Home | About | Contact | Buy the books | Blog
Nature Cures natural health advice


Let food be your medicine



A-Z of ailments

A-Z of food and remedies

 A-Z of nutrients

A-Z of hazards


COUMARINS (benzopyrones)

The benzopyrones are a group of compounds whose members include coumarins and flavonoids. Coumarins are aromatic and potent substances, produced by some plants, which have been found to contain anti-carcinogenic compounds and have multi-biological activities such as being anti-arrhythmia, anti-asthma, antibacterial, antifungal, anti-HIV, anti-hypertension, anti-osteoporosis, antiseptic, anti-tumour and pain relieving.

Due to their strong aromatic compounds coumarins are used in 90% of perfumes.

Many coumarins and flavonoids are named after the Latin names of the plants that are rich in these components. For example: Cow parsnip (Heracleum lanatum) was found to be rich in a particular furanocoumarin compound and thus this substance was named heraclenin. Likewise aniseed (Pimpinella anisum)  was found to contain another kind of furanocoumarin and so this was called pimpinellin.

There are four main classifications of coumarins:

1.   Simple coumarins

2.   Furanocoumarins

3.   Pyrano coumarins

4.   Pyrone substituted coumarins

Most coumarins occur in higher plants, with the richest sources being citrus fruits (Rutaceae). They are also found in certain microorganisms such as novobiocin from Streptomycin and aflatoxin from the Aspergillus species.


Subscribe to the monthly newsletter


Like on Facebook


Follow on Twitter

Plant coumarins

  • Esculetin (aesculetin)

  • Fraxetin

  • Daphnetin

  • Limettin

  • Osthole is found in the Cnidium monnieri plant.

  • Scopoletin found in red peppers.

  • Seselin

  • Xanthyletin

Seselin and xanthyletin are prenylated.

Medicinal properties of coumarins

Studies have also shown that coumarins function as blood thinning agents and also exhibit anti-fungal properties. Studies have also proved the selective cytotoxicity of coumarins for tumour cells and also the positive effect of coumarins in the regulation of immune response, cell growth and differentiation. They also possess anti-aging, and cardioprotective properties.

Note: Coumarins should not be consumed while taking anticoagulants.

A recent study has shown that 7-hydroxycoumarin inhibits the release of Cyclin D1, which is overexpressed in many types of cancer.

Aesculetin is a derivative of coumarin and found in chicory and genistein is an isoflavone. Both genistein and aesculetin exert a very potent inhibitory effect on cancer cell growth.

Not all coumarin associated derivatives are beneficial to human health. Two examples are dicoumarol and furanocoumarins.


Moulds such as Penicillium nigricans, Penicillium jensi and the Aspergillus metabolise coumarin into dicoumarol. Dicoumarol is similar in structure to vitamin K. When consumed by livestock it inhibits vitamin K production. Vitamin K is necessary in the body to activate prothrombin. When tissue is damaged, thromboplastin is released and converts prothronin to thrombin. Thrombin alters the solubility of fibrinogen in blood and causes it to clot and seal the tissue damage. Dicoumarol prevents this process and is used in blood thinning medications such as warfarin and as pesticides for rats and mice.

Note: Dicoumarol can cause significant kidney and liver damage.

Furanocoumarins (furocoumarins)

  • Umbelliferone

  • Aurapten

  • Epoxyaurapten

  • Psoralen (aka psoralene)

  • 5-hydroxy-xanthotoxin

  • 5,8-dihydroxy-psoralen

  • 8-hydroxy-bergapten

  • 5-geranyloxy-7-methoxycoumarin

Furanocoumarins also consist three clusters:

  1. The bergapten cluster:  bergapten, bergamottin, bergaptol, epoxybergamottin, isoimperatorin, oxypeucedanin, oxypeucedanin hydrate, 6’,7’-dihydroxy-bergamottin.

  2. The isopimpinellin cluster: byakangelicin, byakangelicol, cnidicin, cnidilin, isopimpenellin, phellopterin.

  3. The xanthotoxin cluster: heraclenin, heracenol, imperatorin, xanathotoxol, xanpothotoxin, 8-gerynaloxy-psoralen.

Furanocoumarins are toxic compounds found primarily in species of the Umbelliferae (Apiaceae) family which includes  carrots, celery, cow parsnip and parsley and Rutacea (citrus fruits). They are potent chemical defences that have adverse effects on wide variety of organisms, ranging from bacteria to mammals.

