This is from the commentary of Thomas’ forthcoming book…enjoy!
Gotu Kola is a member of the genus Centella in the Apiaceae family, which is a small genus of less than 20 species mostly found in South Africa. The genus is not a common morphological representation of the family which usually has very obvious umbrella shaped inflorescense and include plants like dāngguī, Parsley, and carrot. Centella asiatica is a native of Asia from India east through SE Asia, but is now found as a week throughout the South Pacific islands, parts of Southeastern United States, tropical and subtropical areas of Central and South America, and some areas of Africa. It is a creeping low-growing plant that sends out stolons that generate roots at nodes, these nodes create a rosette of stems with the characteristic roundish leaf that helps to explain another common name for the plant, Asian Pennywort.
This plant is widely used around the world and in systems within its native range such as Ayurveda,1 Thailand,2 and Indonesia3 as well as, more recently, in Western herbal medicine. Its place in Chinese medicine is quite fringe, which is curious. It is found commonly in all the southern provinces of China, and can be assumed to have been in most of that area since the time of antiquity. The Shén Nóng Běn Cǎo Jīng (circa 200CE) states that it is bitter, acrid, and cold, and treats great heat, sores, flat and welling abscesses, acute redness and swelling of the skin, and bodily heat. It is discussed in Newly Revised Materia Medica (659), and again in other important materia medicas, including modern textbooks used in China. The Bēn Cǎo Gāng Mù (1590) has a more complete explanation of this medicinal, and even includes it in two formulas, one for “Lower Abdominal Pain in Women” the other for “Blood Disease in Men.” However, these formulas are not named, nor are the ingredients given. To the author’s knowledge, there are no prominent modern formulas that utilize this medicinal, and I have not seen it prescribed in a Chinese clinic or hospital.
It is a very common weed throughout the tropics and some sub-tropical area. In fact, while I lived in Hawai‘i, I noticed that many people were constantly trying to rid their lawns of this plant; meanwhile, I was cultivating it in my little garden as a groundcover below the basil and other plants.
The body of modern research is relatively large with studies focusing on its wound healing, cognitive, and nerve regenerative actions. The list of studies on its wound healing properties long, but the following from a review paper sums it up very well:
“In numerous pharmacodynamics studies involing animal experiments and in vivo experiments with human fibroblasts, the clinical, mechanical, cellular and bio-chemical effects of Centella asiatica have been investigated. The topical application of Centella extracts has shown to be associated with accelerated wound healing in abnormal conditions of the skin associated with a reduction in granuloma weight, and an increase in the force needed to produce rupture (rupture strength) of the wound. In addition, further studies have revealed a dose-dependent increase in the synthesis of collagen, intracellular fibronectin content, an increase in mitotic activity of the germ layer, and an enlargement of the kerato hyaline granules in the scar tissue.”4
The above is relatively convincing and comprehensive in scope showing Gotu Kola should have a place in the treatment of wounds. In a study done in 2012, aqueous extracts were shown to improve scratch wounds to corneal tissue,5 suggesting a low cost and effective way for people approach eye injuries. There has been work done showing Gotu Kola can increase the growth of nerve tissue. In a paper published in 2005, the authors summarize their findings by saying, “In summary, our findings clearly demonstrate the therapeutic efficacy of oral administration of the ethanolic extracts of Centella asiaitica for accelerating nerve regeneration in the peripheral nervous system in vivo.”6 In a study done with the aqueous extracts (prepared as a solid or powered extract similar to those used in Chinese medicine, but with no binder added) was shown to have significant positive outcomes in rats with Alzheimer’s disease. The authors conclude the paper with the following statement, “In conclusion, the present study demonstrates that C. asiatica significantly prevented cognitive impairment and attenuated the oxidative stress induced by brain glucose metabolism impairment in i.c.v. STZ-treated rats by its neuroprotective property. However, the possibility of an effect of C. asiatica on neurotransmitters in improving cognitive deficits cannot be ruled out.”7 Finally, in a study done in India with an extract using undisclosed solvents showed, “The repetitive administration of Centella asiatica further to 2 showed the significant increase in %accuracy of both numeric working memory and word recognition. In addition, Centella asiatica also showed significan increase in reaction time of both numeric working memory and spatial memory.” And, “It is very striking that Centella asiatica improves not only the cognitive performance but also the mood. The high dose of Centella asiatica could increase calmness and alertness after 1 and 2 months of treatment. In addition, the significant increase in calmness was also observed after Centella asiatica treatment at medium and high doses for 2 months.”8 Medium and high doses were 500mg and 750mg respectively, once a day.
These data show that there appears to be a difference in the method of extraction of this medicinal, aqueous or ethanol. However, most herbalists, if possible prepare Gotu Kola as a fresh plant extract, and I certainly recommend this. This may be worth investigating since the opinion of many prominent herbalists and botanical pharmacists (in most cases), is that production of fresh plants offers not only a more potent representation of the plant, but also tends to yield both water and alcohol soluble constituents. Also, the ethnobotanical literature suggests the traditionally healer prefer the fresh plant over the dried, and often administer this medicinal as a juice. Further investigation is warranted.