12
In the mid-1910s, the German chemist and biochemist Hans Pringsheim used the
name of krystallisiertes polyamylosen, i.e., crystallized polyamyloses, distinguishing two series, the α-series of dextrins containing 2n D-glucose units per molecule
and the β-series containing 3n D-glucose units per molecule. Four substances, i.e.,
α-diamylose, α-tetraamylose, α-hexaamylose, and α-octaamylose, were included in
the α-series of dextrins, while the β-series only contained two substances, i.e.,
β-triamylose and β-hexaamylose. Indeed, for Pringsheim, the Schardinger dextrins
arose through the bacterial depolymerization of starch to the fundamental units: the
amylose fraction being broken down into the α-series of dextrins, i.e., polyamyloses, and the amylopectin fraction being degraded to the β-series (French 1957a;
Thoma and Stewart 1965; Caesar 1968; Szejtli 1998; Morin-Crini et al. 2015).
Pringsheim also used the terms of α-amylosan, α-allo-amylosan, and α-iso-amylosan
and β-amylosan, β-allo-amylosan, and β-iso-amylosan for α-dextrin and β-dextrin,
respectively (Crini 2014). At the same time, the Swiss chemist Paul Karrer also
introduced the notion of series of crystallized dextrins. Like Pringsheim, Karrer was
convinced that the α-series of dextrins was composed of at least four distinct substances differing in molecular size. However, he disagreed with the subdivision of
the β-series into triamylose and hexaamylose. For Karrer, these two products were
identical. In addition, Karrer regarded maltose as the fundamental unit of the whole
of the starch molecule, while Pringsheim considered the polyamyloses as the basic
units of the starch molecule (French 1957a; Thoma and Stewart 1965; Caesar 1968;
Szejtli 1998; Morin-Crini et al. 2015). Like Pringsheim, Karrer also used the
amylosan- based terminology (Crini 2014).
In the 1920s, as a tribute of the pioneering work of Schardinger, the German
chemist Karl Johann Freudenberg called them “Schardinger dextrins” and referred
to these compounds as α-dextrin and β-dextrin (French 1957a; Thoma and Stewart
1965; Caesar 1968; Szejtli 1998; Loftsson and Duchêne 2007; Kurkov and Loftsson
2013; Morin-Crini et al. 2015) and later as pentaosan and hexaosan, respectively
(Crini 2014). For many years, cyclodextrins were called “Schardinger dextrins” in
his honor, almost up to the 1970s, or also sometimes simply as dextrins (Szejtli
1998). Schardinger dextrins were subsequently named “cycloamyloses” by the
American chemist Dexter French in 1942 (French and Rundle 1942), “cycloglucanes” by Freudenberg in 1943 (Freudenberg 1943), and finally “cyclodextrins” in
1949 by the German chemist Friedrich Cramer, a pupil of Freudenberg (Cramer
1949). The model of “cycloamyloses” was constructed from glucopyranose units in
the boat conformation. For French, α-dextrin, β-dextrin, and γ-dextrin must be
called cyclohexaamylose, cycloheptaamylose, and cyclooctaamylose, respectively,
the Greek prefix to the “amylose” corresponding to the degree of polymerization,
i.e., indicating the number of glucose units in the ring (French and Rundle 1942).
However, at that time, Freudenberg claimed that “this new nomenclature was inappropriate and ambiguous” (Freudenberg 1943). Again, in 1947, Freudenberg wrote:
“It appears to be premature to rename the α-dextrin cyclohexa-amylose and the
β-dextrin cyclohepta-amylose” (Freudenberg et al. 1947a, b). In 1943, Freudenberg
proposed the cycloglucane-based nomenclature, e.g., cyclohexaglucane α(1→4),
cycloheptaglucane α(1→4), and cyclooctaglucane α(1→4) for α-dextrin, β-dextrin,
N. Morin-Crini et al.
In the mid-1910s, the German chemist and biochemist Hans Pringsheim used the
name of krystallisiertes polyamylosen, i.e., crystallized polyamyloses, distinguishing two series, the α-series of dextrins containing 2n D-glucose units per molecule
and the β-series containing 3n D-glucose units per molecule. Four substances, i.e.,
α-diamylose, α-tetraamylose, α-hexaamylose, and α-octaamylose, were included in
the α-series of dextrins, while the β-series only contained two substances, i.e.,
β-triamylose and β-hexaamylose. Indeed, for Pringsheim, the Schardinger dextrins
arose through the bacterial depolymerization of starch to the fundamental units: the
amylose fraction being broken down into the α-series of dextrins, i.e., polyamyloses, and the amylopectin fraction being degraded to the β-series (French 1957a;
Thoma and Stewart 1965; Caesar 1968; Szejtli 1998; Morin-Crini et al. 2015).
Pringsheim also used the terms of α-amylosan, α-allo-amylosan, and α-iso-amylosan
and β-amylosan, β-allo-amylosan, and β-iso-amylosan for α-dextrin and β-dextrin,
respectively (Crini 2014). At the same time, the Swiss chemist Paul Karrer also
introduced the notion of series of crystallized dextrins. Like Pringsheim, Karrer was
convinced that the α-series of dextrins was composed of at least four distinct substances differing in molecular size. However, he disagreed with the subdivision of
the β-series into triamylose and hexaamylose. For Karrer, these two products were
identical. In addition, Karrer regarded maltose as the fundamental unit of the whole
of the starch molecule, while Pringsheim considered the polyamyloses as the basic
units of the starch molecule (French 1957a; Thoma and Stewart 1965; Caesar 1968;
Szejtli 1998; Morin-Crini et al. 2015). Like Pringsheim, Karrer also used the
amylosan- based terminology (Crini 2014).
In the 1920s, as a tribute of the pioneering work of Schardinger, the German
chemist Karl Johann Freudenberg called them “Schardinger dextrins” and referred
to these compounds as α-dextrin and β-dextrin (French 1957a; Thoma and Stewart
1965; Caesar 1968; Szejtli 1998; Loftsson and Duchêne 2007; Kurkov and Loftsson
2013; Morin-Crini et al. 2015) and later as pentaosan and hexaosan, respectively
(Crini 2014). For many years, cyclodextrins were called “Schardinger dextrins” in
his honor, almost up to the 1970s, or also sometimes simply as dextrins (Szejtli
1998). Schardinger dextrins were subsequently named “cycloamyloses” by the
American chemist Dexter French in 1942 (French and Rundle 1942), “cycloglucanes” by Freudenberg in 1943 (Freudenberg 1943), and finally “cyclodextrins” in
1949 by the German chemist Friedrich Cramer, a pupil of Freudenberg (Cramer
1949). The model of “cycloamyloses” was constructed from glucopyranose units in
the boat conformation. For French, α-dextrin, β-dextrin, and γ-dextrin must be
called cyclohexaamylose, cycloheptaamylose, and cyclooctaamylose, respectively,
the Greek prefix to the “amylose” corresponding to the degree of polymerization,
i.e., indicating the number of glucose units in the ring (French and Rundle 1942).
However, at that time, Freudenberg claimed that “this new nomenclature was inappropriate and ambiguous” (Freudenberg 1943). Again, in 1947, Freudenberg wrote:
“It appears to be premature to rename the α-dextrin cyclohexa-amylose and the
β-dextrin cyclohepta-amylose” (Freudenberg et al. 1947a, b). In 1943, Freudenberg
proposed the cycloglucane-based nomenclature, e.g., cyclohexaglucane α(1→4),
cycloheptaglucane α(1→4), and cyclooctaglucane α(1→4) for α-dextrin, β-dextrin,
N. Morin-Crini et al.