Indian snakeroot (Rauvolfia serpentina, (L.) Benth. ex Kurz 1877)

Identity

Indian snakeroot (Rauvolfia serpentina (L.) Benth. ex Kurz, 1877), also known as serpentine wood or sarpagandha, is a perennial undershrub in the genus Rauvolfia, family Apocynaceae. Linnaeus first described it as Ophioxylon serpentinum in 1753; Bentham, published by Kurz, transferred it to Rauvolfia in 1877, the name now accepted by POWO. ^{1 2}

Its taproot yielded reserpine in 1952, helping establish one of the earliest modern treatments for high blood pressure. Demand for its alkaloids distinguishes this modest undershrub from the better-known ornamental members of its family.

The Sanskrit name sarpagandha combines sarpa (snake) and gandha (smell or remedy). It evokes both the twisted, unbranched root and the plant's traditional use against snakebites. The Latin epithet serpentina draws on the same snake-like image. ⁴

Recognition

An evergreen undershrub with a thick, unbranched taproot, Indian snakeroot has yellowish-brown root bark. Wild plants commonly reach 50 cm to 1 m (1.5–3 ft) tall; under protected greenhouse cultivation they can exceed 1.5 m (5 ft). ^{5 4}

Leaves grow in whorls of three to five. They are elliptic to lance-shaped, thin-textured, hairless and glossy green above. This whorled arrangement is unusual among woody Apocynaceae, most of which bear opposite leaf pairs, and provides a quick field clue for separating the plant from other understory shrubs. ⁴

Small flowers, white to purplish pink, open in flat-topped clusters at shoot tips or in leaf axils. Each has a long corolla tube and a calyx often tinged red. Fruits form pairs of small drupes, initially green and then black at maturity. ^{4 5}

Useful taxonomy

For Indian snakeroot, POWO/WCVP accepts Rauvolfia serpentina (L.) Benth. ex Kurz. The synonymy mainly records names in the former genus Ophioxylon, under which the species circulated before its transfer to Rauvolfia:

• Ophioxylon serpentinum L. (basionym)
• Ophioxylon album Gaertn.
• Ophioxylon trifoliatum Gaertn.
• Ophioxylon obversum Miq.
• Ophioxylon salutiferum Salisb.
• Rauvolfia obversa (Miq.) Baill.
• Rauvolfia trifoliata (Gaertn.) Baill.

The genus commemorates Leonhard Rauwolf, a 16th-century German physician and botanist whose account of travels in the Levant influenced the botany of his time. Rauvolfia contains about 60 species; only a handful, including the African Rauvolfia vomitoria, reach indole alkaloid concentrations comparable to those of Indian snakeroot. ^{1 3}

Habitat and range

From the Indian subcontinent, Indian snakeroot's native range reaches southern China and western Malaysia. It includes India, Nepal, Pakistan, Bangladesh, Myanmar, Thailand, southern China, Malaysia and Indonesia. The plant occupies moist mountain forest and shaded understory from sea level to about 2,100 m (6,900 ft), in areas with high rainfall. ^{5 3}

Intensive root harvesting for the pharmaceutical industry has reduced wild populations across much of that range. Since 2007, the species has been listed in CITES Appendix II, which regulates international trade without banning it. This conservation status should be distinguished from dedicated agricultural cultivation, now the main source of raw material. ⁷

Annual rainfall requirements are high, about 1,500–3,500 mm (59–138 in), and the soil should never dry out completely. These requirements explain its association with strongly monsoonal regions and the need for a heated greenhouse or conservatory when growing it outside suitable warm, humid climates. ⁵

Life cycle and reproduction

Tropical flowering extends from spring into summer, peaking during the rainy season. After fruit set, the paired fruits ripen within a few weeks, changing from green to glossy black as they mature on the plant. ⁴

Cultivators mainly propagate Indian snakeroot by seed, the most reliable route to a well-formed taproot. Stem cuttings are possible but produce a less dense root system. Roots become harvestable after 18 months to two years, when their alkaloid concentration reaches its maximum; harvesting generally takes place in the dry season. ⁵

Uses and risks

Ayurvedic medicine has used Indian snakeroot roots for centuries under the name sarpagandha, traditionally for snakebites, fever and mental disorders. These historical uses explain its medicinal importance and should be understood as traditional practice rather than directions for treatment. ⁴

Indian chemists isolated several root alkaloids as early as 1931. In 1949, cardiologist Rustom Jal Vakil published a study in the British Heart Journal involving 50 patients with hypertension treated with powdered root: 85% showed lower systolic pressure after four weeks. In 1952, Swiss chemists Müller, Schlittler and Bein isolated reserpine, responsible for about half the plant's activity. ⁶

The whole plant, especially the root bark, contains dozens of bitter indole alkaloids. Uncontrolled ingestion can cause marked low blood pressure, sedation, dizziness and digestive upset. Self-medication with the raw plant is discouraged because the margin between an active dose and a toxic dose is narrow. ⁸

Reserpine's role as a first-line blood pressure medicine declined sharply after the 1960s, limited by documented side effects including sedation, nasal congestion and, at high doses, depressive episodes. The molecule remains studied and prescribed in low doses, often in combination with other treatments. ⁶

Varieties, look-alikes and related plants

Indian snakeroot has no stable horticultural cultivar. In India it remains a medicinal crop for pharmaceutical and Ayurvedic use, and is rarely chosen as an ornamental because decorative selections are not available.

Identification problems chiefly involve the following plants:

• Rauvolfia vomitoria, an African species with similar alkaloids, sometimes substituted in herbal medicine;
• Rauvolfia tetraphylla, with leaves in whorls of four and fruits that turn red when ripe;
• young woody Apocynaceae with whorled leaves, for which flowering is needed for reliable identification.

The full scientific name, checked against a reference such as POWO, is more reliable than the common name sarpagandha alone for distinguishing Indian snakeroot from its relatives. This matters especially when buying dried roots: they take 18 months to two years to reach harvestable size, and a poorly identified batch may come from a related species with a different alkaloid profile.

Main sources

• Plants of the World Online / Kew, Rauvolfia serpentina (L.) Benth. ex Kurz
• International Plant Names Index, Rauvolfia serpentina record
• GBIF, Rauvolfia serpentina (L.) Benth. ex Kurz
• Encyclopaedia Britannica, Rauvolfia serpentina
• Plants For A Future, Rauvolfia serpentina
• Isharwal & Gupta, 2006, Texas Heart Institute Journal, Rustom Jal Vakil and Rauwolfia research
• CITES, Appendices I, II and III (Rauvolfia serpentina, Appendix II)
• USDA PLANTS Database, Rauvolfia serpentina profile (RASE4)