Herb-Drug Interactions

Question 1

Herbal interaction with P-glycoprotein can effect drug pharmacokinetics. In which organ is this interaction most relevant for oral use of herbal medicines

Answer 1

Small intestine (first barrier for absorption for orally administered)

Increased levels p-gp in SI will increase elimination of substances back to SI lumen which creates more opportunity for excretion

Question 2

Plants known to interact via P-glycoprotein and/or cytochrome p450 enzymes

Answer 2

Hypericum perforatum
Citrus paradisi 
Rosmarinus officinalis
Silybum marianum
Ginkgo biloba
Allium sativum & cepa 
Camellia sinensis
Glycyrrhiza glabra
Curcuma longa
Panax ginseng

Question 3

Botanical names of herbs known to be hepatotoxic, and constituent class known for this hepatotoxicity

Answer 3

Chelodium majus- alkaloids

Piper methysticum - alkaloids & kavalactones

Symphytum officinale - alkaloids (pyrrolizidine)

Larrea tridentata - dorihydroguaiaretic acid

Teucrium chamadrys- furanoneoclerodane diterpenoids

Question 4

Botanical names of herbs known to be hepatoprotective, and major active constituents of each herb

Answer 4

Silybum marianum - silymarin

Glycyrrhiza glabra - glycyrrhizin

Pcrorrhiza kurroa - picrosides

Andrographis paniculata - andrographolides

Bupleurum falcatum - saikosaponins

Cynara scolymus - cynarin

Schisandra chinensis - schisandrins

Rosmarinus officinalis - rosmarinic acid

Question 5

Common mechanisms of cellular toxicity

Answer 5

Liver bioactivation - formation of harmful or highly toxic substances from relatively nontoxic compounds, with several damaging mechanisms such as eliciting an immune response or forming reactive metabolites capable of binding and inactivation cytochrome p450s causing interactions

• > oxidative stress; metabolic irregularities (eg: phase I faster than phase II), DNA damage, cellular structure damage
• > autoimmunity; inflammation
• > hypersensitivity