Agriculture Reference
In-Depth Information
fruit is also favored as a laxative and for the treatment of urinary diseases, leprosy, and intestinal
worm infestation. The stem and root yield bitter but effective chewing sticks.
Azadirachta
is a native to India, and it is employed widely in the Indochina region for a variety
of medicinal uses and nonmedicinal purposes. Perry
226
indicated that a tincture of the bark is help-
ful for people with chronic malaria or with jaundice and generalized fatigue and for the treatment of
fevers following injuries. It was also stated that the tincture of the leaves gives an aperitif but consti-
pating tonic and a stimulating rub to treat bruises, sprains, or muscular pains (see Der Marderosian
and Liberti
127
for other uses of this plant in Asia). A proprietary product, Silvose, containing extract
of the bark of
Azadirachta
is claimed to reduce dental caries and inflammation of the mouth when
used as an ingredient in dental preparations. Powdered plant parts and extracts of neem have been
incorporated into toothpastes and tooth powders.
227
Infusion or tincture of
Azadirachta
is listed as
a bitter;
205
for this purpose, the usual dose is 15 to 30 ml of 1-in-20 c. infusion, or 4 to 8 ml of a
1-in-15 c. dilutions tincture.
Methods of Preparations, Administration, and Doses —
In traditional medical practice, the
leaves, stem bark, and root are used for the treatment of malaria in the form of an aqueous decoc-
tion. The selected part is usually reduced to small sizes, placed in a suitable container with water,
and set aside to macerate for a period ranging from 1 day to several weeks. Portions of the extract
are often dispensed as soon as an acceptable brew is achieved, and the marc replenished with fresh-
water. The average concentration is about 100 ml, taken 2 or 3 times a day for about 2 to 3 days. The
drug can also be prepared by macerating the coarsely powdered plant part for a few hours in cold
water and using the hand to press out fluid from the marc. In urban areas, the drug is prepared either
as a decoction with hot water or as an alcoholic extract.
Complementary to the oral therapy is steam treatment, in which the patient is covered with
a thick blanket or cloth and subjected to the vapors from a boiling pot of herbs.
Azadirachta
is a
common ingredient in such hot pot herbs. Other ingredients in the steam therapy include the leaves
of
Cymbopogon citratus
(lemon grass),
Psidium guajava
(guava),
Mangifera indica
(mango), and
Hyptis suavelens.
The drug is used prophylactically once a month in the form of a weak infusion
called “neem tea.”
Constituents —
All plant parts have been shown to contain some bitter principles, composed
of nimbin, nimbidin, nimbinin desacetylnimbin, and structurally related compounds. The seed oil
contains about 45% of these bitter substances, the stem bark yields 0.04%, while the fruit pulp and
leaves contain about 25%.
228,229
Salannolide, a meliacin with a unique feature by the presence of
a hydroxybutenolide side chain in place of the usual furan ring attached at C-17, has been found
to be one of the bitter principles of neem seed oil.
230
A number of other nortriterpenoids, melia-
cins, have also been isolated from the plant. Kraus and his colleagues have reported the presence
of azadirone and nimbin/salannin-type compounds from the seeds of neem.
231
They also isolated
pentanortriterpenoids (nimbadiol and 6-O-acetylnimbandiol) for the first time in nature, from the
seed oil, leaves, and stem bark.
232
Perhaps the most studied constituent of the seed is azadirachtin,
which was isolated together with meladanin by Connolly in 1968 and was later found to inhibit the
feeding response of the desert locust.
233
The structure of this tetranortriterpenoid was determined
by Butterworth and others using modern chemical methods, including spectroscopy.
234
The seeds
have also been shown to contain tiglic acid (5-methyl-2-butanoic acid), which is believed to be
responsible for the distinctive odor of the oil.
235
The fatty acid (diethernoid) present in the seed is
said to aid the ripening of seeds. The gum lavones, which is a good emulsifying agent, is a unique
gum by having D-glucosamine, an amino sugar, as one of its constituents. Other constituents of the
gum include other simple sugars (such as fructose, rhamnose, xylose, and mannose), uronic acid
and proteinaceous materials (e.g., amino acids and dipeptides). The plant contains relatively large
amounts of carotene and vitamin C.
236
Flavonoids have also been found in
Azadirachta.
Simple flavonoids, such as kaempferol and
quercetin, have been isolated from the flowers. The chloroform-soluble fraction of the ethanolic
