aloe

{{Automatic taxobox

| taxon = Aloe

| image = Aloe arborescens on Monte Vumba (4387600468).jpg

| image_caption = Aloe arborescens

| authority = L.

| display_parents = 2

| subdivision_ranks = Species

| subdivision = See Species

| type_species = Aloe perfoliata

| type_species_authority = L.

| synonyms_ref =

| synonyms = {{Species list|hidden=yes

|Agriodendron|Endl.

|× Alamaealoe|P.V.Heath

|× Alchamaloe|G.D.Rowley

|× Aleptoe|G.D.Rowley

|× Allauminia|G.D.Rowley

|× Allemeea|P.V.Heath

|× Aloella|G.D.Rowley

|Aloinella|(A.Berger) Lemée

|× Aloptaloe|P.V.Heath

|Atevala|Raf.

|× Bleckara|P.V.Heath

|Busipho|Salisb.

|Chamaealoe|A.Berger

|× Chamaeleptaloe|Rowley

|Guillauminia|A.Bertrand

|× Lemeea|P.V.Heath

|× Leminia|P.V.Heath

|Leptaloe|Stapf

|× Leptaloinella|G.D.Rowley

|× Leptauminia|G.D.Rowley

|× Lomataloe|Guillaumin

|Lomatophyllum|Willd.

|Pachidendron|Haw.

|Phylloma|Ker Gawl.

|Rhipidodendrum|Willd.

}}

File:Split Aloe.jpgs, such as this aloe, store water in their enlarged fleshy leaves, stems, or roots, as shown in this split aloe leaf. This allows them to survive in arid environments.]]

File:Aloe Vera houseplant.jpg

Aloe ({{IPAc-en|ˈ|æ|l|oʊ|(|i|)|,_|ə|ˈ|l|oʊ|i}};{{cite web | url=https://www.merriam-webster.com/dictionary/aloe | title=Definition of ALOE | date=9 August 2023 }}{{Cite web|url=https://www.oxfordlearnersdictionaries.com/us/definition/english/aloe|title=aloe noun - Definition, pictures, pronunciation and usage notes | Oxford Advanced Learner's Dictionary at OxfordLearnersDictionaries.com|accessdate=6 April 2023}}{{Cite web|url=https://dictionary.cambridge.org/dictionary/english/aloe|title=ALOE | English meaning - Cambridge Dictionary|accessdate=6 April 2023}}{{cite web | url=https://www.ahdictionary.com/word/search.html?q=aloe | title=The American Heritage Dictionary entry: Aloe }} also written Aloë) is a genus containing over 650 species of flowering succulent plants.WFO (2022): Aloe L. Published on the Internet;http://www.worldfloraonline.org/taxon/wfo-4000001341. Accessed on: 06 Nov 2022 The most widely known species is Aloe vera, or "true aloe". It is called this because it is cultivated as the standard source for assorted pharmaceutical purposes.{{cite web |url=http://nccih.nih.gov/health/aloevera |title=Aloe Vera: Science and Safety |publisher=NIH National Center for Complementary and Integrative Health |date=April 2012 |access-date=31 March 2013}} Other species, such as Aloe ferox, are also cultivated or harvested from the wild for similar applications.{{Cite journal|last1=Salehi|first1=Bahare|last2=Albayrak|first2=Sevil|last3=Antolak|first3=Hubert|last4=Kręgiel|first4=Dorota|last5=Pawlikowska|first5=Ewelina|last6=Sharifi-Rad|first6=Mehdi|last7=Uprety|first7=Yadav|last8=Tsouh Fokou|first8=Patrick Valere|last9=Yousef|first9=Zubaida|last10=Amiruddin Zakaria|first10=Zainul|last11=Varoni|first11=Elena Maria|date=2018-09-19|title=Aloe Genus Plants: From Farm to Food Applications and Phytopharmacotherapy|journal=International Journal of Molecular Sciences|volume=19|issue=9|page=2843|doi=10.3390/ijms19092843|issn=1422-0067|pmc=6163315|pmid=30235891|doi-access=free}}

