Aloe vera is one of the oldest known medicinal herbs with
a history of use that spans thousands of years. Today, aloe
vera is cultivated and used in a large variety of commercial
preparations. It is an economic driver in the food, dietary
supplement, and personal care industries worldwide. The
two main commercial materials derived fromaloe vera are
various dietary, cosmetic, and medical purposes such as
burn treatment, wound healing, and skincare. It is available
in several forms including liquid juice, juice powder,
and concentrates. Aloe latex was formerly recognized as
an over-the-counter (OTC) laxative drug in the United
States. It has seen limited use in dietary supplements as
a laxative and in the personal care industry as a skin
Confusion among consumers, researchers, and regulatory
bodies has arisen from the fact that products from
aloe latex are often referred to as simply “aloe” or “aloe
juice” (including in pharmacopoeias and other official
documents around the world), which is physically, chemically,
and biologically distinct from products made from
the charcoal filtered whole leaf or inner leaf aloe vera juice.
These latex-free juice products represent the vast majority
of aloe products on the market. Regardless, the prominence
of, interest in, and use of aloe vera products for
centuries attests to the plant’s myriad value and benefits.
Aloe vera (L.) Burm. f. is one of more than 400 known Aloe
species in the Asphodelaceae family, though it is sometimes
classified in Aloaceae. Because most aloe species
are indigenous to Africa, it is most likely that aloe vera
also originated from that continent. However, because of
its now worldwide cultivation, its origin is difficult to establish.
Linnaeus classified aloe vera as the “true aloe”
hence the name “vera,” meaning true in Latin. Although
it has also been known as Aloe barbadensis, Aloe chinensis,
Aloe indica, Aloe vulgaris, and others, A. vera (L.) Burm.
f. has precedence (1). Its standardized common name is
“aloe vera” though it has also been called Barbados aloe,
Curac¸ao aloe, true aloe, West Indian aloe, Ghrita kumari,
or simply aloe (2).
The plant is cactus-like in appearance with succulent
leaves that grow in a spiral form from a basal rosette
(Fig. 1). An inflorescence is produced annually (typically
December through March) with yellow flowers in a trident
configuration from a single central stalk with many
flowers in each of the three branches. Aloe vera does not
normally reproduce from seeds but from offshoots often
called “pups” that grow out from the mother plant. When
the green outer rind of the leaves is cut or damaged, a
bitter yellow exudate from pericyclic tubules located between
the outer rind and the inner leaf is released. This
sap is commonly referred to as “aloe latex” (3) and contains
several anthraquinone glycosides that have powerful
stimulant laxative properties.
When the rind is completely removed, a semitransparent,
semicrystalline gel-like layer composed of large
thin-walled parenchyma cells is revealed. This inner leaf
material is often called “aloe gel,” or “inner leaf fillet,”
because of its similarity in shape to a fish fillet. When
crushed, it produces a very viscous fluid usually containing
approximately 98.5% water. The solids are composed
mainly of polysaccharides and other carbohydrates,
pectin, and organic acids.
As mentioned earlier, aloe latex–derived products
are used as a laxative agent and the processed leaf or
inner leaf is often employed topically for the treatment
of burns and injury. More recent applications range from
skin-moisturizing agents to the management of cancers in
animals to impregnation in articles of clothing and mattresses
for its softening and moisturizing properties. Aloe
vera juice is also orally ingested to manage digestive ailments
and for its immune-modulating activities and is
sold worldwide in beverage form as a food-based drink
product available in various flavors. Aloe vera is also used
widely in Ayurvedic medicine (4).
Aloe vera is cultivated in subtropical regions around the
globe for commercial use and is widely grown by indoor
and outdoor plant enthusiasts as an ornamental plant because
of its hardiness and beauty. The species is resistant
to most insect pests and needs very little maintenance
or care to flourish, given appropriate temperature
Because of its very low inner leaf solid content of
0.5% to 1.5%, aloe vera plants are highly susceptible to
freezing, which causes extensive damage, even killing
them when the temperature falls below 32◦F. For this reason,
commercial cultivations are typically carried out in
warm weather areas (USDA zones 8–11). Aloe vera is the
most cultivated species of the various Aloe species because
it produces the largest, thickest leaves and therefore yields
the greatest amount of juice. It is cultivated extensively in
removing most of the outer, lower, older leaves. Typically one to
four leaves are removed at a time per plant per harvest.
