World Library  
Flag as Inappropriate
Email this Article

Aloes

Article Id: WHEBN0008326025
Reproduction Date:

Title: Aloes  
Author: World Heritage Encyclopedia
Language: English
Subject: List of Jesus-related topics, Illtyd Buller Pole-Evans, Huntington Desert Garden
Collection:
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Aloes

For other uses, see Aloe (disambiguation).
Aloe succotrina
Species

See Species


Aloe /ˈæl/, also Aloë, is a genus containing over 500 species of flowering succulent plants.[1] The most widely known species is Aloe vera, or "true aloe", so called because, though probably extinct in the wild, it is cultivated as the standard source of so-called "aloe vera" for assorted pharmaceutical purposes.[2] Other species, such as Aloe ferox, also are cultivated or harvested from the wild for similar applications.

The genus is native to Africa; species are found in southern Africa, the mountains of tropical Africa, various islands off the coast of Africa including Sardinia, Madagascar, and the Arabian Peninsula.

The APG III system (2009) places the genus in the family Xanthorrhoeaceae, subfamily Asphodeloideae.[3] In the past, it has also been assigned to families Aloaceae and Liliaceae or lily family. The plant Agave americana, which is sometimes called "American aloe", belongs to the Asparagaceae, a different family.

The genus is native to tropical and southern Africa, Madagascar, and Jordan to the Arabian Peninsula.[4]

Description

Most Aloe species have a rosette of large, thick, fleshy leaves. Aloe flowers are tubular, frequently yellow, orange, pink, or red, and are borne, densely clustered and pendant, at the apex of simple or branched, leafless stems. Many species of Aloe appear to be stemless, with the rosette growing directly at ground level; other varieties may have a branched or unbranched stem from which the fleshy leaves spring. They vary in color from grey to bright-green and are sometimes striped or mottled. Some aloes native to South Africa are tree-like (arborescent).[5]

Systematics

The APG III system (2009) places the genus in the family Xanthorrhoeaceae, subfamily Asphodeloideae.[3] In the past it has also been assigned to the families Liliaceae and Aloeaceae, as well as the family Asphodelaceae, before this was merged into the Xanthorrhoeaceae.

The circumscription of the genus has varied widely. Many genera, such as Lomatophyllum,[6] have been brought into synonymy. Species at one time placed in Aloe, such as Agave americana, have been moved to other genera.[7]

Species

Main article: List of Aloe species

Over 500 species are accepted in the genus Aloe, plus even more synonyms and unresolved species, subspecies, varieties, and hybrids. Some of the accepted species are:[1]

Uses

Aloe species are frequently cultivated as ornamental plants both in gardens and in pots. Many aloe species are highly decorative and are valued by collectors of succulents. Aloe vera is used both internally and externally on humans, and is claimed to have some medicinal effects, which have been supported by scientific and medical research.[2] They can also be made into types of special soaps.

Historical uses

Historical use of various aloe species is well documented. Documentation of the clinical effectiveness is available, although relatively limited.[2][8]

Of the 500+ species, only a few were used traditionally as a herbal medicine, Aloe vera again being the most commonly used species. Also included are A. perryi and A. ferox. The Ancient Greeks and Romans used Aloe vera to treat wounds. In the Middle Ages, the yellowish liquid found inside the leaves was favored as a purgative. Unprocessed aloe that contains aloin is generally used as a laxative, whereas processed juice does not usually contain significant aloin.

Some species, particularly Aloe vera, are used in alternative medicine and first aid. Both the translucent inner pulp and the resinous yellow aloin from wounding the aloe plant are used externally to relieve skin discomforts. As an herbal medicine, Aloe vera juice is commonly used internally to relieve digestive discomfort.[9][10]

Relatively few studies about possible benefits of aloe gel taken internally have been conducted. Components of Aloe have shown the possibility of inhibiting tumor growth in animal studies, but these effects have not been demonstrated clinically in humans.[11] Some studies in animal models indicate that extracts of Aloe have a significant antihyperglycemic effect, and may be useful in treating Type II diabetes, but these studies have not been confirmed in humans.[12]

According to Cancer Research UK, a potentially deadly product called T-UP is made of concentrated aloe, and promoted as a cancer cure. They say "there is currently no evidence that aloe products can help to prevent or treat cancer in humans".[13]

Aloin in OTC laxative products

On May 9, 2002, the US Food and Drug Administration issued a final rule banning the use of aloin, the yellow sap of the aloe plant, for use as a laxative ingredient in over-the-counter drug products.[14] Most aloe juices today do not contain significant aloin.

Chemical properties

According to W. A. Shenstone, two classes of aloins are recognized: (1) nataloins, which yield picric and oxalic acids with nitric acid, and do not give a red coloration with nitric acid; and (2) barbaloins, which yield aloetic acid (C7H2N3O5), chrysammic acid (C7H2N2O6), picric and oxalic acids with nitric acid, being reddened by the acid. This second group may be divided into a-barbaloins, obtained from Barbados Aloe, and reddened in the cold, and b-barbaloins, obtained from Socotrine and Zanzibar Aloe, reddened by ordinary nitric acid only when warmed or by fuming acid in the cold. Nataloin (2C17H13O7·H2O) forms bright-yellow scales, barbaloin (C17H18O7) prismatic crystals. Aloe species also contain a trace of volatile oil, to which their odour is due.

Heraldic occurrence

Aloe rubrolutea occurs as a charge in heraldry, for example in the Civic Heraldry of Namibia.[15]

Images

See also

References

External links

  • Aloe images
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 



Copyright © World Library Foundation. All rights reserved. eBooks from World eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.