Centella Asiatica (Gotu Kola)
Centella Asiatica (Gotu Kola, indian pennywort) is a small ground cover plant native mostly to india and asia. It has a long history of use in traditional medicine including as a brain tonic. Centella Asiatica is relatively new to the world of research and hence it is harder to draw definitive conclusions. Only one study has been conducted in humans regarding cognition. It is of good quality and shows beneficial effects. Although the participants were healthy their age means that it is difficult to extrapolate results to healthy adults.
Much more research exist in the animal space. This research is very promising showing enhancement of normal adult and very young rat cognitive functions as well as enhanced growth of brain cells in corresponding regions of the brain. This enhanced neuron growth has also been demonstrated in human neurons in culture. The evidence points to a likely cognition enhancing effect from centella asiatica however much more research is needed. The likely action appears to enhance neuron growth. If this can be demonstrated in healthy adult humans it would make centella asiatica a very welcome addition to any cognition enhancement regimen.
Most beneficial for - Healthy elderly, possibly very young or healthy adults
Effective dose - At least 750mg extract daily for adults
Length of action - after 14 days
Safety - safe at normal doses
Type of cognition affected - working memory, spacial memory and retention
Enhancers - Unknown
Human Supporting Studies
Positive modulation of cognition and mood in the healthy elderly volunteer following the administration of Centella asiatica (Wattanathorn et al, 2008)
In this double blind placebo controlled study 28 healthy older adults 250mg, 500mg, 750mg of centella asiatica extract or a placebo daily for 2 months. The 750mg dose was found to enhance working memory and results on another cognitive test. Mood was also improved in a self reported test by those taking the centella asiatica.
Animal Supporting Studies
Enhancement of Hippocampal CA3 Neuronal Dendritic Arborization by Centella asiatica (Linn) Fresh Leaf Extract Treatment in Adult Rats (Mohandas Rao et al, 2008)
Adult rats were fed 2, 4 or 6ml/kg of fresh centella asiatica leaf juice daily for 2, 4 or 6 weeks. Analysis of the rat brains showed a significant increase in the dendritic length (intersections) and dendritic branching points along the length of hippocampal dendrites in rats treated with 6 mL/kg body weight/day of Centella asiatica for 6 weeks. However, the rats treated with 2 and 4 mL/kg body weight/day for 2 and 4 weeks did not show any significant change in hippocampal CA3 neuronal dendritic arborization.
Centella asiatica treatment during postnatal period enhances learning and memory in mice (Rao et al, 2005)
Three month old rats were orally given doses of centella asiatica aqueous extract at 200mg/kg for 30 days. Rats showed both after 30day and 6 months significant improvements in maze and hole board tests. There was no effect on locomotor activity. Evaluation of the rat brain showed that those taking the centella asiatica extract had increased acetylcholine esterase activity in the hippocampus and increased branching and growth of connections in CA3 hippocampal neurons. These rats were developing so results may be different in adults.
Effect of different extracts of Centella asiatica on cognition and markers of oxidative stress in rats (Veerendra et al, 2002)
Rats were given an aqueous extract (200mg/kg) of from the whole plant of centella asiatica for 14 days. They showed improvements in some memory and learning tests so more doses were tested (100mg/kg and 300mg/kg) with more areas of cognition. The 200mg/kg and 300mg/kg doses showed improvements in all cognitive tests (shuttle box, step through, step down and transfer latency in a plus maze). These doses also showed lower level of oxidative stress in the brain.
Centella asiatica accelerates nerve regeneration upon oral administration and contains multiple active fractions increasing neurite elongation in-vitro (Soumyanath et al, 2005)
An ethanolic extract was cultured with human neurons in the presence of nerve growth factor. The presence of the extract elicited a marked increase in neurite outgrowth compared to control groups. Several active compounds were identified the strongest being asiatic acid. Rats were then given 300mg/kg a day of the ethanolic extract. Their brains were found to have larger calibre axons and greater myelination than controls indicating the grew faster.
Centella asiatica (linn) induced behavioural changes during growth spurt period in neonatal rats (Mohandas Rao et al, 2005)
Neonatal rat pups (7 days old) were given different doses of fresh leaf juice of Centella asiatica (CeA) orally
for different periods of time. These rats were then subjected to spatial learning (T- Maze) and passive avoidance
tests along with the age matched normal and saline control rats. The results showed improvement in spatial
learning performance and enhanced memory retention in neonatal rats treated with higher doses. These results
indicate that treatment with CeA fresh leaf juice during growth spurt period of neonatal rats enhances memory
retention.
Enhancement of Amygdaloid Neuronal Dendritic Arborization by Fresh Leaf Juice of Centella asiatica (Linn) During Growth Spurt Period in Rats (Mohandas Rao et al, 2009)
Seven day old rats were given 2, 4 or 6ml/kg of fresh centella asiatica juice daily for 2, 4 and six weeks. Analysis of the rat brains showed a significant increase in dendritic length (intersections) and dendritic branching points along the length of dendrites of the amygdaloid neurons of rats treated with 4 and 6 ml/kg body weight/day of CeA for longer periods of time (i.e. 4 and 6 weeks).
Effect of Centella asiatica on pentylenetetrazole-induced kindling, cognition and oxidative stress in rats (Gupta et al, 2002)
Rats were injected with a chemical that causes seizures and cognitive impairment. They were then given either 100mg/kg or 300mg/kg of centella asiatica aqueous extract. Those rats recieving the 300mg/kg dose showed improvement in seizure levels and cognitive tests. Those receiving the 100mg/kg dose showed improvements in cognition only.
Effects of asiatic acid on passive and active avoidance task in male Spraque–Dawley rats Cellular Supporting Studies (Nasir et al, 2010)
Rats received varying dose of asiatic acid (from centella asiatica) and were evaluated for both passive and active avoidance. Treatment with 30mg/kg showed a significant improvement in memory in the passive avoidance tests.
