Aloe (Aloe vera)

pharmacognostic study of aloes

1. 1 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. 2

3. 3 Succinate plant

4. 4 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 ).

5. 5 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.

6. 6 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.

7. 7 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

8. 8 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

9. 9 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.

10. 10 Barbaloin

11. 11 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. 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

12. 12 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 V era. 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 )

13. 13 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

14. 14 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 .

15. 15 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

16. 16 Also have formulation role for oil in water preparations (approved by USFDA ) Clears acne Reduces constipation

17. 17 THANK YOU