This way it is possible to obtain three to six harvests in a
year depending on how many leaves are collected from
each plant at harvest.
Cultivation practices for the industrial production
of aloe extracts made from the yellow latex sap are radically
different from those used to grow aloe vera for juice.
In the case of sap production, plants are not irrigated
and are grown in arid regions. The leaves turn brown
and thin under these conditions but when cut produce
the maximum amount of an anthraquinone glycoside–
rich latex, the principal constituents of which are the
compounds known as “aloins A and B.” The sap exudates
are collected and further processed to produce
two main products, aloe latex concentrate also known as
“aloin paste” and a product commercially known as “aloin
The leaf of aloe vera is normally described as consisting of
three major parts that are used in commercial products: the
outer mesophyll (rind or cuticle), the interior parenchyma
(inner leaf, gel or gel fillet, inner gel, inner leaf gel fillet),
and the aloe latex (sap, bitter element, yellow sap, yellow
latex). Researchers, raw material manufacturers, and finished
goods manufacturers have utilized all three plant
parts separately or in combination for aloe vera research
and in the formulation of consumer products.
Outer Mesophyll (Rind)
Aloe vera rind or cuticle is the site of photosynthesis and
primarily consists of cellulose, monosaccharides, water
soluble and insoluble carbohydrates, chlorophyll, amino
acids, proteins, and lipids.
Interior Parenchyma (Inner Leaf)
Aloe vera inner leaf is the colorless, mucilaginous
parenchyma of the aloe vera plant leaf consisting of
water, monosaccharides, water-soluble carbohydrates,
water-soluble polysaccharides, and water-insoluble fibrous
pulp. The compound -(1–4)-acetylated mannan,
a polysaccharide also known as “acemannan” or “acetylated
polymannose,” is widely considered to be the biologically
most important component of the inner leaf. After
removal of fibrous pulp from the inner leaf, the resulting
juice contains about 0.5% to 1.5% solids.
Histological examination of aloe vera inner leaf pulp
has shown it to be composed of large cells made up of 16%
cell walls, about 1% microparticles, and 83% of a viscous
gel on a dried weight basis. The carbohydrate portion
of each of these components was distinct, with the cell
walls composed of 34% galacturonic acid (an unusually
high level), the microparticles composed of galactose-rich
polysaccharides, and the liquid gel contained mannan (6).
These findings showed that different pulp structures are
associated with different polysaccharides and may therefore
confer different biological activities.
Harvest of the
leaf or the
root not used
the leaves to a
pulp and rind
Enzymatic treatment to
(not all manufacturers)
Charcoal filtration step to
remove phenolic compounds
(not all manufacturers)
microbial load by
Preservation and packaging
Reduction of water content to
increase the percent juice solids
or to produce juice powder
Flowchart 1 Aloe vera whole leaf processing.
Aloe Latex (Aloe Sap, Aloe Bitters)
Aloe latex is a yellow-green bitter exudate that contains
the anthraquinone glycosides aloins A and B, formerly
known as “barbaloin” and “isobarbaloin,” respectively.
The aloin content of aloe latex changes with the season
and the age of the leaf but usually makes up 10% to 25%
of the dried latex by weight. Products made fromaloe latex
have been used historically as a laxative. The source plant
is most commonly Aloe ferox from Africa or Argentina.
COMMERCIAL RAW MATERIAL PROCESSING
Aloe Vera Juice
Aloe vera juice can be manufactured from raw leaves in
two ways-–from the entire leaf or from only the inner leaf
material. In both cases, the leaves are first processed to
remove the side thorns and tips. For aloe vera juice made
from the entire leaf, the leaves are macerated in a grinder
into what is commonly called “guacamole” and then further
processed by enzymatic treatment (usually with cellulase)
to break up cell walls and then charcoal filtered to
remove anthraquinones and other phenolic constituents.
The resulting aloe vera juice is commonly referred to as
juice.” See flowchart 1 for more detail.
When creating juice from only the inner leaf material,
the inner leaf is separated from the outer rind either
manually with a knife or by machine and then washed to
rinse away any aloe latex present. The remaining material
is crushed and further processed to produce the aloe vera
juice. See flowchart 2 for more detail.
