Secondary plant compounds
The more than 30,000 secondary plant substances (phytochemicals) are bioactive substances with different effects. They are produced in the secondary metabolism of plants.
For plants, the secondary substances, in contrast to the primary ones, are not essential for life. They are found here only in very small quantities. It has been in recent years that the importance of phytochemicals for humans has been recognized. They perform a variety of protective functions in the human body. The most important groups of secondary plant compounds are the following:Carotenoids
- present in fruits, tomatoes, carrots, spinach, and broccoli
- Have anticarcinogenic, antioxidant, cholesterol-lowering, and immune-boosting effects
Phytoestrogens
- present in cereals, legumes, and soy
- have hormone-active, and anticarcinogenic effects
Polyphenols
- present in fruits, tea, cabbage, and pomegranate
- have anticarcinogenic, antioxidant, antihypertensive, antibacterial, and antithrombogenic effects
Terpenes
- present in lemon, mint, herbs, spices, kale, garlic, and onions
- have anticarcinogenic effect
Glucosinolates
- present in cabbage, cress, radish, and mustard
- have anticarcinogenic, antioxidant, and antibacterial effects
Sulfides
- present in leeks, garlic, onions, and asparagus
- have anticarcinogenic and antithrombotic effects
Saponins
- present in oats, legumes, vegetables, and spinach
- have anticarcinogenic, anti-inflammatory, cholesterol-lowering, and immune-boosting effects
Phytosterols
- present in nuts, grains, soybeans, sunflower seeds, and sesame seeds
- have antioxidant, anti-diabetic, and cholesterol-lowering effects
Protease inhibitors
- present in legumes, potatoes, and cereals
- have anticarcinogenic and antidiabetogenic effects
Some phytochemicals are toxic to humans but can be made pharmacologically useful, e.g.
- the alkaloids of the opium poppy (morphine, codeine and papaverine),
- nicotine,
- atropine from deadly nightshade and
- the diterpenoids from yew species (paclitaxel).