Re: Gloria, PA's

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Alkaloids These are the most potent of all plant constituents, and are the ones most investigated by modern science. Their potency extends to almost universal toxicity and it would be correct to state that the action of any alkaloid on the body is inherently stressful. Firstly almost all herbs have some alkaloids in their constitution, including those with the most impeccable safety record. Once again it seems to be the case that the whole plant is more than just the sum of its parts. Secondly in those relatively few remedies with a significant alkaloidal content, the toxicity is usually of the most direct kind. In other words exceeding the safe therapeutic dose will give rise to obvious symptoms like vomiting or diarrhea or immediate central nervous symptoms. Rarely will

plant alkaloids display the more insidious toxicity of a synthetic medication which is designed not to produce alarming symptoms. It may be, in fact, that the immediate irritation is the essential part of the provocative action of the remedy. Nevertheless, having said all this, it is incumbent on the herbal practitioner to take especial care with the administration of herbs that contain significant levels of alkaloids. One probably significant factor is that alkaloids tend not to be very soluble in water, but they do dissolve well in alcohol. As most traditional herbal preparations were aqueous infusions or decoctions, then it can be assumed that they were relatively low in available alkaloid. By contrast, the modern

medical herbalist in Britain uses primarily alcohol/water tinctures: the available alkaloidal count is certainly higher in such preparations and would have the effect of making the alcoholic tincture more potent than the infusion. Using herbs in a small way usually involves starting with aqueous preparations: this makes sense. This opens up a wider point of importance, however: it means that the action of an alcoholic tincture is likely to be significantly different from its infused version. The traditional reputation of herbs is mostly based on work with the latter; modern clinical expertise is being developed mainly with the former. The results may be different enough to cause confusion. The attempts to define an alkaloid chemically have never been satisfactory. The word originally derived from the term 'vegetable alkali' used to describe the alkalinity of

some of the early alkaloidal isolates. In general the category can be said to incorporate alkaline nitrogenous substances with marked physiological effects. However, neither colchicine nor ricinine is alkaline, nor are mescaline, ephedrine and muscarine nitrogen-containing, and whereas alkaloids are traditionally said to come from the higher plants, both animals and lower organisms are known to produce them. Whilst most alkaloids are heterocyclic, there are others, such as mescaline, ephedrine and hordenine which are non-cyclic and are sometimes referred to as 'protoalkaloids'. Apart from their toxicity (their main function in plants seems to be deterrence against browsing animals and herbivorous insects) the action of the alkaloids is not easily summarized: each has its own individual character. Instead a list will give some idea of their range and categories. As the individual examples provided are the most well known, and thus often the most notorious or

dramatically active, a more toxic picture of the alkaloidal range may be conveyed than is actually justified. The best approach, followed here, is to take them in groups with common biosynthetic origins. There are many other groups, but these are the significant ones. It will be seen that many of the alkaloids have a particular action on the central nervous system (more precisely on the synapses in the nervous pathways). Their general lipid-solubility is relevant to this action. Pyrrolidine alkaloids Originating from the amino-acid ornithine, this group includes the tropane alkaloids, atropine, hyoscine and hyoscyamine from the nightshade family (henbane, datura, Jimson weed, belladonna and bittersweet, for example). As a group these block parasympathetic nerve activity. The group also includes the 'truth medication' scopolamine and cocaine. Pyridine and piperidine alkaloids Derived from the B vitamin, nicotinic acid, this group includes the alkaloids of lobelia and tobacco (especially nicotine). They act to stimulate and then to block all autonomic nervous activity.MorningGlory113@... wrote: But due to the PA contained in this herb, the use of comfrey in both oral and topical applications should be discouraged What's PA??Gloria Suzi List Owner What is a weed? A plant whose virtues have not yet been discovered.

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