Page 7 - Pharmacognosy-I (02-06-06-102)

According to the disposition of the mesophyll, the leaf is
described as:

• Isobilateral: symmetric mesophyll showing palisade layer
abutting on both upper and lower epidermises.

• Dorsiventral: asymmetric mesophyll, showing only 1
palisade beneath the upper epidermis.

3-The vascular tissue:
Vascular system consists of vascular bundles formed of phloem
towards the lower surface of the leaf and xylem towards the upper
surface. The vascular tissue creates the skeleton of the leaf, and
they are termed as veins.

MEDICINAL AND PHARMACEUTICAL LEAVES

1. Medicinal leaves mainly used as Laxative:

SENNA LEAVES
Definition:
Senna leaf is the dried leaflets of Cassia acutifolia known as
Alexandrian or Khartoum senna, and Cassia angustifolia known as
Indian senna family (Fabaceae).

Senna powder:
It is characterized by:

• Fragments of epidermal cells, showing paracytic stomata.
• Non-glandular, unicellular warty hairs.
• Fragments of lignified pericyclic fibers accompanied by

crystal sheath.

Constituents:
-The major active constituents are anthraquinone glycosides
(2.50%) mainly sennosides A& B.

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