Coffee is one of the most widely consumed beverages worldwide. It is usually identified as a stimulant because of its high content of caffeine. However, caffeine is not the only coffee bioactive component. The coffee beverage is a mixture of many bioactive compounds such as polyphenols, especially chlorogenic acids (in green beans) and caffeic acid (in roasted coffee beans), alkaloids (caffeine and trigonelline), and the diterpenes (cafestol and kahweol). 
Extensive research shows that coffee consumption has beneficial effects on human health. Regular coffee intake may protect from many chronic disorders, including cardiovascular disease, type 2 diabetes, obesity, and some types of cancer. Coffee consumption is linked to a decreased risk of developing some neurodegenerative conditions such as Alzheimer’s disease, Parkinson’s disease, and dementia.
Regular coffee intake also reduces the risk of stroke. The mechanism underlying these effects is still being studied. Epidemiological studies and clinical reports have shown, the potential molecular mechanism(s) by which coffee’s bioactive components may provide neuroprotection and extensive health benefits. So we are going to deconstruct the top 5 compounds found in coffee, these are

  1. Chlorogenic acids (CGAs)
  2. Caffeine
  3. Trigonelline
  4. Melanoidins
  5. Diterpenes

As mentioned above Coffee’s top 5 bioactive components include Chlorogenic acids (CGAs), Caffeine, Trigonelline,  Melanoidins, Diterpenes, and other secondary metabolites.

During roasting, coffee metabolites undergo complex Maillard reactions, producing melanoidins. Coffee is a primary source of polyphenols in our diet, and these antioxidant compounds exert beneficial anti-inflammatory effects in most people.

To understand the relationship between coffee and human health, and to effectively use the active ingredients, it is not essential to understand the sources of coffee’s bioactive ingredients and their mechanisms of action in the human body or the sources of coffee’s active ingredients and the mechanisms of action and their combined effects on common human diseases like the prevention of cardiovascular disease, and antibacterial, anti-diabetic, neuroprotection, and anti-cancer activities. All you have to do is enjoy a really good quality coffee, however, you like it or whatever brand.

Deconstruction of the humble coffee bean

1. Chlorogenic acids (CGAs)

Coffee is the main source of antioxidant compounds in the diet of many populations worldwide mainly due to the high concentration of CGA and lactones in the brew associated with its high consumption. Chlorogenic acids are involved in the bitterness of coffee due to their decomposition in phenolic compounds during roasting. Chlorogenic acids mainly include caffeoylquinic acids (CQA), dicaffeoylquinic acids (diCQA), and feruloylquinic acids (FQA). The antioxidant and anti-inflammatory effects of chlorogenic acid are responsible for, the marked association between coffee consumption and lower incidence of various degenerative and non-degenerative diseases, in addition to higher longevity.

Isomers are compounds that contain exactly the same number of atoms, i.e., they have exactly the same empirical formula, but differ from each other by how the atoms are arranged. 
Chlorogenic acid is a well-known antioxidant it has more isomers. Some examples of DNA-protective activities of chlorogenic acid isomers include three caffeoylquinic acid isomers (3-O-caffeoylquinic acid, 3-CQA; 4-O-caffeoylquinic acid, 4-CQA; and 5-O- caffeoylquinic acid, 5-CQA) and three dicaffeoylquinic acid isomers (3,5-dicaffeoyl-quinic acid, ICAA; 3,4-dicaffeoylquinic acid, ICAB; and 4,5-dicaffeoyl-quinic acid, ICAC). Each of these chlorogenic acid isomers exhibit antioxidant activities and protect against the effects of DNA damage to various extents.

Chlorogenic acid compounds in coffee-

2. Caffeine

Absorption of caffeine in the body can take 15 to 45 minutes, partly due to caffeine being amphiphilic, because it can move freely through all membranes of the body. This feature gives caffeine the ability to pass quickly through the blood-brain barrier, where it goes to work fast. The shape of the caffeine molecule is similar to that of adenosine, a molecule that calms brain activity dilates blood vessels, and promotes relaxation to help us fall asleep. Because caffeine is shaped like adenosine, the two compete to bind to receptors in the brain. When caffeine wins, it prevents adenosine from doing its job (keeping you awake) and makes your nerve cells fire faster and your blood vessels constrict, typically causing feelings of wakefulness and alertness.
The typical half-life of coffee ranges from 5-7 hours, this means it takes 5 to7 hours for your body to eliminate half of the original dose of coffee. The half-life range for coffee can be changed by several factors, including coffee-consumption habits, age, genetics, and overall health. If have a cup of coffee with about 150 milligrams of caffeine around 2:00 pm, by 8:00 pm, you still have about 75 milligrams of caffeine in your system.
Caffeine is broken down (metabolised) by the liver into three major metabolites: Paraxanthine (84%), Theobromine (12%), and Theophylline (4%); all three of which are also active ingredients. After the liver metabolises caffeine, the kidneys excrete what’s remaining into the urine. Caffeine is a central nervous system (CNS) stimulant of the methylxanthine class. It is used as a cognitive enhancer, increasing alertness and attentional performance.
In the 19th century, Hermann Fischer explained the structure of caffeine, it’s similar to adenosine. Caffeine is the most studied bioactive compound found in coffee. The pharmacological effects of caffeine are non-specific antagonism of adenosine receptors. Adenosine regulates bone metabolism in a complex manner, with in vitro studies suggesting that direct stimulation of adenosine A2A and A2B receptors induces bone formation by activating osteoblasts and suppressing osteoclast differentiation and function. 

