2777

12(3): Medicinal and poisonous plants 3

Morinda L.

Sp. pl. 1: 176 (1753); Gen. pl. ed. 5: 81 (1754).

RUBIACEAE

x = 11; Morinda citrifolia: 2n = 22, 44, Morinda umbellata: 2n = 22

Morinda comprises about 50 species and is distributed in all tropical regions: Central and northern South America, tropical Africa, Madagascar and the Mascarene Islands, tropical Asia (from India and Sri Lanka eastwards), northern and north-eastern Australia, Melanesia and Polynesia. Areas with the largest species diversity include South-East Asia and New Caledonia. The number of species in the Malesian region is estimated at 20.

Morinda is commonly applied in traditional medicine in South-East Asia. Various plant parts are used to treat a wide range of complaints including diabetes and beri-beri, asthma, cough and other respiratory problems, ulcers, wounds, boils, haemorrhoids and rheumatoid arthritis. It is also used as an emmenagogue.
Outside South-East Asia, several Morinda species are important medicinal plants. Morinda citrifolia is used medicinally throughout the tropics. Morinda royoc L. is applied to treat many complaints in Central America. In China and Vietnam, the roots of Morinda officinalis How are administered as a tonic and an emmenagogue, as well as to treat rheumatoid arthritis, impotence, spermatorrhoea and hypertension. Some species play a role in traditional medicine in western and central Africa: stem, bark, roots and leaves of Morinda lucida Benth. Morinda geminata DC., Morinda longiflora G. Don and Morinda morindoides (Baker) Milne-Redh. e.g. to treat fever, malaria, yellow fever, jaundice and dysentery, and as an anthelmintic.
The root bark of several Morinda species is used for dyeing, giving a reddish or yellowish dye. The wood is sometimes used e.g. for poles and as fuel, and the fruits are sometimes eaten.

The results of tests with mice suggest sedative properties for aqueous extracts of Morinda citrifolia roots. The extracts did not exhibit any toxic effect, but did show a significant, dose-related, central analgesic activity in the writhing and hotplate tests, decreased all behavioural parameters in the two compartment test, the light/dark choice situation test and the staircase test, and induced sleeping time. Aqueous and alcohol extracts of the roots of Morinda citrifolia significantly lowered blood pressure in rabbits and cats.
The fruit juice of Morinda citrifolia contains a polysaccharide-rich substance which displays antitumour activity in the Lewis lung peritoneal carcinomatosis model in mice. It also stimulated interferon induction, which is important in immunomodulating processes. An aqueous ethanol extract of dried fruits exhibited histaminergic effect on smooth muscles in guinea pigs. Tests with rats and mice suggested that prevention of carcinogen-DNA adduct formation and the antioxidant activity of Morinda citrifolia juice may contribute to the cancer preventive effect. An iridoid glycoside, named citrifolinoside, isolated from the leaves showed significant inhibition of activator protein-1 in cell cultures.
The curative properties of Morinda citrifolia and other Morinda species are ascribed to the presence of medicinally active anthraquinone derivatives. Damnacanthal is an anthraquinone compound isolated from the root; it showed potent inhibitory activity towards tyrosine kinases. This compound induced normal phenotypes in ras-transformed cells. Alcoholic extracts of tender Morinda citrifolia leaves showed good in-vitro anthelmintic activity against human Ascaris lumbricoides.
Anthraquinones (e.g. alizarin) exhibiting potent cytotoxic activity against KB cells and significant activity in the P388 lymphocytic leukaemia assay have been isolated from a Morinda umbellata extract. Antileukaemic anthraquinones have also been found in Morinda parvifolia Bartl., which occurs in Indo-China, southern China, Taiwan and the Philippines.
In China several compounds with antidepressant activities have been isolated from Morinda officinalis roots. Tests with mice indicated that water extracts have anti-fatigue properties, improving immunological action and reducing the excitability of the para-symphatic nervous system, without showing acute toxicity. A root extract of Morinda officinalis enhanced the activity of exogenous androgens and increased the secretion of these hormones in male rats. It also showed a marked anti-inflammatory effect in a rat paw oedema test, and a dose dependent hypoglycaemic activity in streptozotocin-induced diabetic rats.
Leaf extracts of the African Morinda lucida and Morinda morindoides showed in-vitro and in-vivo antimalarial activity. A methanol leaf extract of Morinda lucida showed a strong glucose lowering property when administered to streptozotocin-treated rats, and that of Morinda morindoides showed potent dose-dependent anticomplementary activity. Leaf extracts of Morinda lucida also showed antileishmanial and trypanocidal activities.
The basis of the morindone dyeing matter, called Turkish red, in the root-bark of Morinda citrifolia is the hydrolyzed form of the anthraquinone-glycoside morindin. The fruit contains rancid smelling capric acid and unpleasant-tasting caprylic acid. It is thought that antibiotically active compounds are present. The nutritional value of the fruit and leaves is considerable. The leaves are a rich source of vitamin A.

