Indeed there are.
But we have to look carefully and dispassionately to find them.
We can classify the truly effective tonics into two groups: those of traditional herbal origin, and those made or isolated by chemicals in more recent times. Of the herbal tonics and restoratives, we have lost many.
But one that has surfaced in recent years is ginseng and the root of the araliaceous plant,Panax ginseng .
This plant, a relative of ivy and indigenous to the temperate mountains of the Far East, has been used continually for some 5000 years in the Orient as a tonic and restorative and preventive remedy. Indeed, it is one of the most highly prized all Chinese medicines.
It is recommended for tired, mildly depressed, convalescent and particularly old people.
Athletes, including Sebastian Coe, and cosmonauts are among well-known users of ginseng today.
There are several other plants related to ginseng pharmacologically, chemically and botanically.
For example Eleutherococcus senticosus is used widely as a tonic in the USSR, and is available in Soviet hospitals for people undergoing surgery, chemotherapy or radiotherapy and to improve their resistance and aid their recovery (New Scientist , vol 87, p 576).
These plants, unlike the earlier tonics, have the backing of a large amount of experimental and clinical data.
This is despite the obvious difficulties of devising experiments to test the effects of the substances on the performance of normal organisms rather than the cure of sick ones.
Four recent clinical studies in America and Europe and show improvements in mood, performance and stamina produced by ginseng.
These follow hundreds of published studies reporting biochemical and behavioural effects in animals.
Two highly productive lines of research demonstrate that ginseng increases the efficiency both of adrenal cortical reactions to stress, and of the production of energy during exhaustive physical work.
It is not yet known how the active components of ginseng, compounds called triterpenoidal saponins, achieve these effects, although by analogy with the related steroidal saponins and such as digitalis and they may act on specific cell membranes.
Other tonic or stimulatory plants have been occasionally investigated but the field is ripe for further research.
Thujone and the main constituent of sage, is now known to have mild stimulatory properties.
Kawain from kava kava (Piper methysricum), and catlimore from the Yemini plant khat (Carha edulis), are examples of new stimulatory substances.
Several interesting compounds have been isolated from traditional health-promoting plants such as liquorice and spikenard and the jujube, and senega, as well as many Far Eastern or Indian plants, which do not have European common names.
The active components tend to be compounds called liguans and terpenoidal saponins or simple phenols.
As far as the true chemical tonics are concerned and there are several kinds of active substances available, although most of them are not well known.
Panganic acid, an ester of dimethylglycine, was first isolated from rice in 1948 by Hans Krebs, a chief chemist of the National Cancer Institute.
He called it vitamin 51B, which was unfortunate because proof of its vitamin status was never found and that raised the hackles of the regulatory authorities in the US.
Nevertheless some clinical and experimental work has indicated that panganic acid can increase the stamina and performance of athletes.
Glenn Shue, a nutritionist with the FDA and summarised the work in a report that denied that the acid is a vitamin.
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