Operculina turphetum (PROSEA)
Operculina turphetum (L.) S. Manso
- Protologue: Enum. subst. braz.: 16 (1836).
- Family: Convolvulaceae
- Chromosome number: 2n= 30
Convolvulus turphetum L. (1753), Ipomoea anceps Roem. & Schult. (1819).
- Indian jalap, turpeth-root, wood rose (En). Turbith végétal (Fr)
- Indonesia: areuy jotang (Sundanese), sampar-kedung, balaran (Javanese)
- Philippines: bangbangau, laplapsut (Iloko), kamokamotihan (Tagalog)
- Thailand: chingcho liam (northern)
- Vietnam: chìa vôi, bìm năp.
Origin and geographic distribution
O. turphetum is distributed in the Old World tropics from East Africa, the Mascarene Islands and Seychelles, through India to South and South-East Asia, tropical Australia and Polynesia. It has not yet been recorded from Sumatra, and is rare in Peninsular Malaysia and Borneo.
The rhizome of O. turphetum is officially recorded in many pharmacopoeias, especially in South America and India.I n India, China, Thailand and Indo-China, the rhizome is used as a powerful purgative and as a diuretic, as well as in the treatment of articular pains, fevers, gout, jaundice, bilious disturbances in general, intestinal worms and rheumatism. In India, distinction is made between white rhizomes, which are mildly purgative, and black rhizomes, that give drastic, often poisonous results. The heated stem is applied to the abdomen after parturition to cure colic and to aid in the contraction of the tissues. In Fiji, the leaves or young stems are used to prepare a tea which is drunk frequently as a remedy for bladder stones and against pains in the abdomen or stomach. A decoction of the leaves is used as a tonic after childbirth. In Java, the plant does not seem to be used, despite its frequent occurrence.
In the Philippines, the stems are used for tying purposes. O. turphetum is considered a good browse plant for cattle.
Production and international trade
O. turphetum is cultivated and locally traded in India, Sri Lanka and Indo-China.
The rhizome bark in particular contains up to 10% of a brownish yellow glycosidic resin, called turphetin, which is analogous to jalapin (the resin from Ipomoea purga (Wender.) Hayne).
The main glycosidic acids (glycosides from hydroxy fatty acids, which are responsible for the laxative effects of the resin) from the alcohol-soluble resin fraction were identified as gluco-gluco-gluco-rhamnosides of 11-hydroxy-palmitic acid (jalapinolic acid), 3,12-dihydroxy-pentadecanoic acid (operculinolic acid), 3,12-dihydroxy-palmitic acid, 4,12-dihydroxy-pentadecanoic acid and 4,12-dihydroxy-palmitic acid.
Treatment of susceptible host plants with extracts from the leaves induced systemic resistance to subsequent challenge from sun hemp rosette virus, tobacco mosaic tobamovirus, datura shoestring potyvirus and tomato spotted wilt tospovirus.
Adulterations and substitutes
In India, the tubers of Ipomoea purga or Rheum spp. ( Polygonaceae ) are often used as a substitute for O. turphetum rhizomes, as a strong purgative. Marsdenia tenacissima (Roxb.) Moon ( Asclepiadaceae ) is sometimes applied as an adulteration of O. turphetum .
A perennial twiner, stems 2-4 m long, narrowly 3-5-winged, sulcate or angular, glabrous or pilose at the nodes, rhizomes long, fleshy, much branched. Leaves alternate, simple, very variable in shape, orbicular, broadly ovate, ovate to lanceolate, broad leaves 5.5-15 cm × 4-14 cm, narrow ones 5.5-7.5 cm × 1-2.5 cm, base cordate to hastate, apex acuminate, acute or obtuse, mucronulate, margin entire or rarely coarsely dentate to shallowly lobed, upper surface glabrous or appressed pilose, lower surface pubescent, midrib and 8-11 veins on either side prominent underneath; petiole 2.5-7.5 cm long, terete, sometimes winged. Inflorescence a few-flowered cyme; peduncle 2-18 cm long, terete or sometimes winged, glabrous or pubescent. Flowers actinomorphic, 5-merous, pedicel angular, 12-15(-35) mm long, pubescent, in fruit clavate up to 40 mm long, bracts oblong or elliptical-oblong, mucronulate, 1.5-2 cm long, pubescent, caducous; sepals 5, free, ovate or broadly ovate, acute, outer ones 1.5-2.5 cm long, pubescent outside, inner ones 2 cm long, glabrous, calyx in fruit broadly cup-shaped, up to 6 cm in diameter; corolla broadly funnel-shaped, 3-4.5 cm long, white, sometimes with yellowish base, glabrous, rarely with yellowish gland hairs outside; stamens 5, inserted, filaments adnate to the corolla, sparsely pubescent below. Fruit a capsule, depressed-globose, 1.5 cm in diameter, with up to 4 seeds; epicarp circumscissile in or above the middle, the upper part (operculum) more or less fleshy, separating from the lower part and from the endocarp; endocarp scarious, splitting longitudinally, irregularly. Seed trigonous to globular, 6 mm long, glabrous, dull black.
