Rosy periwinkle berwarna merahThe rosy periwinkle (Catharanthus roseus) is native only to the tropical forests of Madagascar, the world's fourth largest island, found off the east coast of Africa.
In the wild, it is an endangered plant; the main cause of decline is habitat destruction by slash and burn agriculture. It is also however widely cultivated and is naturalised in subtropical and tropical areas of the world. It is an evergreen subshrub or herbaceous plant growing to 1 m tall. The leaves are oval to oblong, 2.5–9 cm long and 1–3.5 cm broad, glossy green, hairless, with a pale midrib and a short petiole 1–1.8 cm long; they are arranged in opposite pairs. The flowers are white to dark pink with a darker red centre, with a basal tube 2.5-3 cm long and a corolla 2–5 cm diameter with five petal-like lobes. The fruit is a pair of follicles 2–4 cm long and 3 mm broad.
In the wild, it is an endangered plant; the main cause of decline is habitat destruction by slash and burn agriculture. It is also however widely cultivated and is naturalised in subtropical and tropical areas of the world. It is an evergreen subshrub or herbaceous plant growing to 1 m tall. The leaves are oval to oblong, 2.5–9 cm long and 1–3.5 cm broad, glossy green, hairless, with a pale midrib and a short petiole 1–1.8 cm long; they are arranged in opposite pairs. The flowers are white to dark pink with a darker red centre, with a basal tube 2.5-3 cm long and a corolla 2–5 cm diameter with five petal-like lobes. The fruit is a pair of follicles 2–4 cm long and 3 mm broad.
Uses
The species has long been cultivated for herbal medicine and as an ornamental plant.
The species has long been cultivated for herbal medicine and as an ornamental plant.
As herbal medicine, this pretty plant gives us two very important cancer-fighting medicines: vinblastine and vincristine. Vinblastine has helped increase the chance of surviving childhood leukaemia from 10% to 95%, while vincristine is used to treat Hodgkins' Disease. Traditional Madagascan healers used the rosy periwinkle for treating diabetes. This led to its study by western scientists who then discovered its anti-cancer properties.
These medicines have proved very profitable for global drug companies. Worldwide sales are worth over £75 million a year, but virtually none of this money finds its way back to Madagascar, one of the poorest countries in the world. Recent international agreements have tried to ensure that more profits from the commercial development of animal and plant species return to the countries of origin.
C. roseus is also used in plant pathology as an experimental host for phytoplasmas. This is because it is easy to infect with a large majority of phytoplasmas, and also often has very distinctive symptoms such as phyllody and significantly reduced leaf size.
As an ornamental plant, it is appreciated for its hardiness in dry and nutritionally deficient conditions, popular in subtropical gardens where temperatures never fall below 5 °C to 7 °C, and as a warm-season bedding plant in temperate gardens. It is noted for its long flowering period, throughout the year in tropical conditions, and from spring to late autumn in warm temperate climates. Full sun and well-drained soil are preferred. Numerous cultivars have been selected, for variation in flower colour (white, mauve, peach, scarlet and reddish-orange), and also for tolerance of cooler growing conditions in temperate regions. Notable cultivars include 'Albus' (white flowers), 'Grape Cooler' (rose-pink; cool-tolerant), the Ocellatus Group (various colours), and 'Peppermint Cooler' (white with a red centre; cool-tolerant).