At this stage, regardless of starting material, the
now-processed aloe vera juice is typically called “single strength.”
The juice from the leaf or inner leaf can also be
further processed to produce concentrates and powders
and are often spray or freeze dried. Some heat is usually
applied in the industrial production of aloe vera juice to
deactivate enzymes that would break down the mannans
into oligosaccharides and simple sugars. Heating also
serves to control the normal microbial load present on the
plant. Enzymatic treatment can be used to further break
down cell walls, with filtration removing any remaining
insoluble fiber. The resulting filtered juice contains all the
major groups of components from the original aloe vera
The commercial production of aloin-rich materials starts
with the specialized cultivation practices mentioned earlier.
In contrast to aloe juice production, the leaves are
- Leaf harvest
- Cleaning and sanitation of the leaves
- Removal of most of the rind
- eduction of fillet to puree
- Removal of the insoluble pulp and rind Enzymatic treatment to
- reduce viscosity
- Reduction of microbial load by pasteurization
- Preservation and packaging
- Reduction of water content to increase the percent juice solids or to produce juice powder
- Dicing/slicing of fillet typically for use in beverage or food, the pulp is not removed
- Reduction of microbial load by pasteurization
- Preservation and packaging
Aloe vera inner leaf processing.
Mannan is a generic name for polysaccharides that are
polymers of the sugar mannose. In aloe vera juice, the
mannose moieties are connected by -(1–4) linkages,
which are partially substituted with acetate units and with
galactose-rich side chains on the mannose backbone. This
-(1,4)-acetylated-polymannose material is also known by
other names such as “aloverose” and “acemannan”; the
latter is also a name given to a proprietary substance
covered by many patents (7) and has been assigned as a
generic name by the United States Adopted Names Council
(8). It is based on the chemical name as it refers to the
acetylated mannan found in all aloe vera inner leaf fillets
Acemannan is not sold as a pure material; however,
many commercial products contain varying amounts of it
depending on the processing of the aloe vera leaf as mentioned
earlier. The therapeutic properties of aloe vera juice
have been largely attributed to its polysaccharide component
and acemannan in particular. This high-molecularweight
material is perhaps the most studied component
of the aloe vera plant aside from the anthraquinone glycosides.
Many industrial methods have been developed
to stabilize the aloe vera juice and prevent polysaccharide
degradation. Drying the juice at temperatures over 60◦C
has been shown to cause deleterious changes in acemannan
and also pectin from the cell walls (9).
ANALYSIS OF COMMERCIAL PRODUCTS
Analysis of 32 commercial products showed wide variations
in polysaccharide content when compared by molecular
weight (10), which was attributed to different manufacturing
procedures. A second study of nine commercial
powders used a method that hydrolyzed the mannan into
mannose as a rapid way to measure the total polysaccharide
content in the powder. One sample was found to have
an abnormally high concentration of free glucose, four
showed signs of spoilage, and all but three were found to
have low levels of polymannose present (11). Both studies
found all samples to have a significantly lower amount
of aloins than the raw unwashed inner leaf fillet, with a
high of 16 ppm of aloin A found in one sample in one of
the studies. Because of the widespread use of aloe vera
juice in personal care products, a voluntary industry limit
of 50ppm aloin content for use in cosmetics as a topical
agent has been established (12).
Manyof the biological properties of aloe vera have been attributed
to acemannan. This compound has been studied
fraction demonstrated wound healing activity (17),
suggesting that more than one aloe compound could be
useful in treating both inflammation and wounds.
Aloe vera applied topically has a moisturizing effect on
skin (18) and has been used for this purpose and as a
Rodent studies have shown blood glucose regulating activity
of an aloe vera alcoholic extract (19) and processed
aloe vera inner leaf juice (20), suggesting its utility in treating
Acemannan has shown significant antitumor activity via
immune system activation. In a mouse model, IP injection
of acemannan at the time of implantation of sarcoma cells
resulted in a 40% survival rate in the treated animals versus
0% of the controls, most likely because of the production
of monokines from macrophage peritoneal stimulation.
