herbal medicine MOA

Question 1

what is the rational for multi herb or whole use herb

Answer 1

• The use of whole plant or multi-herb plant extracts is based on the theory that the active component act in synergy to produce an enhanced therapeutic effect, compared to single agents
• Synergy - the overall effect of 2+ agents together is greater than expected from the sum of their separate effects.

Proposed mechanisms:

Question 2

what are the proposed mechanisms

Answer 2

• 1. Multi-targeting of cells/tissues

2. Pharmacokinetic” effects (improved solubility, bioavailability)
3. Reverse drug resistance
4. Reduction/elimination of adverse effects.

Question 3

why is “Multi-targeting of cells/tissues” a proposed mechanism

part 1

Answer 3

Binding to different cellular targets -> enhanced effect
• Targets - enzymes (incl signal cascade intermediates),
receptors, ion channels, DNA/RNA, other proteins
• E.g studies on extracts of Rhizoma Coptidis (RC).
• TCM - Clears Heat, Resolves Phlegm and Blood
Stasis and Nourishes Kidney Yin
Key constituents - alkaloids (palmatine, berberine,
epiberberine, coptisine)

Question 4

why is “Pharmacokinelic” effects (improved solubility, bioavailability)” a proposed mechanism

Answer 4

• Some compounds with no pharmacological properties may
enhance bioavailability of major constituents -> enhanced
effectiveness
• E.g. The formula Yin Chen Hao Tang (Artemisia annua L,
Gardenia jasmmoides Ellis, Rheum Pa/matum L) is used to treat
liver disorders incl jaundice.
• Tested in rat hepatic injury model.
• Administration of formula significantly increased bioavailability,
slowed elimination rate and increased therapeutic effect compared
to individual or 2 herb combinations.

Question 5

why is “Reverse drug resistance” a proposed mechanism

Answer 5

• Administer antibiotics with agents that suppress
bacterial resistance mechanisms.
• E.g. Berberine plus 5’-methoxy-hydnocarpin (5’-MHC -
flavonolignan) from Hydnocarpus wightiana.
• 5’-MHC magnifies the anti-micobial effect of berberine
by inhibiting bacterial efflux pumps in S. aureus.
Extracts have a better anti-microbial effect than
berberine alone.

Question 6

why is “Reduction/elimination” of adverse effects.a proposed mechanism

Answer 6

• Due to the presence of other components or the
treatment of the extract.
• Pre-treated herbs e.g. heated, addition of alcohol, alum
or other substance.
• Can modify the energetic properties of herbs.

Question 7

why is “Multi-targeting of cells/tissues” a proposed mechanism

part 2

Answer 7

• RC exhibits antihyperglycaemic, anti-inflammatory and antibacterial
effects.
• If treat with extracted alkaloids, get side effects (severe
arrhythmia, liver function disorders, death)
• The LD50 of individual extracts (713 - 1533 mg/kg) is lower
than the whole extract (2.95 g/kg)
• Antihyperglycaemic activity of whole RC extract greater than
alkaloid-rich fraction.
Due to presence of ferulic acid and choline in aqueous
extracts that enhance antihyperglycaemic effects and
reduce cytotoxicity of alkaloid fraction.
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