pharmacognostic study of aloes

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Aloes
Mahesha.K
Shree Siddaganga college of
pharmacy
Tumkur

2. Introduction:
 Aloes is a genus containing over 500 species of
flowering succulent plants(store water in their
enlarged fleshy leaves, stems or roots).
 The most widely known species is Aloe Vera or
“True aloe”, so called because it is cultivated as
the standard source for Medicinal and
Pharmaceutical purposes.
 Other species, such as Aloe ferox also cultivated
for similar applications.
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Succinate plant

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Biological source:
Aloes is obtained from the dried juice of the leaves of
• Aloe barbadensis Miller, known as Curacao aloes,
(Aloe Vera).
• Aloe perryi Baker, known as Socotrine aloes.
• Aloe ferox Miller and hybrids of this species with Aloe
africana Miller and Aloe spicata Baker, known as Cape
aloes, belonging to family Liliaceae.
Family: Asphodelaceae
(In past, it has been assigned to broadly
circumscribed family Liliaceae)
Synonyms:
Aloe, Musabbar, Lolesara(in kannada).

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Geographical source:
Aloes is the indigeneous to eastern and southern
Africa and grown in Cape colony, Zanzibar and islands of
Socotra. It is also cultivated in Caribbean islands, Europe
and many parts of India, including North West Himalayan
region.

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Morphology:
All the 4 commercial forms are compared below here
for their morphological characters.
Curacao aloe (Aloe Vera):
 These are distinguished by their Transparency
 It occurs as Opaque mass
 It is Waxy and some what resinous
 Colour: Yellowish brown to chocolate brown
 Odour: strong odour resembles with Iodoform
 Taste: Bitter & Unpleasant
 It is a short stemmed plant growing to 60-100cm tall,
spreading by offsets.

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Cape aloe:
 It is Vitreous form
 Occurs as olive brown masses
 It breaks with Glassy fracture
 Colour: Dark brown to greenish brown
 Odour: Characteristic, Sour
 Taste: Bitter & Unpleasant
Aloe vera
Cape aloe

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Zanzibar aloe:
 Opaque, more firm than Socotrine
 Colour: Liver Brown
 It is Smooth as wax
 Odour: pleasant
 Taste: Bitter
Socotrine aloe:
 Masses of different shapes and sizes
 Colour: Yellow brown to dark brown
 Irregular and porous surface
 Taste: Bitter
 Odour: Unpleasant
 It is totally soluble in 60% alcohol

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Chemical constituents:
 Anthracene glycosides(11 to 40%).
 Barbaloin or Aloin, a C glycoside (not easily hydrolysable
with dil. Acids and linkage between the sugar and the
aglycone is through C-C).
 Isobarbaloin, aloe-emodin and aloesone.
 Aloinosides A and B (only in Cape aloes).
 Resins (resinotannol +cinnamic acid or coumaric acid).
 Also contains Aloetic acid, homonataloin etc.

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Barbaloin

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Chemical tests:
The chemical tests for aloes are performed either for
general detection or detection of specific variety of
aloes.
General test:
Test solution: For these test, 1g of aloe powder is
boiled with 10ml water and filtered with help of
Kieselguhr. This filtrate is used for below test.
1) Bromine test:
Freshly prepared bromine solution is added to a
small quantity of above filtrate. Pale yellow precipitate
of tetrabromalin is obtained. This is not specific for aloes

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2) Borax test for Anthranol: (schoenteten’s reaction)
0.5g of borax is heated with 10ml of test
solution.Green coloured fluorescence is observed due to
Anthranol.
Special tests:
These tests are meant for distinguishing different
varieties of Aloe Vera.
1) Nitrous acid test:
Crystals of sodium nitrate along with small quantity
of acetic acid are added aqueous solution of aloes.
 Curacao aloe: sharp pink to carmine colour
 Cape aloe: faint pink colour
 Socotrine and Zanzibar aloe: less change in colour
(observed due to isobarbaloin)

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2) Nitric acid test:
This test is carried out either by directly applying nitric
acid to drug or to its aqueous solution.
 Curacao aloes: deep brownish red colour
 Cape aloe: brownish colour changing to green
 Socotrine aloe: pale brownish yellow colour
 Zanzibar aloe: yellowish brown colour
3) Cupraloin test: (Klunge’s isobarbaloin test)
To very dilute aqueous solution of aloes, a drop of
saturated copper sulphate solution is added, followed by
little quantity of sodium chloride and excess of 90% alcohol.
 Curacao aloe: wine red colour persisting 4 hrs
 Cape aloe: faint colouration rapidly changing to yellow
 Socotrine and Zanzibar aloes: no colour

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4) Modified anthraquinone test:
The aqueous solution of aloes is treated with
ferric chloride and dilute hydrochloric acid to bring
out the oxidative hydrolysis of aloe-emodin. The
hydrolysis sets free anthraquinones which are
collected in organic solvent like ether. The organic
layer is separated and shaken with dilute ammonia.
The ammoniacal layer shows rose pink to cherry
red colour, indicating the presence of C-glycosides,
VIZ. aloe emodin.

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Substitutes and Adulterants:
 The east african aloes namely the Socotrine and Zanzibar
aloes are inferior varieties and they can be easily
distinguished by chemically and morphologically.
 Natal aloes and Mocha aloes
 It also adultrated with Black catechu.
Uses:
 Purgative
 Laxative
 Used for Ulcers and burns
 Aloe found many uses in cosmetics nowadays like,
 Hair conditioner
 Hand and body lotion
 Moisture base cleanser
 Shampoo and facewash

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 Also have formulation role for oil in water preparations
(approved by USFDA)
 Clears acne
 Reduces constipation

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THANK YOU