Senna (plant)

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Senna
Senna alexandrina
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Rosids
Order: Fabales
Family: Fabaceae
Subfamily: Caesalpinioideae
Tribe: Cassieae
Subtribe: Cassiinae
Genus: Senna
Mill.
Type species
Senna alexandrina Mill.
Species

Around 260-350, see text

Synonyms

Cathartocarpus (partim)
Chamaefistula
Diallobus
Earleocassia
Herpetica
Isandrina
Palmerocassia
Pseudocassia

Senna (from Arabic sanā), the sennas, is a large genus of flowering plants in the legume family Fabaceae, and the subfamily Caesalpinioideae. This diverse genus is native throughout the tropics, with a small number of species in temperate regions. The number of species is estimated to be from about 260[1] to 350.[2] The type species for the genus is Senna alexandrina. About 50 species of Senna are known in cultivation.[3]

Description[edit]

Senna includes herbs, shrubs, and trees. The leaves are pinnate with opposite paired leaflets. The inflorescences are racemes at the ends of branches or emerging from the leaf axils. The flower has five sepals and five usually yellow petals. There are ten straight stamens. The stamens may be different sizes, and some are staminodes. The fruit is a legume pod containing several seeds.[4]

Systematics[edit]

Chamaecrista, Cassia, and Senna form a monophyletic group which some authors have called Cassia sensu lato.[5] In 1982, the group was named Cassiinae and classified as a subtribe of the tribe Cassieae.[6] Cassieae contains 21 genera and is now known to be polyphyletic,[5] but the classification is still accepted because a revision of Fabaceae has yet to be published.[5]

The genus Senna has had a complex taxonomic history.[7] What is now known as Senna was included by Linnaeus in his concept of Cassia in Species Plantarum in 1753.[8] Philip Miller segregated Senna from Cassia in 1754 in the fourth edition of The Gardeners Dictionary.[9] Until 1982, many authors, following Linnaeus, did not recognize Senna and Chamaecrista, but included them in a broadly circumscribed Cassia sensu lato. Phylogenetic analyses of DNA have shown that Chamaecrista, Cassia, and Senna are all monophyletic, but the relationships between these three genera have not been resolved.[1] They are therefore shown in phylogenetic trees as a tritomy.

Ecology[edit]

Bark of Senna siamea

The caterpillars of many Lepidoptera species feed on Senna plants. The Black Witch (Ascalapha odorata), Two-barred Flasher (Astraptes fulgerator), Common Emigrant (Catopsilia pomona), and Mottled Emigrant (Catopsilia pyranthe) have all been recorded on candle bush (S. alata), for example.

Senna are pollinated by a variety of bees, especially large female bees in genera such as Xylocopa.[1] Some species also have extrafloral nectaries on the leaves or flower stalks, which attract ants but do not benefit pollinators. The ants probably deter herbivores.[1]

Uses[edit]

Some Senna species are used as ornamental plants and landscaping. There are species adapted to many climate types.

Cassia gum, an extract of the seeds of Chinese senna (S. obtusifolia), is used as a thickening agent. The leaves and flowers of Siamese cassia (S. siamea) are used in some Southeast Asian cuisines, such as Thai and Lao cuisines. They are known as khi-lek in Thai, and are used in curries.[10]

Senna italica ssp. italica (syn. Cassia obovata), often called neutral henna, is used as a hair treatment. It has effects similar to henna but without the red color, giving hair more of a yellow tinge. The active component is an anthraquinone derivative called chrysophanic acid or chrysophanol (1,8-Dihydroxy-3-methylanthraquinone), which is also found in higher concentrations in rhubarb root. Chrysophanol has been reported to have antimicrobial[11] and anti-inflammatory properties.[12] It is also a component of the pheromone of the beetle Galeruca tanaceti.[13]

In medicine[edit]

Sennas have for millennia played a major role in herbalism and folk medicine. Alexandrian senna (S. alexandrina) has long been traded commercially.

