Prunus amygdalus

As early as 1908, Rosenthaler found in the ferment mixture of emulsin a u-oxynitrilase , which directed the addition of hydrocyanic acid (hydrogen cyanide) to benzaldehyde asymmetrically to give x-hydroxybenzeneacetonitrilc (mandelonitrile)9. This result was confirmed1 °, however, it was not until 1963 that Pfeil ct al. first isolated and characterized the enzyme (R)-oxyni-trilase [EC 4.1.2.101 from bitter almonds (Prunus amygdalus)1 12. The yellow-colored enzyme contains a flavin-adenine dinucleotide (FAD)11 and loses its activity by splitting off this prosthet-... 

As reported by Griengl and coworkers, benzaldehyde, decanal, undecanal, and dodecanal were reacted with HCN in a two-phase solvent system aqueous buffer and ionic liquids 1 -ethyl-3-methylimidazolium tetrafluoroborate, 1 -methyl-3-propylimidazolium tetrafluoroborate, and l-butyl-3-methyl-imidazolium tetrafluoroborate in the presence of the HNLs from Prunus amygdalus and Hevea brasiliensis. When compared with the use of organic solvents as the nonaqueous phase, the reaction rate was significantly increased and the enantioselectivity remained good [51]. 

Dreveny, I., Kratky, C. and Gruber, K. (2002) The active site of hydroxynitrile lyase from Prunus amygdalus modeling studies provide new insights into the mechanism of cyanogenesis. Protein Science A Publication of the Protein Society, 11, 292-300. 

Inhibition of cytochromes of electron transport system can be caused by cyanogenic glycosides, such as amygdalin (Fig. 11.14) in bitter almonds, Prunus amygdalus, linamarin and lotaustralin in clover and birdsfoot trefoil, or dhurrin (Fig. 11.14) in Sorghum vulgare. The potent effect of cyanide on cell respiration has given rise to a recent serious conservation problem. In Southeast Asia, divers stun fish on coral reefs with a blast of cyanide to collect them for the aquarium trade. In the process, many fish are killed and the corals bleached, because their symbionts die (e.g. Payne, 2001). 

Flavonols Almond Prunus amygdalus) seedcoat Linear (+) THAP 321... 

Rawat, M.S.M. et al., A persicogenin 3 -glucoside from the stem bark of Prunus amygdalus. Phytochemistry, 38, 1519, 1995. 

Bitter almond Prunus amygdalus Batsch. van amara (DC.) Focke Benzaldehyde (min. 98)... 

HNLs are found in over 3000 higher plant species, like Rosaceae, Euphorbiaceae, Linaceae and Filitaceae, in several bacteria, and in some insects [5, 6]. For cyanohydrin synthesis, mainly five HNLs have been used the (R)-selective HNLs from Prunus amygdalus (PaHNL) and Linurn usitatissimum (l.ul INI.) and the (S)-selective ones from Hevea brasiliensis (HfeHNL), Manihot esculenta (MeHNL), and Sorghum bicolor (SfcHNL) [1]. 

Sang, S.M., Lapsley, K., Jeong, W.S., Lachance, P.A., Ho, C.T., and Rosen, R.T. 2002. Antioxida-tive phenolic compounds isolated from almond skins (Prunus amygdalus Batsch). J. Agric. Food Chem. 50 2459-2463. 

R (R)-oxynitrilase (Prunus amygdalus) (S)-oxynitrilase (Sorghum bicolor) (S)-oxynitrilase (Hevea brasiliensis) ... 

Hnl hydroxynitrile lyase Pa Prunus amygdalus Hb Hevea hrasiliensis Sb Sorghum hicolor Me Manihot esculenta. 

Almond Prunus amygdalus var. dulcis, or var. amara (Rosaceae) seed 40-55 oleic (62-86), linoleic (7-30), palmitic (4-9), stearic (1-2) emollient base, toiletries, carrier oil (aromatherapy)... 

Native HNLs from bitter almonds (Prunus amygdalus), cassava (Manihot escu-lenta), millet (Sorghum bicolor), and flax (Linum usitatissimum) were repeatedly used in the synthesis of chiral cyanohydrins [39, 41, 197]. Cyanohydrins are versatile building blocks in natural product synthesis, giving organic chemists the possibility of introducing all kinds of functional groups (Fig. 38) [198]. 

Do not confuse sweet almond with bitter almond (Prunus amygdalus var umu. a). The essential oil is extracted by steam distillation after maceration of pressed nuts. A major component is benzaldehyde (95%), which is moderately toxic. Hydrocyanic acid is also formed, which is poisonous. It is not suitable for aromatherapy but is used in the food industry. 

---