Monographs on 10 Indian Medicinal Plants, ANGIELSKIE
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Chapter- 1
Bulbus allii sativi
Definition
Bulbus Allii Sativi consists of the fresh or dried bulbs of Allium sativum L. (Liliaceae)
Synonyms
Porvium sativum Rehb.
Selected vernacular names
It is most commonly known as "garlic". Ail, ail commun, ajo, akashneem, allium, alubosa
elewe, ayo-ishi, ayu, banlasun, camphor of the poor, dai toan, dasuan, dawang, dra thiam,
foom, Gartenlauch, horn khaao, horn kia, horn thiam, hua thiam, kesumphin, kitunguu-
sumu, Knoblauch, kra thiam, krathiam, krathiam cheen, krathiam khaao, I'ail, lahsun, lai,
lashun, lasan, lasun, lasuna, Lauch, lay, layi, lehsun, lesun, lobha, majo; naharu, nectar
orthe gods, ninniku, pa-se-waa, poor man's treacle, rason, rasonam, rasun, rustic treacles,
seer, skordo, sluon, stinking rose, sudulunu, ta-suam, ta-suan, tafanuwa, tellagada,
tellagaddalu, thiam, toi thum, turn, umbi bawang putih, vallaip- pundu, velluli, vellulli
Description
A perennial, erect bulbous herb, 30-60 cm tall, strong smelling when crushed. The
underground portion consists of a compound bulb with numerous fibrous rootlets; the
bulb gives rise abovc ground to a number of narrow, keeled, grass- like leaves. The leaf
blade is linear, flat, solid, 1.0-2.5cm wide, 30-60 cm long, and has an acute apex. Leaf
sheaths form a pseudostem. Inflorescences are umbellate; scape smooth, round, solid, and
coiled at first, subtended by membraneous, long-beaked spathe, splitting on one side and
remaining attached to umbel. Small bulbils are produced in inflorescences; flowers are
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variable in number and sometimes absent, seldom open and may wither in bud. Flowers
are on slender pedicels; consisting of perianth of 6 segments, about 4-6mm long, pinkish;
stamens 6, anthers exerted; ovary superior, 3-locular. Fruit is a small loculicidal
capsule..Seeds are seldom if ever produced
Plant material of interest: fresh or dried bulbs
General appearance
Bulbus Allii Sativi consists of several outer layers of thin sheathing protective leaves
which surround an inner sheath. The latter enclose the swollen storage leaves called
"cloves". Typically.. the bulb possesses a dozen sterile scathing leaves within which are
6-8 cloves bearing buds making a total of 10-20 cloves and 20-40 well-developed but
short and embedded roots. The cloves are asymmetric in shape, except for those near the
centre.
Organoleptic properties
Odor strong, characteristic alliaceous taste very persistently pungent and acrid.
Geographical distribution
Bulbus Allii Sativi is probably indigenous to Asia
( India)
but it is commercially
cultivated in most countries.
General identity tests
Macroscopic and microscopic examinations and microchemical analysis are used to
identify organic sulfur compounds, thin-layer chromatographic
analysis to determine the presence of alliin.
Chemical assays
Qualitative and quantitative assay for sulfur constituents (alliin, allicin etc.) content by
means of high-performance liquid chromatography or gas chromatography-mass
spectroscopy methods.
Major chemical constituents
The most important chemical constituents reported from Bulbus Allii Sativi are the sulfur
compounds. It has been estimated that cysteine sulfoxides (e.g. alliin )and the non-
volatile y-glutamylcysteine peptides make up more than 82% of the total sulfur content of
garlic.