Senna glycosides, or sennosides, are used in modern medicine as laxatives.[14] Senna drugs contain the dried leaves of S. alexandrina. The glycosides increase gastric fluid secretion and bowel motility, producing laxative action. Senna preparations are available in powders, granules, tablets, oral infusions, and syrups. It is also available in combination with the dietary fiber psyllium to add bulk to the bowel contents.[15] The products are only recommended for short-term use, and chronic use and abuse of senna has been associated with organ failure.[16]

Resveratrol was first isolated from Senna quinquangulata

Several Senna species are used as herbal remedies in Nigeria to treat various conditions, including constipation, fungal skin infections, and hemorrhoids.[17]

Selected species[edit]

References[edit]

  1. ^ a b c d Marazzi, B., et al. (2006). "Phylogenetic relationships within Senna (Leguminosae, Cassiinae) based on three chloroplast DNA regions: patterns in the evolution of floral symmetry and extrafloral nectaries". American Journal of Botany 93 (2): 288–303. doi:10.3732/ajb.93.2.288. 
  2. ^ Randell, B. R. and B. A. Barlow. 1998. Senna. pp 89-138. In: A. S. George (executive editor). Flora of Australia volume 12. Australian Government Publishing Service: Canberra, Australia.
  3. ^ Huxley, A., et al. (1992). The New Royal Horticultural Society Dictionary of Gardening. The Macmillan Press, Limited: London. The Stockton Press: New York. ISBN 978-0-333-47494-5 (set).
  4. ^ Senna. Flora of China.
  5. ^ a b c Lewis, G., et al. 2005. Legumes of the World. Royal Botanic Gardens, Kew: Richmond, England. ISBN 978-1-900347-80-8
  6. ^ Irwin, H. S. and R. C. Barneby. 1982. The American Cassiinae: A synoptical revision of Leguminosae tribe Cassieae subtribe Cassiinae in the New World. Memoirs of the New York Botanical Garden 35, 1-119.
  7. ^ Singh, V. 2001. Monograph on the Indian Subtribe Cassiinae. Scientific Publishers (India): Jodhpur, India.
  8. ^ Linnaeus, C. 1753. Cassia. page 376. In: Species Plantarum volume 1. Cassia (including Senna In:Species Plantarum volume 1 At: Biodiversity Heritage Library
  9. ^ Miller, P. 1754. The Gardeners Dictionary, Abridged 4th edition.
  10. ^ Teangpook, C., et al. (2011). Production and nutrition of Khi Lek (Siamese cassia) curry from central Thailand. Kasetsart. J. (Nat. Sci.) 45, 510-20.
  11. ^ García-Sosa, K., et al. (2006). Chrysophanol, an antimicrobial anthraquinone from the root extract of Colubrina greggii. J. Mex. Chem. Soc. 50(2), 76-78.
  12. ^ Kim, S., et al. (2010). Anti-inflammatory activity of chrysophanol through the suppression of NF-kB/Caspase-1 activation in vitro and in vivo. Molecules 15(9), 6436-51.
  13. ^ http://www.pherobase.com/database/compound/compounds-detail-chrysophanol.php
  14. ^ Spiller, H., et al. (May 2003). "Skin breakdown and blisters from senna-containing laxatives in young children". The Annals of Pharmacotherapy 37 (5): 636–9. doi:10.1345/aph.1C439. ISSN 1060-0280. PMID 12708936. 
  15. ^ Agarwal, V. and M. Bajpai. (2010). Pharmacognostical and biological studies on senna & its products: an overview. International Journal of Pharma and Bio Sciences 1(2) 1-10.
  16. ^ Vanderperren, B., et al. (2005). Acute liver failure with renal impairment related to the abuse of senna anthraquinone glycosides. The Annals of Pharmacotherapy 39(7-8), 1353-57.
  17. ^ Ogunkunle, A. T. J. and T. A. Ladejobi, T. (2006). Ethnobotanical and phytochemical studies on some species of Senna in Nigeria. African Journal of Biotechnology 5(21), 2020-23.
  18. ^ a b GRIN Species Records of Senna. Germplasm Resources Information Network (GRIN).
  19. ^ Senna cardiosperma. The Plant List.
  20. ^ a b Senna. Integrated Taxonomic Information System (ITIS).
  21. ^ "kolomona, kalamona, heuhiuhi, uhiuhi". Hawaiian Ethnobotany Online Database. Bernice P. Bishop Museum. Retrieved 2009-03-10. 
  22. ^ "Senna gaudichaudii". Hawaiian Native Plant Propagation Database. University of Hawaiʻi at Mānoa. Retrieved 2009-03-10. 
  23. ^ Senna magnifolia. The Plant List.
  24. ^ Senna notabilis. Germplasm Resources Information Network (GRIN).
  25. ^ Senna occidentalis. Germplasm Resources Information Network (GRIN).
  26. ^ Senna oligoclada. The Plant List.
  27. ^ Senna pleurocarpa. Germplasm Resources Information Network (GRIN).

External links[edit]