Growth and development
O. turphetum can be found flowering throughout the year when sufficient water is available.
Other botanical information
Operculina consists of about 20 species, present in the tropics. Three species occur in Malesia, O. turphetum , O. brownii Ooststr. and O. riedeliana (Oliv.) Ooststr. O. brownii is closely related to O. turphetum , the main difference being the sepals, which are broadly rounded and glabrous, and the large seeds, 15 mm long. It occurs in tropical Australia, and probably also in the dry savanna regions of southern New Guinea. O. riedeliana differs from O. turphetum in that the stem is wingless, the corolla pale yellow, the mid-petaline bands densely pilose and the capsule up to 3 cm in diameter. It occurs widely in South-East Asia.
O. turphetum is weedy, and occurs in open forest, teak forest, hedges, thickets, roadsides and waste places, occasionally in sugar-cane plantations, restricted to regions with a medium or strong monsoon, from sea-level up to 1300 m altitude.
Propagation and planting
O. turphetum is propagated by seed.
Diseases and pests
In India, O. turphetum is attacked by Pseudocercospora operculinae which causes leaf-spot disease. In nurseries in India, O. turphetum seedlings are attacked by the larvae of Helcystogramma sp. and Papilio demoleus (Lepidoptera), which feed on the young leaves and cause 30-100% loss.
In India, whole plants of O. turphetum are uprooted, to obtain the rhizomes.
Handling after harvest
In India, the rhizome and basal stem of O. turphetum plants are cut into cylindrical pieces, 1.5-15 cm × 1-5 cm, often with the central woody portion removed by splitting the bark on one side. The surface is longitudinally furrowed, grey-reddish, giving it a rope-like appearance. The pieces have a distinct, unpleasant or musty odour, and are powdered before use. The taste is somewhat bland or nauseating at first, then slightly acrid.
Genetic resources and breeding
O. turphetum is a weedy species, occurring in anthropogenic habitats, and does not seem to be threatened by genetic erosion.
The laxative properties of several so-called Ipomoea resins (jalapin, turphetin) are quite well established. They can therefore be used as local substitutes for the better known anthranoid laxatives e.g. Senna or Frangula in communities where these preparations are not available. O. turphetum therefore has some potential for cultivation in the region.
- Austin, D.F., 1982. Operculina turphetum (Convolvulaceae) as a medicinal plant in Asia. Economic Botany 36(3): 265-269.
- Joshi, K.C., Meshram, P.B., Sambath, S., Kiran, U., Shalini, H. & Kharkwal, G.N., 1992. Insect pests of some medicinal plants in Madhya Pradesh. Indian Journal of Forestry 15(1): 17-26.
- Khan, M.M.A.A. & Zaim, M., 1992. Physicochemical properties and mode of action of inhibitors of plant virus replication present in Operculina turphetum L. and Scilla indica Baker. Zeitschrift für Pflanzenkrankheiten und Pflanzenschütz 99(1): 71-79.
- Pételot, A., 1953. Les plantes médicinales du Cambodge, du Laos et du Vietnam [The medicinal plants of Cambodia, Laos and Vietnam]. Vol. 2. Centre National de Recherches Scientifiques et Techniques, Saigon, Vietnam. pp. 189-190.
- Van Ooststroom, S.J., 1953. Operculina. In: van Steenis, C.G.G.J. (Editor): Flora Malesiana. Series I, Vol. 4. Noordhoff-Kolff, Djakarta, Indonesia. pp. 454-457.
- Wagner, H., Wenzel, G. & Chari, V.M., 1978. The turphethinic acids of Ipomoea turphetum L. Planta Medica 33(2): 144-151.
Other selected sources
- Burkill, I.H., 1966. A dictionary of the economic products of the Malay Peninsula. Revised reprint. 2 volumes. Ministry of Agriculture and Co-operatives, Kuala Lumpur, Malaysia. Vol. 1 (A-H) pp. 1-1240, Vol. 2 (I-Z) pp. 1241-2444.