Shrubs, small trees or lianas; branches terete, smooth or with protruding lenticels. Leaves decussately opposite, simple and entire, pinnately veined, domatia usually present in axils of lateral veins, petiolate; stipules interpetiolar, usually partly connate and forming a sheath enclosing basal parts of internode. Inflorescence a terminal and/or axillary head, usually pedunculate, solitary or arranged in umbel-like cymes. Flowers bisexual or unisexual, 3—7-merous, fragrant; calyx campanulate to cupuliform, tubes connate, usually truncate, persistent; corolla hypocrateriform or infundibuliform, carnose, white, yellow, green, pink or red; stamens usually inserted in the throat of the corolla, usually partly to wholly exserted; disk annular, persistent in fruit; ovaries inferior, 2-celled, later often becoming incompletely 4-celled, connate, style filiform with 2-lobed stigma. Fruit a 1-seeded drupe, connate into a globose, transversely elliptical or elongate syncarp. Seed flattened, ovate or elliptical; endosperm carnose, oily.
The seeds of Morinda citrifolia remain viable for at least 6 months. Germination takes place 3—9 weeks after sowing. Plant growth is up to 1.5 m in 6 months. Flowering and fruiting start usually in the third year and continue throughout the year. Maximum age is at least 25 years. The seeds of Morinda citrifolia float in water and this explains its wide distribution and occurrence on many sea-shores. Inland distribution agents are fruit-eating bats and birds.
Morinda is classified in the tribe Morindeae of the subfamily Rubioideae, together with e.g. Gynochtodes and Lasianthus. The connate ovaries have often been regarded as a critical character defining the genus Morinda. However, connate ovaries occur in a number of genera in Morindeae as well as other tribes.
A complete revision of Morinda is lacking, and badly needed to solve species complexes such as Morinda umbellata, where possibly confusion with other species is common in South-East Asia.

Most Morinda species are restricted to tropical lowland and submontane forest, and many species are favoured by a moderate disturbance of the environment. Some of them are abundant in secondary forest, along roads and forest edges. Morinda citrifolia occurs in various habitats, often along seashores and in secondary vegetation near the coast, usually introduced and naturalized.

Morinda citrifolia is propagated by seed sown in nursery beds. After germination, seedlings are transplanted at a spacing of about 1.2 m x 1.2 m in well-tilled soil. Weeding is carried out at least twice and starts about 1 month after transplanting. No maintenance is needed after the first year. Intercropping with cereals and perennials is possible (e.g. as shade in coffee). In Vietnam and southern China Morinda officinalis is cultivated for medicinal purposes and is propagated by seed and cuttings.
Cell suspension cultures of Morinda citrifolia have been maintained successfully for anthraquinone accumulation, e.g. damnacanthal. In Hawaii, capsules containing freeze-dried powder of Morinda citrifolia fruits as well as fruit juice are marketed.

Morinda citrifolia is not likely to be endangered by serious genetic erosion given its pioneering character, its natural variation and its wide, though small-scale cultivation. The other Morinda species treated here are also widely distributed and common in secondary habitats. However, their popularity as a medicinal plant may exhaust natural populations, as is now already the case with Morinda officinalis in Vietnam.

Morinda provides important medicinal plants throughout the tropics. In many regions they rank amongst the most popular sources of traditional medicine. In recent years, Morinda citrifolia fruits have been recommended especially for treatment of diabetes, high blood pressure and cancer. The results of provisional studies seem to confirm at least some of the claimed activities. More elaborate research is recommended, not only for Morinda citrifolia but also for other Morinda species. A next step might be the identification of proper techniques for the cultivation of Morinda for medicinal purposes.

[120]Burkill, H.M., 1985—2000. The useful plants of West tropical Africa. 2nd Edition. 5 volumes. Royal Botanic Gardens, Kew, United Kingdom. Vol. 1 (1985), Families A—D, 960 pp.; Vol. 2 (1994), Families E—I, 636 pp.; Vol. 3 (1995), Families J—L, 857 pp.; Vol. 4 (1997), Families M—R, 969 pp; Vol. 5 (2000), Families S—Z, 686 pp.
[216]Do Huy Bich, Nguyen Tap & Tran Toan, 1993. Medicinal plant resources of Vietnam. Scientific and Technical Publishing House, Hanoi, Vietnam.
[436]Johansson, J.T., 1994. The genus Morinda (Morindeae, Rubioideae, Rubiaceae) in New Caledonia: taxonomy and phylogeny. Opera Botanica No 122. 65 pp.
[542]Lemmens, R.H.M.J. & Wulijarni-Soetjipto, N. (Editors), 1991. Plant Resources of South-East Asia No 3. Dye and tannin-producing plants. Pudoc, Wageningen, the Netherlands. 196 pp.
[646]Morton, J.F., 1981. Atlas of medicinal plants of Middle America. Bahamas to Yucatan. Charles C. Thomas, Springfield, Illinois, United States. 1420 pp.
[671]Nguyen Van Duong, 1993. Medicinal plants of Vietnam, Cambodia and Laos. Mekong Printing, Santa Ana, California, United States. 528 pp.
[760]Quisumbing, E., 1978. Medicinal plants of the Philippines. Katha Publishing Co., Quezon City, the Philippines. 1262 pp.
[817]Saralamp, P., Chuakul, W., Temsiririrkkul, R. & Clayton, T. (Editors), 1996. Medicinal plants in Thailand. Vol. I. Department of Pharmaceutical Botany, Faculty of Pharmacy, Mahidol University, Bangkok, Thailand. 219 pp.

Nguyen Tap & Nguyen Kim Bich

Morinda citrifolia
Morinda elliptica
Morinda umbellata

Tap, N. & Bich, N.K., 2003. Morinda L.. In: Lemmens, R.H.M.J. and Bunyapraphatsara, N. (Editors): Plant Resources of South-East Asia No 12(3): Medicinal and poisonous plants 3. PROSEA Foundation, Bogor, Indonesia. Database record: prota4u.org/prosea

The following species in this genus are important in this commodity group and are treated separatedly in this database:
Morinda citrifolia
Morinda elliptica
Morinda umbellata