389

12(1): Medicinal and poisonous plants 1

Premna L.

Mant. pl. 2: 154, 252 (1771).

VERBENACEAE

x = unknown

Major species Premna herbacea Roxb., Premna odorata Blanco, Premna serratifolia L., Premna tomentosa Willd.

The number of species in Premna varies from 50-200, depending on literature sources. They are widely distributed in the African, Asian and Australian tropics and subtropics. The main distribution area extends from India, Indo-China, China and Japan, through Thailand and the Malesian region to northern Australia. Premna serratifolia has the largest area of distribution, extending from eastern Africa to the whole of southern and eastern Asia (including Malesia) and northern Australia.

Infusions or extracts of the leaves and roots of Premna spp. are widely used in South-East Asian traditional medicine as a diuretic to treat dropsy, as a carminative and stomachic, to treat diarrhoea, bronchial affections, rheumatism and headache, and as a febrifuge and tonic (e.g. after childbirth). In the Philippines, a decoction of the leaves of Premna odorata is used for loosening phlegm and as a cough remedy.
The timber is sometimes used if trees have reached larger dimensions (particularly Premna tomentosa). Some Premna spp. are used in hedges, occasionally also as ornamentals. Ripe fruits and cooked leaves are occasionally eaten.

Plant parts of Premna are only collected for local use and are not traded on a larger scale.

Premnazole (an isoxazol alkaloid) has been isolated from the leaves of Premna serratifolia. This compound has anti-inflammatory activity. In rats, it has reduced granuloma formation with an activity comparable to phenyl butazone and has lowered the weight of adrenal glands and their ascorbic acid content. In the same experiment, the enzyme activities of acid phosphatase, glutamate pyruvate transaminase (GPT, ALAT) and glutamate oxaloacetate transaminase (GOT, ASAT) were reduced in serum and liver, whereas the protein content was lowered in serum. The terpenoid compound 'BETA'-sitosterol and the flavonoid luteolin have also been isolated from the leaves of Premna serratifolia. The major alkaloid in the stem bark of Premna serratifolia was found to be aphelandrine (a spermine alkaloid) which occurs together with two other alkaloid compounds. Several sesquiterpenoids and diterpenoids have been isolated from the root bark, e.g. caryophyllen-3-one, premnenol. Phytochemical investigations of the leaves of Premna odorata (methanol extract) have revealed the presence of six iridoid-glycoside-caffeoyl esters, two of them having a monoacyl-rhamnopyranosyl-catapol structure and four being diacyl-rhamnopyranosyl-catapols (named premnosides A-D). Premnaodoroside A-C (acyclic monoterpenediol-iridoidglucoside diesters verbascoside, decaffeoyl verbascoside and isoverbascoside) were also isolated from the same extract.
The leaves of Premna tomentosa have been shown to contain limonene, caryophyllene and other di- and sesquiterpenoids. The flavone 6,8-di-C-glycoside has been isolated from the heartwood. Root nodules of Premna herbacea have been reported to contain a diterpenoid quinone, methide. The heartwood yields the flavonoid vicenin 3.
Several African Premna species (e.g. Premna schimperi Engl., Premna oligotricha Baker) contain diterpenes, which showed antibacterial and cytotoxic effects in vitro.
An extract of Premna serratifolia showed antifeedant and anti-ovipositional effects on Callosobruchus chinensis, which is a pest of stored crop products. However, the action persisted for no longer than one week. The water extract of the stem bark exhibits myocardial depressant, skeleton and smooth muscle stimulant, uterine stimulant and hypoglycaemic activity.

Perennial herbs or undershrubs, shrubs (sometimes lianescent) to small or medium-sized trees up to 20 m tall; bole up to 30(-50) cm in diameter, often with fissured flaky bark. Leaves decussately opposite, simple, entire or serrate, crenate or dentate in upper half, with reticulate tertiary venation, with foetid smell when crushed, petiolate or sessile, exstipulate. Inflorescence terminal, cymose, compound and often much branched, pedunculate; bracts small. Flowers small, bisexual, zygomorphic, usually white, greenish-white or yellowish, pedicellate or subsessile; calyx tubular or somewhat campanulate, variously toothed or truncate, often almost 2-lipped with one lip entire or 2-toothed, the other entire or 3-toothed, persistent; corolla tubular below with usually densely villous tube in upper half, almost 2-lipped above, usually with entire upper lip and 3-lobed lower lip; stamens 4, didynamous, inserted at about the middle of the corolla tube, filaments filiform, anthers dorsifixed; ovary superior, 4-locular, style filiform, with 2 short stigmatic lobes. Fruit a small globose or obovoid succulent drupe with a hard 4-celled kernel, green but usually turning dark purple or black at maturity, 1-4-seeded. Seeds without endosperm. Seedling with epigeal germination; cotyledons thin-coriaceous, hairy; hypocotyl elongate, hairy, epicotyl present.