Contradictory Studies
None
Combinational Studies
None
Safety Studies
None
Much more research exist in the animal space. This research is very promising showing enhancement of normal adult and very young rat cognitive functions as well as enhanced growth of brain cells in corresponding regions of the brain. This enhanced neuron growth has also been demonstrated in human neurons in culture. The evidence points to a likely cognition enhancing effect from centella asiatica however much more research is needed. The likely action appears to enhance neuron growth. If this can be demonstrated in healthy adult humans it would make centella asiatica a very welcome addition to any cognition enhancement regimen.
Most beneficial for - Healthy elderly, possibly very young or healthy adults
Effective dose - At least 750mg extract daily for adults
Length of action - after 14 days
Safety - safe at normal doses
Type of cognition affected - working memory, spacial memory and retention
Enhancers - Unknown
Human Supporting Studies
Positive modulation of cognition and mood in the healthy elderly volunteer following the administration of Centella asiatica (Wattanathorn et al, 2008)
In this double blind placebo controlled study 28 healthy older adults 250mg, 500mg, 750mg of centella asiatica extract or a placebo daily for 2 months. The 750mg dose was found to enhance working memory and results on another cognitive test. Mood was also improved in a self reported test by those taking the centella asiatica.
Animal Supporting Studies
Enhancement of Hippocampal CA3 Neuronal Dendritic Arborization by Centella asiatica (Linn) Fresh Leaf Extract Treatment in Adult Rats (Mohandas Rao et al, 2008)
Adult rats were fed 2, 4 or 6ml/kg of fresh centella asiatica leaf juice daily for 2, 4 or 6 weeks. Analysis of the rat brains showed a significant increase in the dendritic length (intersections) and dendritic branching points along the length of hippocampal dendrites in rats treated with 6 mL/kg body weight/day of Centella asiatica for 6 weeks. However, the rats treated with 2 and 4 mL/kg body weight/day for 2 and 4 weeks did not show any significant change in hippocampal CA3 neuronal dendritic arborization.
Centella asiatica treatment during postnatal period enhances learning and memory in mice (Rao et al, 2005)
Three month old rats were orally given doses of centella asiatica aqueous extract at 200mg/kg for 30 days. Rats showed both after 30day and 6 months significant improvements in maze and hole board tests. There was no effect on locomotor activity. Evaluation of the rat brain showed that those taking the centella asiatica extract had increased acetylcholine esterase activity in the hippocampus and increased branching and growth of connections in CA3 hippocampal neurons. These rats were developing so results may be different in adults.
Effect of different extracts of Centella asiatica on cognition and markers of oxidative stress in rats (Veerendra et al, 2002)
Rats were given an aqueous extract (200mg/kg) of from the whole plant of centella asiatica for 14 days. They showed improvements in some memory and learning tests so more doses were tested (100mg/kg and 300mg/kg) with more areas of cognition. The 200mg/kg and 300mg/kg doses showed improvements in all cognitive tests (shuttle box, step through, step down and transfer latency in a plus maze). These doses also showed lower level of oxidative stress in the brain.
Centella asiatica accelerates nerve regeneration upon oral administration and contains multiple active fractions increasing neurite elongation in-vitro (Soumyanath et al, 2005)
An ethanolic extract was cultured with human neurons in the presence of nerve growth factor. The presence of the extract elicited a marked increase in neurite outgrowth compared to control groups. Several active compounds were identified the strongest being asiatic acid. Rats were then given 300mg/kg a day of the ethanolic extract. Their brains were found to have larger calibre axons and greater myelination than controls indicating the grew faster.
Centella asiatica (linn) induced behavioural changes during growth spurt period in neonatal rats (Mohandas Rao et al, 2005)
Neonatal rat pups (7 days old) were given different doses of fresh leaf juice of Centella asiatica (CeA) orally
for different periods of time. These rats were then subjected to spatial learning (T- Maze) and passive avoidance
tests along with the age matched normal and saline control rats. The results showed improvement in spatial
learning performance and enhanced memory retention in neonatal rats treated with higher doses. These results
indicate that treatment with CeA fresh leaf juice during growth spurt period of neonatal rats enhances memory
retention.
Enhancement of Amygdaloid Neuronal Dendritic Arborization by Fresh Leaf Juice of Centella asiatica (Linn) During Growth Spurt Period in Rats (Mohandas Rao et al, 2009)
Seven day old rats were given 2, 4 or 6ml/kg of fresh centella asiatica juice daily for 2, 4 and six weeks. Analysis of the rat brains showed a significant increase in dendritic length (intersections) and dendritic branching points along the length of dendrites of the amygdaloid neurons of rats treated with 4 and 6 ml/kg body weight/day of CeA for longer periods of time (i.e. 4 and 6 weeks).
Effect of Centella asiatica on pentylenetetrazole-induced kindling, cognition and oxidative stress in rats (Gupta et al, 2002)
Rats were injected with a chemical that causes seizures and cognitive impairment. They were then given either 100mg/kg or 300mg/kg of centella asiatica aqueous extract. Those rats recieving the 300mg/kg dose showed improvement in seizure levels and cognitive tests. Those receiving the 100mg/kg dose showed improvements in cognition only.
Effects of asiatic acid on passive and active avoidance task in male Spraque–Dawley rats Cellular Supporting Studies (Nasir et al, 2010)
Rats received varying dose of asiatic acid (from centella asiatica) and were evaluated for both passive and active avoidance. Treatment with 30mg/kg showed a significant improvement in memory in the passive avoidance tests.
Contradictory Studies
None
Combinational Studies
None
Safety Studies
None