Study of Tyrosinase inhibitors from natural sources

1
Study of Tyrosinase inhibitors from natural
sources
CMLS, Cell. Mol. Life Sci. 62 (2005)1707-1723 Pre
sented by Hoi Young Kim
Organic Natural Product Chemistry Lab
2
Contents
Melanin
Biosynthetic pathway of melanin Function of
melanin
Tyrosinase
Mechanism of tyrosinase action
Tyrosinase inhibitors
Natural and synthetic sources
New Development of Tyrosianse inhibitors
Applicaton
Organic Natural Product Chemistry Lab
3
Melanin
Melanin is one of the most widely distributed
pigments and is found in bacteria, fungi, plants
and animals. It is a heterogeneous
polyphenol-like biopolymer with a complex
structure and color varying from yellow to black.
melanine
keranocyte
melanoine
melanocyte
Melanocyte
Organic Natural Product Chemistry Lab
4
Biosynthetic pathway of melanin
Organic Natural Product Chemistry Lab
5
Melanin Function

• Several types
• - Eumelanin (predominant in human)
• - Pheomelanin
• Functional bio-macromolecule found throughout
  nature
• - Increases that live and competition
• - protect the skin from ultraviolet(UV)
• - Detoxification for cell toxicity
  substances
• Melanin overproduction
• bring about freckles, hyperpigmentation and
  cancer
• Melanin is formed through a series of oxidative
  reactions involving the
• amino acid tyrosine in the presence of
  tyrosinase

Organic Natural Product Chemistry Lab
6
Tyrosinase (EC 1. 14. 18. 1)

• Phenolase, Monopheol oxidase, Catechol oxidase,
  etc.
• Copper-containing enzyme.
• Catalyzes two distinct reactions of melanin
  synthesis

Monophenolase activity
Diphenolase activity
Organic Natural Product Chemistry Lab
7
Classification and properties of tyrosinase
Table 1. Properties of Well-Characterized
Tyrosinases
Spectroscopy of oxy form
Molecular weight Of subunit (kDa)
Number of subunits
source
Absorption (nm)
CD (nm)
30.9 46 13.4 43 40 66.7
345 640 345 425 600 345 600 345 -a
345 470 575 740 345 520 600 750 353 -a -a
Streptomyces glaucescens (Eubacteria)
Neurospora crassa (Fungi) Agaricus
bisporus (Fungi mushroom) Beta vulgaris
(Plant spinach-beet) Human melanocyte
(Animal)
1 1 2 1 1
a No data available.
Organic Natural Product Chemistry Lab
8
Mechanism of tyrosinase action
Diphenolase Catalytic cycle
Monophenolase Catalytic Cycle
Figure . Catalytic cycles of the hydroxylation of
monophenol and oxidation of o-quinone by
tyrosinase
Organic Natural Product Chemistry Lab
9
Tyrosinase inhibitors from natural sources
Structure of tyrosinase inhibitors
Organic Natural Product Chemistry Lab
10
Tyrosinase inhibitors from natural sources

• Mushroom Tyrosinase inhibitory activities of the
  Flavonoids

Organic Natural Product Chemistry Lab
11
Tyrosianse inhibitors from synthetic sources
Structure of tyrosinase inhibitors
Organic Natural Product Chemistry Lab
12
Plant Source Sophora flavescens

• Plant taxonomy
• - Leguminous
• - Herbaceous perennial plant

• Pharmacological reserch
• - Antipyretic - Antibiotic
• - Diuretic - Antifungal
• - Anthelmintic - Antitumor
  

• Main component
• - Flavonoids
• - Quinolizidine alkaloids
• - Triterpenoid

Organic Natural Product Chemistry Lab
13
Reported compounds from Sophora flavescens
Organic Natural Product Chemistry Lab
14
Isolated compounds from Sophora flavescens
Compound 2 Sophoraflavanone G
Compound 3 (2S)-2-methoxykurarinone
Compound 1 Kushenol
Compound 4 Kurarinone
Compound 5 Kurarinol
Organic Natural Product Chemistry Lab
15
Tyrosinase inhibition compounds from Sophora
flavescens
2. Sophoraflavanone G
5. Kurarinol
4. Kurarinone
Ki (µM) - 77.0 - 4.1 45.0 - -
Inhibition type - Noncompetitive - Noncompetitive
Competitive - -
Compound 1 2 3 4 5 Arbutin Kojic acid
IC50 (µM) gt30 2 gt93 0.1 0.05 10 15
Organic Natural Product Chemistry Lab
16
Enzyme kinetic analysis
Lineweaver-Burk plot
Lineweaver-Burk plot
Figure. Lineweaver-Burk plots for inhibition of
Kurarinone on mushroom tyrosinase for catalysis
of L-tyroine at 30?, pH 6.8
Figure. Lineweaver-Burk plots for inhibition of
Kurarinol on mushroom tyrosinase for catalysis of
L-tyroine at 30?, pH 6.8
Organic Natural Product Chemistry Lab
17
Conclusion

• Tyrosinase inhibition mechanism stydy.

• SAR (Structure Activity Relationship) from
  Flavonoids

• Active site
• - Hydroxyl groups at the R7 and R4' sites
• in the A and B rings.
• Dihydroxyl group in the A and B rings.

• Isolated of potent tyrosinase inhibitors from
  Sophora flavescens
• - Sophoraflavaone G (IC50 2µM ,
  noncompetitive inhibition)
• - Kurarinone (IC50 0.1µM, noncompetitive
  inhibition)
• - Kurarinol (IC 50 0.05µM, competitive
  inhibition)

• Development of Whitening agent

Organic Natural Product Chemistry Lab