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Plants and the chemicals they make: the coffee plant and caffeine

Important: don’t thank plants (or Mother Nature, or Gaia) for the fantastic chemicals that benefit you. They are not made for your benefit. Conversely, those lethal poisons that may be hiding in the pretty fruits are probably meant for you or other predators. Chemical ecology studies the interactions between organisms and their environment that are mediated by naturally occurring chemicals.

Many of us wake up in the morning looking forward to a hot water extract of the roasted seeds from Coffea arabica L., a.k.a. coffee.  I like to drink my capuccino in the morning. It stimulates me (caffeine!) and it is a lovely way to start my day.

Let’s look first at the plant that produces the coffee grains, Coffea Arabica.  You can make coffee using  the beans from other Coffea species, like  Robusta (Coffea robusta L. Linden), Liberian (Coffea liberica Hier.) and wild coffee species like Bengal coffee (Coffea benghalensis Roxb. Ex Schult.).

A botanical illustration of the coffee plant, Coffea Arabica.

For more information on the structure of the coffee fruit (coffee cherry) please see this webpage. In short, the coffee bean is the endosperm of the coffee seed.

Coffee fruits are fleshy berries, each containing two seeds which are pressed together so that the inner side of each one is flattened. The coffee beverage is made from the ground, roasted seed endosperm (coffee beans) that are removed from the coffee cherries. When the seeds were collected, the rest of the fruit was usually discarded but now the skin care industry has made the coffee fruit a hot commodity (mislabeled as coffee berry). You can also make tea using the dry coffee fruit. We use the coffee fruit extract as an ingredient in our Skin Actives antioxidant cream.

The coffee grain is processed after harvest, and the processing will affect the chemical composition (and taste) of the coffee we make in our kitchen. It may not be obvious, but the way we make coffee will also affect the composition of the final beverage.

What chemicals will you find in coffee fruit extract and in coffee bean extract?

Coffee Fruit Extract

I think it was a great idea to  use the until recently discarded coffee fruit, because it contains chlorogenic and caffeic acids (antioxidant, anti-inflammatory), ferulic acid (antioxidant),  quinic acid (antioxidant, antiviral), trigonelline (antioxidant, anticancer, antibacterial), proanthocyanidins, caffeine, mannans and arabinogalactans,  actives truly beneficial to our skin and our bodies.

Coffee bean extract

Let’s start with caffeine. Caffeine, a monoterpenoid alkaloid, decreases the risk of skin cancer promoted by UV irradiation; apparently by slowing down repair of DNA mutations caused by UV making it more precise and preventing mutations that may lead to cancer.  Caffeine also decreases the thickness of subcutaneous fat layer by inducing lipolysis, useful for “cellulite” but not for aging faces, because we already lose enough sub-dermal fat without using caffeine.  Topical application of caffeine is safe, as shown by its use to facilitate breathing of newborns. Other beneficial effects of caffeine are analgesia, antiviral, antidermatitis, antioxidant.  The “de-puffing” effect of caffeine on “post-party” eyes, may be mediated by the promotion of sodium export from the cell, which is followed by water loss. Still, I’s rather suggest enough sleep rather than caffeine to de-bloat your eyelids!  Caffeine is a very useful chemical, also found in tea (an extract from the leaves of Camellia sinensis L.). The coffee beans contain 1.25%–2.5% caffeine (roasted seeds: 1.3%–2.9%),

What else is in there besides caffeine?   Theobromine, theophylline, 4%–7% chlorogenic acid (roasted seeds:0.3%–0.6%), 0.8%–1.2% trigonelline (roasted seeds: 0.3%–0.6%), 0.02% choline, 10%–16% fatty oil, quinic acid, sitosterol, dihidrositosterine, stigmasterol, coffeasterin, tannin, wax, caffeic acid, sugar, cellulose, hemicellulose, non-volatile aliphatic acids (citric, malic, and oxalic acid), volatile acids (acetic, propanoic, butanoic, isovaleric, hexanoic, and decanoicacids), soluble carbohydrates (e.g. monosaccharides: fructose,glucose, galactose, and arabinose), oligosaccharides and polysaccharides.

The differences in coffee taste and aroma have to do with the chemistry, and this is affected by the variety of coffee, the growing conditions, the processing of the beans and many other factors. Also remember that how you make coffee will affect the proportion of the chemical components in the beans that will be extracted by the hot water.

A complex assortment of chemicals of the terpenoid family is responsible for the complex aroma of coffee. You will find alpha-2-furfurylthiol,4-vinylguaiacol, some alkyl and 3-methylbutane yrosine derivatives, furanones, acetaldehyde, propanal, methylpropanal, cafesterol and bengalensol.

Polyphenols: the high polyphenol content of coffee beans makes them an ideal ingredient source for the food, cosmetic, and pharmaceutical industries. Plants synthesize phenolic commpounds because they protect them against pathogens and environmental stress like changes in temperature, water content, exposure to UV light, and deficiency of mineral nutrients. They contain two types of carbon structures derived from hydroxycinnamic and hydroxybenzoic acids.  Caffeic, p-coumaric, vanillic, ferulic, and protocatechuic acids are present in the coffee plant.  Polyphenols are good for humans too.

How to use coffee in your skin beauty routine.

Use some instant coffee to give you body lotion the aroma and color of a cappuccino. After making an espresso in your home coffee machine, use the grounds to exfoliate your skin.

For a review see:

Patay, É. B., Bencsik, T., & Papp, N. (2016). Phytochemical overview and medicinal importance of Coffea species from the past until now. Asian Pacific Journal of Tropical Medicine, 9(12), 1127–1135.    doi:10.1016/j.apjtm.2016.11.008