Abstract
Digestion with endo-α-(1→4)-polygalacturonase liberated the enzyme-resistant region
(PG-1c) as an active site of the anti-complementary and mitogenic pectic polysaccharide
(GR-2IIc) from Glycyrrhiza uralensis . Partial acid hydrolysis of PG-1c resulted in acidic oligosaccharides, and methylation
analysis and GC-MS analysis of the acidic oligosaccharides suggested that PG-1c comprised
a rhamnogalacturonan core such as
as the acidic moiety. Degradation of uronic acids by lithium decreased the anti-complementary
and mitogenic activities of PG-1c. Although the products from PG-1c were still active,
the methylglycoside of α-L -Rha-(1→4)-α-D -GalA-(1→2)-α-L -Rha-(1→4)-α-D -GalA did not show both activities.
The products obtained by the lithium degradation from PG-1c gave fractions containing
various neutral oligosaccharide-alditols. Among these fractions the longest and the
short oligosaccharide-alditol fractions had relatively potent anti-complementary activity,
whereas all oligosaccharide-alditol fractions expressed weak but significant mitogenic
activity. GC-MS analysis indicated that the short oligosaccharide-alditol fraction
contained various kinds of di- to tetrasaccharide-alditols. However, malto-oligosaccharide-alditols,
and malto-, isomalto-, and laminari-oligosaccharides did not show anti-complementary
and/or mitogenic activities, and these results suggested that certain neutral carbohydrate
chains in PG-1c were responsible for the expression of mitogenic activity as well
as anti-complementary activity of PG-1c.
Key words
Glycyrrhiza uralensis
- Fabaceae - pectic polysaccharide - ramified region - anti-complementary activity
- mitogenic activity - active neutral carbohydrate chains
