Yohimbine Chemical Properties

Melting point:

231-233 °C(lit.)

alpha 

D20 +50.9 to +62.2° (ethanol); D20 +108° (pyridine); 20546 +129° (c = 0.5 in pyridine)

Boiling point:

487.66°C (rough estimate)

Density 

1.1640 (rough estimate)

refractive index 

1.6500 (estimate)

storage temp. 

Sealed in dry,Room Temperature

solubility 

THF; DMSO; Chloroform;

form 

Solid

pka

14.39±0.40(Predicted)

color 

Beige

InChI

InChI=1S/C21H26N2O3/c1-26-21(25)19-15-10-17-20-14(13-4-2-3-5-16(13)22-20)8-9-23(17)11-12(15)6-7-18(19)24/h2-5,12,15,17-19,22,24H,6-11H2,1H3/t12-,15-,17-,18-,19+/m0/s1

InChIKey

BLGXFZZNTVWLAY-SCYLSFHTSA-N

SMILES

[C@@H]1(O)[C@H](C(OC)=O)[C@]2(C[C@@]3(N(C[C@@]2(CC1)[H])CCC1C2=C(NC3=1)C=CC=C2)[H])[H]

LogP

2.730

CAS DataBase Reference

146-48-5(CAS DataBase Reference)

NIST Chemistry Reference

Yohimbine(146-48-5)

Safety Information

Hazard Codes 

T

Risk Statements 

23/24/25-39

Safety Statements 

27-36/37/39-45

RIDADR 

1544

RTECS 

ZG1000000

HazardClass 

6.1(a)

PackingGroup 

II

Yohimbine Usage And Synthesis

Overview Information

Yohimbe is the name of an evergreen tree found in parts of central and western Africa. The bark of yohimbe contains a chemical called yohimbine, which is used to make medicine. Yohimbine hydrochloride (Aphrodyne, Yocon) is a form of yohimbine that is a prescription drug in the US.
Yohimbe supplements often list yohimbe bark extract or yohimbine as the active ingredient. However, some of these products might not provide accurate information about the amount of yohimbine in the supplement. Also, some yohimbe supplements list yohimbine hydrochloride as an active ingredient. Yohimbe products containing man-made yohimbine hydrochloride as an ingredient are not legal to sell as a dietary supplement in the US.
Yohimbe is taken by mouth arouse sexual excitement, for erectile dysfunction (ED), sexual problems caused by medications for depression called selective-serotonin reuptake inhibitors (SSRIs), and general sexual problems in both men and women. It is also used for athletic performance, weight loss, exhaustion, chest pain, high blood pressure, low blood pressure that occurs when standing up, diabetic nerve pain, and for depression along with certain other medications.

Effectiveness

Anxiety. There is mixed evidence about the effectiveness of yohimbine, the active ingredient in yohimbe, for treating anxiety related to phobias. Some research suggests that it does not improve anxiety when combined with therapy. However, other research suggests that it reduces fear related to certain phobias.
Depression. Early research suggests that taking yohimbine, the active ingredient of yohimbe, daily for 10 days does not improve depression symptoms.
Erectile dysfunction (ED). There is evidence that yohimbine, the active ingredient of yohimbe, can be helpful for ED. Some herbalists suggest that the yohimbe bark actually works better than the yohimbine ingredient alone. However, so far yohimbe bark has not been evaluated in research studies.
Exercise performance. Early research suggests that taking yohimbine, the active ingredient in yohimbe, daily for 21 days does not improve exercise performance or build muscle mass in soccer players.
Head rush (orthostatic hypotension). Early research suggests that taking a single dose of yohimbine, the active ingredient in yohimbe, increases blood pressure in people with a head rush due to low blood pressure. However, other early research suggests that it does not improve blood pressure.
Sexual problems caused by selective-serotonin reuptake inhibitors (SSRIs). There is evidence from many studies that yohimbine, the active ingredient of yohimbe, can improve sexual problems associated with this class of medications used for depression. However, this benefit has not been described specifically for the yohimbe bark.
Dry mouth. Early research suggests that taking yohimbine, the active ingredient in yohimbe, improves symptoms of dry mouth in people taking antidepressants. The effect of the yohimbe bark on dry mouth is not clear.

Side Effects

Yohimbe, taken by mouth, is POSSIBLY UNSAFE. Yohimbe has been linked to reports of severe side effects including irregular or rapid heart beat, kidney failure, seizure, heart attack, and others.
The primary active ingredient in yohimbe is a drug called yohimbine. This is considered a prescription drug in North America. This drug can be safely used short-term when monitored by a health professional.
However, it is not appropriate for unsupervised use due to potentially serious side effects that it can cause.
Children should not take yohimbe. It is POSSIBLY UNSAFE for children because children appear to be extra sensitive to the harmful effects of yohimbe.
When taken by mouth in typical doses, yohimbe and the ingredient yohimbine can cause stomach upset, excitation, tremor, sleep problems, anxiety or agitation, high blood pressure, a racing heartbeat, dizziness, stomach problems, drooling, sinus pain, irritability, headache, frequent urination, bloating, rash, nausea, and vomiting.
Taking high doses can also cause other severe problems, including difficulty breathing, paralysis, very low blood pressure, heart problems, and death. After taking a one-day dose of yohimbine, one person reported an allergic reaction involving fever; chills; listlessness; itchy, scaly skin; progressive kidney failure; and symptoms that looked like the auto-immune disease called lupus.

