Category BI L07 South African plants for skin hyperpigmentation disorders

Abstract The purpose of this project was to determine whether certain plant extract

could inhibit tyrosinase production in the skin. I first prepared the extracts

that were used in the experiments, dissolved them in dimethyl sulphoxide,

and tested them against different concentrations of tyrosinase to see if

they had any inhibitory effects. 70 µl of each extract dilution was

combined with 30 µl of tyrosinase in triplicates in microtitre well plates.

Kojic acid was used as a positive control in the experiment. Optical

densities of the wells were then determined at 492 nm with the BIO-TEK

PowerWave XS multi-well plate reader. The IC50 value was then

determined by the use of MSTATC software. The best results for tyrosine

testing went on to DOPA testing.



DOPA testing allowed me to determine the IC50 values of each extract.

The IC50 is a measure of the effectiveness of a compound in inhibiting

biological or biochemical function. Then I went on to antioxidant testing. I

also found the EC50 value through this process. By performing these

experiments, I concluded that Greyia sutherlandi was the most active plant

extract for inhibiting tyrosinase formation in the skin.

Bibliography http://www.umm.edu/altmed/articles/tyrosine-

000329.htmhttp://www.emedicine.com/derm/topic528.htm
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