David -
This was posted on the Yahoo! board in December by "Currentinfo." Hope it helps.
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I'm not an expert either - but let me take a shot at explaining the different approaches.
A "drug," which is a synthetic, has just one active ingredient (along with the inert stuff). Testing is pretty straightforward; a given batch has that single compound (within a given range) or it does not.
Herbals, in sharp contrast, have hundreds of compounds. And these emerge and recede, and interact, in incredibly complex ways, due to many different variables: soil, climate, lifecycle of the plant, part of the plant that is harvested, specific features of the harvesting itself, etc. (Think of the variables that affect growing grapes, and producing fine wines.)
Now suppose we know that a certain herb, as one of its many compounds, produces something that prevents the re-uptake of seratonin in humans - and we know that inhibiting that re-uptake stabilizes, or enhances, mood. Call this Compound A.
At least, we know that the herb produces Compound A in some of its parts, during some elements of its lifecycle, if the climate and soil are favorable.
We also know that that herb produces hundreds of other compounds.
Let us suppose that the herb sometimes produces Compound B. Let us suppose further that, in the human body, Compound A does NOT inhibit the re-uptake of seratonin in the presence of Compound B. In such a case, testing a batch for the presence of Compound A, which we know inhibits seratonin re-uptake, is no guarantee at all that the product will help people feel better. For it has that effect only if it is taken in the absence of Compound B. So the PharmaPrint of the herb would have to check not only for the presence of Compound A, but the absence of Compound B.
Consider another case. Suppose that Compound A has the desired effect in humans only in the presence of Compound C, which is produced by the herb only in some of its parts, or segments of its lifecycle, or climates, etc. Then the appropriate PharmaPrint would have to check for both the presence of Compound A and the presence of Compound C, as well as the absence of Compound B.
But this is WAY too simple. Suppose that there is some Compound D, that enhances the bioactivity of A, and blocks the activity of B. In such a case, the presence of B would not be a problem, so long D is present too.
And so on.
And at the end of the PharmaPrinting, the whole model is still an inferential model: even if one has tested for the presence and absence of all the relevant compounds, with all their different bioactivities and interactions, there's still the inference that the human being who ingests it will experience the desired result.
These complexities can be "bypassed," as it were, by using assays that model the herb's activity in the human being. And that's the Paracelsian route.
So: while it is true that PharmaPrint checks for biologically active ingredients, they check the stuff in the bottle. And we can have no assurance that they are checking for the presence and/or absence of precisely the right compounds; the complexity of natural products may well defeat - or make prohibitively expensive - this approach.
I say again - we will have to wait and see which approach is accepted by the experts, and the producers of natural products. And it would be most interesting to discover that some natural product, certified by PharmaPrint, proved sub-optimal, or inactive, in humans. This would show, I believe, that they had not in fact mastered the complexities of herbs.
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