Healing Weeds

Nature has generously offered humans and other animals its bounty, which includes a wide range of weedy colonizers, rich in many bioactive compounds with strong biochemical properties. Some have been associated with humans for many millennia. Others, perhaps, for the past few hundred years. Among the Nature’s bounty are weeds of exceptional medicinal value, which commonly occur on disturbed habitat around human habitations. Two of the most outstanding, both natives of South Asia, are Asian pennywort (Centella asiatica) and brahmi (Bacopa monnieri).

Photo: Likhitha Lily, CC BY-SA 3.0

Centella asiatica – Asian pennywort 

The typical Indian name for the plant is ‘Brahmi’, derived from ‘Brahma’, the supreme creator god in Hinduism. This name reflects the recognition of the plant for more than 5000 years as the ‘herb of enlightenment’ or ‘friend of the brain’ in Ayurveda. High praise indeed for a humble weed species! 

Centella is found in most tropical and subtropical countries in Asia, Africa, Madagascar, South-Pacific islands, and even Eastern Europe, growing in swampy areas. In Australia, it is considered ‘naturalized’. Although Centella is not promoted in Eastern Australia, it is widely encouraged in Western Australia. In Perth’s Canning River suburbs, not far from where I live, it is an important groundcover species used in rehabilitating disturbed vegetation remnants and other areas. 

Increased research has resulted in a vast repository of information on Centella’s pharmacological profile, which is quite complex. Triterpenoids and saponins are Centella’s primary constituents, considered responsible for a range of its therapeutic effects. 

The dominant phyto-chemicals: asiaticosides: A and B, and triterpene acids – asiatic acid, madacassic acid, madasiatic acid, are implicated in anti-oxidant and neuro-protective roles. The same compound, possibly in mixture, cause improved venous blood flows that can affect various body functions. 

These cosmetic products are not well regulated but are popular in Europe, Asia, South-East Asia and North America with large market volumes. In Singapore, China and Korea, there are various commercial products with Centella preparations made into skin creams, moisturising lotions and eye treatment serums. Preparations of the weed are now available as teas, capsules, tinctures, and tablets, standardized to about 10% asiaticosides ⁸. 

While we await more scientific proof of pharmacological effects, Centella must be considered among the undoubted top ten weed candidates globally, valued for therapeutic uses. Its uses for potential benefits are likely to expand further in the coming decades in Western countries, including Australia.

Photo: Forest & Kim Starr, CC BY 3.0

Bacopa monnieri – ‘brahmi’

Given that the brain is the central organ for intelligence, any medicine that improves the brain’s health is called ‘Brahmi’. As a result, in India, apart from Centella asiatica, a second weed species – Bacopa monnieri – is also called ‘Brahmi’. Both are used to boost memory, restore cognitive deficits, and improve mental function. 

Bacopa monnieri (Family: Scrophulariaceae) is a fleshy, small-leaved aquatic herb, now spread throughout the tropics and sub-tropics. In India, the species is a highly-valued Ayurvedic herb used to treat nervous system disorders, including neuralgia, hysteria, epilepsy and insanity, and snakebites. 

Alcohol extracts of the plant have shown anticancer activity against Walker carcinoma. Extracts have also shown promise as muscle relaxants and cardiovascular relaxants. Generally, there is significant evidence emerging that Bacopa offers increased cerebral blood flow, anti-oxidative neuro-protection and acetyl-cholinesterase enzyme inhibition ^{1, 3}.

Research not just in India but also in other countries is convinced of Bacopa monnieri becoming even more critical in the future in treating cognitive impairments, such as the neuro-degenerative Alzheimer’s disease. 

Dr. Nimal Chandrasena, based in Perth, Australia, is the Editor-in-Chief of the new journal WEEDS: Journal of the Asian-Pacific Weed Science Society. You can visit this informative journal here. (https://weeds-apwss.scholasticahq.com/)

1. Bandara, M.S., et al (2011). Gotu Kola (Centella asiatica L.): An under-utilized Herb. The Americas Journal of Plant Science and Biotechnology, 5: 20-31.↩︎

2. Chandrika, U.G. and Prasad Kumara, P.A.A.S. (2015). Gotu Kola (Centella asiatica): Nutritional Properties and Plausible Health Benefits. Advances in Food & Nutrition Research, Vol. 76. Chapter 4: 125-157. Elsevier.↩︎

3. Susrutha Samhita. See Note 338 (2) (p. 162). The Sanskrit name for gotu kola is mandukaparni, or “frog-leaved,” as the leaves are reminiscent of the webbed feet of a frog.↩︎

