Plants Used for Respiratory Problems - I

1. Plants Used forRespiratory Problems - I

2. Respiratory Problems • Various conditions can interfere with the gas exchange in the lungs • Infectious disease • Chronic diseases • Asthma • Emphysema

3. Asthma • Chronic breathing disorder • Characterized by inflammation of the airways, bronchial constriction, excessive mucous secretion - results in wheezing, coughing, and choking • Responsible for 5,000 deaths/yr in the US • Attacks triggered by exposure to allergens and also infections, stress, exercise

4. Airway constriction • Narrowing of airways due to • contraction of the smooth muscles • Inflammation/edema of bronchial walls • retention of viscid bronchial secretions

5. Normal Function of Airway

6. Asthmatic lungs

7. Asthma Increase • Close to 18 million people in US suffer from asthma including 5 million children (12 million under 16 yrs) • Over $11.3 billion in medical costs each year – including direct medical costs and lost productivity • Since 1980, asthma reports have increased 75% - up 160% in children • Increase especially seen in inner city – survey in south Bronx indicated that 28% of children had asthma symptoms • Exact reason not certain - possibly better diagnosis, possibly increased exposure to indoor allergens, outdoor pollutants, possibly lifestyle changes, lots of theories!

11. Asthma Treatment • Many treatment options • Bronchodilators • Anti-inflammatory drugs • Allergy shots (desensitization)

12. Bronchodilators • Help to stop asthma attacks after they've started • Can help prevent expected attacks, as from exercise • Relax smooth muscles of bronchioles - this opens bronchioles and makes breathing easier

13. Bronchodilators • What do they do • Adrenergic agents • Increase the volume and diameter of bronchial smooth muscles by relaxing them • Include norepinephrine, epinephrine, and ephedrine • Theophylline drugs • Act of the bronchial muscles to relieve obstruction, increase coronary blood flow and stimulate respiration

14. A very short list of plant extracts • Ephedrine • Theophylline

15. Ephedra Ephedrine and Pseudoephedrine

16. Ephedra spp. Gymnosperm in the Division Gnetophyta Ephedra sinica well known as source of drug ephedrine

19. Medicinal Use of Ephedra • Long history of use as a medicinal plant especially as a decongestant for asthma, bronchitis, and other respiratory conditions • In China, Ephedra sinica – called Ma Huang has been used for thousands of years • Also well known as a stimulant

20. Alkaloids in Ephedra • Ephedrine, pseudoephedrine, others • Ephedrine used in prescription drugs since the 1920s • Also used in OTC drugs • Very effective decongestants – relaxes bronchial muscles and opens airways • Also CNS stimulant that increases heart rate and blood pressure and blood flow to brain • Stimulating properties of pseudoephedrine not as great and preferred today

21. Ephedrine and Pseudoephedrine are stereo-isomers Ephedrine Pseudoephedrine

22. Mode of action • Mimic adrenal hormones – epinephrine and norepinephrine • Stimulates a and b-adrenergic receptors • b-2 receptors in the lungs are stimulated to open the airways - this is responsible for its effectiveness as a bronchodilator • Other receptors also stimulated: • b-1 receptors in the heart increase heart rate and force of contraction • a-1 receptors increase blood pressure and decrease circulation to the renal system and other parts of the body

23. Adrenal Hormones • Increased rate and force of contraction of the heart muscle: predominantly an effect of epinephrine acting through beta receptors • Constriction of blood vessels: norepinephrine, in particular, causes widespread vasoconstriction, resulting in increased resistance and blood pressure • Dilation of bronchioles: assists in pulmonary ventilation

24. More on adrenal hormones • Stimulation of lipolysis in fat cells: provides fatty acids for energy production in many tissues and aids in conservation of dwindling reserves of blood glucose. • Increased metabolic rate: oxygen consumption and heat production increase in response to epinephrine • Hormones also promote breakdown of glycogen in skeletal muscle to provide glucose for energy production

25. Epinephrine and Norepinephrine Synthesized in the body from a.a. Tyrosine

26. New b-2 agonists • Epinephrine (adrenaline) was once a conventional treatment for asthma • similar to ephedrine but much more active and short-acting • Epinephrine was replaced by current asthma medications which are able to act more selectively on b-2 receptors • Epinephrine still used in emergency treatment of asthma – Epi-pens

27. Common side effects of ephedrine • Headache, irritability, restlessness of muscles, nausea, sleeplessness, increased heart rate, urinary disturbances and vomiting • Higher dosages may result in drastic increases in blood pressure and cardiac rhythm disorders, heart palpitations • Since ephedrine chemically similar to epinephrine, it works like a powerful cardiac stimulant and may cause cardiac arrest in infants and heart patients

28. Ephedrine contra-indicated • Non-specific stimulation of adrenergic receptors means that Ephedra products should not be used in people with • anxiety and restlessness • high blood pressure • glaucoma • impaired circulation of the cerebrum • prostate adenoma

29. Ephedrine and pseudoephedrine uses • Originally Ephedra sinica • Synthesized in lab today • New synthetics available • Pseudoephedrine preferred • Many OTC • Herbal supplements – Ma Huang • Ephedrine abuse

30. Many OTC products