Ryania speciosa Ryanodine

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. 

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. 

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. 

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. 

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

Many of the antifeedant compounds discussed above have insecticidal activity as well. Moreover, other diterpenes are toxic to insects and nematodes when consumed. Ryanodine (81), from Ryania speciosa (Flacourtiaceae) and several related species, is unique in that its insecticidal activity was discovered as a part of a search for new insecticides (Crosby, 1971). The toxic principle, ryanodine, is a diterpene esteri-fied to a pyrrole-2-carboxylic acid (Crosby, 1971). Ryanodine inhibits cardiomuscular calcium transport (Croteau and Johnson, 1985). 

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. 

Ryania. A genus of tropical American shrubs and trees belonging to the Flacourtiaceae family. The wood of various species is insecticidal. Oround stem wood of Ryanie speciosa Vahl., Flacourtiaceae is employed in the commercial insecticide formulations Ryanex, Ryanicide (formerly). See Polkers et al., U.S. pat. 2,400,295 (1946 to Merck Co.) Pepper, Carruth, J. Econ, Entomol 38, 59 (1945) Heal, Agr. Chem. 4, 37 (May. 1949). Insecticidal components such as ryanodine, g.v., are extractable by water, chloroform, or methanol. Toxicity data Kuna, Heal, J. Pharmacol Exp. Then 93, 407 (1948). 

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