Page 107 - PG 504-theoretical notes-phyto-1-2024-2025..

Clinical pharmacy PharmD program Third level Phytochemistry-1 (PG-504)

▪ Uronic acids: All true gums contain D-glucuronic acid; D-Galacturonic

acid is present only in gum tragacanth.

Properties: They swell in water to form either gels or viscous, sticky solution that

is acidic in reaction, and levorotatory and unfermented by yeast.

Differences between plant gums and dextrin:

Item Plant Gum Dextrin.

1) Structure Sugars + Uronic acids Dextrin

2) Reaction of Acidic Neutral.

solution

3) Optical Levo. Dextro.

rotation

4) Test: Pentoses Positive Negative.

5) Test: Uronic acid Positive “yellow with green Negative“blue ”

florescence”

1) Gum Arabic

Gum arabic is an exudate from the stem of Acacia specially Acacia senegal
(Family Leguminosae) in Sudan.

Collection: On the bark, a transverse incision is made to expose the cambium.

Within a month, phloem cells are produced in cambium. Gum tears are formed on

this and these are collected.

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