RSS feedRecently the International Herald Tribune reported on a Brazilian project set up to protect the interests of an Amazonian Indian tribe. The interests involve the tribal knowledge and use of the secretion from a frog to treat various ailments.
Sapo mono, the local name for the Giant Monkey Frog (Phyllomedusa bicolor), is found in the primary and secondary forests of the Amazon in Peru and Brazil. Male frogs, slightly smaller than females, measure approximately 10cm in length and make a loud ‘cluck’ call from branches at heights of more than 8 metres from the ground! The skin secretion from adult frogs is what has captured the interest of the scientific and medical communities. The dried skin secretion from the frog has been used to treat ailments by the Amazonian Indians for years. For example, when the Mayoruna Indians in the Amazon experience pain and gastric distress, they mix the dried secretion with human saliva and then introduce it into the blood stream through deliberate breaks in the skin. The absorption of this mixture into the body leads them to feel refreshed and energized! The Matses Indians in Northern Peru use the dried secretion to sharpen their senses during hunting trips. They also use it as a way to increase their stamina during long hunts when it was difficult to carry food and water. Scientific studies have shown that the secretion and the frog skin are rich in a variety of protein molecules (peptides) which exert effects on blood vessels (vasoactive peptides), have pain relieving properties (opiod) and anti-microbe activities (anti-microbial peptide). The isolated antimicrobial peptides are of the dermaseptin family. One of these has been shown to have lethal effects against a broad spectrum of bacteria, fungi and protozoa. Furthermore, its mode of action as an antimicrobial has been shown to be different from the antimicrobials we are using now. This may eventually lead to a new class of antibiotics which will help us to fight against the increasing number of multi-resistant microbes of today.
The medical world is replete with examples of drugs derived from plants. The simple tablet aspirin, used for treating a headache or muscle aches, was first isolated from the willow bark in 1828. When we stroll through the woods of England in summer, we see the beautiful flower of the purple foxglove, Digitalis purpura. From the dried leaves of foxglove, we have an important drug called digitalis which is used to treat congestive heart failure and irregular heart beat. While Dr William Withering of Shropshire, England, has been credited as the man who introduced digitalis into the practice of medicine in the 18th century, the medicinal effect of the leaves of foxglove has been known since 1500 B.C. A more recent example of drug discovery from the plant kingdom is the discovery of the anticancer drugs of paclitaxel, from the Pacific Yew tree (Taxus brevifolia) and camptothecin, from ‘xi shu’ or ‘happy tree’ (Camptotheca acuminate) by Drs Monroe E Wall and Mansukh C. Mani in early 1970s. It took almost 25 years before paclitaxel was entered into its first clinical trial. Now paclitaxel is a major cancer drug used on a daily basis in oncology centres all over the world. While camptothecin possess anticancer properties, it is found to be too toxic as an anticancer drug. However, knowledge of its molecular structure led to the synthesis of two semi-synthetic derivatives, topotecan and irinotecan. Irinotecan is now used widely in the treatment of colon cancer.
Although 95% of the earth is covered with water, compounds from the aquatic environment are still under-represented in the current pharmacopoeia. The development of marine compounds as medicinal agents is hampered by the relative technical difficulties in collecting these organisms at depths which require the use of manned and unmanned submersibles. Compared to land based material, collecting the aquatic specimens will require more expenditure as well. However, interest in this huge resource has been increasing over the last decade due to greater funding support from governmental agencies and pharmaceutical companies. No doubt the aquatic world will yield many new products in years to come.
Mother Earth is truly a treasure trove! It holds the keys to many of the scourges of mankind. While the practice of using herbs, plants and animal products to heal has been practiced in all cultures since time in memorial, the knowledge of the actual active components and how much to use is still an inexact science. The criticism that western trained doctors ‘poo-pooed’ the use of herbal medicine may well be a touch harsh. These western trained practitioners merely want to have a bit more science incorporated into the medicine they use on their patients. They fear the potential side-effects of the other components within a herbal brew.
The path of discovery and synthesis of the relevant medicinal products from the fruits of the earth is difficult and very long. While this process is taking place, our desire to build more houses, catch more fish and make more things material available will inevitably lead to greater destruction of our environment. If we are not careful, in our quest to give more things to our children, we are going to end up destroying nature’s treasure troves for our future generations.
