Unassuming Weeds Join Forces in the Battle Against Cancer–A Recent Review

An Unexpected Source of Medicinal Power

Recently, I found myself presenting a talk on the topic of edible plants at my local library. The focus was on common kitchen herbs that also have medicinal properties and can be easily cultivated in home gardens or on windowsills. In the process of preparing for this talk, I was struck by the sheer volume of information on this topic. One statistic, in particular, gave me pause.

According to data from the Center for Biological Diversity, there are between 50,000 and 80,000 plants used for medicinal purposes worldwide. This staggering figure made me realize the vastness of the field and my own limited knowledge of a few hundred of these plants.

Herbal medicine, a practice as old as time itself, is employed across the globe and is supported by a wealth of international research. This includes research from the Near East, Russia, East Africa, North East India, and even Transylvania, to name a few regions.

Renewed Interest in Plants' Anti-Cancer Properties

In recent years, there has been a resurgence of interest among scientists in learning more about the medicinal properties of plants. This renewed curiosity is likely driven by the need to find alternative treatments for diseases that modern medicine struggles to combat effectively.

A 2024 review published in the journal Pharmaceuticals aligns with this trend. This new publication spotlights 15 medicinal plants with potential anti-tumorigenic properties, meaning these plants contain active compounds that can combat abnormal cell growth.

The selection of plants featured in the review was intriguing. Some, like dandelion, nettles, and Curcuma longa (more commonly known as turmeric), are well known. Others, such as the Madagascar periwinkle, the tropical soursop, and the houseplant Kalanchoe blossfeldiana, are less familiar. However, all these plants share a common trait—they are effective "against the Majority of Common Types of Cancer," according to the review's headline.

Urgent Need for More Effective Treatment

The International Agency for Research on Cancer paints a grim picture of the global cancer situation. According to their 2022 report, lung cancer was the leading cause of death worldwide (18.7 percent), followed by colorectal cancer (9.3 percent), and liver cancer (7.8 percent), with a total of 3,480,213 individuals lost to these diseases.

Given this alarming situation, the researchers behind the current review are calling for the immediate development of "more targeted and efficient treatment plans." They believe that "Plants and products derived from them have promising potential as a source of less toxic anticancer drugs."

Combining Traditional Knowledge with Cutting-Edge Technologies

To achieve this goal, herbs are used to bolster the immune system, eliminate carcinogens, and enhance antioxidant levels in our bodies. Scientists are exploring innovative approaches such as new nanomedicines and bioengineering techniques for immune cell therapies to treat the disease.

As a community herbalist, I look at this issue from a long-term perspective. What traditional wisdom about these herbs has been handed down over centuries? How can we merge the worlds of modern research and ancient knowledge for the benefit of patients?

Anti-Cancer Plants: From Research to Application

The recent review mentions several herbs that may be abundantly growing in our gardens—often, we may even consider them pesky weeds that need to be eliminated. Dandelions are a common example of this.

My herbal teacher often said, "Often, the herbs show up where we need them." This certainly holds true for one of the hardiest herbaceous perennials native to Europe but found all over the world in gardens, lawns, roadsides, fields, and even wastelands.

Common Dandelion

Taraxacum officinale, commonly known as dandelion, is not just a medicinal herb but also an edible vegetable. Particularly, young leaves are tender and add a slightly bitter flavor to salads, which aids digestion.

The Taraxacum genus comprises over three hundred species, many of which have been used in traditional and folk medicines for centuries. For instance, German botanist Leonhart Fuchs highlighted the health benefits of the plant in his 16th-century herbal compendium, "De Historia Stirpium."

Dandelion was also recognized as a medicinal herb in Arabian medicine as early as the 10th century. Indian and Chinese medicine have used the common dandelion to treat liver and digestive diseases, according to an article published in the National Library of Medicine.

Dandelion is a versatile plant, containing vitamins A, C, B, and D, minerals like potassium and calcium, and traces of iron, magnesium, manganese, and zinc.