The APG IV system (2016) places the genus in the family Asphodelaceae, subfamily Asphodeloideae. Within the subfamily it may be placed in the tribe Aloeae.Stevens, P.F. (2001 onwards). "[http://www.mobot.org/MOBOT/research/APweb/orders/asparagalesweb.htm#aspasphodelaceae Asphodelaceae]". Angiosperm Phylogeny Website. Retrieved 2016-06-09. In the past, it has been assigned to the family Aloaceae (now included in the Asphodeloidae) or to a broadly circumscribed family Liliaceae (the 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, Jordan, the Arabian Peninsula, and various islands in the Indian Ocean (Mauritius, Réunion, Comoros, etc.). A few species have also become naturalized in other regions (Mediterranean, India, Australia, North and South America, Hawaiian Islands, etc.).{{cite web |url=https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:30106039-2 |title=Aloe |date=2022 |work=Plants of the World Online |publisher=Royal Botanic Gardens, Kew |access-date=16 December 2022}}

Etymology

The genus name Aloe is derived from the Arabic word al'uluh, meaning "bitter and shiny substance" or from Hebrew {{lang|he|אוהלים}} ahalim, plural of {{lang|he|אוהל}} ahal.{{cite web|url=https://www.etymonline.com/word/aloe |title=Aloe |last1=Harper |first1=Douglas |publisher=Online Etymology Dictionary |access-date=1 July 2021 |date=2021}}{{cite journal |last1=Guo |first1=Xiaoqing |last2=Mei |first2=Nan |title=Aloe vera: A review of toxicity and adverse clinical effects |journal=J Environ Sci Health C Environ Carcinog Ecotoxicol Rev |date=2 April 2016 |volume=34 |issue=2 |pages=77–96 |doi=10.1080/10590501.2016.1166826 |pmid=26986231 |pmc=6349368 |bibcode=2016JESHC..34...77G }}{{cite web |url=https://www.balashon.com/2008/03/aloe.html |title=aloe |last1=Curwin |first1=David |date=16 March 2008 |website=Balashon - Hebrew Language Detective |access-date=16 December 2022 }}

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).{{cite book|last=Rodd|first=Tony|title=Trees: a Visual Guide|year=2008|publisher=University of California Press|location=Berkeley|isbn=9780520256507|page=131|author2=Stackhouse, Jennifer}}

Systematics

The APG IV system (2016) places the genus in the family Asphodelaceae, subfamily Asphodeloideae. In the past it has also been assigned to the families Liliaceae and Aloeaceae, as well as the family Asphodelaceae sensu stricto, before this was merged into the Asphodelaceae sensu lato.

The circumscription of the genus has varied widely. Many genera, such as Lomatophyllum,{{cite web |title=Lomatophyllum |work=World Checklist of Selected Plant Families |publisher=Royal Botanic Gardens, Kew |url=http://apps.kew.org/wcsp/namedetail.do?name_id=280369 |access-date=2013-02-25}} have been brought into synonymy. Species at one time placed in Aloe, such as Agave americana, have been moved to other genera.{{cite web |title=Aloe americana |work=World Checklist of Selected Plant Families |publisher=Royal Botanic Gardens, Kew |url=http://apps.kew.org/wcsp/namedetail.do?name_id=297041 |access-date=2013-02-25}} Molecular phylogenetic studies, particularly from 2010 onwards, suggested that as then circumscribed, Aloe was not monophyletic and should be divided into more tightly defined genera. In 2014, John Charles Manning and coworkers produced a phylogeny in which Aloe was divided into six genera: Aloidendron, Kumara, Aloiampelos, Aloe, Aristaloe and Gonialoe.

= Species =

Over 600 species are accepted in the genus Aloe, plus even more synonyms and unresolved species, subspecies, varieties, and hybrids. Some of the accepted species are:

