Carbohydrates and Proteins
The gum exudate from the stem was found to be a very complex condensate of proteins and
heteropolysaccharides. The proteins are linked very tightly to the polysaccharides, which
constitute the major components. The nature of these complexes hampers the total
elucidation of the structure of the gum. The material is well protected against enzymatic attack
and the usual chemical or physical techniques applied to separate the proteins from the
polysaccharide matrix are not very successfull.107. A variety of smaller gum components,
however, have been identified after more drastic degradation methods. D-glucose,
D-glucuronic acid, L-arabinose, L-fucose,I02 mannose, xylose, rhamnose, I
D-glucosamine,81 the aldobiouronic acids,16 4-0-(4-0-methyl-a¬D-glucopyranosyl uronic
acid)-D-galactose and 4-0-(a-D-glucopyranosyl uronic acid)-D¬galactose I and aldotriouronic
acidsl6 were reported. The amino acid composition of the gum was investigated 1.2. The
most abundant amino acid was aspartic acid, while considerable amounts of serine and
threonine were also found. A glycopeptide from the gum after pronase digestion had
molecular weight of about 2000 D. The carbohydrate moiety consisted of arabinose,
galactose and glucosamine in a molar ratio of 2.96:2.0:4.9. The protein part (about 40 weight
per cent) was composed of eight different amino acids 107.
The gum exudate from the stem was found to be a very complex condensate of proteins and
heteropolysaccharides. The proteins are linked very tightly to the polysaccharides, which
constitute the major components. The nature of these complexes hampers the total
elucidation of the structure of the gum. The material is well protected against enzymatic attack
and the usual chemical or physical techniques applied to separate the proteins from the
polysaccharide matrix are not very successfull.107. A variety of smaller gum components,
however, have been identified after more drastic degradation methods. D-glucose,
D-glucuronic acid, L-arabinose, L-fucose,I02 mannose, xylose, rhamnose, I
D-glucosamine,81 the aldobiouronic acids,16 4-0-(4-0-methyl-a¬D-glucopyranosyl uronic
acid)-D-galactose and 4-0-(a-D-glucopyranosyl uronic acid)-D¬galactose I and aldotriouronic
acidsl6 were reported. The amino acid composition of the gum was investigated 1.2. The
most abundant amino acid was aspartic acid, while considerable amounts of serine and
threonine were also found. A glycopeptide from the gum after pronase digestion had
molecular weight of about 2000 D. The carbohydrate moiety consisted of arabinose,
galactose and glucosamine in a molar ratio of 2.96:2.0:4.9. The protein part (about 40 weight
per cent) was composed of eight different amino acids 107.
Sulphurous Compounds
A number of cyclic tri- and tetrasulfides (130 and 131) were identified from the steam
distillate of the fresh matured leaves and pure neem oil by GC-MS analysis.110 Several di-
and trisulphides were also identified by capillary GC-MS analysis of the headspace volatiles
from crushed seeds.17 Di¬n-propyl disulphide was shown to be the major compound. The
structures of two of the reported constituents were reassigned. 101 The steam volatiles of
neem oil were shown to possess contraceptive action and several constituents were
identified.12O The volatile constituents so far identified in neem seeds/oil are given in Table
10.
A number of cyclic tri- and tetrasulfides (130 and 131) were identified from the steam
distillate of the fresh matured leaves and pure neem oil by GC-MS analysis.110 Several di-
and trisulphides were also identified by capillary GC-MS analysis of the headspace volatiles
from crushed seeds.17 Di¬n-propyl disulphide was shown to be the major compound. The
structures of two of the reported constituents were reassigned. 101 The steam volatiles of
neem oil were shown to possess contraceptive action and several constituents were
identified.12O The volatile constituents so far identified in neem seeds/oil are given in Table
10.
