Plants As A Source of Opioid Peptides

Plant are important dietary components for humans and animals. Plants contain a large number of proteins and many of these are enzymes. Plants use enzymes to synthesise phytochemicals. Evidence suggests that some of these enzyme may be useful as pharmacological agents in humans and animals. For example, the most abundant protein known to man is a protein called rubisco. Rubisco is an enzyme found in all plant leaves and it is therefore consumed when edible plant leaves are eaten, which might be the case for tea, spinach or kale. Rubisco is digested in humans to form a number of metabolites and one of these is called rubiscolin-6. Evidence suggests that rubiscolin-6 is able to interact with the delta opioid receptor in humans and animals, and in this way it may be able to alter central nervous system function. That rubiscolin-6 is able to alter central nervous system function was shown in mice that showed improved learning following administration of the compound.

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Food derived opioids are less likely to cause dependance, addiction and tolerance, and other deleterious side effects, because they are weaker in their activity than pharmaceutical drugs or endogenous opioids. There are many opioid chemicals in a large number of plant foods, and many of these may have beneficial effects. Green leafy vegetables are a source of the plant enzyme rubisco, which is metabolised in humans and animals to the opioid rubiscolin-6.

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Hirata, H., Sonoda, S., Agui, S., Yoshida, M., Ohinata, K. and Yoshikawa, M. 2007. Rubiscolin-6, a δ opioid peptide derived from spinach Rubisco, has anxiolytic effect via activating σ1 and dopamine D1 receptors. Peptides. 28(10): 1998-2003

About Robert Barrington

Robert Barrington is a writer, nutritionist, lecturer and philosopher.
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