Understanding phytotherapy
The science behind plant-based healing
Common phytotherapeutic practices and herbs
The future of plant-based medicine
Conclusion
References
Further reading
Plants are and have long been a natural source of chemical products with therapeutic properties; many of the earliest, most prominent, and still regularly utilized drugs were either discovered in plants, or in many cases are still predominantly sourced from plants for commercial manufacture.
For example, aspirin was first noted in the bark of Willow trees, potentially as early as 2,500 BCE, and later extracted and manufactured into drug form in 1897 to now become one of the most popular drugs in the world, though now it is typically synthetically manufactured.
Similarly, morphine and related drugs such as codeine are derived from the opium poppy, and still largely are in modern day manufacture. Many plant products containing such compounds can be utilized directly as medicines, known as phytotherapy.
This article will discuss the resurgence in interest in plant-based treatments in modern medicine, and explore the efficacy and potential of phytotherapy in contemporary healthcare practices.
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Understanding phytotherapy
Phytotherapy, sometimes termed herbal medicine, has been utilized by humans for many millennia and around the world, with ancient civilizations such as the Egyptians, Sumerians, Greeks, and Chinese having compiled lists of plants and herbs thought to possess therapeutic properties.
In many cases modern medicine has been able to identify the therapeutic aspect of these plant materials, typically a particular chemical produced by the plant for other reasons, such as acting as an insect repellant, and has thereafter been able to extract and refine the product.
Phytotherapy is differentiated from traditional herbalism, herbal medicine, or herbal healing in that it is a deeply scientific approach, aiming to identify and explain the active properties of plant materials, rather than relying on traditional or ethnic knowledge.
Herbal medicines are typically applied as broad chemical mixtures, in that the plant matter has been minimally prepared before application, and thus still contains a multitude of compounds besides the actual active and therapeutic one.
Further, herbal medicines are frequently applied as mixtures of many plants thought to act synergistically in traditional settings, further enhancing the possibility of the inclusion of toxic compounds, the introduction of drug contraindications and interactions, or the possibility of side effects.
Identifying precisely which chemical compounds provide any therapeutic benefit can therefore be difficult, and investigation must be supported broadly by evidence of effectiveness. Within the practice of phytotherapy herbal medicines with proven efficacy are administered on a scientifically sound basis.
The science behind plant-based healing
Nature produces a seemingly inexhaustible array of novel molecules with the potential to interact with proteins, glycogens, and other biomolecules within the human body.
Over time humans have noted where these plants impart therapeutic benefit; interestingly, a study by Fabricant and Farnsworth (2001) indicated that around 80% of a selection of 122 plant-derived drugs had function related to their enthopharmacological function, though this figure is likely significantly lower when considering the plethora of specific anti-cancer or other types of drugs that have been derived from natural products in the last two decades, for which ancient peoples couldn't possibly have drawn any connection.
For example, chemotherapeutic drug Paclitaxel is derived from the Pacific Yew tree, and acts by targeting tubulin, blocking mitosis and causing cellular apoptosis. The chemical is present at extremely low concentration in the bark, and thus could not have been sufficiently extracted without modern chemistry.
Most therapeutic compounds within plants are secondary metabolites, which are not essential to the growth or propagation of the organism and can come in almost infinite variety from the same building blocks: acetyl coenzyme A, shikimic acid, mevalonic acid, 1-deoxyxylulose-5-phosphate, and others.
They are usually the result of an adaptation to the environment, such as defense against predators, insects, disease, or other specific conditions. For example, Digitalis purpurea L. (foxglove) has been known since at least the 10th century in Europe, and its active ingredient, digitoxin, was identified in the 1700s.
The compound and its drug derivatives are cardiac glycosides, used for the treatment of heart failure and some arrhythmias, though as the name suggests can be toxic when improperly administered.
In humans the drug inhibits ATPase in heart muscle cells, resulting in increased force of contractions, reduced speed of electric conduction, increased excitability, and reduced frequency of heartbeat. In small mammals or other animals even small doses are enough to make them feel unwell or worse, and thus this natural product evolved as a chemical defense against herbivory.
