onion

Names and Synonyms

Common Names

• onion
• cultivated onion
• garden onion
• Onion
• Shallot
• Spring Onion
• bulb onion
• common onion

Scientific Names

Accepted name

Synonyms

• Allium cepa f. viviparum
• Allium ascalonicum var. majus
• Allium cepa var. roseum
• Allium cepa var. sanguineum
• Allium cepa var. tripolitanum
• Cepa alba
• Cepa rubra
• Ascalonicum sativum
• Cepa esculenta var. rubra
• Cepa esculenta var. hispanica
• Cepa esculenta var. ramosa
• Allium ascalonicum f. rotterianum
• Allium cepa var. aggregatum
• Allium cepa var. solaninum
• Allium cepa var. multiplicans
• Porrum cepa
• Allium cepa var. crinides
• Allium cepa var. viviparum
• Allium cepa var. argenteum
• Allium cepa var. praecox
• Allium cepaeum
• Allium cepa var. hispanicum
• Cepa esculenta
• Allium cepa var. lisboanum
• Allium cepa var. luteum
• Allium cepa var. bifolium
• Allium cepa var. portanum
• Cepa pallens
• Allium cepa var. flandricum
• Allium aobanum
• Allium cepa var. anglicum
• Allium cepa var. globosum
• Allium cepa var. jamesii
• Allium angolense
• Allium ascalonicum var. condensum
• Allium esculentum
• Allium ascalonicum var. fertile
• Allium salota
• Allium ascalonicum var. sterile
• Allium napus
• Kepa esculenta
• Allium pauciflorum

Regional and Traditional Names

Sources: Wikidata, Catalogue of Life

Taxonomical Classification

This plant belongs to the kingdom Plantae and is classified under the phylum Streptophyta and class Equisetopsida. Within the subclass Magnoliidae, it is further organized into the order Asparagales and the family Amaryllidaceae. Finally, its taxonomic identity is defined by its genus, Allium.

Sources: The World Checklist of Vascular Plants (WCVP)

Distribution

This plant exhibits a widespread presence across several key regions of the European continent. In Northern Europe, its distribution can be observed within the borders of Great Britain. Moving into Middle Europe, the species is found in Austria as well as throughout Germany. Its range also extends across the territories of Czechia and Slovakia within the same central region. Finally, the geographical footprint reaches into Southwestern Europe, specifically within France.

Sources: The World Checklist of Vascular Plants (WCVP)

Botanical Identification

Ecology

The ecology of Allium cepa is characterized by its ability to thrive within specific altitudinal gradients, typically occupying environments found at elevations ranging from a minimum of 1400 m AMSL to a maximum of 2700 m AMSL. Within this vertical range, the plant adapts to varying atmospheric pressures and temperature fluctuations, favoring well-drained soils that support its bulbous development. Its distribution within these specific elevational bounds suggests a preference for temperate to sub-alpine climatic conditions, where the seasonal shifts provide the necessary chilling periods required for optimal growth cycles.

Elevational range max:

2700 m AMSL

Elevational range min:

1400 m AMSL

Life history

The life history of Allium cepa is characterized by a flexible lifecycle that can be categorized as annual, biennial, perennial, or variable depending on the environmental conditions and cultivation practices. As a plant that survives unfavorable seasons by retreating underground, its life form is classified as a geophyte, specifically functioning as a cryptophyte where the perennating buds are protected beneath the soil surface. This specialized growth strategy allows the organism to store significant energy reserves within its bulb, facilitating its development through different stages of its biological cycle.

Life form :

geophyte

Life form :

cryptophyte

Lifecycle :

perennial

Morphology

The morphology of Allium cepa is characterized by a non-woody, herbaceous structure, specifically classified as a forb. As a terrestrial species, it grows independently without being an epiphyte or a parasite. The plant is self-supporting rather than being a climber, liana, or vine. In terms of stature, it exhibits a variable plant height, with a minimum height of 0.15 m, a mean height of 0.4 m, and a maximum height reaching up to 1.2 m.

Aquatic :

terrestrial

Climber :

self-supporting

Epiphyte :

terrestrial

Growth form :

herb

Growth form :

forb

Parasite :

independent

Plant height max:

1.2 m

Plant height mean:

0.4 m

Plant height min:

0.15 m

Woodiness :

non-woody

Physiology

The physiology of Allium cepa is characterized by a C3 photosynthetic pathway, utilizing the Calvin cycle to fix carbon dioxide during the light-independent reactions. The plant does not exhibit succulence, lacking the specialized water-storage tissues found in succulent species, and it is classified as non-carnivorous, relying solely on soil-based nutrient uptake rather than capturing insects. Furthermore, Allium cepa is not a nitrogen fixer, meaning it lacks the symbiotic relationship with nitrogen-fixing bacteria required to convert atmospheric nitrogen into usable forms, and instead depends on the availability of nitrates and ammonium within the substrate.

Carnivory :

non-carnivorous

Nitrogen fixer :

no

Photosynthetic pathway :

C3

Succulence :

no

Reproduction

The reproduction of Allium cepa is characterized by a sexual process, as asexual reproduction is noted to be absent. The flowering period typically commences in July and concludes in August, featuring flowers that range in length from a minimum of 0.5 cm to a maximum of 0.7 cm and are green in color. The pollination syndrome is primarily biotic, specifically relying on insects for the transfer of pollen. Following successful pollination, the plant produces dry fruit in the form of a capsule. This fruit is dehiscent, meaning it opens at maturity to facilitate seed release. The dispersal syndrome is classified as autochorous, where seeds are dispersed by the plant itself. The resulting seeds are quite small, with a mean seed mass of 0.004161 g (ranging from a minimum of 0.00223 g to a maximum of 0.00372 g) and a consistent seed volume of 3.1 mm³.

