Coriaria intermedia (PROSEA)
Coriaria intermedia Matsum.
- Protologue: Bot. Mag. Tokyo, Bot. Soc. 12: 62 (1898).
- Family: Coriariaceae
- Chromosome number: 2n= 40
Coriaria japonica A. Gray subsp. intermedia (Matsum.) T.C. Huang (1992).
- Philippines: baket, buakat, bikit (Igorot).
Origin and geographic distribution
Taiwan and the Philippines (northern Luzon).
C. intermedia is used in Taiwan to treat gastro-intestinal disorders, rheumatism and cancer of the uterus. In the Philippines, a decoction of the leaves and fruits is considered deadly poisonous. Other Coriaria species are also used medicinally, e.g. C. papuana Warb. as an emetic in Papua New Guinea, and C. myrtifolia L., which is sometimes used in southern Europe as an intestinal astringent and for the preparation of astringent compresses. However, caution is required when using Coriaria as a medicinal plant, because of the presence of toxic principles.
Coriaria species have been used in various regions of the world for tanning and dyeing blackish. Several of them possess root nodules with atmospheric nitrogen-fixing properties and may be useful in planting programmes for erosion control.
C. intermedia and many other Coriaria species contain bitter, toxic lactones and produce large amounts of ellagitannins. The toxic principles are picrotaxan-type sesquiterpenes such as coriamyrtin, corianin, coriatin and tutin. These have convulsive, insecticidal and ichthyotoxic activities. Coriamyrtin, which is present in C. intermedia fruits (up to almost 0.2%), is a bulbar and medullar stimulant. Symptoms of intoxication include epileptiform convulsions, myosis and dyspnoea; a coma might follow, as well as death by respiratory or cardiac arrest. In China, a mixture of the crystalline sesquiterpenes, including coriamyrtin and tutin, has been used by muscle injection for the treatment of catatonia; it is applied as a shock therapy for schizophrenia. Glycosides of the flavonols kaempferol and quercetin were present in all Coriaria species investigated. The seeds contain much fatty oil, coriolic acid being the main fatty acid. Honey produced from Coriaria may be toxic, as reported from New Zealand.
Leaves of C. japonica are known to show antitumour and antiviral properties.
A shrub up to 3 m tall; roots forming nodules. Leaves decussately opposite, simple and entire, oblong to slightly ovate, (3-)5-7 cm × 1.5-2.5 cm, cuneate at base, acute at apex, glabrous, 3-veined; petiole c. 2 mm long; stipules absent, but near the leaf axils numerous minute emergentia often present. Inflorescence consisting of subaxillary fascicles of 1-3 racemes 4-10 cm long, with ovate bracts up to 5 mm long. Flowers bisexual or unisexual, regular, 5-merous, yellowish-green; pedicel 2-7 mm long; sepals free, broadly ovate, c. 3 mm long, persistent; petals free, shorter than sepals, accrescent and becoming fleshy; stamens 10; carpels 5, free, 1-celled, each with a papillose style. Fruit (pseudo-fruit) consisting of laterally compressed achenes, more or less enclosed by the fleshy-accrescent petals, up to 5 mm in diameter. Seeds one per achene, compressed.
When plants start flowering, the first inflorescences consist of male flowers, followed by racemes of female flowers, which again overlap slightly with a second phase of male ones. The flowers with exerted stamens and styles are adapted to wind pollination. The fleshy pseudo-fruits are probably dispersed by birds.
Coriaria comprises about 20 species with a much interrupted distribution: the West-Mediterranean region of Europe and northern Africa, the Himalayas, eastern Asia, New Zealand, and western South America and Central America. In Malesia, 2 species are found: C. intermedia in the Philippines, and C. papuana in Papua New Guinea. C. intermedia is closely allied to C. japonica A. Gray and is even considered by some authors to be conspecific.
C. intermedia occurs in thickets, open forest, on sunny and stony slopes, and often in dry riverbeds and watercourses, in the Philippines in the mountains at 1400-2400 m altitude. In general, Coriaria species are often pioneer plants, growing gregariously in exposed locations.
Management Experiments with C. nepalensis Wallich in India showed that propagation by cuttings is possible, but with a maximum rooting success of only 40% when using growth promotors.
Although C. intermedia has a limited distribution, its pioneer character would seem to protect it sufficiently against threats.
The possibilities for using C. intermedia as a medicinal plant seem to be limited due to its toxicity. However, some interesting properties found in Coriaria species warrant more research, such as the antitumour and antiviral properties of the leaves.
142, 247, 760, 929.
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