Earthworms for Medicine and the Environment
In Chinese traditions the Earthworm is a respected remedy that continues to be employed to this day. Powdered, liquefied or made into an ash (depending on the prescription), the remedy is sourced from two species of worm: Pheretima aspergillum, (family Megascolecidae) and Allolobophora caliginosa trapezoides (family Lumbricidae). Clinically, worm remedies are considered useful for feverish disorders (malaria, typhoid, childhood fevers). They possess anticonvulsant and analgesic properties useful for treating seizures, rheumatic pain and the after-effects of stroke (hemiplegia). Earthworm has been a specific for disorders classified as ‘true heat’ conditions, and its use is contraindicated when these characteristics are not present. Experimentally, Di Long has demonstrated sedative and hypotensive properties. It has been used clinically for the treatment of essential hypertension – with a good rate of success (90%). Its vasodilatory activity was attributed to an effect on the central nervous system (Bensky & Gamble 1986; Yeung 1985).
Its traditional use is supported by studies showing the Earthworm has diuretic, antispasmodic, antimicrobial and anti-inflammatory properties (Cooper & Bal-amurugan 2010). In India, Earthworms have been equally valued as an antiulcer, antioxidant and anti-inflammatory remedy. Investigations of an ‘earthworm paste’ made from Lampito mauritii demonstrated activity comparable to the anti-ulcer drug ranitidine in animal studies (Prakash & Rangansthan 2007). Other investigations of anti-inflammatory, febrifugal, liver-protective (hepatoprotective) and liver-restorative properties of earthworm paste (sourced from Lampito mauritii and Perionyx excavatus) are equally significant. Earthworms are rich in phenolic compounds, which doubtless contribute to their pharmacological properties (Cooper & Balamurugan 2010; Balamurugan 2008, 2009, 2007; Prakash 2008; Ismail 1992).
The earthworm Lumbricus rubellus contains a rather interesting proteolytic enzyme complex named lumbrokinase. Even in the 1880s Charles Darwin had ob-served the Earthworm’s remarkable digestive capacity, which he compared to the pancreatic secretions in humans: “The digestive fluid of worms is of the same nature as the pancreatic secretions of the higher animals; and this conclusion agrees perfectly with the kinds of food which worms consume. Pancreatic juice emulsifies fat, and we have just seen how greedily worms devour fat: it dissolves fibrin, and worms eat raw meat; it converts starch into grape-sugar with won-derful rapidity, and we shall presently show that the digestive fluid of worms acts on starch.”
Lumbrokinase has experimental anti-thrombotic properties and has been investigated clinically for the treatment of angina pectoris (Kasim 2009; Ge 2005; Zhao 2005; Kim 1998; Hahn 1997; Mihara 1991). This means that lumbrokinase can decrease fibrinogen in the blood, thereby reducing blood viscosity and platelet aggregation – which reduces the tendency of the blood to clot. The body’s coagulation system is very finely tuned and, interestingly, lumbrokinase does not appear to upset the balance, rather it acts to restore normal coagulation parameters (Cooper & Balamurugan 2010). Its use did not have the side-effects (no-tably bleeding) that have been associated with other drugs such as streptokinase and urokinase (Cooper 2004b). There are also suggestions that some fibrinolytic (fibrin-dissolving and clot-preventative) molecules have useful antimicrobial potential. This is of interest because an antimicrobial peptide, lumbricin I, from Earthworm extracts has demonstrated a broad spectrum of activity against fungi, gram-positive and gram-negative bacteria (Cho 1998).
Certainly, the research tends to support many of the traditional recommendations for the use of Di Long in conditions such as stroke, limb numbness and hemiplegia. It appears that Earthworm enzymes may have medicinal qualities that could be utilized in the treatment of a greater range of ischaemic problems (loss of blood supply) including cardiovascular, cerebrovascular and eye disorders, pulmonary infarction and hearing loss – as well as some forms of cancer. Ex-tracts of the earthworm Eisenia fetida have shown anti-tumor activity in various cancer cell lines and animal studies. Earthworm components (particularly lombricine and eisenin I) have experimental cancer inhibitory and retardant activities. There are numerous other conditions associated with blood clotting (hy-percoaguability) that tend to suggest the therapeutic value of this remedy could be substantially more extensive (Cooper & Balamurugan 2010; Yan 2010; Cheng 2008; Ji 2008; Sun 2006; Zhao 2005; Cooper 2004a, 2004b; Hrzenjak 1998; Ryu 1994). Even so, a lot of work remains to be done to determine the true value of the humble Earthworm.
Despite the fact that there have been numerous advances in understanding this small, crawling denizen of the earth, even today many do not truly appreciate the role the Earthworm has played in producing and maintaining the planet’s basic organic structure. Soils are hard to develop – for every couple of centimeters of soil, 1000 years of climatic weathering and organic decomposition have passed. Earthworms make a huge difference to soil quality, opening avenues for the access and distribution of nutrients and oxygen. Truly, the work of a worm is never done.
Ecotoxicology is a new aspect of earthworm biology which studies them as indicators of soil quality and, consequently, for the detection of toxic residues. Pes-ticides and herbicides affect earthworms directly, quickly influencing their ability to reproduce and survive. The number and viability of egg cocoons is a sensi-tive measure of the quality of life underground. Even the membrane of the worm blood cell can be used as a sensitive indicator of chemical stress. Earthworm burrowing habits can promote the clean-up of contaminated land sites, by allowing beneficial compounds to detoxify the soil. With over 3000 species of earth-worm, some have unique adaptive skills – such as the large blue earthworms of the northern Queensland tropics, or the Giant Gippsland Earthworm that grows up to 4 meters long.