Dehiscence :

dehiscent

Dispersal syndrome :

autochorous

Flower colour :

green

Flower length max:

0.7 cm

Flower length min:

0.5 cm

Flowering time :

Jul

Flowering time :

Aug

Fruit dryness :

dry

Fruit type :

capsule

Pollination syndrome :

insect

Pollination syndrome :

biotic

Reproduction asexual :

absent

Seed mass max:

0.00372 g

Seed mass mean:

0.004161 g

Seed mass min:

0.00223 g

Seed volume max:

3.1 mm³

Sources: Global Inventory of Floras and Traits (GIFT)

Plant Parts

Allium cepa has 2 reported plant parts identified across 5 scientific publications and several other databases that are studied for medicinal purposes. The most consistently reported plant part include root, leaf.

Root

1. Cytobios
2. Journal of toxicology and environmental health. Part A
3. Revista brasileira de pesquisas medicas e biologicas

Leaf

1. International journal of mycobacteriology
2. Cytobios

Chemicals

Allium cepa has 337 reported phytochemicals identified across 5 scientific publications and several other databases. The most consistently reported chemicals include quercetin, Flavonoids, DIALLYL SULFIDE, DIALLYL DISULFIDE, Diallyl trisulfide.

quercetin

1. Dr. Duke
2. Microorganisms
3. Pharmaceutical biology
4. Journal of food biochemistry
5. Advances in pharmacological and pharmaceutical sciences

Flavonoids

1. Biomedical chromatography : BMC
2. Pharmaceutical biology
3. Journal of the science of food and agriculture
4. Nutrition (Burbank, Los Angeles County, Calif.)
5. Critical reviews in food science and nutrition

DIALLYL SULFIDE

1. Dr. Duke
2. Cancer research
3. Nutrition and cancer
4. Journal of cellular biochemistry. Supplement
5. Carcinogenesis

DIALLYL DISULFIDE

1. Dr. Duke
2. Nutrition and cancer
3. Journal of cellular biochemistry. Supplement
4. Pharmaceutical research
5. Journal of biochemical toxicology

Diallyl trisulfide

1. Dr. Duke
2. BMC complementary and alternative medicine
3. Cancer research
4. Journal of cellular biochemistry. Supplement
5. Carcinogenesis

ALLYL METHYL TRISULFIDE

1. Cancer research
2. Journal of cellular biochemistry. Supplement
3. Carcinogenesis
4. Journal of biochemical toxicology

Methyl propyl disulfide

1. Dr. Duke
2. Cancer research
3. Journal of cellular biochemistry. Supplement
4. Cancer letters

ONION OIL

1. Cancer biochemistry biophysics
2. BioFactors (Oxford, England)
3. Nutrition and cancer
4. Carcinogenesis

Saponins

1. Dr. Duke
2. Biomedical chromatography : BMC
3. Pharmaceutical biology
4. Heliyon

Tannins

1. Biomedical chromatography : BMC
2. Current rheumatology reviews
3. Asian Pacific journal of tropical medicine
4. Heliyon

Activities

Allium cepa has 786 reported activities identified across 5 scientific publications and several other databases. The most consistently reported activities include Antioxidant, Antibacterial, Antidiabetic, Antimicrobial, Fibrinolytic.

Antioxidant

1. Dr. Duke
2. BMC complementary and alternative medicine
3. Pharmaceutical biology
4. Scientific reports
5. Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association

Antibacterial

1. Dr. Duke
2. Journal of microbiology (Seoul, Korea)
3. Biometals : an international journal on the role of metal ions in biology, biochemistry, and medicine
4. Zhonghua Minguo wei sheng wu ji mian yi xue za zhi = Chinese journal of microbiology and immunology
5. Microbiological research

Antidiabetic

1. Dr. Duke
2. Biology
3. Iranian journal of basic medical sciences
4. Indian journal of experimental biology
5. Evidence-based complementary and alternative medicine : eCAM

Antimicrobial

1. Critical reviews in food science and nutrition
2. Frontiers in pharmacology
3. Prostaglandins, leukotrienes, and essential fatty acids
4. Anais da Academia Brasileira de Ciencias

Fibrinolytic

1. Dr. Duke
2. Indian journal of physiology and pharmacology
3. Indian journal of experimental biology
4. Archives des maladies du coeur et des vaisseaux

Antihypertensive

1. Dr. Duke
2. Iranian journal of basic medical sciences
3. Evidence-based complementary and alternative medicine : eCAM

Antitumor

1. Dr. Duke
2. Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association
3. Prostaglandins, leukotrienes, and essential fatty acids

Cardioprotective

1. Dr. Duke
2. Biology
3. Frontiers in pharmacology

Hypoglycemic

1. Dr. Duke
2. Indian journal of clinical biochemistry : IJCB
3. Prostaglandins, leukotrienes, and essential fatty acids

Analgesic

1. Dr. Duke
2. Critical reviews in food science and nutrition

Medicinal Uses

Allium cepa has 105 reported medicinal uses identified across 5 scientific publications and several other databases. The most consistently reported uses include cancer, oxidative stress, platelet aggregation, diabetes mellitus, hyperlipidemia.

Most Reported Uses

Preparations