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[Athena]

Datasheet: Voacanga thouarsii



1. NOMENCLATURE

Synonyms: Orchipeda thouarsii (Roem. & Schult.).
Common Names (english): Wild frangipani
Common Names (non-english): Voacanga de Thouars (Fr). Mlindaziwa (Sw)
Taxonomic Position: Apocynaceae

2. DESCRIPTION

Plant Type: Small tree.
Morphology: Usually a small tree, 2–15(20) m. high; trunk terete, 4–40(80) cm. in diam., bark pale grey-brown, smooth, with small lenticels, with some white latex. Branches with or without some large lenticels; branchlets glabrous or minutely puberulous, with much latex. Leaves shortly petiolate; petiole 8–25 mm. long, glabrous or minutely puberulous at the base, those of a pair connate into a short ocrea (widened into intrapetiolar stipules), with a single row of colleters in the axils; lamina often slightly glaucous with the costa often pale, often thickly coriaceous (also when fresh), narrowly obovate or less often narrowly elliptic, 2–4 times as long as wide, 6–25 x 2–9 cm., obtuse or rounded, cuneate or decurrent into the petiole, glabrous and usually with numerous minute pits on both surfaces; secondary veins 12–20 on each side, inconspicuous in fresh leaves; tertiary venation inconspicuous. Inflorescences long-pedunculate, fairly lax, without peduncle 4–7 x 4–7 cm., few-flowered, monochasial or nearly so. Peduncle 5–14 cm. long, stout, glabrous; pedicels 8-15 mm. long except for the thickened 2–5 mm. long apex, often mintuely puberulous above. Bracts dediduous and leaving conspicuous scars, ovate, rounded at the apex, with a single row of large colleters in the axils; lower up to 10 x 7 mm., other smaller. Flowers sweet-scented. Calyx pale, to dark green, with hyaline margin, fleshy, clasping the corolla tube and shed together with the corolla, from abscission layer 13–25 mm. long, 7–13 mm. wide, outside minutely papilose except for the glabrous apices of the lobes, inside with several irregular rows of colleters in the lower half of the tube; tube barrel-shaped to cylindrical, 2·5–4 times as long as the lobes, 10-16 mm. long; lobes usually broadly ovate, 3–10 x 4–10 mm., rounded, entire, erect. Corolla pale yellow with the tube often pale green, creamy, or white, carnose, in the mature bud 29–33 mm. long, incl. the lobes (the lobes 2/5–2/5 of the bud-length, being 13–19 x 10–13 mm., forming an almost conical head with a blunt apex), glabrous on both sides; tube as long as the calyx or slightly longer, almost cylindrical, 17–23 mm. long, twisted, widest around the ovary and there 5–8 mm. wide, contracted above, narrowest just below the insertion of the stamens and there 4–6 mm. wide, widened and thickened at the insertion of the stamens, inside with 5 small incrasations in the mouth (touching the connectives); lobes not twisted, broadly obcordate, 1·1–1·3 times as long as the tube, 1·2–1·5 times as wide as long, 19–30 x 28–43 mm., with basal portion about 3–5 x 3–5 mm., abruptly widened from there, at the apex emarginate, entire, spreading to recurved. Stamens exserted for 2–3 mm. (seemingly more in dry specimens), inserted 3–4 mm. below mouth of the corolla; anthers sessile, narrowly triangular, 6–7 x 3 mm., acuminate at the sterile apex (sterile part 2 mm.), glabrous. Pistil glabrous, approximately as long as the corolla tube, 17–23 mm. long; carpels 2, separate 2–3 x 2–3·5 x 1–1·7 mm., rounded, connected at the apex by the base of the style; style not split at the base, 12–19 x 1 mm., more or less gradually thickened at the apex; clavuncula capitate, 1–1·6 x 1–1·6 mm., with a ring 1·5–2 x 3·4 mm., being long-fimbriate at the base. Disk annular, lower or higher than the ovary, 2–4·5 mm. high, shallowly to deeply 5-lobed. Ovules about 80 in each carpel. Fruit of two free subglobose mericarps being slightly longer than wide and about as thick as wide, 4–10 cm. in diam., pale and dark green-spotted, also when mature, wall creamy inside and on section, 5(?)–15 mm. thick. Seeds with orange aril, dark brown, obliquely ovoid or ellipsoid, 8–9·5 x 6-6·5 x 4–5 mm., rough, densely papillose and shallowly grooved all over.
Similarity to Other Species: The uses of Voacanga thouarsii are similar to those of Voacanga africana. [1]

3. DISTRIBUTION AND ECOLOGY

Geographical Distribution: Voacanga thouarsii occurs throughout tropical Africa, from Senegal eastwards through the forest zone to Sudan and Kenya, and south to Mozambique and the east coast of South Africa. It also occurs in Madagascar.
Native Habitat: Often in swampy ground; growing in valley bottoms; ravines and stream-banks of the wooded savannah. Mostly in semi-deciduous forest and savannah, often in moist localities, sea-level to 600 metres. It easily colonizes disturbed habitats. [2]
Hardiness and Environmental Requirements: Global hardiness zones 9-13.
Soil Requirements: ---

