Page 75 - Pharmacognosy 2 PG303 (1)

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

The seeds if present are flattened ovoid, yellowish white to dark brown, 6 to
8 mms long, 4 to 5 mm wide and 2 mm thick. The seed is albuminous. showing a
narrow oily endosperm and a straight embryo of 2 oily cotyledons and small
radicle.
The drug has a slight odor and an intensely bitter persistent taste.

Microscopical Characters
Colocynth, the pulp i.e., the mesocarp and placentae, is formed of spongy
tissue composed of large, rounded parenchymatous cells almost devoid of contents,
with large intercellular spaces and having thin, cellulosic occasionally lignified
walls with oval or circular pitted areas at the junction of contiguous cells. The pulp
is traversed by bicollateral vascular bundles, having spiral and annular vessels, and
accompanied in the phloem by irregularly tubular laticiferous vessels.

The rind (epicarp) when present, shows an epidermis of polygonal, radially
elongated cells, the outer and radial walls are thickened and cuticularized,
occasional large anomocytic stomata are present. The epidermis is followed by
about 15 rows of thin-walled parenchyma forming the hypodermis. Within the
hypodermis is a layer of thick-walled lignified sclerenchyma. The outer cells are
small and have heavily thickened walls, while the inner is layered with thinner
walls, gradually merging into the parenchyma of the pulp.
The seed has a palisade-like epidermal cells being polygonal with straight
beaded anticlinal walls due to the presence of lignified bar-like thickenings. The
remainder of the seedcoat consists of a heavily thickened sclerenchyma (8-10 rows)
within which is a narrow layer of collapsed parenchyma. The cells of the innermost
layer of sclerenchyma have dome-shaped projections and lignified reticulate
thickening. The layer above this is very regular and the cells have stellate
projections laterally.
The embryo consists of thin-walled cellulosic cells containing fixed oil and
small aleurone grains.

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