Spring cleaning? What about intestinal parasites? - Phytotherapy Review & Commentary

Townsend Letter for Doctors and Patients,  April, 2003  by Kerry Bone

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Spring is traditionally a time for cleaning. This was well-recognized by European herbalists who used a number of herbs as "spring tonics" or "spring cleansers." Many of these spring tonics provided much needed vitamins after a lengthy period of consuming stored foods. But they also included the depurative herbs (herbs which clean the blood by unknown mechanisms) and herbs for promoting digestion, including the bitter herbs wormwood and gentian. Wormwood, as the name implies, was also traditionally used to treat gastrointestinal worm infestation. So it could be that this aspect was also part of the use of spring tonics.

Whether this is the case or not, it is true to say that the plant world has long provided options to assist in the control of intestinal parasites. A few of the more popular herbs are viewed below, together with a significant and highly active anthelmintic herb from Traditional Chinese Medicine. But the main thrust of this review is to suggest that synergistic activity via a combination of these key herbs (with other herbal treatments as well to support digestion and immunity etc.) will yield the best results.

Wormwood

Artemisia absinthium is well known to herbalists with particular application to treating nematode infestation, especially infestation with Enterobius or Ascaris. (1, 2) Wormwood has been used as an anthelmintic since ancient times and is currently utilized in many countries throughout the world for this purpose. Wormwood tincture is employed in the West Indies as a worm preventative. (3) Wormwood has also been used for the de-worming of horses, cows and sheep. (4, 5)

Key Constituents

Constituents of the aerial parts of wormwood include bitter substances (sesquiterpene lactones, mainly absinthin) and an essential oil containing mainly terpenes. The essential oil contains the potentially toxic monoterpene thujone and for this reason the recommended therapeutic doses of wormwood should not be exceeded. (6)

Anthelmintic Activity

In vitro wormwood aqueous extract demonstrated anthelmintic activity towards the nematode Trichostrongylus colubriformis. (7) Thujone is also implicated in the anthelmintic activity of wormwood. Experiments carried out in Edinburgh in 1955 indicated the efficacy of thujone in eliminating Ascaris lumbricoides. (8)

Other Related Activity

Wormwood aqueous extract and alcohol extract strongly inhibited the in vitro growth of the parasitic protozoa Naegleria fowleri. The sesquiterpene lactone fraction isolated from the alcohol extract was also active. (9)

Wormwood powder (1.5 g/day) provided effective treatment for acute intestinal amebiasis in an uncontrolled trial of 20 patients. Symptoms were relieved and 70% of cases were cleared of the protozoa Entamoeba histolytica according to stool analysis. (10)

Wormwood is also used to treat other gastrointestinal conditions such as appetite loss, disturbed digestion, flatulence and disordered bile flow. (11) Clinical trials have demonstrated the ability of wormwood to increase the flow of gastric enzymes, pancreatic enzymes and bile. (12, 13)

Black Walnut Hulls

A globular fruit is produced from the black walnut tree which contains a corrugated nut in its yellowish-green hull (also called husk or fruit wall). Upon ripening the hull softens and turns dark brown to black due to chemical oxidation. A decoction of the hull of Juglans nigra fruit has been used traditionally to expel worms. (2)

Key Constituents

The unripe hulls of Juglans nigra contain 1,4-naphthoquinones including juglone and plumbagin. (14) The juglone content in hulls varies with different cultivars and different months of growth. (16)

Anthelmintic Activity

In vitro studies indicate that plumbagin inhibited the motility of and hatching of Haemonchus contortus first stage larvae. Plumbagin was larvacidal towards Ascaris suum at the highest test concentration (100 mM). Partial inhibition of embryonic development of A. suum occurred with plumbagin. (16) The authors suggested that because of the relatively high doses required for the maximal effect on inhibiting the development of larval stages, plumbagin may not find practical application. The combination with other anthelmintic herbs would however, boost the activity of blumbagin.

Stemona

Radix Stemona, the tuberous root of Stemona sessilifolia, Stemona tuberosa or Stemona japonica, is used in Traditional Chinese Medicine (TCM) mainly for the treatment of acute and chronic cough. Externally it is used for the treatment of fungal infections, lice infestation and as an enema for pinworm infestation. (17-19) In addition to its primary use for the treatment of cough, in Vietnam Stemona japonica root is prescribed for Ascaris infestation and is used externally to treat scabies (mite infestation). (20)

Key Constituents

A series of complex alkaloids have been isolated from the root of these Stemona species. (21) The unusual and complex alkaloids exist only in Stemona plants and in a few related species and include tuberostemonine and stemonine. (22)