Umbelliferone, also known as 7-hydroxycoumarin, hydrangine, skimmetine and beta-umbelliferone, is also found in aniseed (Pimpinella anisum) and liverwort.

Parsnips (Pastinaca sativa) contain the furanocoumarins bergapten, imperatorin, isopimpinellin and xanthotoxin.

Cow parsnip (Heracleum lanatum) contains apterin, vaginidiol, isobergapten, xanthotoxin (8-methoxypsoralen), umbelliferone, lanatin, pimpinellin, isopimpinellin, coumaric and ferulic acids, bergapten, sphondin, xanthotoxol, psoralen, heraclenin

Parsley contains isobegaptin and parsley and celery contain scopoletin.

Citrus fruits, are able to produce defence the compounds furanocoumarins to avoid attacks by herbivorous insects and pathogens. In humans, these chemical compounds are strong photosensitisers and can interact with medications, leading to the “grapefruit juice effect”.

Citrus species can be separated into four groups that correspond to the four original species (ancestral taxa).

  1. Citrons

  2. Mandarins

  3. Papedas

  4. Pummelos

Three of the four (pummelos, citrons and papedas) synthesise high amounts of coumarins and furanocoumarins, whereas mandarins are devoid of them.

The genetic origin of the grapefruit is a hybrid mix. One ancestor was the Jamaican sweet orange (Citrus sinensis), itself an ancient hybrid of Asian origin; the other was the Indonesian pomelo (Citrus maxima). This cross-breeding resulted in higher levels of furancoumarins in the grapefruit and is an example of why tampering with natural food crops is not advisable before knowing their complete chemical make-up and the outcome of doing so.

According to new research, it is not the flavonoids in grapefruit that interact dangerously with some drugs as once thought, it is the furanocoumarins. Some medications, such as those for cholesterol and hypertension, are affected by furanocoumarins so that they enter the bloodstream too quickly.

Furanocoumarins influence the function of certain enzymes, along the gastrointestinal tract or in the liver, and these interactions influence the rate at which certain medications can be broken down or removed from the body. Once such medication is felodipine (marketed as Plendil), a drug used for treating hypertension. When grapefruit juice is consumed, the level of the blood pressure lowering medication in the body becomes as much as five times higher and the blood pressure may fall too low, causing symptoms of light-headedness, dizziness, weakness or even fainting. It does not take much grapefruit or grapefruit juice to make this happen, especially if it is consumed on a regular basis.

Another group of medications that interact with grapefruit are the “statins,” which are now widely prescribed to lower blood cholesterol levels. There are many other medications, however, that also interact with grapefruits. A partial list (using drug generic names) includes the following:

  • Alprazolam

  • Aorvastatin

  • Benzodiazepines

  • Buspirone

  • Carvediol

  • Cerivastatin

  • Cisapride

  • Clomipramine

  • Coumadin

  • Cyclosporine

  • Ethinyl       

  • Estradiol

  • Felodipine

  • Lovastatin

  • Nifedipine

  • Nimodipine

  • Saquinavir

  • Simvastatin

  • Tacrolimus

  • Testosterone

  • Triazolam

Natural food sources of coumarins in alphabetical order

  • Alfalfa

  • Angelica

  • Ashitaba

  • Cassia leaves

  • Celery

  • Chickpeas (kala Chana)

  • Chicory

  • Cleavers

  • Bilberries

  • Brussel sprouts

  • Cloudberries

  • Dill

  • Ladino clover sprouts

  • Lemons

  • Lima beans

  • Limes

  • Liverwort

  • Lomatium

  • Maqui berry

  • Nuts

  • Oranges

  • Parsley

  • Parsnips

  • Pinto beans

  • Seeds

  • Spinach

  • Tangerines

  • Tea especially green tea

  • Wine

Rich plant sources of coumarins

  • Cassia cinnamon (Cinnamomum cassia) Not to be confused with true cinnamon (Cinnamomum zeylanicum) which contains little coumarin.

  • Cherry blossom tree leaves (of the Prunus genus)

  • Cnidium monnieri seeds

  • Deertongue (Dichanthelium clandestinum)

  • Lavender (Lavandula)

  • Mullein (Verbascum spp.)

  • Red clover (Trifolium pratense)

  • Sweet-clover (Melilotus sp.)

