Standardized Common
Name: Licorice
Other Common Names: Liquorice, Persian
Licorice, Russian Licorice, Spanish Licorice, Turkish Licorice
Family: Fabaceae
(Leguminosae)
Taxonomy: Glycyrrhiza
includes about 18 species, ranging from Eurasia to North and South America and
Australia. Many, if not most of these are used medicinally. According to Herbs
of Commerce, Glycyrrhiza echinata L. may be sold interchangeably
with G. glabra as “Licorice.” Contrarily, the United States National
Formulary states that “Licorice” may include G. glabra and G.
uralensis Fisch. ex DC., the latter of which is kept separate as Chinese
Licorice by Herbs of Commerce. The description herein pertains primarily
to G. glabra, which is by far the most common cultivated species.
This species may be divided into two or more
varieties. The most important is the European plant, widely cultivated from
China to North America, which normally has long stolons or rhizomes. It is sometimes
termed var. typica Regel & Herd. in pharmacognostic literature, but
would be more properly called var. glabra. The West Asian var. glandulifera
(Waldst. & Kit.) A. I. Galushko (Russian licorice), alternatively called
subsp. glandulifera (Waldst. & Kit.) Ponert, lacks stolons and is
often wild-collected.
Description: Perennial herb, with
taproots to 1 m long and sometimes with horizontally spreading rhizomes or
stolons to 2 m long, multiple branches arising at base, 0.5–1.5(–2.0) m tall;
stems pubescent. Leaves alternate, pinnately compound with a terminal leaflet,
(3–)4–8(–9) pairs of lateral leaflets; leaflets 2.0–4.0(–5.5) cm long,
short-petiolate, elliptical to oblong or ovate, sometimes with sticky coat of
glandular hairs; bases somewhat rounded to tapering; apices obtuse, sometimes
mucronulate; margins entire. Inflorescences racemose, borne in leaf axils,
curving upwards, 5–15 cm long. Calyx slightly bilabiate, 5-lobed; corolla 8–12
mm long, pale violet to lilac or rarely yellowish, 5-petaled, bilaterally
symmetrical with upper petal central and largest, the lowermost 2 petals fused
at apex into keel; stamens 10, the lower part of all filaments fused or nine
filaments fused and one separate; ovary 1-carpellate. Fruit a legume, narrowly
oblong, 1.5–3.0 cm long, brown, (1–)3–5(–6)-seeded, laterally compressed
between seeds and the margins slightly constricted; seeds broadly elliptical,
laterally compressed.
Parts
in Commerce:
Roots and stolons, if present
Identification: The following
description applies primarily to the cultivated European var. glabra
(“var. typica”).
- Thickened root
crown produces multiple very long taproots and slender stolons (or
rhizomes), which are usually cut into shorter segments
- 0.5–2.0(–3.0) cm
in diameter, nearly cylindrical
- Outer bark
variable in color, grayish to dark reddish-brown or dark brown,
longitudinally wrinkled by drying; sometimes peeled off at harvest
- Stolons bear
occasional small dark buds and small roots at nodes; bark sometimes has
lenticels
- Fracture fibrous,
the wood of cut pieces easily splitting longitudinally
- Inner portions
lemon-yellow
- Stolon in
cross-section shows several-layered brownish cork (if not peeled); yellow
to yellowish gray phelloderm, narrow cortex and thick ring of secondary
phloem with numerous narrow radiating strands of phloem separated by
parenchyma rays; distinct cambial region several cells thick; yellow wood
with numerous narrow xylem rays separated by narrow parenchyma rays; small
yellow pith
- Root
cross-section lacks pith
- Odor weak,
characteristic
- Taste distinctly
sweet, with very little bitterness or acridity
Russian
and Southwest Asian material (such as var. or subsp. glandulifera)
differs from the above in several features:
- Thick rootstock
often included, to 10 cm in diameter, bearing buds and stem remains, with
a central pith
- Roots thicker,
usually 1–5 cm in diameter
- Stolons absent
(so no long narrow pieces have pith)
- Bark purplish,
often scaly
- Taste sweet but
with a bitter note
Adulterants: Material in modern
commerce is cultivated, so confusion with other species virtually never occurs.
Glycyrrhiza uralensis (Chinese Licorice, also termed Manchurian
Licorice) can be distinguished by its dark brown, peeling cork, curved
parenchyma rays in the phloem, and lacunae (large pores or intercellular
spaces) in the wood. It is less sweet and more bitter than G. glabra.
References:
Evans WC. Trease and Evans’ Pharmacognosy, 14th ed. London: WB Saunders
Company Ltd.; 1996:305–308.
Wichtl M, ed. Herbal Drugs and
Phytopharmaceuticals, 3rd English
ed. Stuttgart: medpharm Scientific Publishers and Boca Raton, FL: CRC Press;
2004:347–351.
World Health
Organization. WHO Monographs on Selected Medicinal Plants. Vol. 1. Geneva: World Health Organization;
1999–2002:183–194.
Yeo PF. Glycyrrhiza. In: Tutin TG, Heywood VH, Burges NA, et al.,
eds. Flora Europaea. Vol. 2. Cambridge: Cambridge University
Press; 1968:127.
Youngken HW. Text-Book of Pharmacognosy, 5th ed. Philadelphia, PA: The
Blakiston Company; 1943:428–434.
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