The thiosulfinates (e.g. allicin) ajoenes (e.g. E-ajoene, Z-ajoene). vinyldithiins (e.g. 2-
vinyl-(4H)-1,8-dithiin [5], 8-vinyl-(4H)-1.2-dithiin [6]), and sulfides (e.g.diallyl disulfide,
diallyl trisulfide), however, are not naturally occurring compounds,. Rather, they are
degradation products from the naturally occurring cysteeine sulfoxide, alliin . When the
garlic bulb is crushed, minced, or otherwise processed, alliin is released from
compartments and interacts with th eoenzyme alliinase in adjacent vacuoles. Hydrolysis
and immediate condensation of the reactive intermediate (allylsulfenic acid) forms alicin
. One milligram of alliin is considered to be equivalent to 0.45mg of allicin. Allicin itself
is an unstable product and will undergo additional reactions to form other derivatives
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(e.g. products), depending on environmental and processing condition. Extraction of
garlic cloves with ethanol at <0 o C gave alliin; extraction with ethanol and water at 25o
C led to allicin and no allin; and steam distillation (100o C) converted the alliin totally to
diallyl sulfides. Sulfur chemical profiles of Bulbus Allii Sativi products reflected the
processing procedure: bulb, mainly alliin, allicin; dry powder, mainly alliin. allicin;
volatile oil, almost entirely diallyl sulfide, diallyl disulfide, diallyl tisul fide, and diallyl
tetrasulfide; oil macerate, mainly 2-vinyl-[4H]-1.8-dithiin, 8-vinyl-[4H]-1,8-dithiin, E-
ajoene, and Z-ajoene .The content of alliin was also affected by processing treatment:
whole garlic cloves (fresh) contained 0.25-1.15% alliin, while material carefully dried
under mild conditions contained 0.7-1.7% alliin.
Gamma-glutamylcysteine peptides are not acted on by alliinase. On prolonged storage or
during germination, these peptides are acted on by y-glutamyl transpeptidase to forn1
thiosilfinates.
Dosage forms
Fresh bulbs, dried powder, volatile oil, oil macerates, juice, aqueous or alcoholic extracts,
aged garlic extracts (minced garlic that is incubated in aqueous alcohol (15-20%) for 20
months, then concentrated), and odorless garlic products (garlic products in which the
alliinase has been inactivated by cooking; or in which chlorophyll has been added as a
deodorant; or aged garlic preparations that have low concentrations of water-soluble
sulfur compounds).
The juice is the most unstable dosage form. Alliin and allicin decompose rapidly, and
those products must be used promptly.
Dried Bulbus Allii Sativi products should be stored in well-closed containers, protected
from light, moisture, and elevated temperature.
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Medicinal uses
Uses supported by clinical data
As an adjuvant to dietetic management in the treatment of hyperlipidaemia, and in the
prevention of atherosclerotic (age-dependent) vascular changes. The drug may be useful
in the treatment of mild hypertension.
Uses described in pharmacopoeias and in traditional systems of medicine
The treatment of respiratory and urinary tract infections, ringworm and rheumatic
conditions. The herb has been used as a carminative in the treatment of dyspepsia.
Uses described in folk medicine, not supported by experimental or clinical data
As an aphrodisiac, antipyretic, diuretic, emmenagogue, expectorant, and sedative, to treat
asthma and bronchitis, and to promote hair growth.
Pharmacology
Experimental pharmacology
Bulbus Allii Sativi has a broad range of antibacterial and antifungal activity.The essential
oil, water, and ethanol extracts, and the juice inhibit the in vitro growth of Bacillus
species,
Staphylococcus aureus
,
Shigella sonnei
,
Erwinia carotovora
,
Mycobacterium
tuberculosis
,
Escherichia coli
,
Pasteurella multocide
,
Proteus species
,
Streptococcus
faecalis
,
Pseudomonas aeruginosa
,
Candida species
,
Cryptococus species
,
Rhodotorula
rubra,
Toruloposis species, Trichosporon pullulans
, and
Aspergillus niger
.Its anti
microbial activity has been attributed to allicin, one of the active constituents of the drug.
However, allicin is a relatively unstable and highly reactive compound and may not have
antibacterial activity in vivo. Ajoene and diallyl trisulfide also have antibacterial and anti
fungal activities. Garlic has been used in the treatent of roundworm (
Ascaris
strongyloides
) and hookworm (Ancylostoma caninum and Necator americanus) (44=45).
Allicin appears to be the active anthelminthic constituent, and diallyl disulfide is not
effective.
