Gleditsia (PROSEA)

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Plant Resources of South-East Asia
Introduction

List of species

Gleditsia L.

Protologue: Sp. pl. 2: 1056 (1753); Gen. pl. ed. 5: 476 (1754).

Family: Leguminosae

Chromosome number: x= unknown; G. sinensis, G. triacanthos: 2n= 28

Major species

Gleditsia australis Hemsley ex Forbes & Hemsley,
G. sinensis Lamk,
G. triacanthos L.

Vernacular names

Honey locust (En).

Origin and geographic distribution

Gleditsia comprises about 14 species, of which 2-3 are native to eastern North America, 1 species is found in southern South America, and 1 species in Malesia; the majority of species are found in temperate and tropical Asia.

Uses

The uses of G. australis, G. japonica Miq. and G. sinensis are very similar. The fruits and seeds of the three species are important as a mucus-loosening and diuretic drug. A decoction of the leaves is used to bathe wounds. The root and bark are ingested as an anthelmintic and an antifebrile. The pods are said to be bechic and depurative, emetic and purgative; they are used to treat flatulence, chronic dysentery, as well as intestinal and urinary obstructions, and prolapse of the rectum. The thorns, dried and powdered are prescribed for swellings, especially on breasts, however, pregnancy is noted as a contra-indication. Likewise or in decoction they are used as a mouthwash for abscesses, or a wash for ulcers and skin diseases in general. The fruit pulp of G. triacanthos is used for catarrh of the lung. The pods of G. officinalis Hemsley, traded as "ya-tsao", are used to treat coughs and lung disorders.

Properties

Phytochemical investigations of the fruits of G. sinensis revealed the presence of a series of oleanane type triterpene saponins, acetylated with one monoterpenic acid (gleditsiosides A-D) or two monoterpenic acids (gleditsiosides E-G).

Several benzenoids were isolated from G. triacanthos including turgorine PLMF-4, turgorine PLMF-5, turgorine PLMF-6, 40-(3,6-di-O-sulpho-b-D-glucopyronosyl gallic acid and 40-(6-O-sulpho-b-D-glucopyranosyl gallic acid.

The anti-inflammatory activity of the aqueous extract from dried thorns of G. sinensis was investigated utilizing carrageenin-induced oedema, granuloma pouch and adjuvant arthritis in rats. The effects of this agent on vascular permeability and acetic acid-induced writhing in mice were also examined. Its anti-inflammatory activity on carrageenin-induced oedema was observed with oral administration. The aqueous extract from G. sinensis thorns, at 400 mg/kg for 7 days, showed significant inhibitory effects on granuloma and exudate formation in rats. In the method of adjuvant arthritis, the aqueous extract at 400 mg/kg, orally administered for 21 days, inhibited the development of hind paw oedema in rats. The aqueous extract also inhibited the increase in vascular permeability and the number of writhings induced by acetic acid in mice. The methanol (80%) extract exhibited tyrosinase inhibition at 100 μg/ml, which may be useful in cosmetics as a whitening agent.

Test results in the 1,1-diphenyl-2-picryl hydrazyl free radical generating system indicate that G. japonica may well prove to be a potential source of free radical scavengers. Gleditsia saponin C (a triterpene saponin) was isolated from G. japonica as an anti-HIV principle. It demonstrated inhibitory effects against HIV replication in H-9 cells with EC₅₀ values of 1.1 μM. Evaluation of the anti-HIV activities of the pro-sapogenins suggested that the unusual monoterpenyl moieties are essential for the anti-HIV activity. Derivatives of echinocystic acid, the aglycone of Gleditsia saponin C, were also prepared and evaluated: 3,16-di-O-acetylechinocystic acid was shown to be active at an EC₅₀ 2.3 μM.

The juice of G. triacanthos pods is reported to possess antibiotic activity. Furthermore, an enzyme inhibitor could be isolated from G. triacanthos, which inhibits chymotrypsin (a group of major proteolytic enzymes found in the pancreatic juice), but had no effect on other proteases e.g. trypsin.

