Buddleja asiatica (PROSEA)
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Introduction |
Buddleja asiatica Lour.
- Protologue: Fl. cochinch.: 72 (1790).
- Family: Buddlejaceae
- Chromosome number: 2n= 38
Vernacular names
- White butterfly bush (En)
- Indonesia: jugul (Sundanese), daun putihan (Javanese), kayu saludang (Sumatra)
- Philippines: malasambung (Tagalog), lagundisalasa (Bisaya), tugnang (Iloko)
- Laos: dok fon², dok khap
- Thailand: khrai bok (northern), kiang phaa lai (Chiang Mai), mae maai (Kanchanaburi)
- Vietnam: bọ chó, túy ngư thảo, búp lệ.
Origin and geographic distribution
B. asiatica occurs from Pakistan, eastern India, Burma (Myanmar), Laos, Vietnam and southern China, through Thailand and the whole of Malesia, to the Mariana Islands. It is sometimes cultivated and naturalized in other tropical and subtropical regions. B. asiatica is the only native species of the genus in the Malesian region, but a few other species are cultivated and sometimes naturalized.
Uses
In the Philippines, B. asiatica plants are used as an abortifacient, to treat skin diseases and as a cure to stop weight loss. In Vietnam, the leaves are applied in an inhalation to treat headache, to treat skin diseases, and, in combination with other drugs, after childbirth. Dried roots are used to treat malaria in China, and as a tonic in Burma (Myanmar). The leaves are often used for stupefying fish, e.g. by the Dayak Kenyah people in East Kalimantan (Indonesia). B. asiatica is used as forage in Nepal.
A decoction of flower buds of B. officinalis Maxim., found wild in northern Vietnam and southern China, is used to treat eye diseases such as eye inflammation, nyctalopia, asthenopia and cataract, often in combination with other medicinal plants.
B. americana L. is used in traditional medicine in Central America, e.g. to treat respiratory diseases, gastro-intestinal disorders, headache and diarrhoea. B. madagascariensis Lamk is also used to treat respiratory diseases in Madagascar, and is sometimes planted and rarely naturalized in South-East Asia (Peninsular Malaysia).
Several Buddleja species are widely planted as ornamentals, e.g. B. davidii Franch., which is also commonly cultivated in the Malesian region and is locally naturalized (Cameroon Highlands, Peninsular Malaysia).
Properties
The alcoholic extract from B. asiatica leaves produced a persistent hypotensive effect on pentobarbitone-anaesthetized dogs and cats. The extract had an α-receptor antagonist activity. The essential oil isolated from B. asiatica leaves inhibited the growth of the pathogenic fungi Aspergillus flavus , A. fumigatus (causing bronchial and pulmonary infections), Trichoderma viride (causing dermatitis), Trichophyton rubrum (causing infection of keratinized tissues and skin) and Curvularia prasadii (causing leaf spot). The oil is rich in-caryophyllene epoxide (22%), citronellol (17%) and-caryophyllene (16%). A crude petroleum-ether-acetone extract of B. asiatica showed distinct larvicidal activity on the filarial mosquito Culex quinquefasciatus .
Four phenylethanoid glucosides have been isolated from B. officinalis flowers; one of these, verbascoside (= acetoside), showed antibacterial and anticancer activities, and is also known to exhibit antihypertensive and analgesic activities. Several flavonoid compounds (e.g. apigenin, luteolin and luteolin-7-O-glucoside) have been isolated from B. officinalis . A 70% methanolic extract of B. officinalis flowers showed an inhibitory effect on unpurified rat lens aldose reductase, an enzyme involved in the complications of diabetes. Luteolin, luteolin-7-O--D-glucopyranoside, apigenin and acacetin-7-O--L-rhamnopyranosyl-(6-1)--D-glucopyranoside have been isolated as active compounds.
Aqueous extracts of several Buddleja species (amongst which B. officinalis ) showed an inhibitory effect against induced cytotoxicity of cultured hepatocytes. Testing of the isolated compounds indicated that the activity is most likely due to flavonoid constituents and phenylpropide glycosides.
Botany
A shrub or small tree up to 7 m tall; branches terete, densely appressed or woolly stellate-hairy when young. Leaves opposite, simple, narrowly lanceolate to oblong- or ovate-lanceolate, 3-30 cm × 0.5-7 cm, cuneate at base, long-acuminate at apex, margin remotely serrate-dentate to entire, densely hairy beneath, pinnately veined; petiole 2-15 mm long; stipules absent, but 2 opposite petioles connected by a stipular line. Inflorescence a terminal and/or axillary spike-like thyrse up to 25 cm long, composed of 1-3-flowered cymes in the axils of linear bracts, densely tomentose. Flowers bisexual, 4-merous, occasionally a few 5-merous, sessile or subsessile; calyx campanulate, 1.5-4.5 mm long, with triangular-oblong lobes; corolla 3-6 mm long, lobes distinctly shorter than tube, outside stellate-hairy, white, sometimes pale violet or greenish; stamens inserted on the corolla tube, filaments extremely short; ovary superior, 2-celled, style short, stigma club-shaped. Fruit an ovoid or oblong, flattened capsule 3-5 mm long, 2-valved, glabrous, brown, many-seeded. Seeds ellipsoid, small, with a short wing at both sides, endosperm fleshy.
B. asiatica may flower throughout the year. The flowers are pollinated by insects, whereas the tiny seeds are wind-dispersed.
Buddleja comprises approximately 100 species, and is distributed in all tropics and subtropics. It is sometimes included in the family Loganiaceae .
Ecology
B. asiatica prefers open, often disturbed or secondary vegetation, and behaves more or less as a pioneer. It is found in logged-over forest, regularly burned grassland, in gravel-beds, and on former lava-streams and landslides, and occurs there often gregariously. It may be found up to 3000 m altitude.
Management Seeds of B. asiatica start germinating 1-2 weeks after sowing. In glasshouse tests in India, the average germination rate was 21%. After 4 months, the average height and stem diameter of seedlings were 27 cm and 0.4 cm, respectively. B. asiatica can also be propagated using semi-hardwood cuttings.
Genetic resources
B. asiatica is widespread, locally common and prefers disturbed habitats. This means that there is no risk of genetic erosion.
Prospects
Like other Buddleja species, B. asiatica shows interesting pharmacological activities (e.g. antifungal activity), which deserve more attention in research. Especially the treatment of skin and eye diseases should be further investigated. In India, B. asiatica has been suggested as a promising shrub for regreening degraded habitats.
Literature
247, 270, 671, 760, 866, 958.
Other selected sources
250, 269, 370, 371, 603.
Main genus page
Authors
Siti Susiarti
