Page 36 - Pharmacognosy 2 PG303

Pharmacognosy-2 (PG303) Level 2 Clinical Pharmacy-Pharm D

Trichomes of different types are present (Anise, Cumin, Senna & Compositae
fruits).

The hypodermis may be thin and parenchymatous (Capsicum),
collenchymatous (Datura, Vanilla) or sclerenchymatous interrupted by
parenchyma (Cubebs) or thick layers of parenchyma and sclerenchyma
(Colocynth).

The Mesocarp
It corresponds to the mesophyll of the carpel (modified leaf) and is
responsible for the variation appears in thickness of the pericarp. It may be very
thin as in achenes or very thick as in succulent fruits. It consists mainly of
parenchyma and traversed by vascular strands. Sometimes, the mesocarp contains
sclerenchyma (Coriander), fibers accompanying the vascular bundle (Cardamom),
scattered sclereids (Pimento) or maybe fibrous (Coconut). The mesocarp may
show other elements such as lignified idioblasts (Lobelia), reticulate parenchyma
(Fennel), oil cells (Pepper), oil glands (Citrus), vittae (Umbelliferous fruits) and
laticiferous elements (Poppy). The mesocarp cells may contain starch (Pepper),
Calcium oxalate crystals (Capsicum & Vanilla) or oil droplets (Capsicum),
mucilage (Malva) or hesperidin crystals (Citrus fruits).

The Endocarp
It may be membranous (Date) or thick and either leathery (Cassia pod) or
woody (Olive). It forms the inner epidermis of the pericarp, which is sometimes
accompanied by one or more layers of modified endocarpal hypodermis (Pepper).

The Inner epidermis exhibits marked characters, which are very diagnostic,
and provides an important mean in differentiating medicinal fruits. The inner
epidermis may be lignified (Hyoscyamus) or show islands of sclerenchyma in the
parenchymatous epidermis (Capsicum) or formed of groups of narrow parallel cells
(Umbelliferous fruits) or formed of hair-like secreting cell (Vanilla) or filled with
the juice (Citrus fruits). It shows occasional stomata and trichomes (Hyoscyamus).

The hypodermis of the endocarp may be formed of a single layer (Cubebs)
or of several layers of sclerenchyma (Olive) or is formed of a single layer of giant
cells (Capsicum).

UMBELLIFEROUS FRUITS
Official fruits comprise some fruits related to a single family which is the
family Umbelliferae. Accordingly, these fruits have common macr- and micro-
scopical characteristics. The study of these common features eases the study of
these fruits with reference to the main differences between them.

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