The taste of bitterness has been described as being of intrinsic importance, and it is this taste which has a key pharmacological action. As Simon Mills explains in The Dictionary of Modern Herbalism, "Essentially, the action of bitter substances is mediated by the bitter-sensitive taste-buds . . . [which] do more than simply signify the taste of food or medicine, and are actually connected neurally in such a way that their stimulation leads to the release. . . into the bloodstream of hormones . . . among other probable rEsponses. These claims are ambitious, but well-supported. . . The bitter option is one of the most central choices facing the medical herbalist. A great many herbs have notable bitter tastes (and it follows from the above that it is the taste that matters-the bitter effect is completely lost unless one tastes the bitter, and the intensity of the effect is in direct proportion to the strength of the taste" (Mills SY. The Dictionary of Modern Herbalism. Wellingborough, Northants, UK: Thorsons Publishers, 1985, pp 39-40; ISBN-0722511272).
According to another standard reference text on the subject, "Bitters are stimulants to the autonomic nervous system. They stimulate bitter taste-buds . . . that reflexly initiate secretion of . . . hormones into the bloodstream" (Bartram T. Bartram's Encyclopaedia of Herbal Medicine. London: Robinson Publishing, 1998, p 58; ISBN-1854875868).
Conventional wisdom has long assumed that the bitter taste receptors on the tongue evolved to evoke signals to prompt the avoidance of ingesting plant toxins. However, to everyone's surprise, taste buds have now also been found on human airways smooth muscle cells (Nat Med, 2010; 16: 1299-304). This finding led to the automatic assumption that these bronchial taste buds were avoidance receptors for inhalants that, when activated, led to airways smooth muscle contraction and bronchospasm.
However, paradoxically, when bitter 'tastants' (such as saccharin, chloroquine and denatonium) were introduced experimentally to asthmatic mice in a form to be inhaled, these bitter agents caused relaxation of the smooth muscle instead. In fact, the dilatation observed in the mouse airways was three times greater than that elicited by the conventional beta2-adrenergic receptor agonists, which are the standard orthodox medical inhalants dispensed in those familiar puffers, including salbutamol (Ventolin) and salmeterol (Serevent).
Indeed, the inhaled bitter tastants decreased airways obstruction in a way that allows natural medicine to experiment with its multitude of very bitter remedies as potential inhalants. Given the need for effective bronchodilators for the treatment of obstructive lung disorders, such as asthma and chronic obstructive pulmonary disease (COPD), the inhalation pathway may now be exploited by naturopathic medicine-but, of course, only after carrying out controlled randomized clinical trials of each of the hundreds of the known, naturally occurring, bitter tastants.
At present, however, and only under the guidance of a registered naturopath or medical herbalist, only Lobelia inflata (Indian tobacco) and Hyssopus officinalis (hyssop) may be used as inhalants for respiratory conditions. In this case, 30 g of the herb are infused in 11/4 L of boiling water for 15 minutes, then strained and placed in a large basin. The steam is then inhaled, with the aid of a towel draped over both the head and basin.
Aromatherapy offers oil of H. officinalis: 10 drops are floated on the surface of 11/4 L of boiling water that has been allowed to stand for at least 3 minutes.
An alternative method of inhalation involves using, instead of a basin, a thermos bottle into which the boiling water is poured, to which 10 drops of the oil of H. officinalis
is then added. A large funnel is inserted into the mouth of the bottle, with the patient's mouth and nose placed into the wide end of the funnel to breathe in the vapours. Any free space in the neck of the bottle should be stopped up with a tissue.
Warning: The advice given here is not intended to take the place of diagnosis, guidance and treatment by a medical practitioner, registered naturopath or qualified consulting medical herbalist.
Also, diabetics should not inhale H. officinalis or take it internally, and all medicines are best avoided during pregnancy.
WDDTY VOL. 21 ISSUE 09