Aloe is a succulent plant that is indigenous to Africa, the Caribbean, and tropical regions. Several Aloe species produce a resin known as aloes that is used medicinally. Cape aloes comes from Aloe ferox and is a dark green, semi-transparent resin. Barbados aloes comes from Aloe barbadensis and is opaque with a waxy texture. Both contain anthraquinone glycosides like barbaloin that are responsible for their laxative effects. Aloes is used as a purgative, vermifuge, emmolient, and for its antibacterial and wound healing properties.

1. ALOE

3. ALOE
Common names:
Aloe, Kawar gandal etc.
Botanical Source:
Aloe vera, Aloe barbadensis, Aloe ferox, Aloe perryi.
Family:
Liliaceae
Geographical Source:
Indigenous to East and South Africa, West Indies and
tropical countries, Countries bordering on the
Mediterranean.

4. General Description:
Aloes is the solid residue (dried juice)obtained by
evaporating the liquid which drains from the
transversely cut leaves of various species of Aloe
(Liliaceae).
The juice is usually concentrated by boiling and solidifies
on cooling.

5. Plant Description:
• Succulent plant
• Perennial plant
• Strong and fibrous roots
• Numerous, Narrow, Thick and fleshy leaves,proceeding
from the upper part of the root, Strongly
cuticularized and usually prickly at the margins.

6. Official Varieties:
The official (BP, EP, USP) varieties of aloes are:
• Cape Aloes
• Barbados Aloe
Cape Aloes:
Cape from South Africa and Kenya.
Barbados Aloe:
Barbados (Curacao) from the West Indian lslands of
Curacao,Aruba and Bonaire.
• There are separate pharmacopoeial monographs for
each type.
•Socotrine and Zanzibar varieties are no longer official.

7. Sources of Drug:
Of about 180 known species of Aloe, the drug is mainly
obtained from the following:
• Cape variety from Aloe ferox and its hybrids.
• Curacao variety from Aloe barbadensis.
• Socotrine and Zanzibar varieties from Aloe perryi.

8. Leaf Structure:
Transverse sections of an Aloe leaf usually show the
following zones:
(1) A strongly cuticularized epidermis with numerous
stomata on both surfaces.
(2) A region of parenchyma containing chlorophyll, starch
and occasional bundles of needles of calcium oxalate.

9. Leaf Structure:
(3) A central region which frequently occupies about
three- fifths of the diameter of the leaf, consisting of
large mucilage-containing parenchymatous cells.
(4) A double row of vascular bundles which lie at the
junction of the two previous zones and have a well-
marked pericycle and endodermis.

10. Leaf Structure:
• The aloetic juice from which the drug is prepared is
contained in the large, pericyclic cells and sometimes in
the adjacent parenchyma.
• When the leaves are cut, the aloetic juice flows out.
No pressure should be applied or the aloes will be
contaminated with mucilage.
• The mucilage, contained in zone 3 as above is used in
the cosmetic and herbal industries in 'aloe vera'
preparations.

11. Cultivation and Collection:
• Prefer light(Sandy), medium(Loamy) soils.
• Well-drained soil, Can grow in nutritionally poor soil or
can tolerate drought (Xerophytic plant).
• Prefers acid, neutral and basic (alkaline) soils.
• Can not grow in shade.
• Seeds are sown in the Spring in a warm green house.
• The seed usually germinates in 1-6 months at 16°C.
• Seedlings transferred to pots containing well drained
soil, allowed to grow in sunny part for atleast their first
two winters.
• The offsets will be available, usually in Spring.

12. Cultivation and Collection:
• Young offsets are planted in soil after the rainy season in
rows situated at a distance of 60 cm.
• Leaves are collected in the second year.
• The leaves are cut near the base, kept inside of
Kerosene tins and taken them to a central place for the
preparation of Aloe.

