Catharanthus is a genus of flowering plants in the family Apocynaceae, order Gentianales, commonly known as periwinkles. The genus comprises eight or nine accepted species of perennial herbs and subshrubs, nearly all endemic to the island of Madagascar; the sole exception is Catharanthus pusillus, native to India, Sri Lanka, and the Western Himalayas.
Plants of the genus are characterized by simple, opposite leaves and solitary flowers borne in the leaf axils. Each flower has a calyx with five narrow lobes and a tubular corolla with five spreading lobes, typically in shades of pink, purple, or white. Fruits consist of two divergent follicles containing many seeds.
The genus was originally treated under Vinca by Carl Linnaeus in 1753, who described the flagship species as Vinca rosea. After several partial proposals in the early nineteenth century — including Reichenbach's 1828 genus Lochnera — George Don formally established Catharanthus in 1838, distinguishing it from Vinca on the basis of fruit shape and growth habit. Subsequent revisions by de Candolle (1844) and Pichon (1949) refined species delimitation, and in 2015 the genus was expanded with the discovery of Catharanthus makayensis in Madagascar.
By far the best-known member is Catharanthus roseus (rosy periwinkle, Madagascar periwinkle), which is the source of roughly 130 monoterpenoid indole alkaloids — often called vinca or catharanthus alkaloids — including vinblastine and vincristine, two chemotherapy drugs used to treat leukemia, lymphoma, and testicular cancer. The species is also widely cultivated as an ornamental garden plant, with cultivars producing flowers in pink, red, lilac, and white. Catharanthus roseus has been naturalized throughout tropical and subtropical regions worldwide.
Etymology
The genus name Catharanthus derives from the Greek words meaning "pure flower." It was formally established by George Don in 1838 to separate the Madagascar periwinkles from the genus Vinca, with which they had previously been classified since Linnaeus first described Vinca rosea in 1753.
Distribution
Almost all species of Catharanthus are endemic to Madagascar, where they can grow at elevations up to 2000 m, particularly in the central plateau mountains. One species, C. pusillus, is native to India, Sri Lanka, and the Western Himalayas. Catharanthus roseus has been widely introduced and naturalized in tropical and subtropical regions around the world through cultivation.
Cultural Uses
Catharanthus roseus has a long history of use in traditional medicine across India, Africa, the Caribbean, Cuba, Jamaica, Malaysia, and the Americas — for treating hyperglycemia, asthma, hypertension, malaria, eye conditions, sore throats, and insect stings. From the 1950s onward, intensive pharmaceutical research yielded the vinca alkaloids vinblastine and vincristine, now standard chemotherapy drugs for leukemia, lymphoma, and testicular cancer. The root alkaloid ajmalicine is used to treat hypertension. Many cultivars of C. roseus are grown worldwide as ornamental garden plants.
Taxonomy Notes
The genus has undergone repeated revision since Linnaeus first described Vinca rosea in 1753. Reichenbach proposed the genus Lochnera in 1828; Endlicher and Don independently established Catharanthus in 1838. De Candolle (1844) subdivided the group into sections within Vinca, and Pichon (1949) added C. scitulus and renamed the section Androyella. The most recent addition, C. makayensis, was described in 2015. The fruits of Catharanthus (filiform follicles) and the erect or procumbent perennial habit formally distinguish the genus from the climbing Vinca.
