About Catharanthus roseus (L.) G.Don
Catharanthus roseus (L.) G.Don is an evergreen subshrub or herbaceous plant that reaches 1 m (39 in) in height. Its leaves are oval to oblong, 2.5–9 cm (1.0–3.5 in) long and 1–3.5 cm (0.4–1.4 in) wide. They are glossy green, hairless, with a pale midrib and a short 1–1.8 cm (0.4–0.7 in) petiole, and arranged in opposite pairs. Flower colors range from white with a yellow or red center to dark pink with a darker red center. Flowers have a basal tube 2.5–3 cm (1.0–1.2 in) long and a five-lobed corolla 2–5 cm (0.8–2.0 in) in diameter. The fruit is a pair of follicles 2–4 cm (0.8–1.6 in) long and 3 mm (0.1 in) wide.
In its natural range along the dry coasts of southern Madagascar, Catharanthus roseus is considered weedy and invasive, often self-seeding prolifically in disturbed areas along roadsides and in fallow fields. It is also widely cultivated, and naturalized in subtropical and tropical areas of the world including Australia, Bangladesh, India, Malaysia, Pakistan, and the United States. It is so well adapted to growth in Australia that it is listed as a noxious weed in Western Australia, the Australian Capital Territory, and parts of eastern Queensland.
C. roseus can be extremely toxic if consumed orally by humans, and is cited under its synonym Vinca rosea in Louisiana State Act 159. All parts of the plant are poisonous. If consumed, symptoms include mild stomach cramps, cardiac complications, hypotension, and systemic paralysis that eventually leads to death. According to French botanist Pierre Boiteau, generations of Malagasy people have known about its poisonous properties, as it was used as a poison in ordeal trials even before tangena fruit was used for this purpose. This gave the flower one of its Malagasy names, vonenina, from vony enina meaning "flower of remorse".
As an ornamental plant, it is valued for its ability to grow in dry and nutritionally deficient conditions. It is popular in subtropical gardens where temperatures never drop below 5–7 °C (41–45 °F), and is grown as a warm season bedding plant in temperate gardens. It is known for its long flowering period: it blooms year-round in tropical conditions, and from spring to late autumn in warm temperate climates. It prefers full sun and well-drained soil. Numerous cultivars have been selected for variation in flower color (including white, mauve, peach, scarlet, and reddish orange) and for tolerance of cooler growing conditions in temperate regions. Notable cultivars include 'Albus' with white flowers, 'Grape Cooler' which is rose-pink and cool-tolerant, the Ocellatus Group with various colors, and 'Peppermint Cooler' which is white with a red center and cool-tolerant. In the southern United States, it is still often referred to by the common name "Vinca" even though botanists have reclassified it, and it can often be found growing along roadsides. In the United Kingdom, it has gained the Royal Horticultural Society's Award of Garden Merit, confirmed in 2017.
The chemotherapy medications vinblastine and vincristine, used to treat several types of cancers, are produced by this plant and are biosynthesized from the coupling of the alkaloids catharanthine and vindoline. Vinorelbine, a newer semi-synthetic chemotherapeutic agent used to treat non-small-cell lung cancer, can be prepared either from vindoline and catharanthine or from the vinca alkaloid leurosine, via anhydrovinblastine in both cases. The insulin-stimulating compound vincoline has been isolated from the plant.
