CNS: Anthraquinones and MAO Inhibitors

Study Notes

Anthraquinones (Hypericin) from St John's Wort inhibit MAO, increasing epinephrine, serotonin, and dopamine
Hyperforin decreases GABA binding to receptors
Side effects: activating CYP 450, reducing concentrations of anticonvulsants, theophylline, contraceptives, and warfarin
Contraindications: pregnancy, lactation
Dosage form: Tablets (300 mg)

Sesquiterpene volatile oils (0.8% Valerianic acid) stimulate GABA synthesis and release
Inhibit GABA reuptake and catabolism, increasing extracellular GABA concentrations
Side effects: severe depression, cardiac function disturbance (high dose)
Contraindications: pregnancy, children (oxytocic due to Iridoids)
Dosage form: Infusion (2-3 gm) at bedtime

Gama-Pyrone derivatives (Maltol & Ethyl maltol) and Flavonoids C-glycosides (vitexin) have affinity for GABA receptors
Increase GABA release and inhibit reuptake and catabolism (CNS depressant)
Monoamine oxidase inhibition effect (can be used as an antidepressant, CNS stimulant)
Side effects: uterine stimulant, not used in pregnancy
Certain aminoglycosides (Clindamycin) potentiate the relaxing action of Passion flower

Kavalactones (Kavapyrones): Kavain, Methysticin, and Yangonin increase GABA binding sites
Inhibit noradrenaline uptake and catabolism, leading to mood elevation and depression treatment
Side effects: dermopathy (reversible yellow discoloration), liver damage
Interactions: diuretics, alcohol, and other depressants may potentiate the action of Kava
Dosage form: Decoction (1.5-3 gm) at bedtime

Alpha acid (Humulone) and Beta acid (Lupulone) increase GABA release and receptors
Side effects: menstrual cycle disturbance, not used in pregnancy
Dosage form: Decoction (1-2 gm) at bedtime

Opiate alkaloids derived from opium (dried exudates of poppy capsule, Papaver somniferum)
Examples: Morphine, Levorphanol, Methadone, Fentanyl
Mechanism: mimics the action of endogenous opioids at receptors, inhibiting release of neurotransmitters
Therapeutic indications: relieve pain associated with myocardial infarction, cancer, and post-operation
Side effects: sedation, miosis, depression, respiratory depression, constipation, biliary spasm, hypotension, euphoria, and dependence

Sesquiterpene Lactone (Parthenolide) inhibits Arachidonic acid synthesis, prostaglandin and leukotriene synthesis
Decreases smooth muscle spasm, inhibits platelet aggregation, and histamine release (anti-allergic) and serotonin secretion
Side effects: mouth ulcers, tongue swelling, bleeding disorders with warfarin
Contraindications: patients hypersensitive to drugs of family Asteraceae (Chamomile)
Dosage form: 50-250 mg daily

6% Terpene (Ginkgolides) and 24% flavonoids
Ginkgolides A and B are platelet-activating factor antagonists and neuro-protective
Inhibit monoamine oxidase (increase dopamine and acetylcholine), protect against amyloid peptide synthesis
Relieve cerebral ischemia and prevent memory deterioration (dementia)
Side effects: ototoxicity with aminoglycosides, hypoglycemia, bleeding, hypertension, loss of appetite
Dosage forms: Tablets, Capsules, Syrup