Biotransformation of Steroids and Sterols

1. Biotransformation of Steroids and Sterols
Biotransformation is process an organisms or Enzymes
bring out chemical changes on compounds that are not
part of their metabolism and they result in the
formation of novel or useful products that are often
difficult or impossible to obtain by conventional
chemical methods.
Microorganisms have the ability to Chemically modify
a wide variety of organic compounds such changes are
called “ Biological or Microbial Transformation”
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2. Steroids
• Steroids are biological active organic compounds
• Found- plant,
• Animal
Bacteria
and Fungi
• Manufactured from Sterols
Lanosterol (Plant) and
Cyclosterol (Animal).
• Fused Four Membered Rings (A,B,C,D) and composed
of 17 carbon atoms and 28 hydrogen atoms
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3. Structure of steroid
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4. Steroids
• Naturally occurring steroids have
hormonal properties
very important to human beings.
Cell membrane
As a signaling Molecules
• Example:
Adrenal hormones- Cortisone, Cortisol and
Corticosterone.
Progestational Hormone-progesterone’s
Testerosterons, Dihydrosteron
Estradiol, Estrone.
The These steroids are widely used medically as
•
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5. Steroids
• Anti-inflammatory agents (Cortisone)
• Anesthetics,
• Antifertility agents
• Contraceptives
• Sedatives
• Rreduce mineral corticoid activity by
Triamcinolone and Medrol
• Recent applications of steroid compounds
include the treatment.
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6. TYPES OF STEROIDAL TRANSFORMATION
• Oxidation –
• Hydroxylation –
• Dehydrogenation. –
• Epoxidations –
• Oxidation to ketone through hydroxylation –
• Ring AAromatization –
• Degradation of steroid nucleus
–
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7. TYPES OF STEROIDAL TRANSFORMATION
• Oxidation of alcohols to ketone: 3β-OH to 3-keto –
Side chain cleavage of steroids – Decarboxylation of
acids
• Reduction – Double bond – aldehyde and ketone to
alcohol
• Hydrolysis
• Isomerization
• Resolution of racemic mixture
• Other reactions – Aminations – Enolization of
carbonyl compounds –
• Esterification.
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8. Hydroxylation
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9. Rhizopus arrhizus and R. nigricans
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10. Dehydrogenation
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11. Dehydrogenation
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12. Dehydrogenation
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13. Aromatization by
Pseudomonas testosteroni
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14. Degradation of steroid nucleus
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15. Epoxidation
• Curvularia lunata,
• Cunninghamella blakesleeana
• Helicostylum piriforme
• Mucor griseocyanus
• Mucor parasiticus
• Rhizopus nigricans
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17. Esterification
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21. ADVANTAGES
• Microorganisms have great potential for
inducing new or novel enzyme systems
capable of converting foreign substrates.
• • Microorganisms are capable of producing
unique enzymes which are stable toward heat,
alkali and acid.
• • A combination of microbial transformation
and chemical transformations (chemo-
enzymatic synthesis) can be exploited for
partial, as well as the total synthesis of the
organic compounds
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22. DISADVANTAGES
• If the substrate is toxic, it can kill the
microorganisms. Hence no transformation will
be observed.
• Alternatively, if the micro-organisms use the
substrate as an energy source (carbon source
food), no transformed or untransformed
material will be recovered.
• Very low chemical yields are obtained due to
the involvement of a complex biological
system
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