Aloe aculeata Pole-Evans
Aloe africana Mill.
Aloe albida (Stapf) Reynolds
Aloe albiflora Guillaumin
Aloe arborescens Mill.
Aloe arenicola Reynolds
Aloe argenticauda Merxm. & Giess
Aloe bakeri Scott-Elliot
Aloe ballii Reynolds
Aloe ballyi Reynolds
Aloe brevifolia Mill.
Aloe broomii Schönland
Aloe buettneri A.Berger
Aloe camperi Schweinf.
Aloe capitata Baker
Aloe comosa Marloth & A.Berger
Aloe cooperi Baker
Aloe corallina Verd.
Aloe dewinteri Giess ex Borman & Hardy
Aloe erinacea D.S.Hardy
Aloe excelsa A.Berger
Aloe ferox Mill.
Aloe forbesii Balf.f.
Aloe helenae Danguy
Aloe hereroensis Engl.
Aloe inermis Forssk.
Aloe inyangensis Christian
Aloe jawiyon S.J.Christie, D.P.Hannon & Oakman ex A.G.Mill.
Aloe jucunda Reynolds
Aloe khamiesensis Pillans
Aloe kilifiensis Christian
Aloe maculata All.
Aloe marlothii A.Berger
Aloe mubendiensis Christian
Aloe namibensis Giess
Aloe nyeriensis Christian & I.Verd.
Aloe pearsonii Schönland
Aloe peglerae Schönland
Aloe perfoliata L.
Aloe perryi Baker
Aloe petricola Pole-Evans
Aloe polyphylla Pillans
Aloe rauhii Reynolds
Aloe reynoldsii Letty
Aloe scobinifolia Reynolds & Bally
Aloe sinkatana Reynolds
Aloe squarrosa Baker ex Balf.f.
Aloe striata Haw.
Aloe succotrina Lam.
Aloe suzannae Decary
Aloe thraskii Baker
Aloe vera (L.) Burm.f.
Aloe viridiflora Reynolds
Aloe wildii (Reynolds) Reynolds

In addition to the species and hybrids between species within the genus, several hybrids with other genera have been created in cultivation, such as between Aloe and Gasteria (× Gasteraloe), and between Aloe and Astroloba (×Aloloba).

File:Aloe diversity.jpg ]]

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 as folk or alternative medicine.{{Cite journal |last1=Woźniak |first1=Anna |last2=Paduch |first2=Roman |date=2012-02-01 |title=Aloe vera extract activity on human corneal cells |journal=Pharmaceutical Biology |volume=50 |issue=2 |pages=147–154 |doi=10.3109/13880209.2011.579980 |issn=1388-0209 |pmid=22338121|s2cid=40123094 |doi-access=free }} The Aloe species is known for its medicinal and cosmetic properties.{{Cite journal|last1=Fentaw|first1=Eshetu|last2=Dagne|first2=Kifle|last3=Wondimu|first3=Tigist|last4=Demissew|first4=Sebsebe|last5=Bjorå|first5=Charlotte S.|last6=Grace|first6=Olwen M.|date=2020-11-11|title=Uses and perceived sustainability of Aloe L. (Asphodelaceae) in the central and northern Highlands of Ethiopia|journal=South African Journal of Botany|volume=147 |pages=1042–1050 |language=en|doi=10.1016/j.sajb.2020.11.001|s2cid=228929133|issn=0254-6299|doi-access=free}} Around 75% of Aloe species are used locally for medicinal uses. The plants can also be made into types of special soaps or used in other skin care products (see natural skin care).{{Cite journal |last1=Radha |first1=Maharjan H. |last2=Laxmipriya |first2=Nampoothiri P. |date=2015-01-01 |title=Evaluation of biological properties and clinical effectiveness of Aloe vera: A systematic review |journal=Journal of Traditional and Complementary Medicine |language=en |volume=5 |issue=1 |pages=21–26 |doi=10.1016/j.jtcme.2014.10.006 |issn=2225-4110 |pmc=4488101 |pmid=26151005}}

Numerous cultivars with mixed or uncertain parentage are grown. Of these, Aloe 'Lizard Lips' has gained the Royal Horticultural Society's Award of Garden Merit.{{cite web | url= https://www.rhs.org.uk/Plants/249001/i-Aloe-i-Lizard-Lips/Details

| title = RHS Plantfinder - Aloe 'Lizard Lips'

| publisher=Royal Horticultural Society | date=2012 | access-date=5 January 2018}}

Aloe variegata has been planted on graves in the belief that this ensures eternal life.{{cite web |last1=Klopper |first1=Ronell |last2=Smith |first2=Gideon |title=Aloe genus L. |url=http://pza.sanbi.org/aloe-genus |website=PlantZAfrica |access-date=16 December 2020}}

=Historical uses=

File:Aloe, Juliana Anicia Codex.jpg, a copy, written in Constantinople in 515 AD, of Dioscorides' 1st century AD work.Folio 15 Juliana Anicia Codex]]

Historical use of various aloe species is well documented. Documentation of the clinical effectiveness is available, although relatively limited.{{cite book|title=Aloes: the Genus Aloe |year=2004 |publisher=CRC Press |location=Boca Raton |isbn=978-0-415-30672-0 |editor=Tom Reynolds}}

