Non-toxic to self but deformer for others

Quinolizidine alkaloids are non-toxic to the legumes which produce them. On the other hand, the quinolizidine alkaloids can be toxic and in some cases very toxic to other organisms. The biotoxicity of alkaloids has for some time been considered to be connected with their bitter taste ° . The quinolizidine alkaloids are certainly bitter in taste to humans. However, not all alkaloids are. Literature states that some pyrrolizidine and indolizidine alkaloids are not bitter in their pure forms Furthermore, there are many non-alkaloid compounds, such as flavonoids, that are bitter in taste but non-toxic. Therefore, although quinolizidine alkaloids are bitter, the connection between biotoxicity and bitter taste is not absolute. 

The most toxic quinolizidine alkaloids are tetracyclic with a pyridone nucleus. One of these is anagyrine. One case mentions in anagyrine being passed to the human body via milk from goats foraging on Lupinus latifolius. The anagyrine caused severe bilateral deformities of the distal thoracic limbs in a baby boy. 

The biological effect of the quinolizidine alkaloids is on the nervous system. Tremors, convulsions and pulmonary arrest have been noted in laboratory animals. Quinolizidine alkaloids cause depression, laboured breathing, trembling, convulsions and respiratory paralysis in sheep . 

Yovo et al. stated that these alkaloids act via inhibition of ganglionic impulse transmissions of the sympathetic nervous system. It is evident that each alkaloid has its own effect. Anagyrine caused skeletal deformity in foetuses when pregnant cows consumed toxic lupines . On the other hand, some quinolizidine alkaloids are used as a drug in folk medicine . They probably have chronic toxicity. However, adequate knowledge about the chronic toxicity of these alkaloids and especially of chronic toxication across generations is not available. The premise that quinolizidine alkaloids have not produced hereditary symptoms has not been checked with total reliability. 

The biotoxicity of pyridine alkaloids is well studied and the toxicity of nicotine is one of the best examples of the very active alkaloids study area. Aydos et al. have studied 20 rats injected daily with nicotine at doses 0.4 mg 100 of body weight during 3 months and made comparisons to a control group of 20 rats. The researchers concluded that ultra-structural alternations in rats exposed to nicotine occurred. 

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