Foxglove, a charming and vibrant flowering plant, has an intriguing history in the realm of medicine, particularly in the treatment of heart diseases. However, it is not, as the name might suggest, a fox wearing a glove but a significant player in the evolution of cardiac treatments.
In the 1700s, the quest for heart disease remedies was a challenging endeavor. While humans have been searching for a treatment for heart disease, it was difficult to get this at the time because we had a sketchy understanding of the hearth physiology, it was close to impossible. Scientists like Hippocrates believed in the Humor theory of disease where disease had to do with the balance of the fluids in humans, where an imbalance would mean being sick. The humors were blood, phlegm, black bile and yellow bile.
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With the theory of humors, it was easy to identify dropsy which was swelling. At that time, Swelling wasn't seen as a sign of a possible diagnose, it was seen as a disease itself. Scientists began to look for cure for this disease, and this was were they found foxglove but the plant was seen as a cure all for all disease without any experiment.
The foxglove plant first gained medical attention in the sixteenth century when a Bavarian botanist, Digitalis, endorsed it in his 1542 book as a potential remedy for dropsy and swelling. While early applications involved the external use of foxglove to reduce swelling, it was not until the 1700s that a breakthrough occurred, thanks to the work of William Withering, a botanist and physician. He decided to look at foxglove along with dropsy in 1775 when an old woman treated a case of dropsy with a tea at her home. The tea was actually composed of 20 or more herbs but then, the subject perceived by William was foxglove.
He was able to write his experiment in his book tittled "An account of the foxglove" where he mentioned over 158 patients' cases, and about 101 of them would have suffered from congestive heart failure. In the 19th century, doctors started to let go of foxglove because they had better ways of examining patients such as discoloration, as well as using the equipment "the Stethoscope". The stethoscope was used to measure the efficacy of a treatment then, and since foxglove only reduced the heart rate of patients, it didn't have much more effect.
With the Stethoscope, they were able to check the heart rate of patients with heart disease and with autopsy, it became clear the the heart problem was responsible for the swelling, as the heart also got bigger. Lots of doctors thought of the cause of heart failure to be different things including faulty valves but then James McKenzie, a prominent figure in the field of cardiology, published a textbook proposing that heart failure was linked to insufficient oxygen supply to the myocardium (heart muscles).
https://www.textbookofcardiology.org
According to his theory, the heart responds by increasing muscle mass in an attempt to pump blood effectively. This ongoing cycle of muscle deterioration and increased heart rate leads to vascular constriction, rising blood pressure, and ultimately fluid leakage from veins, resulting in ankle and foot swelling.
In the 1930s scientists were able to isolate digoxin from foxglove which is a glycoside that has effect on the heart as it inhibits ATPase which prevents the heart to pump which then causes more calcium to get into the heart muscles helping it to contract but there was a problem. Too much of it was toxic, and too little dose was not effective. With this, the therapeutic window of digoxin was 0.8 - 2.0 nanogram per millileter of blood.
With this small window, we can see that it would be very difficult for doctors to treat heart failure properly. Although, scientists have found ways of treating digitalis toxicity, safer drugs like beta blockers, and Ace inhibitors were available in the 1980s. Foxglove's journey from a mystical plant to a heart disease treatment reflects the evolving understanding of cardiology and the ongoing pursuit of safer and more effective therapies for heart-related conditions. More researches are done on treating cardiac failure and foxglove is still be researched extensively.
Read More
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7939868/pdf/annmedhist155570-0022.pdf
https://www.trianglegardener.com/fascinated-by-foxglove/
https://www.jstor.org/stable/24931913
https://pubmed.ncbi.nlm.nih.gov/15685783/
https://pdf.sciencedirectassets.com
https://www.gutenberg.org/files/24886/24886-h/24886-h.htm
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1117316/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6791096/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4159698/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6932336/
https://cen.acs.org/articles/83/i25/Digoxin.html