Appendices 

I

N

D

I

A

N

M

E

D

I

C

I

N

A

L

P

L

A

N

T

S

Dry flowers are stomachic. Seed oil is a stimulant, antiseptic, alterative in rheumatism and skin diseases (Indian Pharmacopoeia).

Berries are purgative, emollient and anthelmintic.

An extract of leaves is used in toothpastes. Neem oil is effective in the treatment of leprosy and skin diseases.

b) Homoeopathy:

c) Unani:

Neem finds use as a resolvent and blood purifier. Leaves expel wind, heal ulcers in urinary passages.

Used as an emmenagogue and in skin diseases.

Fruit is used as an astringent and in leprosy and bronchitis.

Chemistry :

The general class of natural products present in neem are triterpenes or limonoids. New limonoids are still being discovered in neem. Azadirachtin, salannin, meliantriol and nimbin are well known. The bitter constituent, the nimbin contains an acetoxy, a lactone, an ester, a methoxy and an aldehyde group. Nimbidin contains sulphur. The bark exudes a clean bright amber coloured gum which is collected in small tears or fragments. It contains a bitter alkaloid named "margosine". Leaves contain a small quantity of bitter substance of a similar character but much more soluble in water. This substance is a hydrate of the resin. Seeds contain 10% to 31% of a yellow bitter fixed oil with a strong disagreeable acrid taste. The volatile fatty acids probably consist of a mixture of stearic and oleic acids with a small amount of lauric acid.

Flowers have been found to contain a flavonoid. Nimbicetin is identical to kaempferol. In the dried bark the same bitter components as in the seed oil have been found and in the pericarp of the fruit a bitter principle bakayanin was found (Narayanan and Iyer, 1967).

Roy and Chatterjee (1921) analysed the oil and found the following constituents:

Sulphur 0.427%; a very bitter yellowish substance obtained from the alcoholic extract of the oil, which is supposed to be an alkaloid; resins; glucosides and fatty acids

Meliacins found in the seeds include gedunin, 7-desacetylgedunin, desace-tylnimbin and azedarachtin.

The seed oil mainly contains nimbidin, nimbin and nimbinin, which also occur in the stembark (Chatterjee et al., 1948).

Trunk bark yields 0.04% nimbin, 0.001 nimbinin, 0.4% nimbidin, and essential oil 0.02%.

Tetracyclic triterpenoids and their derivatives have been isolated from the stem bark (Siddiqui et al.,1988) along with tricyclic diterpenoids (Ara et al., 1988).

The toddy or sap contains glucose, sucrose, gums and colouring matter.

Nimbin and nimbidin have been found to have antiviral activitiy. They affect potato virus X, vaccinia virus, and fowl pox virus.

Neem oil suppresses several species of pathogenic bacteria such as Staphylococcus aureus and Salmonella typhosa

Neem showed no antibacterial activity against Escherichia coli, Enterobacter, Pseudomonas aeruginosa, Citrobacter, Klebsiella pneumoniae, Proteus mirabilis, Proteus morgasi, Pseudomonas EO1 and Streptococcus faecalis.

The growth of all strains of Mycobacterium tuberculosis and Micrococcus pyogenes var. aureus was inhibited by a concentration of 1:800,000 and the growth of Shigella typhosa, Salmonella paratyphi and Vibrio cholerae was inhibited by a concentration of 2mg/l. Nimbidin from seed oil has shown potent anti-inflammatory activity in experimental animals.

Neem oil (2.5ml), and nimbidin (200mg/kg body weight) lowered the blood sugar level by 24 and 26 per cent respectively at the 5th hour of feeding.

Aqueous extracts of seeds and leaves contain sodium nimbinate (triterpene) which showed antifertility activity (Sharma and Saksena, 1959; Garg et al., 1970; Farnsworth and Waller, 1982).