Unlike many other Solanaceae species , they do not contain tropane alkaloids , which are often poisonous to humans and other animals .
However , tobaccos tend to contain a much higher concentration of nicotine than the others .
Unlike many other Solanaceae species , others do not contain tropane alkaloids , which are often poisonous to humans and other animals .
However , tobaccos tend to contain a much higher concentration of nicotine than the others .