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Herba Chelidonii
Microscopic characteristics
The transverse section of the stem is circular, lightly ribbed, covered by
a thin cuticle. The epidermal cells have very thick walls. One or two layers
of thin-walled chlorenchymatous hypodermis partly transformed
into collenchyma. Cortex consists of polygonal, very thick-walled cells
(sclerenchyma). Very few covering trichomes of 5–10 cells, long, uniseriate,
thin-walled. Stomata anomocytic, not numerous. The petiole has a
stem-like structure. The chlorenchyma is almost entirely transformed in
collenchyma. There are multicellular, very long covering trichomes. Leaf
epidermis with sinuous anticlinal walls. Very few covering trichomes,
long, uniserate of 5–10(20) thin-walled cells (striated cells, cellular nucleus
visible). Area with papilla on the epidermis. Stomata anomocytic, exclusively
on the lower epidermis. Hydathodes at the lobed margins. The
mesophyll is differentiated into a layer of palisade and two layers of
spongy parenchyma (transverse section), made up of thin-walled chlorenchyma.
Cells of spongy parenchyma have aquifer stomata. Midrib
with 1- or 2-layered collenchyma below the upper epidermis and thinwalled
parenchymatous ground tissue. Palisade ratio 7.6:13.22. Calcium
oxalate absent. Larger veins associated with dark brown articulated nonbranched
laticifers. Latex cells especially in vascular region. Pollen grains
spherical, with a finely pitted exine and 3 furrows, about 35 µm in diameter
(2, 5, 30, 37–39).
Powdered plant material
The powder shows the characteristic elements of stems, leaves and flowers:
numerous fragments of leaves, the epidermal cells with sinuous walls;
anomocytic stomata occur on the abaxial surface only; fragments of covering
trichomes or entire ones. Groups of vascular tissue from the petiole
and main veins with attached laticifers.
General identity tests
Macroscopic and microscopic examinations, thin-layer chromatography,
paper chromatography and high-performance liquid chromatography for
the presence of the characteristic alkaloids (1, 2, 12, 40). The addition of
two or three drops of Mayer reagent to the acidic extract results in a purple
precipitation of needles (14). Addition of two or three drops of
Dragendorff’s reagent to the acidic extract results in a yellow precipitate
(41). Under ultraviolet light at 365 nm without treatment, the thin-layer
chromatogram of Herba Chelidonii usually shows 2 or 3 blue and yellow-green
fluorescent zones at Rf approximately 0.2; directly above this
is the narrow yellow-green zone of chelerythrine, followed by the tailing
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