web caffeine Coffee Bean

3. Trigonelline

Over the last few decades, extensive studies have proven that trigonelline has an anti-diabetic effect. Its mechanism includes regulating insulin secretion, reducing oxidative stress, and improving glucose tolerance and insulin resistance. Trigonelline has proven to have a neuroprotective effect, including improving Alzheimer’s disease, Parkinson’s disease, stroke, and depression. It has the potential to be an alternative drug for the treatment of neurodegenerative diseases. In specific disease models, trigonelline also exerts protection of the heart, liver, and skin.
Plasma levels of trigonelline vary depending on the coffee type, and the amount of coffee consumed is a reliable predictor of plasma trigonelline values, absorption of trigonelline appears to take place primarily in the small intestine, and the circulating levels of this compound are significantly elevated within the first hours of consumption.

The molecular structure of trigonelline is similar to the anti-Alzheimer’s drug Cotinine. Trigonelline as a coffee ingredient is one of the most frequently consumed alkaloids and its beneficial influence on lipid profile has also been proven.

Trigonelline is important as one of the constituents of aroma and flavour in coffee and a useful source of nutrition. Trigonelline is known to be beneficial for carbohydrate metabolism, is believed to protect against lipid peroxidation, and protein oxidative damage, and efficiently scavenges free radicals.

Trigonelline prevents Streptococcus mutans from adhering to teeth and has anti-invasive activity against cancer cells. During roasting trigonelline partially degrades to produce two important compounds – pyridines and nicotinic acid so very dark roast will only contain a fraction of its original trigonelline content.
Trigonelline can prevent beta-amyloid aggregation, it significantly contributes to the beneficial effects of coffee consumption in neurodegenerative diseases. Its anti-microbial, anti-carcinogenic, and anti-hyperglycemic effects have been investigated in many research studies. 

4. Melanoidins

Studies have shown the number of melanoidins ingested during regular coffee intake protects against colon cancer by inhibiting matrix metalloproteases, which prevents bacterial growth in the mouth and the appearance of dental caries, and promotes selective bacterial growth in the colon, and exerts anti-inflammatory and antiglycative effects.

From a nutritional point of view, coffee melanoidins are considered a source of dietary fibre. Coffee melanoidins have been demonstrated to be more powerful antioxidants compared to melanoidins from other thermally processed foods. They can act as anticarcinogenic, antimicrobial, and anti-inflammatory agents, and can be used as a nitrogen and carbon source for intestinal probiotic bacteria, such as bifidobacteria, exhibiting prebiotic capacity.

 

 

 

 

web Melanoidins Coffee Bean

5. Diterpenes

Brewed coffee contains Diterpenes the two best-known are cafestol and kahweol. According to studies. Cafestol and Kahweol show similar biological activities but are not the same, they are recognised as having health-enhancing properties like:

Anti-inflammation:
Inhibits the expression of Inducible nitric oxide synthase and Cyclooxygenase-2 and the secretion of pro-inflammatory cytokines
Inhibits phase I enzyme and induce phase II detoxifying enzymes Nuclear factor erythroid-2-related factor 2

Anti-diabetes:
Increases insulin secretion and glucose uptake in muscle cells
Inhibits adipogenesis

Anti-osteoclastogenesis:
Promotes Osteoblasts differentiation
Inhibits differentiation and bone-resorbing activity of Osteoclasts

Neuroprotection:
Activates the cytoprotective transcription factor Nrf2

Anti-carcinogenesis:
Inhibits metastasis
Synergistically inhibit the progression of prostate cancer
Exert’s multiple pharmacological effects on renal cancer
Induces apoptosis by regulating B-cell lymphoma-2 family proteins and cyclins

Anti-angiogenesis:
Inhibiting extracellular matrix remodelling and regulating Vascular endothelial growth factor pathway

Cafestol and Kahweol, have been shown to increase cholesterol levels when drinking over 4/5 cups of coffee daily over extended periods although this can be drastically reduced by drinking filtered coffee. Cafestol and Kahweol are recognised as having chemoprotective properties and could serve as specific protective agents against benzo[a]pyrene and aflatoxin BI, both are well-known carcinogens.

web diterpenes coffee bean

Conclusion