AOAC SPDS Mid Year 2016

Existing Methods

• HPTLC – Lobo et al .,  A HPTLC densitometric method for the determination  of aloeverose in Aloe vera gel. Fitoterapia 2010 , 81, 231–233.

HPTLC conditions: Plate: Si-gel Si60F 254 Developing: n-butanol: n-propanol: l i l ti id t g ac a ace c ac : wa er (30:10:10:10 v/v/v/v). Reagents: anisaldehyde sulphuric acid reagent; heating the plate at 105–110°C for 5min.

aloeverose

Fig. HPTLC chromatogram of A. vera gel (from the above paper).

Existing Methods • Colorimetric Assay by Red Dye – Congo Red – Eberendu et al ., Quantitative Colorimetric Analysis of Aloe 

Polysaccharides as a Measure of Aloe Vera Quality in Commercial  Products.  J. AOAC International , 2005 , 88 , 684‐691.

NH 3

O O

N

S

O - Na +

N

N

O O

+ Aloe polysaccharides

N

S

O - Na +

H 2 N

Congo red dye

• Complex of Congo red with polysaccharides and assayed  at 540nm