4. Gohil, K.J. et al. (2010). Pharmacological Review on Centella asiatica: A Potential Herbal Cure-all. Indian Journal of Pharmaceutical Sciences, 72(5): 546–556.↩︎

5. James, J. and Dubery, I.A. (2009). Pentacyclic Triterpenoids from the Medicinal Herb, Centella asiatica (L.) Urban. Molecules, 14, 3922-3941.↩︎

6. Krishnamurthy, R.G. et al. (2009). Asiatic acid, a pentacylic triterpene from Centella asiatica, is neuroprotective in a mouse model of focal cerebral ischemia. Journal of Neuroscience Research, 87: 2541–2550. ↩︎

7. Shinomol G.K., et al. (2011). Exploring the Role of “Brahmi” (Bacopa monnieri and Centella asiatica) in Brain Function and Therapy. Recent Patents on Endocrine, Metabolic & Immune Drug Discovery, 5 (1): 33-48 (https://pubmed.ncbi.nlm.nih.gov/22074576/).↩︎

8. (1) Ointments and tablets of Centellase ® – https://www.mims.com/singapore/drug/info/centellase; (2) Generic Drugs Website – Centallase ®; Madecassol ®; Blastostimulina ® Eye Drops (https://www.ndrugs.com/?s=centellase).↩︎

9. European Medicines Agency (2010). Assessment report on Centella asiatica (L.) Urban, herba. p. 44 (https://www.ema.europa.eu/en/documents/herbal-report/final-assessment-report-centella-asiatica-l-urban-herba-first-version_en.pdf).↩︎

10. Faerman, J. (2019). Gotu Kola: The Many Benefits of the Ancient Herb of Enlightenment and Longevity. ConsciousLifestyles Magazine (https://www.consciouslifestylemag.com/gotu-kola-benefits-of-the-herb-of-enlightenment/). ↩︎

11. Mato L, et al. (2011). Centella asiatica improves physical performance and health related quality of life in healthy elderly volunteers. Evidence-Based Complementary Alternative Medicine, 2: 465–73.↩︎

12. Source: The Directorate of Medicinal & Aromatic Plants Research (DMAPR), Anand, Gujarat, India. The new variety produces 4-5 times larger biomass than local varieties and has much higher quantities of active ingredients (http://dmapr.icar.gov.in//Research/Varieties.html). ↩︎

13. (1) Belwal, T. et al. (2019). Chapter 3.22 – Gotu Kola (Centella asiatica), pp. 265-275. In: Nabavi, S.M. et al. (Eds.) Nonvitamin and Nonmineral Nutritional Supplements, Academic Press; (2) Murray, M.T. and Nowici, J. (2020). Chapter 64 – Centella asiatica (Gotu Kola), pp. 501-505. In: Pizzorno, J.E. and Murray, M.T. (Eds.) Textbook of Natural Medicine 5^th Edition, Elsevier Inc.↩︎

1. Shinomol G.K., et al. (2011). Exploring the Role of “Brahmi” (Bacopa monnieri and Centella asiatica) in Brain Function and Therapy. Recent Patents on Endocrine, Metabolic & Immune Drug Discovery, 5 (1): 33-48 (https://pubmed.ncbi.nlm.nih.gov/22074576/).↩︎

2. A Collection of Medicinal Plants in Sri Lanka. Bacopa monnieri (http://www.instituteofayurveda.org/plants/plants_detail.php?i=1232&s=Local_name).↩︎

3. Chaudhari, K.S., et al. (2017). Neurocognitive Effect of Nootropic Drug Brahmi (Bacopa monnieri) in Alzheimer’s Disease. Annals of Neurosciences, 24: 111–122 (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3746283/).↩︎

4. Aguiar, S. and Borowski, T. (2013). Neuropharmacological Review of the Nootropic Herb Bacopa monnieri. Rejuvenation Research, 16(4): 313-326.↩︎

5. Nemetchek, M.D. et al. (2017). The Ayurvedic plant Bacopa monnieri inhibits inflammatory pathways in the brain. Journal of Ethnopharmacology, 197: 92–100.↩︎

6. Kahol, A.P., et al (2004). United States Patent US006833143B1. Council of Scientific and Industrial Research: Process for the preparation of a extract rich in Bacosides from the herb Bacopa monnieri. (December 21, 2004).↩︎

from Hacker News https://ift.tt/3lGzMno