A Detailed Explanation of Ephedra's Benefits, Effects and Side Effects
Ephedra, also known as Cao Ma Huang or Hua Ma Huang, is a medicinal herb listed in the Pharmacopoeia of the People's Republic of China. Its medicinal source is the dried herbaceous stem of the Ephedraceae plants Ephedra sinica, Ephedra intermedia, or Ephedra equisetina. The green herbaceous stems are harvested in autumn and dried in the sun. It is warm in nature, pungent and slightly bitter in taste, and has the benefits of inducing sweating and dispelling cold, diffusing the lungs and calming asthma, and promoting diuresis to reduce edema. It has a therapeutic effect on conditions such as wind-cold common cold, chest tightness with wheezing and cough, wind-edema with floating edema, and bronchial asthma.
I. Ephedra's Benefits
1. Inducing sweating and releasing the exterior
Ephedra is light and rising, reaching upward, warm in nature and pungent in dispersion. It is good at diffusing lung qi, opening the interstices, penetrating the hair pores, and dispersing wind-cold. It is commonly used for externally contracted wind-cold with excess exterior pattern and absence of sweating.
2. Diffusing the lungs and calming asthma
Ephedra is pungent and warm, and enters the lung meridian, diffusing and smoothing lung qi and warming and dispersing lung cold. It is commonly used for patterns such as wind-cold cough and asthma.
Promoting diuresis and reducing edema
Ephedra is pungent and warm, and enters the lung and bladder meridians. The lung is the upper source of water; by diffusing and descending lung qi and regulating the water passages, water is sent down to the bladder, thereby giving it the effect of promoting urination and reducing edema.
3. Dispersing cold and unblocking painful obstruction
Ephedra is pungent, dispersing, warm, and unblocking. According to the Discussion of Medicinal Properties (Yao Xing Lun): “It treats toxic wind and stubborn painful obstruction of the body, and numbness of the skin and flesh.” The Materia Medica of Rihua Zi and Various Schools (Rihua Zi Zhu Jia Ben Cao) also states: “Ephedra can regulate blood vessels and open the pores and skin.” The Record of the Hundred Kinds in the Divine Farmer's Materia Medica (Shen Nong Ben Cao Jing Bai Zhong Lu) proposes: Ephedra “is light, yang, and reaches upward, without qi or flavor; it is the lightest among those with qi and flavor. Therefore it can penetrate beyond the skin and hair pores, and can also deeply enter into congealed phlegm and stagnant blood. Wherever the power of medicine cannot reach, this can reach every subtle place; compared with those that are powerful and rich in qi, its power is even greater.” Thus, from the Song, Jin, Yuan, Ming, and Qing dynasties onward, this substance has been used as an assistant or envoy medicine, widely used to treat wind-cold-damp painful obstruction, skin disorders, carbuncles and abscesses with swelling and pain, and traumatic injuries with blood stasis and swelling. It can be used both internally and externally.
II. Ephedra's Effects
1. Exciting the central nervous system
It has an excitatory effect on the cerebrum, midbrain, and medulla oblongata, as well as the respiratory and circulatory centers; it also has an adrenaline-like effect. Therefore, after taking Ephedra preparations internally, the following manifestations appear:
① The whole body feels warm, heartbeat accelerates, peripheral blood vessels constrict, and blood pressure rises
② Increased secretion of sweat glands and salivary glands
③ Relief of bronchial and gastrointestinal spasms
④ It promotes tension and spasm of the internal bladder sphincter.
2. Affecting sweat gland secretion
Because the distribution of sweat glands differs between humans and animals, under ordinary circumstances ephedrine cannot induce sweating in humans. However, when a person is in a high-temperature environment and takes 50-60 mg of ephedrine, after 1.5-2 hours, sweat gland secretion is greater and faster than when ephedrine is not taken. However, subcutaneous injection of ephedrine into the skin does not cause special sweat gland secretion, so this effect of ephedrine is presumably central in nature.
3. Anti-allergic
It can also be used for urticaria; locally, it can constrict blood vessels in the nasal mucosa, so it can treat rhinitis; it has an anti-fatigue effect on skeletal muscle and can promote neuromuscular transmission inhibited by curare, so it can be used in the treatment of myasthenia gravis; it can also cause hyperglycemia, but its effect is weak and inconstant. The water extract has an anti-allergic effect, and Ephedra has the effect of inhibiting the release of sensitizing substances. Ma Xing Shi Gan Tang can inhibit mast cell degranulation; inhibit the release of histamine from the intestinal tract of sensitized guinea pigs, and relieve intestinal movement. Therefore, the clinical use of Ma Xing Shi Gan Tang is effective in treating allergic and hypersensitivity diseases.
4. Anti-inflammatory
Various Ephedra alkaloids have an inhibitory effect on inflammatory edema of the foot pad. Ephedra extract has an anti-inflammatory effect on experimental inflammation. The delphinidin contained in Ephedra has an inhibitory effect on experimental arthritis.
5. Analgesic
Ephedrine has a central analgesic effect and can significantly enhance the analgesic effect of morphine.
6. Antibacterial and antiviral
Ephedra volatile oil has an inhibitory effect on influenza virus (Asian type A AR8). In experiments treating influenza in mice with the volatile oil, the average survival time was significantly increased and the average lung injury was significantly reduced, showing a certain therapeutic efficacy. The water decoction and Ephedra volatile oil have varying degrees of antibacterial effect on multiple bacteria, have an inhibitory effect on Asian type A influenza virus, and have a therapeutic effect on mice infected with type A influenza virus strain PR8.
7. Antipyretic and diaphoretic
Ephedra volatile oil has an antipyretic effect on artificially induced fever in rabbits, with the cooling effect of terpineol being more pronounced.