A 2023 review examined the dandelion in detail and noted its bioactive compounds. "Sesquiterpenoids, phenolic compounds, essential oils, saccharides, flavonoids, sphingolipids, triterpenoids, sterols, [and] coumarins" contribute to its "therapeutic potential, including anti-bacterial, anti-oxidant, anti-cancer, and anti-rheumatic activities."

Korean research demonstrated that the amount of phenols and flavonoids in the plant drives its anticancer and antioxidant activities. This varies in different taraxacum species but is present in the common dandelion.

A 2023 study investigated a combination of dandelion extracts and found that it inhibited the "rapid proliferation of cancer cells and its invasion into healthy tissues" specific to breast cancer. Essentially, dandelion extract stops their spread and "induces death in them."

Photodynamic Therapy, another method to target cancerous tissue, involves stimulating a photosensitizing agent with light, such as a laser. A 2023 article in Nanomedicine tested this process with dandelion for "synergistic chemotherapy and photo-dynamic cancer therapy." This method successfully delivered the active compound to the cancer cells and disrupted their homeostasis, demonstrating anti-cancer and anti-tumor effects.

Stinging Nettle

Urtica dioica, or stinging nettle, is another highly medicinal weed that grows abundantly in many temperate areas and is often considered a nuisance by many.

Despite its reputation, I recently transplanted some nettles into my garden and even spread nettle seeds to establish them there. Nettles are a nutritious plant and make a great addition to soups and salad dressings, as the stinging hairs lose their potency when processed.

Rich in provitamin beta-carotene, vitamins A, B, and C, minerals like iron, magnesium, potassium, and calcium, this protein-rich perennial herb has numerous health benefits. But there's more to this plant than meets the eye.

A 2020 research article highlighted the potential anticancer properties of nettles. When tested, the extract of Urtica dioica showed promising effects on the proliferation rate of "hepatocarcinoma and colon-cancer cell lines at specific doses."

A 2022 study published in the Asian Pacific Journal of Cancer Prevention demonstrated the anticancer qualities of plant medicine against three different types of cancer cell lines. Testing of Urtica dioica's cytotoxicity was performed in vitro (via mycoplasma testing) and in vivo (in a living organism, in this case, rats). The results were positive and showed that nettles may work against breast cancer through their anti-tumoral properties.

Another study aimed to research the herb's potential healing qualities in regards to human colon and gastric cancer. The study found that nettles also induced apoptosis and "inhibited proliferation of gastric and colorectal cancer cells," without having any toxic side effects on normal cells.

Greater Burdock

Moving on to another common weed that grows in many disturbed areas around the United States and can often be found in empty parking lots, pastures, or along fields and roads is burdock.

Like dandelion, burdock is a member of the Asteraceae family (the Aster family) and grows almost everywhere. The medicinal parts of burdock include the roots and leaves, as well as the seeds.

Arcticum lappa is also high in minerals and vitamins, including the B vitamins thiamine, riboflavin, and niacin. Moreover, it contains lignans in the roots and seeds, amino acids in the roots, phenols, sterols, and fatty acids in the seeds, and a "plethora of biological activities and pharmacological functions."

One of burdock's compounds, lappaol F (a natural lignan), is an anticancer agent that "inhibits tumour cell growth by inducing cell cycle arrest," according to a 2021 study. However, the underlying processes of burdock's anticancer qualities remain unclear.

Nevertheless, the plant is effective, and researchers suggest that a potential anticancer drug could be developed from this medicinal herb.

A review published in Inflammopharmacology emphasizes the centuries-old traditional medicinal uses of burdock in Europe, North America, and Asia. It highlights the plant's anti-inflammatory qualities, detoxifying effects, and anti-tumor properties, particularly its "potent inhibitory effects on the growth of tumors such as pancreatic carcinoma."

Burdock has even proven effective against "multi-drug resistant cancer cells." A study investigated six lignans present in the burdock seed and combined them as non-toxic chemotherapeutic agents. The results showed that they "possess promising MDR [multidrug resistant] reversal activities." The study also tested and verified this effect in combination with a chemotherapy drug named doxorubicin.