Fresh garlic, garlic juice, aged garlic extracts, or the volatile oil all lowered chlesterol and
plasma lipids, lipid metabolism, and athero9genesis both in vitro and in vivo. In vitro
studies with isolated primary rat hepatocytes and human HepG2 cells have shown that
water-soluble garlic extracts inhibited cholesterol biosynthesis in a dose-dependent
manner . Anti hyperchlesterolaemic and anti hyperlipidameic effects were observed in
various animal models (rat, rabbit, chicken, pig) after oral (in feed) or intragastric
administration of minced garlic bulbs; water, ethanol, petroleum ether, or methanol
extracts, the essential oil; aged garlic extracts and the fixed oil. Oral administration of
allicin to rats during a 2-month period lowered serum and liver levels of total lipids,
phospholipids, triglycerides, and total cholesterol.Total plasma lipids and cholesterol in
rats were reduced after intraperitoneal injection of a mixture of diallyl disulfide and
diallyl trisulfide .The mechanism of garlic's anti hypercholesterolaemic and anti
hyperlipidaemic activity appears to involve the inhibition of hepatic
hydroxymethylglutaryl-CoA (HMG-CoA) reductase and remodeling of plasma
lipoproteins and cell membranes.At low concentrations (<0.5mg/ml), garlic extracts
inhibited the activity of hepatic HMG-CoA reductase, but at higher concentrations
(>0.5mg/ml)cholesterol biosynthesis was inhibited in the later stages of the biosynthetic
pathway (68). Alliin was not effective, but allicin and ajoene both inhibited HmG-CoA
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reductase in vitro (IC 50 = 7 and 9 mmol/l respectively) . Because both allicin and ajoene
are converted to allyl mercaptan in the blood and never reach the liver to affect
cholesterol biosynthesis, this mechanism may not be applicable in vivo. In addition to
allicin and ajoene, allyl mercaptan (50mmol/l) and diallyl disulfide (5mmol/l) enhanced
palmitate-inducedinhibition of chgolesterol biosynthesis in vitro. It should be noted that
water extracts of garlic probably do not contain any of these compounds; therefore other
constituents of garlic, such as nicotinic acid and adenosine, which also inhibit HmG-CoA
reductase activity and cholesterol biosynthesis, may be involved.
The anti hypertensive activity of garlic has bee demonstrated in vivo. Oral or intragastric
administration of minced garlic bulbs, or alcohol or water extracts of the drug, lowered
blood pressured in dogs, guinea pigs, rabbits, and rats. The drug appeared to decrease
vascular resistance by directly relaxing smooth muscle.The drug appears to change the
physical state functions of the membrane potentials of vascular smooth muscle cells.
Both aqueous garlic and ajoene induced membrane hyperpolarization in the cells of
isolated vessel strips. The potassium channels opened frequently causing
hyperpolarization, which resulted in vasodilatation because the calcium channels were
closed.The compounds that produce the hypotensive activity of the drug are uncertain.
Allicin does not appear to be involved, and adenosine has been postulated as being
associated with the activity of the drug. Adenosine enlarges the peripheral blood vessels,
allowing the blood pressure to decrease, and is also involved in the regulation of blood
flow in the coronary arteries; however, adenosine is not active when administered orally.
Bulbus Allii Sativi may increase production of nitric oxide, which is associated with a
decrease in blood pressure. In vitro studies using water or alcohol extracts of garlic or
garlic powder activated nitric-oxide synthase, and these results have been confirmed by
in vivo studies
Aqueous garlic extracts and garlic oil have been shown in vivo to alter the plasma
fibrinogen level, coagulation time, and fibrinolytic activity. Serum fibrinolytic activity
increased after administration of dry garlic or garlic extracts to animals that were
artificially rendered arteriosclerotic. Although adenosine was thought to be the active
constituent, it did not affect whole.
Garlic inhibited platelet aggregation in both in vitro and in vivo studies. A water,
chloroform, or methanol extract of the drug inhibited collagen-, ADP-, arachidonic acid-,
epinephrine-, and thrombin-induced platelet aggregation in vitro. Prolonged
administration (intragastric, 3 months) of the essential oil or a chloroform extract of
Bulbus Allii Sativi inhibited platelet aggregation in rabbits. Adenosine, alliin, allicin, and
the transformation products of allicin, the ajoenes; the vinyldithiins; and the
dialkyloligosulfides are responsible for inhibition of platelet adhesion and aggregation. In
addition methyl allyl trisulfide, a minor constituent of garlic oil, inhibited platelet
aggregation at least 10 times as effectively than allicin. Inhibition of the arachidonic acid
cascade appears to be one of the mechanisms by which the various constituents and their
metabolites affect platelet aggregation. Inhibition of platelet cyclic AMP
phosphodiesterase may also be involved.
Ajoene, one of the transformation products of allicin, inhibited in vitro plate-let
aggregation induced by the platelet stimulators-ADP, arachidonic acid, calcium
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