Description

Yohimbine is a natural alkaloid. It was first extracted from the barks of Corynanthe yohimbe, a species of Rubiaceae trees in West Africa. It was reported that, in the dried bark of Pausinystalia johimbe, the content of mixed alkaloids is higher than 6.1%, in which the main component is yohimbine, indicating a great prospect for development . Yohimbe bark has been used as an aphrodisiac in Africa since ancient times. In 1900, it was applied by Kowit and Muller to patients with impotence and paralytic insensitivity caused by neurasthenia and obtained curative effect. From then on, clinical application of yohimbine began. Currently, yohimbine is a pure plant preparation in the treatment of erectile dysfunction with more affirmation and more applications.

Chemical Properties

Glistening, needle-like alkaloid, soluble in alcohol and ether, very slightly soluble in water.

Physical properties

Appearance: white powder. Solubility: soluble in ethanol, chloroform, and hot benzene; slightly soluble in water and ether, usually salified by hydrochloric acid to increase its solubility in water. Specific rotatory power (°): D22 +105° (in water). Melting point: 241–246?°C.

History

Yohimbine has been used as an aphrodisiac for many years. At first, pharmacologists attributed its aphrodisiac effects to psychological effects similar to placebo or increasement of peripheral vascular congestion, rather than real sexual stimulation. Physiologists at the Stanford University first conducted a study on the pharmacological effects of yohimbine and found that yohimbine could increase the mating ability of rats , which was then published on Science in 1984 . In addition, researchers in the Queensland University in Canada conducted experiments on 23 patients with sexual dysfunction. Six of them recovered after taking the drug for 10?weeks. In 1987, Canadian scientists confirmed that yohimbine treatment in psychogenic impotence was safe and effective and this drug could restore the patient’ssexual ability . Besides, they proved that this medicine showed good curative effects on organic impotence.

Uses

Yohimbine occurs in Corinanthe johimbeK. and Rubiaceae trees. It is also foundin the roots of Rauwolfia serpentina L.and Apocyanaceae. Its derivatives areused therapeutically as adrenergic blockingagents.

Uses

Obtained from leaves and bark of Corynanthe johimbe. Formerly used as an aphrodisiac in veterinary medicine, yohimbine works primarily by acting as an antagonist at α2-adrenergic receptors.

Definition

ChEBI: Yohimbine is an indole alkaloid with alpha2-adrenoceptor antagonist activity. It is produced by Corynanthe johimbe and Rauwolfia serpentina. It has a role as an alpha-adrenergic antagonist, a serotonergic antagonist and a dopamine receptor D2 antagonist. It is functionally related to a yohimbic acid.

Indications

This product is listed in the 2017 edition of the British Pharmacopoeia, 40 editions of the American Pharmacopoeia, and 9.0 edition of the European Pharmacopoeia. The main clinical application of yohimbine includes tablets and injections. It is mainly used to treat various types of impotence and sexual dysfunction in men.

General Description

Yohimbine (Yocon)is a competitive and selective 2-blocker. The compound isan indolealkylamine alkaloid and is found in the bark of thetree Pausinystalia yohimbe and in Rauwolfia root.

Health Hazard

Pharmacologically, yohimbine is an adrenergic blocking agent. It exhibits hypotensive and cardiostimulant activities. Poisoningfrom excessive doses may become severe,causing convulsions and respiratory failure
LD50 value, intraperitoneal (mice): 16 mg/kg
LD50 value, oral (mice): 37 mg/kg.

Biological Activity

α 2 -adrenoceptor antagonist (pK i values are 8.52, 8.00 and 9.17 for human a 2A , a 2B and a 2C receptors respectively).

Pharmacology

Studies have shown that yohimbine has extensive pharmacological effects and has been developed for the clinical treatment of arteriosclerosis, rheumatism, and other diseases. The most obvious pharmacological action is in the treatment of male sexual dysfunction. Yohimbine tablets have been approved by the FDA and circulate in international markets. Yohimbine can selectively block the presynaptic alpha 2 receptors and promote the release of norepinephrine . It stimulates more norepinephrine released by cavernous nerve endings and reduces reflux of phallic vein, which is conducive to congestive erection. A small amount of application can make the perineum swell and stimulate the erection center at the spinal cord, leading to sexual hyperfunction . Yohimbine hydrochloride also has a psychological stimulant effect and increases libido. Like other types of adrenergic blocking drugs, yohimbine’s resistance to adrenergic mediator in blood circulation is much stronger than to sympathetic nerve impulse. Again, like tolazoline, yohimbine shows slight effect in resisting adrenergic response in ocular smooth muscle. This drug does not block the frequency and inotropic effects of epinephrine on mammalian hearts. Yohimbine has minor direct effects on smooth muscle, and its effect on the central nervous system is far less than that of ergot alkaloids, because yohimbine performs an excited-to-paralyzed action. This drug produces diuretic effect, probably due to the stimulation of the hypothalamus, resulting in release of posterior pituitary hormone. In addition, yohimbine has a significant local anesthetic effect .

Clinical Use

Yohimbine increases heart rate and blood pressure as aresult of its blockade of 2-receptors in the CNS. It has beenused experimentally to treat male erectile impotence.

Purification Methods

Crystallise the alkaloid from EtOH, and dry it in a vacuum to remove EtOH of crystallisation. [Van Tamelen et al. J Am Chem Soc 91 7315 1969, Stork

Mode of action

Yohimbine is a selective α2-adrenergic antagonist. It is chemically similar to the alkaloid reserpine. Being a derivative of indolylalkylamine, it selectively blocks α2-adrenergic receptors. It weakens the negative feedback mechanism of norepinephrine release in nerve endings. It has a sympathomimetic effect, and can also cause sympathomimetic action. Additional research is evidently needed to conclusively delineate its pharmacological action.

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