Alkaloids - is a general term for basic (alkaline) nitrogen containing organic compounds, generally bitter in taste and strong physiological action, many plant derived drugs and medicines are alkaloids, eg quinine, scopolomine, codiene, morphine, ephedrine, tryptamines etc. A lot of them can be potentially toxic, even fatal, especially when in the form of purified alkaloids extracted from plants, quite often only a small amount of the alkaloids can have a strong effect. Obviously some or at least the plants that contain them have proved immensely useful to people for disease and illness, for thousands of years.
1.2.8Alkaloids from the species of acacia
Alkaloids are relatively common in the leguminosae as a whole, and within the genus acacia in Australia alkaloids that have been reported include N, N-dimethyltryptamine, N-methyltryptamine, tryptamine, tetrahydroharman, N-methyl-tetrahydroharman, b-phenethylamine, N-methyl-b-phenethylamine, hordenine (N, N-dimethyl-4-hydroxy-b-phenethylamine), N-cinnamoylhistamine….. For the number of species, there has been little research on the alkaloids of Australian acacias, and like many studies of Australian plants there has been quite a lot of variability in the results. For example the root bark of Acacia holoserica is reported in a few publications as containing the B-phenethylamine alkaloid hordenine, up to 1.22% of the dry weight. Yet in a recent study of aboriginal medicinal plants all parts of this species were found to give a negative result for alkaloids. It was still used medicinally and another species, Acacia auriculiformis, which was used in a similar way, was found to give a positive test for alkaloids, both are members of section Juliflorae . Other studies have found that there can not only be variation in the amount, but also in the type of alkaloids present, eg A. baileyana has been found to contain both B-carboline and tryptamine alkaloids at different times of the year. Qualitative studies of the alkaloids have found that B-phenethylamine alkaloids are quite common in the uninerved members of section Phyllodineae with flowers in racemes, with some specimens found to contain more than 1% alkaloids. B-phenethylamines have been found in other species from section Phyllodineae . N-cinnamoylhistamine has been isolated from at least one member of section Juliflorae . Tryptamine or its N-methyl and N, N-dimethyl derivatives have been found in a number of members of section Juliflorae , and a single species from the Botrycephalae . An extra-Australian member of sub-genus Phyllodineae is recorded as containing methylated tryptamine and B-carboline alkaloids together. A member of section plurinerves is reported to contain B-carboline alkaloids.
So the picture regarding alkaloids seems complex, with much variation from different areas or amongst types or chemical races. Other plants in the Australian flora exhibit this sort of phenomena, with great variation in the amount and even the constitu ents of the volatile oils (Eucalyptus, Melaleuca ), alkaloids (Duboisia) or other compounds between types or localities. Many Aboriginal people recognised this trait in the Australian bush by using plants from one
area, and claim that the same plant from a different spot would not be effective, or may even be toxic.