Many Premna species flower all year round. Fruits mature a few months after flowering.

Premna is closely related to Gmelina, but it can easily be distinguished by its short and cylindrical corolla tube; in Gmelina the corolla tube is long and ampliate above. Vitex is another closely related genus.
Pygmaeopremna is often kept separate from Premna, but the only reliable differential character is the dwarf habit, which does not seem to justify a distinct generic status.
Some Premna spp. have minor or obscure medicinal uses. In Peninsular Malaysia, leaves of Premna divaricata Wallich ex Schauer have been used to treat headache and colds. Premna parasitica Blume has been used in Indonesia after childbirth and as fish poison and in Peninsular Malaysia as febrifuge. Premna cordifolia Roxb. has been used to treat shortness of breath and as febrifuge. The leaves of Premna nauseosa Blanco have been used in the Philippines to treat stomach-ache.

Premna species usually occur in the lowland up to 1000 m altitude, in secondary forest, open forest, brushwood and hedges. Premna serratifolia often grows near the sea. Premna herbacea, which is a subshrub, often occurs in grasslands exposed to periodic fires.

Premna is rarely planted and, if so, it is probably propagated by seed.

The plant parts of Premna like leaves and roots needed to make medicinal preparations are collected from the wild.

The collected leaves and roots are washed and dried in the sun. An infusion or extract is made when needed.

The Premna spp. treated here are usually common in secondary forest, scrub vegetation and sometimes even in grassland, and are not easily liable to genetic erosion. Premna odorata is endemic to the Philippines, but occurs there abundantly and is not threatened; Premna cumingiana and Premna peekelii also have limited areas of distribution but do not seem to be immediately endangered. However, several species in South-East Asia appear to be narrow endemics and might easily be endangered.

Very little pharmacological research has been done, and little is known about active compounds of Premna species. There is so little information available that no statements about prospects in modern medicine are warranted. However, the few studies done indicate that the therapeutic properties attributed to several Premna species may have a scientific basis.

Barik, B.R., Bhowmik, T., Dey, A.K., Patra, A., Chatterjee, A., Joy, S., Susan, T., Alam, M. & Kundu, A.B., 1992. Premnazole, an isoxazole alkaloid of Premna integrifolia and Gmelina arborea with anti-inflammatory activity. Fitoterapia 63(4): 295-299.
Dasgupta, B., Sinha, N.K., Pandey, V.B. & Ray, A.B., 1984. Major alkaloid and flavonoid of Premna integrifolia. Planta Medica 50(3): 281.
de Padua, L.S., Lugod, G.C. & Pancho, J.V., 1978. Handbook on Philippine medicinal plants. Vol. 2. Documentation and Information Section, Office of the Director of Research, University of the Philippines at Los Baños, the Philippines. p. 49.
Habtemariam, S., 1995. Cytotoxicity of diterpenes from Premna schimperi and Premna oligotricha. Planta Medica 61: 368-369.
Holdsworth, D.K., 1977. Medicinal plants of Papua New Guinea. South Pacific Commission, Noumea, New Caledonia. p. 51.
Munir, A.A., 1984. A taxonomic revision of the genus Premna L. (Verbenaceae) in Australia. Journal of the Adelaide Botanic Gardens 7(1): 1-44.
Nguyen Van Duong, 1993. Medicinal plants of Vietnam, Cambodia and Laos. Mekong Printing, Santa Ana, California, United States. p. 426.
Otsuka, H., Kubo, N., Yamasaki, K. & Padolina, W.G., 1989. Premnosides A-D: diacyl 6-O-'ALFA'-L-rhamnopyranosylcatalpols from Premna odorata. Phytochemistry 28(11): 3063-3067.
Otsuka, H., Kashima, N., Hayashi, T., Kubo, N., Yamasaki, K. & Padolina, W.G., 1992. Premnaodorosides A, B and C, iridoid glucoside diesters of an acyclic monoterpenediol from leaves of Premna odorata. Phytochemistry 31(9): 3129-3133.
Quisumbing, E., 1978. Medicinal plants of the Philippines. Katha Publishing Co., Quezon City, the Philippines. pp. 798-801.

L.B. Cardenas

Premna cumingiana
Premna herbacea
Premna odorata
Premna peekelii
Premna serratifolia
Premna tomentosa

Cardenas, L.B., 1999. Premna L.. In: de Padua, L.S., Bunyapraphatsara, N. and Lemmens, R.H.M.J. (Editors): Plant Resources of South-East Asia No 12(1): Medicinal and poisonous plants 1. 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:
Premna cumingiana
Premna herbacea
Premna odorata
Premna peekelii
Premna serratifolia
Premna tomentosa