  • Sweet grass (Hierochloe odorata)

  • Sweet woodruff (Galium odoratum)

  • Tonka bean (Dipteryx odorata),

  • Vanilla grass (Anthoxanthum odoratum),

  • Water willow (Justicia pectoralis)

Note: Richest sources of coumarins are cassia leaf oil, cassia cinnamon bark oil, lavender oil and citrus fruits.

Caution: Excessive consumption of coumarins may damage the liver and kidneys in some individuals.


Coumestan is a heterocyclic organic compound that is a derivative of coumarin and forms the central core of a variety of natural compounds known collectively as coumestans. These, and isoflavones, flavones, deoxybenzoins and lignans are all classes of phytoestrogens.

Coumestans are oxidation products of pterocarpan and similar to coumarin. Coumestans, including coumestrol, a phytoestrogen, are found in a variety of plants that has oestrogenic activity that is 30 to 100 times greater than that of isoflavones.

Coumestans have been shown to decrease bone resorption and promote the mineralisation of bone. Regular consumption of foods rich in this compound can help treat menopause symptoms and lowers the risk of hip fractures, breast cancer and heart disease.

Natural sources of coumestan in alphabetical order

  • Alfalfa sprouts

  • Butterbeans

  • Clover sprouts

  • Soya beans

  • Split peas

Find out more about the conditions coumestans can help to treat

Latest research

More flavonoids have been discovered and named by Japanese scientists while studying the Sophora root, Ku shen (Sophora flavescens) plant.

  • Formonometin

  • Kurarinol

  • Kuraridinol

  • Neokurarinol

  • Nor-kurarinol

  • Isokurarinone

The prenylated isoflavone, 8-Prenylkaempferol  can also be found in Sophora flavescens.

 They also found new ones in the Sophora augustifolia plant and named them thus:

  • Isoanhydroicaritin

  • Isoxanthohumol

  • Kuraridin

  • Kurarinone

  • Nor-anhydroicaritin

  • Nor-kurarinone

  • Xanthohumol

Read more about the other phytoestrogens


  • http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0142757

  • https://www.medicalnewstoday.com/articles/43420.php

Associated articles

"Nature cures not the physician..." Hippocrates 460 BC


Subscribe to the Nature Cures monthly newsletter

Search Nature Cures for an ailment, health disorder or disease


A-Z of health disorders

A-Z of health hazards

Acid/alkaline balance


29 x Air-purifying houseplants



Bacterial infections



Drug dangers

Fungi and yeast infections

Corneal graft information

Health and welfare links

Home-made air fresheners

Home-made cleaning products

Hygiene, toxins and health

Increase your energy

Injury, surgery and infection

Make your own home remedies

Nature cures for babies

Nature cures for pets

Obesity and how to lose weight

Pain and inflammation

Parasite and worms

Plea for cornea donations

Pregnancy and childbirth

Raw juice therapy

Shopping list

The human body

Virus infections


A-Z of minerals

A-Z of vitamins and organic nutrients

Amino acids


Antioxidants and free radicals


Cleanse and detoxify


Fatty acids

Food combinations

Food intolerances


Nature's colour codes

Nutrient deficiencies

Prebiotics and probiotics


Sports nutrition




A-Z of natural food and beverages

A-Z of medicinal herbs and spices

A-Z of root vegetables

Alcohol dangers

Ancient kitchen cures



Brine pickling

Butter v margarine

Calories in foods

Citrus fruit

Coffee and caffeine dangers

Daily essentials

Food allergies

Grow your own health garden

Healthy recipes

Juicing recipes



Oily fish

Organ meats

Raw juice therapy

Salt in the diet



Sprouting micro-diet

Sugar dangers

Whole Grains

Nature Cures

About Nature Cures

Advertise on this website

Buy the Nature Cures book

Nature Cures news

Nature Cures pocketbook series

Site map

Subscribe to the monthly newsletter

Terms of service

Web site index




DISCLAIMER: The information on this website is not intended to diagnose medical problems, prescribe remedies for illness, or treat disease. Its intention is solely educational. If you are in any doubt about your health, please consult your medical or health professional. Nature Cures does not warrant or assume any legal liability or responsibility for the accuracy, completeness or usefulness of the information provided here or the outcome of using it.

Nature Cures is not responsible for, and does not endorse, any content or items purchased from any external websites linked to this website. 

© Copyright 2010 Nature Cures. All rights reserved.

Email: health@naturecures.co.uk