Organizing co mmittee

 
 

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Poster presentation 
156 
PECTIN SUBSTANCES OF Scutellaria adenostegia AND Scutellaria 
comosa AND THEIR ANTIMICROBIAL ACTIVITY 
A. Siddikova, R. K. Rakhmanberdyeva, M. H. Malikova 
 
S.Yu. Yunusov Institute of the Chemistry of Plant Substances Academy of sciences of the 
Republic of Uzbekistan st. Mirzo-Ulugbek, 77, 100170 Tashkent 
e-mail: [e-mail],
 (90)318 65 68 
From aerial parts of 
Scutellaria adenostegia
and 
Scutellaria comosa
by extraction 
with 0.5% solutions of ammonium oxalate and oxalic acid the pectin substances with 
yield PS-Sa- 4.3% and PS-Sc-3.5% respectively were isolated.
PS are amorphous powders of light yellow colour, completely soluble in water, 
forming a viscous solution with η
rel 
- 3.18 and 5.25 (p1%;0.1% H
2
O). The molecular 
weight of the pectins is 310 and 288 kDa, respectively. 
Table 1. Pectin substances of 
S. adenostegia 
and
 S. comosa
PS 
Monosaccharide composition, % 
UAc (%) Kc,% Ke,% DE % 
Gal
Glc 
Ara 
Xyl 
Rhа 
PS-Sa 
13.4 
4.6 
67.4 
- 
19.2 
90 
9.0 
10.6 
54.0 
PS-Sc 
5.6 
1.0 
11.7 
- 
5.5 
85 
2.7 
2.16 
44.4 
To determine the monosaccharide composition of PS hydrolysed with 2 n H
2
SO
4
, 
100
℃
, 24 h and identified mainly galacturonic acid, rhamnose, arabinose, glucose and 
galactose. Table 1 shows that the pectin substances differ in the quantitative content of 
monosaccharides. In PS-Sa the main monosaccharide is arabinose (67.4%). 
By titrometric analysis the content of free (Kc) and - esterified carboxyl (Ke) groups 
was established (Table 1). The degree of esterification (DE) of PV-Sa was 54% and PS-
Sc - 44.4%. Consequently, PV-Sa belongs to highly esterified and PS- Sc to low 
esterified pectins. The study of PS by IR- spectroscopy identified a number of the 
following characteristic absorption bands: 832 cm
-1
characteristics of pectins having α-
configuration of glycosidic bonds between D- GalA residues and 889 cm
-1
characteristics of 1,4 type of this bond. An absorption band in the region of 1749 cm
-1
shows the oscillation of the carboxylic group and 1370 cm
-1
shows the presence of 
methoxy groups. Ionized carboxyl bound to metals is reflected by absorption bands of 
1420 and 1601 cm
-1
.
The antimicrobial activity of pectin substances against opportunistic pathogens was 
studied. The results showed that PV-Sa and PS-Sc effectively inhibited the growth of 
Pseudomonas aeruginosa 003841/114 (17 and 15 mm), Proteus mirabilis 9 (16 mm), 
and Bacillus subtilis VCM (13 and 14 mm), but both pectins had no inhibiting effect on 
the growth of 
Escherichia coli
002673/477 and 
Candida albicans
. It should be noted 
that PS-Sa showed sensitivity to 
Staphylococcus aureus
and the diameter of the growth 
inhibition zone was 17 mm.
Thus methoxylated pectins with antimicrobial activity were isolated from the aerial