Table 10. Steam volatile constituents of neem seed/oil identified by GC-MS
Sl. Constituent Relative Sl. Constituent Relative
No. abundance No. abundance
(%) (%)
1. 2-Methyl-2-Pentanal Traces 24 Ethyl propyl disulfide 0.1
2. 2.4 Dimethyllthiophene Traces 25 2-Phenylethanol 0.3
3. 3,4-Dimethylthiophene 0.1 26 1,2,3-Trithiacyclohexane 7.8
4. Methyl n-propyl disulfide Traces 27 5-Methyl-2-furfuryifuran 1.4
5. Methyl-I-propenyl disulfide Traces 28 Trithiacyclononane 2.4
6. Methyl butyl disulfide Traces 29 Longifolene 0.1
7. Di-n-propyl disulfide 75.75 30 2-Methyldecalin 0.6
8. n-Propyl cis-I-prpenyl disulfide 2.76 31 (7)8,9,10(11)-Tetrahydro 0.2
9. n-Propyl trans-I-propenyl disulfide 9.67 naphtho(2,1-B)-thianaphthene
10. Methyl n-propyl trisulfide Traces 32 Nona-2,4-dienal 0.3
11. Methyl cis-1-propenyl trisulfide Traces 33 1,2-Bis(2-propyl merc.) etha. 0.2
12. Methyl trans-I-propenyl trisulfide Traces 34 Hexahydrofarnesol 0.2
13. 2-Nonanone Traces 35 Methypalmitate 0.6
14. n-Propyl butyl disulfide 0.38 36 Ethypalmitate 1.2
15. I-Propenyl butyl disulfide Traces 37 Palmitic acid 17.5
16. 2-Undecanone Traces 38 Farnesyl acetate 0.3
17. Di-n-propyl trisulfide 2.19 39 Methyl stearate 0.3
18. n-Propyl 2-propenyltrisulfide 0.62 40 Stearic acid 16.1
19. Di-cis-I-propenyltrisulfide 0.42 41 Ethyl oleate 0.9
20. Di-trans-I-propenyltrisuflide 0.23 42 cis-3,5-Diethyl-1,2,4-trithiolane 8.5
21. Di-n-propyl tetrasulfide Traces 43 trans-3,5-Diethyl-1,2,4-trithio. 14.1
22. n-Propyl cis-I-prpneyl tetrasulfide 0.11
23. n-Propyl trans-I-propenyl
tetrasuflide 0.10
No. abundance No. abundance
(%) (%)
1. 2-Methyl-2-Pentanal Traces 24 Ethyl propyl disulfide 0.1
2. 2.4 Dimethyllthiophene Traces 25 2-Phenylethanol 0.3
3. 3,4-Dimethylthiophene 0.1 26 1,2,3-Trithiacyclohexane 7.8
4. Methyl n-propyl disulfide Traces 27 5-Methyl-2-furfuryifuran 1.4
5. Methyl-I-propenyl disulfide Traces 28 Trithiacyclononane 2.4
6. Methyl butyl disulfide Traces 29 Longifolene 0.1
7. Di-n-propyl disulfide 75.75 30 2-Methyldecalin 0.6
8. n-Propyl cis-I-prpenyl disulfide 2.76 31 (7)8,9,10(11)-Tetrahydro 0.2
9. n-Propyl trans-I-propenyl disulfide 9.67 naphtho(2,1-B)-thianaphthene
10. Methyl n-propyl trisulfide Traces 32 Nona-2,4-dienal 0.3
11. Methyl cis-1-propenyl trisulfide Traces 33 1,2-Bis(2-propyl merc.) etha. 0.2
12. Methyl trans-I-propenyl trisulfide Traces 34 Hexahydrofarnesol 0.2
13. 2-Nonanone Traces 35 Methypalmitate 0.6
14. n-Propyl butyl disulfide 0.38 36 Ethypalmitate 1.2
15. I-Propenyl butyl disulfide Traces 37 Palmitic acid 17.5
16. 2-Undecanone Traces 38 Farnesyl acetate 0.3
17. Di-n-propyl trisulfide 2.19 39 Methyl stearate 0.3
18. n-Propyl 2-propenyltrisulfide 0.62 40 Stearic acid 16.1
19. Di-cis-I-propenyltrisulfide 0.42 41 Ethyl oleate 0.9
20. Di-trans-I-propenyltrisuflide 0.23 42 cis-3,5-Diethyl-1,2,4-trithiolane 8.5
21. Di-n-propyl tetrasulfide Traces 43 trans-3,5-Diethyl-1,2,4-trithio. 14.1
22. n-Propyl cis-I-prpneyl tetrasulfide 0.11
23. n-Propyl trans-I-propenyl
tetrasuflide 0.10
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