The data suggested that this acemannan-stimulated
synthesis “resulted in the initiation of immune attack,
necrosis, and regression of implanted sarcomas in mice”
(21). A study involving acemannan treatment as an adjunct
to surgery and radiation in confirmed fibrosarcoma
in dogs and cats showed tumor shrinkage in one-third
of the animals after four to seven weeks of treatment administered
by intraperitoneal and intralesional injections
(22). An earlier study by the same group showed similar
Studies on Aloin-Rich Materials
Aloin-rich extracts derived from aloe latex belong to the
stimulant laxatives drug class. Aloins are inactive until
deglycosylated by intestinal flora to form aloe-emodin, the
putative active compound (24). Their mechanism of action
is believed to involve increasing peristalsis and water accumulation
in the colon (25). Aloe latex has been subjected
to a human clinical trial as a laxative in combination with
other ingredients (26).
The potential toxicities of aloin and its metabolites
are not well established though studies have shown it
does not promote colon cancer in a mouse model (27) and
induces cell changes that could be a sign of anticancer
activity (28). Selective activity against certain cancers has
also been demonstrated by aloe-emodin, a metabolite of
aloins A and B (29,30).
Although one study showed a delay in healing wound
complications after cesarean delivery or gynecological
surgery following treatment with “aloe vera dermal
wound gel” (31), another recorded a 6-day statistically
significant reduction (from 18 to 12 days) in the healing
time of partial thickness burns. A systematic review of
the literature for the use of topical aloe vera in treating
burn wounds included four controlled clinical trials involving
371 patients. A meta-analysis based on the time
for healing showed almost nine fewer days required for
the aloe vera–treated group over the controls (32). No specific
conclusions could be drawn because of the difference
in preparations and outcome measures. Further studies
with well-characterized materials were called for by the
authors as cumulative evidence tended to support the use
of aloe vera for the treatment of first- and second-degree
burns. A bioadhesive patch of an aloe vera preparation
was evaluated in an open uncontrolled trial for the management
of mouth ulcers in children with apparent good
Ulcerative Colitis and Irritable Bowel Syndrome (IBS)
Ulcerative colitis is caused by a dysfunction of the immune
system (34). A 2004 clinical trial involving 44 patients
with mild or moderately active ulcerative colitis compared
with placebo for four weeks. The aloe vera–consuming
patients showed positive clinical responses more often
than placebo. Clinical remission was seen in 30% of the
active group, clinical improvement in 37%, and a clinical
response in 47% of patients compared with 7%, 7%,
and 14% in the placebo group, respectively. Histological
scores and the Simple Clinical Colitis Activity Index did
not change in the placebo group but decreased significantly
for those who consumed aloe vera. No significant
differences were seen between the two groups with regard
to laboratory values or sigmoidoscopic scores (35).
Ahuman clinical study using aloe vera for treatment
of irritable bowel in refractory secondary care patients
failed to show a benefit, though the authors could not rule
out that diarrhea-predominant patients were helped (36).
Aloe dried sap has demonstrated hypoglycemic activity
in a study involving five patients with non–insulindependent
A preliminary clinical trial on the use of orally administered
“aloe vera tincture” for untreatable metastatic solid
tumor patients with and without melatonin treatment
showed a significantly higher percentage of nonprogressing
patients in the group that received the aloe treatment
(50% vs. 27%, P < 0.05) (38). Another human trial on 240
patients treated with Aloe aborescens (used because of purported
immunostimulating activity from this plant owing
to its acemannan component) suggested that oral aloe
therapy may be a successful adjunct to chemotherapy in
patients with metastatic solid tumors. Tumor regression
rate and survival time were improved in this study (39).
No conclusions can be drawn from this study because
details on characterization of the test material were not
A four-week subacute oral toxicity study in mice administered
a freeze-dried aloe juice product reported no remarkable
subacute toxic effects but did note a decrease
in male kidney weights. The report also provided a review
of several adverse reaction case studies associated
with aloe vera (40). They ranged from skin irritation from
topical use to one report of acute hepatitis in a 73-yearold
A second case of acute hepatitis involving a 26-year-old
man who had been drinking “aloe vera tea” has also been
The National Toxicology Program of the U.S. government
nominated “aloe vera gel” for study in 1998 (42).
