Why Use The Whole Herb?

Due to the lack of processing, they also have less environmental impact than medicines which are highly processed.

Philosophically, the whole plant is seen as having co-evolved with the animals and humans. Plants produce various secondary metabolites which apparently have no effect on their own metabolic processes, but which have significant effects on animals and humans. They are felt to have a more harmonious therapeutic effect on the human organism and to balance the system rather than suppress disease processes.

They can be used to bring the organism into a better state of health, and to strengthen parts of the constitution which are either congenitally weak, or weakened by disease or stress. For an interesting discussion of this philosophy see Hoffmann D, The New Holistic Herbal, pp. 12-22, 1996. pub. Element. These components act together on the organism, so that the action of the whole is greater than that of the individual components (synergy), or may increase the bioavailability of the compounds present in the whole herb. For example: Hypericum perforatum contains hypericin and pseudohypericin, which have been demonstrated to have an antidepressant activity. It also contains procyanidins, and it has been demonstrated that the antidepressant activity is more effective when both classes of compounds are present.

Daidzin, an isoflavone glycoside present in Pueraria lobata achieves much higher plasma concentrations when a crude whole herb is given rather than equivalent doses of pure daidzin.

Ascorbic acid in a crude citrus extract is more effective than ascorbic acid administered in isolation.

Other examples are cited in a review by EM. Williamson, such as lemongrass components, valerian, senna, and Artemisia annua.

In other cases the whole plant appears to contain substances which act as buffers or quenchers of undesirable effects.

For example:

Dandelion leaf is commonly used as a diuretic. With many pharmaceutical diuretics it is necessary to take potassium concomitantly to prevent potassium depletion. However, dandelion leaf contains so much potassium that it will give a net gain in potassium, even whilst acting as a diuretic.

Meadowsweet is one of the plants from which aspirin precursors were originally extracted (the name aspirin means from Spirea the former botanical genus name for meadowsweet). As is well known one side effect that can occur with aspirin is gastric irritation/ hyperacidity and bleeding. However, due to the other constituents in meadowsweet, it not only has an anti-inflammatory action but is used to reduce over secretion of acid it the stomach and to treat ulcers.

Whole herbs   also contain significant amounts of vitamins and minerals which assists the human metabolic processes, and in some cases are present in significant enough levels to act as vegetable sources of supplementation.

When standardised extracts are used which contain the whole herb, but have what is seen as the principal active constituent corrected to a higher level, problems can occur. With such products there tends to be a higher incidence of adverse events, including side effects and undesirable interactions with pharmaceutical drugs. This has been seen with herbs such as kava kava, St. John's Wort and Gingko biloba.

As Sharma says:
....."the active ingredient model does not stem from a strength of the scientific method, as often supposed: rather it stems from a weakness - from the inability of the reductionist methods to deal with complex systems"

References:

Hoffmann, D: The New holistic Herbal , Dorset, 1996 Element

Bone, K : A Clinical Guide to Blending Liquid Herbs, Edinburgh, 2003. Churchill Livingstone.