Of the 500+ species, only a few were used traditionally as herbal medicines, 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.{{cite web|url=http://www.superfoodliving.com/aloe-vera-juice-how-to-make-it-and-its-side-effects|title=Aloe Vera Juice - How to Make it and its Side Effects|date=November 20, 2015}}

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".{{cite web

|url=http://www.cancerresearchuk.org/cancer-help/about-cancer/treatment/complementary-alternative/therapies/aloe-vera

|title=Aloe

|publisher=Cancer Research UK

|access-date=30 August 2013

|archive-date=6 August 2014

|archive-url=https://web.archive.org/web/20140806214058/http://www.cancerresearchuk.org/cancer-help/about-cancer/treatment/complementary-alternative/therapies/aloe-vera

|url-status=dead

}}

=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.{{cite journal |title=Status of certain additional over-the-counter drug category II and III active ingredients. Final rule |journal=Fed Regist |volume=67 |issue=90 |pages=31125–7 |year=2002 |pmid=12001972 |publisher= Food and Drug Administration, HHS|last1=Food Drug Administration |first1=HHS }} 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 Aloe Socotrina 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 are used in essential oils as a safety measure to dilute the solution before they are applied to the skin.{{Cite journal|last1=Orchard|first1=Ané|last2=Kamatou|first2=Guy|last3=Viljoen|first3=Alvaro M.|last4=Patel|first4=Namita|last5=Mawela|first5=Patricia|last6=van Vuuren|first6=Sandy F.|date=2019-01-14|title=The Influence of Carrier Oils on the Antimicrobial Activity and Cytotoxicity of Essential Oils|journal=Evidence-Based Complementary and Alternative Medicine|volume=2019|pages=1–24|doi=10.1155/2019/6981305|issn=1741-427X|pmc=6348851|pmid=30733812|doi-access=free}}

= Flavoring =

Aloe perryi, A. barbadensis, A. ferox, and hybrids of this species with A. africana and A. spicata are listed as natural flavoring substances in the US government Electronic Code of Federal Regulations.{{cite web| url = http://www.ecfr.gov/cgi-bin/text-idx?SID=3a096fd1d813e0b6f476ecd1470e7e4a&node=pt21.3.172&rgn=div5#se21.3.172_1510| title = §172.510 Natural flavoring substances and natural substances used in conjunction with flavors e-CFR}} Aloe socotrina is said to be used in yellow Chartreuse.John Tellman (1900) [https://archive.org/details/practicalhotelst01tell The Practical Hotel Steward], The Hotel Monthly, Chicago

Gallery

File:Aloe vossii - plant (aka).jpg|Aloe vossii

File:Aloe rubroviolacea2.jpg|A. rubroviolacea

File:Aloe albiflora flowers.png|Not all aloes only have tublar flowers

File:Aloe africana 1.jpg|Aloe africana (Uitenhage aloe)

File:Gardenology-IMG 5394 hunt10mar.jpg|Aloe marlothii (flat-flowered aloe)

File:Aloe pluridens (3).jpg|Aloe pluridens (French aloe)

File:Aloe excelsa at Mount Coot-tha.JPG|Aloe excelsa (Zimbabwe aloe)

File:Aloe rupestris, vroeë bloeiwyse, Pretoria.jpg|Aloe rupestris (bottlebrush aloe)

File:Aloe speciosa - tilt head aloe.jpg|Aloe hexapetala (tilt-headed aloe)

File:Blooming aloes wide view alternate, with bright sun behind.jpg|Blooming Aloe arborescens

File:Aloe cooperi in flower IMG 1702e.JPG|Aloe cooperi (Aloe plicatilis in background on the right)

File:Aloe hereroensis Auob C15.JPG|Aloe hereroensis

File:Aloe molederana.jpg|Aloe molederana

File:Aloe dijboutiensis whole plant.jpg|Aloe dijboutiensis

File:Aloe peglerae01.jpg|Aloe peglerae

File:Aloe saponaria 1.jpg|Aloe maculata - prev. A. saponaria (soap aloe)

File:Aloe reitzii flowers.jpg|Aloe reitzii

File:Aloe arborescens leaf cross section.jpg|Aloe arborescens leaf cross section

File:Aloe karasbergensis young plant.jpg|Aloe karasbergensis - Plant 2023-0010-3

References

{{Reflist|refs=

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}}