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Common phytotherapeutic practices and herbs
One widely known example of a phytotherapeutic substance is the Ginkgo biloba tree, native to East Asia and only known to the rest of the world for a few hundred years.
Ginkgo biloba extract has been associated with a range of positive health effects, in particular associated with memory and cognitive decline, though no study has yet demonstrated any form of benefit towards cognitive impairment, cardiovascular disease, psychiatric disorders, glaucoma, or any of the other purported benefits of the plant, and it remains non-approved by the FDA for any medical purpose.
The plant extract does reportedly possess anti-inflammatory properties, along with a host of others containing flavinoids, carotenoids, polyphenols, lycopene, anthocyanidins, omega-3 fatty acids, phytoestrogens, and glucosinolates.
Cannabis is increasingly being exempt from drug laws around the world when used for medical purposes, and where administered as bulk plant matter, rather than specific compounds such as cannabidiol (CBD) or tetrahydrocannabinol (THC) being extracted and administered, can be considered phytotherapy.
The future of plant-based medicine
Currently, genetic engineering technologies are utilized in several plant species in order to maximize yield, improve resistance to disease, pests, extreme temperatures, alter their nutritional profile, and a host of additional beneficial alterations.
Perhaps the most prominent example is the soy plant, the global cultivation of which is now almost entirely genetically modified.
Where plants naturally produce chemical compounds with therapeutic benefit they could potentially be modified to maximize this production, or the ability to produce the drug could be introduced to rapidly growing and easily harvested plants.
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Conclusion
One of the primary difficulties with phytopharmacology is in dose regulation; compared to the conventional process of extracting or manufacturing the active compound synthetically, phytopharmaceutical products contain the active ingredient within the plant, along with a range of neutral or potentially unwanted chemicals.
Phytotherapy is therefore generally only suitable for the treatment of mild conditions where risk of overdose or the consequences of underdosing are minimal. Where plants with some therapeutic benefit can replace mild medications such as non-steroidal anti inflammatories they may provide long term environmental benefit, in that the costs associated with extracting and refining the drug are no longer present.
References
- Firenzuoli, F., & Gori, L.. (2007). Herbal Medicine Today: Clinical and Research Issues. Evidence-based Complementary and Alternative Medicine, 4(s1), 37–40. https://doi.org/10.1093/ecam/nem096
- Nasim, N., Sandeep, I. S., & Mohanty, S.. (2022). Plant-derived natural products for drug discovery: current approaches and prospects. The Nucleus, 65(3), 399–411. https://doi.org/10.1007/s13237-022-00405-3
- Singh, S. K., Srivastav, S., Castellani, R. J., Plascencia-Villa, G., & Perry, G.. (2019). Neuroprotective and Antioxidant Effect of Ginkgo biloba Extract Against AD and Other Neurological Disorders. Neurotherapeutics, 16(3), 666–674. https://doi.org/10.1007/s13311-019-00767-8
- Kotakadi, V. S., Jin, Y., Hofseth, A. B., Ying, L., Cui, X., Volate, S., Chumanevich, A., Wood, P. A., Price, R. L., Mcneal, A., Singh, U. P., Singh, N. P., Nagarkatti, M., Nagarkatti, P. S., Matesic, L. E., Auclair, K., Wargovich, M. J., & Hofseth, L. J.. (2008). Ginkgo biloba extract EGb 761 has anti-inflammatory properties and ameliorates colitis in mice by driving effector T cell apoptosis. Carcinogenesis, 29(9), 1799–1806. https://doi.org/10.1093/carcin/bgn143
- Kumar, P. et al. (2021). Pharmacological properties, therapeutic potential, and legal status of Cannabis sativa L.: An overview. Phytotherapy Research. https://doi.org/10.1002/ptr.7213
- Dias, D. A., Urban, S., & Roessner, U.. (2012). A Historical Overview of Natural Products in Drug Discovery. Metabolites, 2(2), 303–336. https://doi.org/10.3390/metabo2020303
Further reading