Caffeine

[lpetrich]

 Caffeine is a favorite stimulant regularly used by large numbers of people.

It is a "purine", chemically similar to nucleobases adenine and guanine, and it works by blocking adenosine (adenine + ribose) from a certain receptor because of its chemical resemblance. That blocking increases the production of the neurotransmitter acetylcholine, thus the stimulant effect.

It is an  Alkaloid a catch-all category of nitrogen-containing compounds produced by a great variety of organisms.

Caffeine is made from guanine with a few biochemical steps, and it is made by a variety of plants.

Eudicots

• Rosids - Eurosids - Malvids
  • Malvales - Malvaceae
    • Theobroma cacao -- cocoa/cacao tree
    • Cola spp. -- kola-nut tree
  • Sapindales - Sapindaceae - Paullinia cupana -- guaraná climbing plant
• Asterids
  • Euasterids
    • Lamiids - Gentianales - Rubiaceae - Coffea arabica, canephora -- coffee tree
    • Campanulids - Aquifoliales - Aquifoliaceae - Ilex vomitoria (yaupon), guayusa, paraguariensis (yerba maté) -- holly tree
  • Ericales - Theaceae - Camellia sinensis -- tea tree

What does it do for these plants? "Caffeine in plants acts as a natural pesticide: it can paralyze and kill predator insects feeding on the plant." That is also the case for many other secondary metabolites: Chapter 9. Alkaloids as Botanical Pesticides for Plants Protection – Nova Science Publishers and Molecules | Free Full-Text | Plant-Derived Pesticides as an Alternative to Pest Management and Sustainable Agricultural Production: Prospects, Applications and Challenges and (PDF) The Use of Alkaloids as Botanical Insecticides and A Review of Bioinsecticidal Activity of Solanaceae Alkaloids - PMC and Recent advances for alkaloids as botanical pesticides for use in organic agriculture: International Journal of Pest Management: Vol 69, No 3 and Alkaloid - an overview | ScienceDirect Topics

Returning to caffeine, its synthesis originated several times, widely scattered over the family tree of eudicot flowering plants.

But why might it be rare? The theory I've come up with is the  Kill the Winner hypothesis - if a lot of plants make caffeine, then the bugs that eat them would have a lot of selection pressure to develop caffeine resistance. But if only a few plants make caffeine, then there is much less pressure on the bugs to become resistant. That same hypothesis also works for all the others, explaining their relative rarity.

More generally, "Kill the Winner" explains biodiversity - a big success would become a victim of its success by presenting a big target for disease organisms.

"Kill the Winner" also explains the multitude of histocompatibility surface-protein variants. These proteins are used to recognize fellow cells of a multicelled organism, and a bug (general, informal sense) can fake that recognition by having a surface with a similar protein. A multitude of h-c surface proteins can limit the success of that strategy.

That has the side effect of organ-transplant rejection, but what helps us reject transplants is what keeps us from being too big a target for infectious bugs.

 

[Rhea]

I empty myt coffee grounds into my garden. Is that why it’s so low on bugs?

 

[steve_bank]

I know nothing about gardening, but I heard it said on a show coffee grounds are good for plants.

 

[Rhea]

They are definitely good for plants. New news that they are bad for bugs, tho!

In my case, the coffee grounds do a great job of adding orga nic matter, anti-clumping and draining capability in my clay soil.

 

[steve_bank]

Plus the plants get a buzz

 

[T.G.G. Moogly]

I empty myt coffee grounds into my garden. Is that why it’s so low on bugs?

Not all bugs are evil and caffeine is another indiscriminate killer that should be applied with care, knowledge and sensitivity. That said I enjoy my cup of joe and bring home lots of coffee grinds for the garden. I typically sprinkle the grounds on top of a layer of mulch such as leaves. The grounds are relatively high in nitrogen which helps the breakdown process. Just got done applying a bag of grounds around the grapes.

The local coffee shop saves the grounds and are available for the taking if you want to carry an 18 pound bag home with you when you take a walk. It is indeed a great soil additive.

 

[southernhybrid]

https://www.recycleacup.com/compost-tea-bags/

We compost the scraps of vegetables, fruits and my husband's coffee grounds but I only get my caffeine from tea, and I never thought about composting my tea bags until now. Since the ones I use have no strings or stables it will be very easy, so I'll start adding them to the compost bin when I make a little pot of tea this afternoon.