4. PROPAGATION AND CYCLE

Types of Propagation: Propagation is by seed or cutting.
Seed Germination Notes: Pre-soaking for 12 hours in warm water can improve germination results. The seed is quite easy to germinate - it can be sown in light shade in nursery seedbeds or individual containers. Voacanga thouarsii regrows well when coppiced or pollarded. [2]
Seed Storage: Since the seeds are sticky, they should be stored in a medium such as sand.
Life Cycle: ---

5. TRADITIONAL USES

The tree is harvested from the wild, providing medicines and various commodities to the local population. The root bark of Voacanga species is generally ingested to combat fatigue and increase endurance of drummers and hunters and, in higher doses, also for magic and religious purposes. The wood is used in Liberia for hut posts and in Uganda for tool handles and sheaths for knives. The ripe seeds are scattered on the ground of rice-farms in Liberia when the grain is ripening to scare off wild pigs which depredate the rice crop.  The wood is also used as firewood and for making charcoal. The latex was formerly used to adulterate Hevea rubber. It is used as birdlime, e.g. in rice fields in Madagascar and as a glue for fastening handles to knife blades and to repair baskets. The wood is burnt in Sudan and Ghana to produce a salt. The bark yields a fibre, which is used for making hunting nets in East Africa. Voacanga thouarsii is planted along watercourses for soil and water conservation. [3]

6. PROPERTIES AND BENEFITS

Documented properties: The latex or decoctions or infusions of the stem bark, leaves and roots are applied to wounds, boils and sores, and are used to treat gonorrhoea, eczema, fungal infections and scabies. The infusions are also taken to treat heart problems, hypertension and rheumatic afflictions. The latex is put in carious teeth as a temporary filling. In Tanzania the bark, roots and seeds are used as medicine for stomach-ache, snakebites and high blood pressure. Seeds of Voacanga thouarsii and Voacanga africana appear to be the best sources of tabersonin, and V. thouarsii seeds are reported to give a higher yield in tabersonin than V. africana seeds. In France and Germany tabersonine is extracted from the seed, which is converted into vincamine, a compound widely used in Europe as a depressant of the central nervous system and for the treatment of cerebral vascular disorders in geriatric patients. It also enhances memory and mental alertness. Seeds are also exported to be used in medicines to treat heart diseases, to lower blood pressure and to treat cancer. There is a steady market for Voacanga thouarsii seed, as there is for Voacanga africana. Several hundreds of tonnes of Voacanga seed are exported especially from West Africa, Cameroon and Madagascar to pharmaceutical companies in France and Germany for processing. [2]
Parts of the plant with therapeutic/psychoactive value: Seeds, stem bark, leaves and roots.
Phytochemical Information: In pharmacology indole alkaloids are by far the most important compounds of Voacanga spp., including Voacanga thouarsii. The main alkaloids of the root bark are dimers of the corynanthean-ibogan class dimers, chiefly voacamine, but also voacamidine and voacorine; vobtusine (a dimer of the plumeran-plumeran class) is an important alkaloid from the root bark. In the stem bark, voacamine and congeners predominate, while vobtusine is often also present. Voacangine and voacristine (= voacangarine) are also major constituents. The leaves contain mainly dimeric alkaloids of the corynanthean-ibogan and the plumeran-plumeran classes, but ibogan monomers, including ibogaine and voacangine, are also found. The alkaloid composition of the seeds is similar to other Voacanga species, and consists almost exclusively of the plumeran-class tabersonine (1.6–1.8%). Voacamine, vobtusine and voacangine have hypotensive, cardiotonic and sympatholytic activities. The leaves of specimens from Madagascar were shown to contain the flavonoid-glycosides rutin and kaempferol-3-glucoside. Callus grown in vitro from leaf material containing 0.9% alkaloids produced 0.3% alkaloids (0.2% in the tissue and 0.1% excreted into the medium). Tabersonine was the only alkaloid isolated from the culture; it was not a constituent of the leaves. [1]



6. REFERENCES AND CITATIONS

STS Threads with Information:
External Links:
https://en.wikipedia.org/wiki/Voacanga_thouarsii
http://www.zimbabweflora.co.zw/speciesdata/species.php?species_id=145090
Citation Sources:
[1] http://www.prota4u.org/protav8.asp?g=psk&p=Voacanga+thouarsii+Roem.+&+Schult.
[2] http://tropical.theferns.info/viewtropical.php?id=Voacanga+thouarsii
[3] http://www.prota4u.org/protav8.asp?p=Voacanga+thouarsii
Images: https://www.ispotnature.org/species-dictionaries/sanbi/Voacanga%20thouarsii

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