|
Allium cepa L. (Liliaceae)
Synonyms
Allium esculentum Salisb., Allium porrum cepa Rehb.
Local names
It is most commonly known as “onion”. Basal, basl, cebolla, cebolla
morada, cepa bulb, cepolla, cipolla, common onion, cu hanh, hom hua yai, hom
khaao, hom yai, hu-t’sung, hu t’sung t’song, hua phak bhu,
i-i-bsel, kesounni, khtim, Küchenzwiebel, l’oignon, loyon, Madras
oignon, oignon, palandu, piyaj, piyaz, pyaz, pyaaz, ralu lunu, red globe onion,
sibuyas, Spanish onion, tamanegi, umbi bawang merah, vengayan, yellow Bermuda
onion, white globe onion, Zwiebel
Description
A perennial herb, strong smelling when crushed; bulbs vary in size and shape
from cultivar to cultivar, often depressed-globose and up to 20 cm in diameter;
outer tunics membranous. Stem up to 100cm tall and 30 mm in diameter, tapering
from inflated lower part. Leaves up to 40 cm in height and 20mm in diameter,
usually almost semicircular in section and slightly flattened on upper side;
basal in first year, in second year their bases sheathing the lower sixth of
the stem. Spathe often 3-valved, persistent, shorter than the umbel. Umbel 4–
9cm in diameter, subglobose or hemispherical, dense, many-flowered; pedicels
up to 40mm, almost equal. Perianth stellate; segments 3–4.5 2–2.5mm,
white, with green stripe, slightly unequal, the outer ovate, the inner oblong,
obtuse or acute. Stamens exserted; filaments 4–5mm, the outer subulate,
the inner with an expanded base up to 2 mm wide and bearing short teeth on each
side. Ovary whitish. Capsule about 5mm, 2n 16.
Plant material of interest
fresh or dried bulbs
Chemical assays
Assay for organic sulfur constituents, cysteine sulfoxides and sulfides by means
of high-performance liquid chromatographic or gas–liquid chromatographic
methods, respectively. Quantitative levels to be established by appropriate
national authority.
Major chemical constituents
Sulfur- and non-sulfur-containing chemical constituents have been isolated from
Bulbus Allii Cepae; the sulfur compounds are the most characteristic. The organic
sulfur compounds of Bulbus Allii Cepae, including the thiosulfinates, thiosulfonates,
cepaenes, S-oxides, S,S'-dioxides, monosulfides, disulfides, trisulfides, and
zwiebelanes occur only as degradation products of the naturally occurring cysteine
sulfoxides (e.g. (+)-S-propyl-L-cysteine sulfoxide).When the onion bulb is crushed,
minced, or otherwise processed, the cysteine sulfoxides are released from compartments
and contact the enzyme alliinase in adjacent vacuoles. Hydrolysis and immediate
condensation of the reactive intermediate (sulfenic acids) form the compounds
as indicated below. The odorous thiosulphonates occur (in low concentrations)
only in freshly chopped onions, whereas the sulfides accumulate in stored extracts
or steamdistilled oils. Approximately 90% of the soluble organic-bound sulfur
is present as γ-glutamylcysteine peptides, which are not acted on by alliinase.
They function as storage reserve and contribute to the germination of seeds. However,
on prolonged storage or during germination, these peptides are acted on by γ-glutamyl
transpeptidase to form alk(en)yl-cysteine sulfoxides, which in turn give rise
to other volatile sulfur compounds.
Dosage forms
Fresh juice and 5% and 50% ethanol extracts have been used in clinical studies.
A “soft” extract is marketed in France but is not recognized as
a drug by French authorities. Dried Bulbus Allii Cepae products should be stored
in well-closed containers, protected from light, moisture, and elevated temperature.
Fresh bulbs and juice should be refrigerated (2–10°C)
Medicinal uses
Uses supported by clinical data
The principal use of Bulbus Allii Cepae today is to prevent age-dependent changes
in the blood vessels, and loss of appetite.
Uses described in pharmacopoeias and well
established documents
Treatment of bacterial infections such as dysentery, and as a diuretic. The
drug has also been used to treat ulcers, wounds, scars, keloids, and asthma.
Bulbus Allii Cepae has also been used as an adjuvant therapy for diabetes. Uses
described in folk medicine,
Uses described in traditional medicine
As an anthelminthic, aphrodisiac, carminative, emmenagogue, expectorant, and
tonic, and for the treatment of bruises, bronchitis, cholera, colic, earache,
fevers, high blood pressure, jaundice, pimples, and sores
Proven pharmacological activity
Animal studies
Antibacterial, Antihyperlipidemic, Platelet aggregation inhibitor, Antihyperglycemic,
Diuretic, Smooth muscle relaxant, Anti-inflammation, Anti-allergy, Keloid treatment
Human studies
Platelet aggregation inhibitor, Antihyperlipidemic,
Antihyperglycemic, Anti-allergy
Contraindications
Allergies to the plant. The level of safety of Bulbus Allii Cepae is reflected
by its worldwide use as a vegetable.
Warnings
No warnings have been reported.
Precautions
Carcinogenesis, mutagenesis, impairment of fertility Bulbus Allii Cepae is not
mutagenic in vitro.
Other precautions
No general precautions have been reported, and no precautions have been reported
concerning drug interactions, drug and laboratory test interactions,
Posology
Unless otherwise prescribed: a daily dosage is 50 g of fresh onion or 20 g of
the dried drug; doses of preparations should be calculated accordingly
|
