I. What are phytochemicals?
Phytochemicals are chemical compounds in natural plants, which are normally nonessential nutrients to human body, but may have biological significance such as protective or preventive properties from diseases. It is estimated that there are tens of thousands phytochemicals in our world fighting against various diseases, for instance, the antioxidant (to protect our cells against oxidative damage and further to avoid the occurrence of some cancers), the Hormonal action (to help to reduce menopausal symptoms and osteoporosis), the Stimulation of enzymes (to reduce the risk of breast cancer).
II. How to get phytochemicals?
- Freshly picked plant tissues are plunged into boiling alcohol before they are collected, or stored dry in a plastic bag if the materials need to be supplied through long transportation.
- The plants for extraction are thoroughly dried as quickly as possible under controlled conditions, without using high temperatures, and then it could be stored for quite a long time before any further analysis.
- Classical chemical techniques are used to extract materials from dried plant tissues with a range of solvents. However, one still can’t get complete separation of required constituents at this stage.
- Clarify the extract by filtration and further concentrate it in vacuo, which is usually carried out in a rotary evaporator. This concentrated extract may deposit crystals, and if so, these crystals should be collected by filtration and then be tested in solvents.
- Otherwise, a single substance presents and is purified by crystallization for further analysis. However, the normal cases are presented as mixtures of substances, so redissolvement is required to separate the constituents by chromatography.
III. Phytochemicals in our daily life
Some healthy food we consume everyday could benefit us by providing us necessary phytochemicals or essential nutrients, as the examples listed below:
- Apiol from parsley and celery leaf
Apiol is an organic chemical compound in the essential oils of celery leaf and all parts of parsley. It was firstly discovered in 1715, and be identified as an effective treatment of amenorrhea or lack of menstruation in 1855. It is mainly used for the treatment of menstrual disorders, and could be toxic to cause liver and kidney damages if used in high doses.
- Kaempferol from tea, strawberries, gooseberries, cranberries, grapefruit, apples, peas, brassicates (broccoli, kale, brussels sprouts, cabbage), chives, spinach, endive, leek, tomatoes
Kaempferol is a type of natural flavonoid, and is found to be powerful to lower the risk of pancreatic cancer among smokers, to reduce lung cancer incidence, to be a potent prophylactic against NOX-mediated neurodegeneration, and to inhibit the enzyme fatty acid amide hydrolase (FAAH).
- Peonidin from bilberry, blueberry, cherry, cranberry and peach
Anthocyanidins are a class of polyphenols present at high levels in fruits. Peonidin is thus an O-methylated anthocyanidin and a plant pigment, due to its high pH sensitivity. It is primarily used in food coloring, and as an inhibitor to treat cancer cells in vitro, e.g. metastatic human breast cancer cells.
- Delphinidin from bilberry, blueberry and eggplant
Delphinidin is a dietary anthocyanidin, a plant pigment and also an antioxidant. It is a potent angiogenic inhibitor against the phosphorylation of VEGF receptors, suggesting its hopeful usage to prevent and treat cancer.
- Silymarin – from artichokes, milk thistle
Silymarin has anti-hepatotoxic properties to protect liver cells against toxins, and has vitro anti-cancer effects against human prostate adenocarcinoma cells, estrogen-dependent and -independent human breast carcinoma cells, human colon cancer cells, etc.