Dendrobine

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Dendrobine
Dendrobine.png
Identifiers
Properties
C16H25NO2
Molar mass 263.381 g/mol
Appearance Colorless
Melting point 136°C
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Dendrobine is the major bioactive chemical in the Chinese herbal medicine "Chin-Shih-Hu", a tea brewed from the dried stems of the Dendrobium nobile plant.[1] It is a colorless solid at room temperature. In small doses, it has analgesic (pain-killing), antipyretic (anti-fever), and hypotensive (low blood pressure) effects. The alkaloid Dendrobine is found in the plant Dendrobium nobile at an average of 0.5% by weight. It is related to the picrotoxin family of natural products. When given a fatal dose, death is usually caused by convulsions.[1] It possesses an intriguing molecular structure that represents a challenging target for synthetic chemists.

Synthesis[edit]

This picture illustrates the main steps in the Kreis synthesis of (-)Dendrobine

There have been 3 successful enantioselective syntheses of Dendrobine reported with yields ranging from 0.2-4.0%. The structure of dendrobine is intriguing due to its tetracyclic ring system with seven contiguous stereocenters. Most recently, a full synthesis of (-)Dendrobine was carried out by Kreis et al. with a yield of 4.0%.[1] The novelty of Kreis' synthesis is the key reaction cascade with an amine functioning as the linchpin that initiates the sequence of reactions while embeding itself in the target structure. This reaction cascade occurs stereoselctively only when it is carried out without isolation of intermediates. The cascade successfully installs a key quaternary center while simultaneously designating a stereosymetric carbon center.

Effects[edit]

While Dendrobine's effects on humans have not been studied extensively, studies of its pharmocological effects on various small animals were conducted in 1935 by Chen and Chen.[2] It was concluded that Dendrobine exhibited a weak analgesic effect when administered to mice (5–15 mg/kg), and an antipyretic effect when administered to rabbits (8.5 mg/kg).[2] Hypotensive effects were reported in experiments with frogs, cats, and a dog. The minimum lethal doses by intravenous injection are 20 mg/kg for mice and rats, 22 mg/kg in guinea pigs, and 17 mg/kg in rabbits.[2] Dendrobine is a strongly selective competitive antagonist of β-alanine, taurine, and glycine. While structurally related to picrotoxinin, Dendrobine is not an antagonist of GABA.

Dietary Supplement[edit]

There have been some claims that dendrobium extracts can contain phenylethylamines (PEAs), a type of stimulant that can have effects similar to those of amphetamines. So far, however, no reliable evidence indicates that PEAs occur naturally in any dendrobium species, which suggests some dendrobium-containing products may have been “spiked.” One dietary supplement product with “dendrobium” as an ingredient was removed from the market because of this.

If Dendrobium nobile is listed as one of the constituents of a proprietary blend, there is no way to tell how much dendrobine is present without laboratory testing. Therefore, dendrobium as a dietary supplement ingredient may pose health risks, including convulsions, seizures, or low blood pressure. In addition, there is always a risk that dendrobium-containing products may contain ingredients not listed on the label and there is no way to know what is actually in any dietary supplement unless it is analyzed in a laboratory or has been third-party certified.

References[edit]

  1. ^ a b c Kreis, L. M., Consice textbook of forensic medicine & toxicology, Elsevier, 2008
  2. ^ a b c Chen, K. K.; Chen, A. Ling (1 November 1935). "The Pharmacological Action of Dendrobine. the Alkaloid of Chin-Shih-Hu" (PDF). Journal of Pharmacology and Experimental Therapeutics. 

External links[edit]