13. Preparation of Cape Aloes:
Cape aloes is prepared from wild plants of A.ferox and
its hybrids.
The leaves are cut transversely near the base and about
200 of them are arranged round a shallow hole in the
ground, which is lined with plastic sheeting or more
traditionally a piece of canvas or a goatskin.

14. Preparation of Cape Aloes:
After about 6 h all the juice has been collected and it is
transferred to a drum or paraffin tin in which it is boiled
for about 4 h on an open fire.
The product is poured while hot into tins, where it
solidifies.

15. Preparation of Barbados (Curacao) Aloes:
Curacao aloes is produced from cultivated plants of
A. barbadensis.
The cut leaves are stacked in V- shaped troughs,
arranged on a slope so that the juice flows from a hole
at one end of the trough into a collecting vessel.
When sufficient juice has been collected, it is
evaporated in a copper vessel.

16. Preparation of Barbados (Curacao) Aloes:
The temperature used is generally lower than in the case
of Cape aloes and the product is, therefore, usually
opaque (Livery or Hepatic), although some which is
semi-transparent may be produced and is known in
commerce as 'Capey Barbados'.
On cooling, it is then poured into boxes or other
convenient receptacles, and solidifies.

17. Characters:
Evaporation Vs Appearance:
• Livery or Hepatic
• Glassy, Vitreous, Lucid

18. Characters:
Livery or Hepatic:
Slow and moderate concentration tending to induce
crystallization of Aloin, thus causing the drug to appear
opaque. Such Aloes termed as Livery or Hepatic, and
splinters of it exhibit minute crystals of Aloin when
examined under microscope.

19. Characters:
Glassy, Vitreous, Lucid :
If evaporation is carried as far as possible, the Aloin does
not crystallize and small fragments of drug appear
transparent. It is then termed Glassy, Vitreous, Lucid
Aloes and exhibits no crystals of Aloin under
microscope.

20. Characters of Cape Aloes:
• The drug occurs in dark-brown or greenish-brown,
glassy masses.
• Thin fragments have a deep olive colour and are semi-
transparent.
• The powder is greenish-yellow and when pieces of the
drug have rubbed against one another, patches of
powder are found on the surface.
• The drug has a very characteristic, sour odour.
• Taste, nauseous and bitter.
• The powder when examined under the microscope in
lactophenol is usually amorphous.

21. Characters of Barbados (Curacao) Aloes:
• Typical Barbados aloes varies in colour from yellowish-
brown to chocolate-brown, but poorer qualities that
have been overheated may be almost black.
• The drug is opaque and breaks with a waxy fracture.
• The semi-transparent 'Capey Barbados‘ becomes more
opaque on keeping.
• Curacao has a nauseous and bitter taste and a
characteristic odour recalling iodoform. Mounted in
lactophenol it shows small acicular crystals.

22. Chemical Constituents:
• Aloes contain C -glycosides and resins.
• The crystalline glycosides known as 'aloin‘.
• Aloin contains not less than 70% anhydrous barbaloin.
• The main crystalline glycoside, barbaloin is found in all
commercial varieties.
• On heating to about 160°C barbaloin is partly converted
into amorphous β-barbaloin. This substance is said to be
absent from the Barbados variety, but present to the
extent of about 8% in the Cape.

23. Chemical Constituents:
• Small quantities of aloe-emodin are sometimes present
in aloes, and Cape aloes also contains aloinosides A and
B, which are O-glycosides of barbaloin.
• In South Afiican spp. (e.g. A. ferox) aloesin (now often
referred to as aloeresin B ) was identified.
• Other isolated from Cape aloes include aloeresin A and
C.
• Aloenin A was isolated from A. arborescens leaves.
• Aloenin B has now been obtained from Kenya aloes.

24. Barbaloin

25. Uses:
• Aloes is employed as purgative. It is seldom prescribed
alone.
• Vermifuge
• Emmolient
• Stimulant
• Stomachic
• Tonic
• Antibacterial
• Vulnerary
• Treatment of wounds, burns and other skin disorders
• Soothing effect on burns