No long-term carcinogenicity studies of aloe vera gel in
animals were identified at that time. NTP subsequently
chose to conduct a two-year carcinogenicity study on mice
and rats with a “whole leaf extract” (43) that includes a
considerable amount of latex aloins. The majority of aloe
vera juice products intended for long-term internal use
are either charcoal filtered whole leaf preparation or are
made from washed inner leaf juice with aloin concentrations
typically under 10 parts per million. The NTP
report was still in progress at the time of publication of
Aloe and aloin are present in the first approved food additives
list published by the U.S. Food and Drug Administration
in 1959. Although initially approved in the United
States in 1975 as an OTC drug to treat chronic constipation,
aloe latex is no longer approved for such use in the
United States as of May 9, 2002 (44). Standard quality tests
for aloe latex have been described in detail in many official
pharmacopeias including the United States Pharmacopeia,
Japanese Pharmacopoeia, and the European Pharmacopoeia,
though, as mentioned in the introduction, these texts typically
define aloe latex as simply “aloe” or incorrectly as
Aloe vera juice products can be labeled and marketed
as dietary supplements. Aloe latex may also be used
in dietary supplements in the United States with laxative
or constipation claims as long as such claims are not for
the treatment of chronic constipation.
Aloe vera inner leaf (called “aloe barbadensis”) is eligible
for use as an active or excipient ingredient in Australia
in “Listed” medicines in the Australian Register of Therapeutic
Goods. Acemannan is approved as a component.
Components are not approved as substances for use in
their own right and can only be used in conjunction with
an approved source.
Some aloe vera juice and juice concentrate beverages
are viewed as “nontraditional foods” and not as “novel
foods” and there are some listed medicines described as
Aloe vera inner leaf, when included as a Natural Health
Product (NHP) active ingredient, requires premarket authorization
and a product license number for OTC human
use. Such products must comply with the minimum specifications
outlined in the current NHPD Compendium of
Aloe vera inner leaf was listed as “currently not on the
priority list” in the inventory of herbal substances for assessment
by the European Medicines Agency as of March
2009. There is an EU regulatory limit established for aloin
content of 0.1 ppm in orally ingested products based on
a flavoring regulation in which the aloin is defined as an
added ingredient as opposed to naturally occurring. The
International Aloe Science Council (IASC) (a trade association)
has taken a position that these regulations are not
applicable to aloe vera juice products.
Aloe vera juice is regulated as a food beverage product in
Japan and is not to contain more than 0.60 mg/kg of benzoic
acid. Various forms of aloe vera and extracts thereof
are used as components of functional food products or in
Foods for Specified Health Use such as in fortified waters
and fermented yogurt drinks.
Aloe products, known as “edible aloe concentrate” and
“edible aloe gel,” are regulated as food products by the
Korean Food and Drug Administration. Juice or concentrate
from the inner leaf or dried and powdered inner
leaf material containing not-less-than 30 mg/g of total
aloe polysaccharides is able to carry the health claim
of “smoothing the evacuation” on the basis of 20 to
30 mg delivered as aloe polysaccharides. Processed aloe
vera leaf or concentrates thereof, after removal of the
inedible parts, and containing 2.0 to 50 mg/g of anthraquinones
(as anhydrous barbaloin), is permitted to
make the same health claim at the specified daily intake.
Aloe vera is also one of the four botanical ingredients allowed
to make immune system enhancement claims in
Of the 400 known species of aloe, Aloe vera is the most
commonly used in commerce and is cultivated in many
different areas of the world. The plant yields two raw
materials for use in various consumer products including
foods, dietary supplements, cosmetics, and drugs, namely
from processing either the entire leaf or only the inner leaf
material. Aloe vera juice is often further processed into a
powder or concentrate.
Preliminary scientific evidence suggests that aloe
vera has therapeutic benefits; however, more studies need
to be conducted to definitively demonstrate efficacy. Consumers
should be aware and informed when buying aloe
vera products; although there are many quality products
on the market, there are also many products that may
bring little or no benefit to the user. The IASC maintains a
certification program using validated analytical methods
to determine and ensure products displaying the IASC
program seal contain aloe vera of a particular quality. It
is recommended that consumers verify that products displaying
the IASC seal are current participants in the IASC
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