Description

Trees, with trunk and branches armed with simple or branched thorns.
Leaves alternate, pinnate and/or bipinnate; petiole present; stipules minute, caducous; leaflets subopposite or alternate, slightly asymmetrical, often with a crenate margin; petiolule present.
Inflorescence axillary, racemose, solitary or fasciculate, rarely paniculate; bracts and bracteoles absent at anthesis; pedicel articulate.
Flowers perfect or imperfect, unisexual or bisexual, the plants dioecious or polygamous; hypanthium campanulate, lined with nectariferous tissue; calyx 3-5-lobed, subequal; petals 3-5, subequal, imbricate, not clawed; stamens 5-10, exserted in male and bisexual flowers, filaments free, somewhat unequal; ovary subsessile, rudimentary or absent in male flowers, 2-30-ovuled; style short; stigma terminal, 2-lobed.
Fruit an indehiscent or tardily dehiscent pod, oblong or elongate, compressed, variably coriaceous, 1-many-seeded.
Seed transverse, broadly ellipsoid to subquadrate, compressed, albuminous.

Growth and development

G. triacanthos may start bearing fruit from the fourth or fifth year of planting. Pods of G. triacanthos are distributed by water and wind.

Other botanical information

Linnaeus named the genus Gleditsia in honour of J.G. Gleditsch. In later publications the spelling Gleditschia is used. However, the original spelling is to be retained. Some controversy exists on the status of some of the South Chinese species of the genus, including G. australis, G. officinalis and G. sinensis. In some Vietnamese literature G. fera (Lour.) Merr., G. rolfei S. Vidal and G. sinensis are considered synonyms of G. australis, adding further confusion to uses of the species involved. The status of G. fera and G. rolfei in particular still causes confusion. Gleditsia is in general considered an archaic taxon and therefore placed near Ceratonia. Species of Gleditsia show an unusually high level of variability in many inflorescence and floral development characters.

Ecology

Gleditsia is found on damp sandy soils, on rich alluvial soils and on limestone. Most species tolerate atmospheric pollution and a range of soil types and pH.

Propagation and planting

The native North-American G. triacanthos, naturalized in Australia and various parts of Europe, can easily be propagated by seed, cuttings or suckers and is fairly fast-growing. Plants coppice vigorously when cut. Germination is enhanced by scarification.

Harvesting

Fruits of Gleditsia are collected when mature. Thorns are harvested throughout the year whenever the need arises.

Handling after harvest

The thorns of the various Gleditsia species are collected, sliced and dried, for later use. Likewise, fruits can be dried for later use.

Genetic resources and breeding

Breeding efforts in Gleditsia have concentrated on G. triacanthos for ornamental purposes.

Prospects

There is little prospect for Gleditsia in South-East Asia unless plants that are well-adapted to the tropics, are selected. Some biological effects of extracts are interesting e.g. anti-inflammatory, anti-HIV. Activity guided isolation procedures might yield new leads for drug development.

Literature

Kim, B.J., Kim, J.H., Kim, H.P. & Heo, M.Y., 1997. Biological screening of 100 plant extracts for cosmetic use (II): Anti-oxidative activity and free radical scavenging activity. International Journal of Cosmetic Science 19(6): 299-307.
Konoshima, T., Yasuda, I., Kashiwada, Y., Cosentino, L.M. & Lee, K.H., 1995. Anti-AIDS agents, 21. Triterpenoid saponins as anti-HIV principles from fruits of Gleditsia japonica and Gymnocladus chinensis, and a structure-activity correlation. Journal of Natural Products 58(9): 1372-1377.
Paclt, J., 1982. On the repeatedly confused nomenclature of Chinese species of Gleditsia Caesalpiniaceae. Taxon 31(3): 551-553.
Park, E.H. & Shin, M.J., 1993. Anti-inflammatory activity of aqueous extract from Gleditsiae Spina. Journal of the Pharmaceutical Society of Korea 37(2): 124-128. (in Korean)
Schnabel, A. & Wendel, J.F., 1998. Cladistic biogeography of Gleditsia (Leguminosae) based on NDHF and RPL16 chloroplast gene sequences. American Journal of Botany 85(12): 1753-1765.
Zhang, Z., Koike, K., Jia, Z., Nikaido, T., Guo, D. & Zheng, J., 1999. Triterpenoidal saponins acylated with two monoterpenic acids from Gleditsia sinensis. Chemical and Pharmaceutical Bulletin (Tokyo) 47(3): 388-393.

Selection of species

Authors

H.C. Ong