Ephedra alkaloids cannot induce sweating. Ma Huang Tang has an antipyretic effect on fever in rats and can cause sweat gland secretion and sweating. This confirms the observations of the ancients: using Ephedra alone does not induce sweating; only when Ephedra is used together with Gui Zhi (cassia twig) can sweating be induced. Ma Xing Shi Gan Tang has an antipyretic effect on fever in rabbits. Experiments have shown that for rabbits with artificial fever caused by sterilized cow's milk, the Ephedra volatile oil emulsion has an antipyretic effect. However, Ephedra volatile oil has a relatively strong irritant effect on both skin and mucous membranes.
8. Effects on the heart
The structure and pharmacological effects of ephedrine contained in Ephedra are similar to those of adrenaline. It can strengthen myocardial contraction, increase cardiac output, accelerate heart rate, and even cause arrhythmia.
9. Blood pressure-lowering effect
The main alkaloids of Ephedra can cause blood pressure to rise, with both systolic and diastolic pressure increasing. Ephedra secondary alkaloids and volatile oil have vasodilatory and blood pressure-lowering effects.
10. Effects on blood vessels
Ephedrine can dilate blood vessels in the heart, brain, and muscles, increasing blood flow, while causing constriction of internal organs such as the lungs, kidneys, and spleen, as well as skin and mucosal blood vessels, reducing blood flow; and it can simultaneously raise both systolic and diastolic pressure of the pulmonary artery. Therefore, Ephedra is unfavorable for asthma patients with pulmonary hypertension.
11. Diuretic effect
Pseudoephedrine has a more obvious diuretic effect than ephedrine: after administration of water, saline, and urea (Urea), urine output is further increased. However, in anesthetized dogs, urine output instead decreases. In dogs with mild experimental renal tubular nephritis, a diuretic response is still produced, but in severe cases there is no diuretic effect.
12. Effects on smooth muscle
Bronchodilation: Various Ephedra alkaloids can relax bronchial smooth muscle and have an anti-asthmatic effect; enols and pyrazine derivatives in the volatile oil also have an anti-asthmatic effect.
Inhibition of peristalsis: Ephedrine has the effect of relaxing gastrointestinal smooth muscle and inhibiting its peristalsis, and can delay the propulsion and emptying of gastrointestinal contents, so Ephedra can affect appetite.
Inhibition of uterine smooth muscle: Ephedra can inhibit human uterine smooth muscle, thereby relieving dysmenorrhea. In animals, it can increase the tension of uterine smooth muscle. Ephedrine has a contracting effect on the vas deferens.
Strengthening the bladder sphincter: Ephedra can increase the tension of the bladder trigone muscle and sphincter and reduce the frequency of urination, so it can treat enuresis in children.
Ephedrine can also cause contraction of the anococcygeus muscle.
13. Central excitatory effect
It can excite the cerebral cortex and subcortical centers. Its excitatory effect is stronger than that of adrenaline. Therefore, it can cause symptoms such as insomnia, nervousness, restlessness, and tremor.
14. Respiratory excitatory effect
Ephedrine can excite the respiratory center and increase minute respiratory volume. Ephedrine and Ephedra water extract have a central antitussive effect.
Ephedra volatile oil has anti-asthmatic and phlegm-resolving effects, but no antitussive effect.
15. Muscle excitatory effect
Ephedrine can increase muscle tension and restore tension to fatigued muscles. Therefore, Ephedra is classified as a muscle stimulant and is prohibited for use by athletes.
16. Anti-renal failure
Ephedra extract can reduce creatinine and urea nitrogen in the blood of rats with renal failure and increase blood calcium. This is because it inhibits the production of creatinine and oxygen free radicals, thereby markedly inhibiting the formation of methylguanidine, thus improving renal function. Pseudoephedrine has a diuretic effect on dogs.
17. Weight loss
Ephedrine can promote fat breakdown and has a weight-loss effect.
18. Inhibiting platelet aggregation
Ephedra extract can inhibit rabbit platelet aggregation and inhibit the production of platelet thromboxane A3. It can reduce blood viscosity.
19. Cholagogic effect
Ephedra extract has a cholagogic effect in rabbits.
20. Anti-tumor
Ephedra delphinidin has an anti-tumor effect in mice.
III. Ephedra's Side Effects
Ephedrine is relatively toxic, while pseudoephedrine is less toxic; the latter is also metabolized very slowly in the body. Ephedrine is often used to induce sweating and calm asthma. When taken in excess, central excitatory symptoms such as restlessness and insomnia, as well as side effects such as elevated blood pressure, often occur. When ephedrine is used in patients with prostatic hypertrophy, it can sometimes cause difficulty urinating and lead to urinary retention.
For adults taking Ephedra internally, the toxic dose is 30-45 g. The mechanism of Ephedra poisoning is mainly: ephedrine inhibits monoamine oxidase activity, slowing the breakdown of adrenaline and the chemical transmitter substances of adrenergic nerves, thereby causing excitation of the sympathetic nervous system and central nervous system, with particularly significant effects on the respiratory center and vasomotor center.
In Ephedra poisoning, the initial manifestations are symptoms of central nervous system and sympathetic nervous system excitation, such as restlessness, nervousness, headache and dizziness, tinnitus and insomnia, nausea and vomiting, upper abdominal discomfort, thirst and sweating, elevated blood pressure, dilated pupils, palpitations and shortness of breath, and precordial pain. In severe cases: difficulty urinating, blurred vision, shock, coma, and difficulty breathing. Death ultimately occurs due to respiratory failure and ventricular fibrillation. Long-term use of this substance can cause addiction.