Rheum australe

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                           Rheum australe D. Don, Prodr. Fl. Nepal. 75. 1825.
Rheum australe with young inflorescence

Nomenclature and Taxonomy

Rheum australe is known as Rhubarb in English but it is called Khaghyun (Gurung), Akase chuk, Chulthi amilo, Padamchal (Nepali), Atvhowa, Chyurcha (Sherpa), Kyunpa-rim (Tamang), Gyasa (Tibetan) in different languages of Nepal. It belongs to family Polygonaceaeand is given with synonyms Rheum emodi Wallich ex Meissner. [1]

Plant Description

Rheum australe is a herb, 0.7-2 m tall. Rhizomes and roots are stout. Stem is sulcate, glabrous, pubescent only at nodes. Petiole of basal leaf is equal to blade or slightly longer, pubescent. Leaf blade is ovate-elliptic or broadly ovate, large, 20-50 × 18-40 cm, abaxially pilose, basal veins are 5-7, base cordate, margin entire, sinuolate, apex obtuse. Stem leaves are ovate, narrow; ocrea large, pubescent, clasping. Panicle is large, 2- or 3-branched, densely papilliferous. Pedicel is muricate, jointed below middle. Perianth is spreading, purple-red, 3-3.5 mm; with outer 3 smaller, oblong-elliptic, ca. 1.5 × 1 mm; inner 3 very broadly elliptic or rarely orbicular, ca. 2.5 × 2 mm. Filaments are subulate. Ovary is rhomboid-obovoid; stigma oblate, muricate. Fruit is ovoid-ellipsoid or broadly ellipsoid, 9-10 × 7-8.5 cm, base subcordate, apex retuse or not; wings are purple-red, ca. 2.5 mm wide; longitudinal veins near margin. Seeds are ovoid. [2]

Ecology and Distribution

Rheum australe is distributed in China, India, Myanmar, Nepal, Pakistan, Sikkim. It grows in grassy slopes at 3400 - 4300 m. [2] In Nepal, it grows throughout the country at 3200 - 4200 m on open rocky ground. [1]

Phenology and Reproduction

Rheum australe flowers in June to July and fruits in August to September. It propagates by seeds or root offshoots. [1]

Economic Value

Rheum australe is important for dyestuff, food, and medicine. Its rhizome yields a bright yellow dye; petioles are pickled after drying. Rhizome is used as medicine. ref name="b_c_mandha"> Manandhar, N. P. (2002). Plants and People of Nepal. Portland, Oregon, USA: Timber Press. pp. 394.</ref>

Phytochemistry and Pharmacology

Rheum australe is used in different diseases and ailments. Its rhizome is purgative, astringent, tonic, aperient, and stomachic. [1]

Rheum australe exhibits different pharmacological activities such as antidiabetic, anti-inflammatory, antifungal, antimicrobial, antioxidant, anticancer, hepatoprotective and immune-enhancing activities. [3]

Rheum australe contains numerous secondary metabolites belonging to anthraquinones, stilbenes, anthrones, oxantrone ethers and esters, chromones, flavonoids, carbohydrate, lignans, phenols and sterols. [3]

Diseases and Pathogens

References

  1. 1.0 1.1 1.2 1.3 Manandhar, N. P. (2002). Plants and People of Nepal. Portland, Oregon, USA: Timber Press. pp. 394.
  2. 2.0 2.1 Bao, B. J. & Grabovskaya-Borodina, A. E. (2003). RHEUM Linnaeus, Sp. Pl. 1: 371. 1753. 大黄属 da huang shu. In Flora of China Editorial Committee (Eds.), Flora of China Volume 5 [PDF Online], pp. 341 - 350. Retrieved from http://flora.huh.harvard.edu/china//PDF/PDF05/Rheum.pdf
  3. 3.0 3.1 Rokaya, M. B., Münzbergová, Z., Timsina, B., & Bhattarai, K. R. (2012). Rheum australe D. Don: a review of its botany, ethnobotany, phytochemistry and pharmacology. Journal of Ethnopharmacology, 141(3), 761-74. doi: 10.1016/j.jep.2012.03.048. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/22504148