The Other 12 Anti-Cancer Plants

The remaining 12 plants examined in the recent review are soursop (Annona muricata), black calla (Arum palaestinum), hemp (Cannabis sativa), Madagascar periwinkle (Catharanthus roseus), turmeric (Curcuma longa), licorice (Glycyrrhiza glabra), moringa (Moringa oleifera), hibiscus (Hibiscus rosa-sinensis), milk thistle (Silybum marianum), oleander (Nerium oleander), kalanchoe (Kalanchoe blossfeldiana), and ashwagandha (Withania somnifera L).

Turmeric, licorice, hibiscus, hemp, ashwagandha, and milk thistle are well known—even beyond the herbalist community. Soursop might also be familiar to some, especially those living in tropical regions.

Some of the plants, like oleander, the black calla, Madagascar periwinkle, or kalanchoe, might be more commonly known as decorative garden or house plants. Moringa, native to the Indian subcontinent and mostly used in Southern Asia, may be the least familiar of them all.

However, all these plants are recognized as potent plant medicines.

Continued Phytopharmaceutical Research

A 2022 review praises the healing qualities of soursop. Its "pharmacological effects of anti-cancer, anti-microbial, antioxidant, anti-ulcer, anti-diabetic, anti-hypertensive, and wound healing" are impressive.

Another review features a study in which patients were given 300 milligrams of soursop extract (leaf water) in capsules after breakfast. This treatment inhibited the growth of colorectal cancer cells.

Ashwagandha, another phytotherapeutic that targets colorectal cancer, was found in a 2023 study to "kill cancer cells via at least five separate routes."

It has even been dubbed "a wonder drug" in the alternative field and has demonstrated remarkable bioactive compounds that function as "anti-cancer, anti-inflammatory, apoptotic, immunomodulatory, antimicrobial, anti-diabetic, hepatoprotective, hypoglycaemic, hypolipidemic, cardio-protective and spermatogenic agents," as outlined in a comprehensive review.

However, many studies and reviews stress the unfortunate fact that further research is needed due to "the lack of established quantities and concentration measurements," or simply the lack of extensive medical research about our floral surroundings.

Contraindications and Side Effects

Phytopharmaceuticals are potent medicines. While many of the plants do not have any side effects and often naturally target cancer cells without affecting healthy cells—a mechanism not quite understood by science yet—it's important to remember that consuming the wrong plant or the wrong dosage can be harmful or even fatal.

For dandelions, nettles, and burdock, there are some guiding principles:

• Nettles should not be eaten raw as the fresh leaves will sting.
• Dandelions can upset your stomach if consumed in large quantities or over a long period, as they can increase the production of hydrochloric acid (HCl) in the stomach and lead to loose stool.
• Dandelion root should be taken with caution if the individual suffers from excess HCl, gastritis, ulcers, or heartburn.
• Burdock should be prescribed in mild doses during the first trimester of pregnancy. Also, it should be taken with caution if suffering from hypoglycemia.

Tips:

When gathering herbs or plants in the wild or public spaces, please collect your specimens wisely. This means, pick plant matter only away from dirty or polluted areas and wash before eating or processing. Also, never take the whole plant (you want it to continue to live and come back the next year).

Note:

For all individualized herbal recommendations and dosages, please consult with your local herbalist. If you are on any medications consult with a physician before taking herbal supplements. The author is writing for informational purposes only and is not acting in the capacity of a doctor or licensed dietitian-nutritionist.

Closing Thoughts

The potential of plants in the fight against cancer is a fascinating field of study. It's intriguing to think that the answer to some of our most challenging health issues might be growing in our own backyards. However, it's also a reminder of the importance of further research and caution when it comes to self-administration of these potent natural medicines.

What are your thoughts on this topic? Do you think there's untapped potential in the plants around us? Share this article with your friends and let's get the conversation started. Don't forget to sign up for the Daily Briefing, which is everyday at 6pm.