Drug interactions are not well-documented, though theoretically, Centella asiatica may interact with antiepileptic drugs (e.g., phenytoin, valproate, and gabapentin) [24]. As natural products, Centella asiatica formulations may contain pesticides and heavy metals [25].
NOTE: This is not a comprehensive safety evaluation or complete list of potentially harmful drug interactions. It is important to discuss safety issues with your physician before taking any new supplement or medication.
Centella asiatica is an herbal medicine used in Ayurvedic and traditional Chinese medicine. It is also known as gotu kola, Asiatic pennywort, Indian pennywort, jal brahmi, mandookaparni, and tsubokusa. Centella asiatica is available over-the-counter as whole herbs, powder, capsules, or liquid extracts. Dosage is not established for any indication. Doses of Centella asiatica extracts most commonly tested in clinical trials have ranged from 200 to 1,000 mg per day, taken orally [1; 3; 4]. A review on Centella asiatica noted that the extraction method, biochemical profile, and dosage information of the extract are not standardized [26], and therefore potencies and qualities may vary across products [25].
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