Ryania speciosa

Ryanodine is a neutral plant alkaloid from Ryania speciosa and was used as an insecticide. It also has been well known by the characteristic action on mammalian skeletal muscle of slowly developing, and intensive and irreversible contracture. Ryanodine binds specifically to the open RyR channel at the stoichiometry of 1 mol/mol homotetramer with a high affinity (ATD nM) and leads the channel to ryanodine modified state characteristic of long-lasting subconductance ( 50% of normal) opening. At higher concentration, it blocks the channel. 

Ryania speciosa Vahl., Flacourtiaceae, Ang. from tn ical Amwica MI... 

Ryania speciosa (Flacourtiaceae) and several related species are unique in that their insecticidal activity was discovered as a part of a search for new insecticides (89). The toxic principle is a diterpene esterified to pyrrole-2-carboxylic acid. This insecticide proved to be somewhat selective in its activity (89). 

Ryanodine (Figure 3.24) is derived from Ryania speciosa and represents the first successful discovery of a natural insecticide in a collaborative programme between Merck and Rutgers University. The compound acts by binding to the calcium channels in the sarcoplastic reticulum of muscles, thereby causing calcium ions to enter the cells with death following rapidly thereafter. 

Two other important natural products are rotenone and ryanodine. Rotenone (101) (B-71MI10700) is the main insecticidal constituent of certain Derris and Lonchocarpus species, and derris dust is still available as an insecticide. It has been the subject of extensive structural and synthetic studies (B-72MI10704). Ryanodine (102) (B-7lMH070i) is extracted from the wood of Ryania speciosa and has been used in crude extract form as ryania. Despite its extreme complexity it has been totally synthesized (77PAC1329). 

Ryania. The root and stem of the plant Ryania speciosa, family Flacourtiaceae, native to South America, contain from 0.16—0.2% of insecticidal components, the most important of which is the alkaloid ryanodine [15662-33-9], C25H3509N (8) (mp 219-220°C). This compound is effective as both a contact and a stomach poison. Ryanodine is soluble in water, methyl alcohol, and most organic solvents but not in petroleum oils. It is more stable to the action of air and light than pyrethrum or rotenone and has considerable residual action. Ryania has an oral LD5Q to the rat of 750 mg/kg. The material has shown considerable promise in the control of the European com borer and codling moth and is used as a wettable powder of ground stems or as a methanolic extract. Ryanodine uncouples the ATP—AD P actomyosin cycle of striated muscle. 

Ryania consists of the powdered stem of the tropical shrub, Ryania speciosa. The extract contains ryanodine and related compounds, and has a low toxicity to mammals. The powder is used as a stomach poison on vegetables and fruit. Ryanodine induces paralysis in insects by direct action on the muscles, resulting in sustained contraction and paralysis. 

Ryanodine Poaceae seed low in fea mays (corn seed) (Poaceae) - pellagra from deficiency Ryania speciosa (Flacourtiaceae) irritability, skin rash, dementia (insane asylum before cure recognized)] Opens RY-R [ER Ca +... 

Ryania is made from the ground roots of the tropical shrub Ryania speciosa. The active principle of ryania is the alkaloid ryanodine (C25H35NOu). Ryania is used for controlling aphids, cabbage loopers, Colorado potato beetles, diamondback moths, cucumber beetles, leafhoppers, corn earworms, European corn borers, codling moths, citrus thrips, and so on. Its oral LD30 in rats is 1200 mg/kg so it is practically nontoxic to mammals. 

Areas of application Mode of action How obtained Remarks Codling moths, tortrix moths, aphids, leaf miners Contact insecticide Ryania is obtained from the wood of Ryania speciosa Broad spectrum of action More persistent than pyrethrum-rotenone sprays Poisonous to fish Not registered in the EU at present... 

Ryanodine is the active, insecticidal ingredient of a tropical shrub Ryania speciosa). For years, this botanical insecticide has been recommended for use against citrus thrips, corn earworms, European corn borers, codling moths, and a variety of other pests. However, ryania is also quite toxic to mammals and water life. For this reason, it s better to rely on safer pest control measures,. such as iasecticidal soap, neem, or pyrethrin. 

RX 783006 DAMGO. ryanodine is an alkaloid from Ryania speciosa (Flacourtiaceae). It has been used as an INSECTICIDE, but is now superseded. It is a calcium-transport blocker, binding to intracellular receptor channels in the endoplasmic reticulum. It is used as a pharmacological tool. 

The ryanodine receptors are calcium release channels found in the endoplasmic reticulum and sarcoplasmic reticulum of muscle cells. One type of receptor can be activated by a depolarization signal (depolarization-induced calcium release). Another receptor type is activated by calcium ions (calcium-induced calcium release). The proteins received their name because they bind ryanodine, a toxin obtained from the stem and roots of the plant Ryania speciosa. Ryanodine inhibits sarcoplasmic reticulum calcium release, and acts as a paralytic agent. It was first used commercially in insecticides. 

Ryania speciosa Dust containing powdered stemwood (50%) Ryanodine (0.05%) and related alkaloids... 

Ryania was recognized about 50 years ago as an insecticide (1) but was known much earlier as a toxicant for mammals (2,3). The current commercial insecticide is the ground stem-wood of Ryania speciosa Vahl (Flacourtiaceae) from Trinidad supplied by Agrisystems International (Windgap, PA). The roots are even more insecticidal but for reasons of convenience, conservation and regrowth the stem-wood is used. This genus is also found in the Amazon basin and adjacent parts of South America (3). 

The aldol reaction plays a key role in biosynthesis of poly-ketide natural products. It is also one of the most used transformations for stereoselective C—C bond formation. Deslongchamps and co-workers described one of the early examples of transannular aldol reactions in the synthesis of (it)-ryanodol, a compact and highly functionalized polycyclic diterpenoid isolated from Ryania speciosa The 1,5-diketone 48 that was requisite for the transannular aldol reaction was generated in situ from 47 by ozonolysis of its alkene (Scheme 20.14). Conformational equilibration of 48 to the less strained conformer B was followed by a transannular aldol reaction to give 49 in 90% yield. The polycyclic molecular framework provided the conformational bias for stereoselective formation of 49, which was converted to ryanodol after additional transformations. 

Quinolizidine alkaloids are found in many species of the Fabaceae, Ber-beridaceae, Leguminosae, and Solanaceae and are derived from lysine (67, 68). Some quinolizidine alkaloids are very toxic insecticides that have the potential of commercial use for the control of insects. For example, the alkaloid ryanodine, which is found in the stems and roots of Ryania speciosa, is effective as both an insect contact and stomach insecticide and is particularly effective against Lepidoptera. It has been used to control the codling moth without affecting parasites and predators of the moth (69). 

Ryanodine [15662-33-6] is the active ingredient of the roots of Ryania speciosa, (Flacourtiaceae). It is more stable against sunlight and air than pyrethrum and rotenone and is used for codling moth control. 

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