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Tsutomu Nakayama - One of the best experts on this subject based on the ideXlab platform.
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Efficient Synthesis of Theaflavin 3-Gallate by a Tyrosinase-Catalyzed Reaction with (−)-Epicatechin and (−)-Epigallocatechin Gallate in a 1-Octanol/Buffer Biphasic System
Journal of Agricultural and Food Chemistry, 2018Co-Authors: Asako Narai-kanayama, Yoshinori Uekusa, Fumiyuki Kiuchi, Tsutomu NakayamaAbstract:Theaflavins, the orange–red pigments contained in black tea, have attracted attention as a result of their health-promoting effects. However, their synthetic preparation, in which the enzymatic oxidation of catechol-type catechin is followed by the quinone-induced oxidative dimerization of selectively combined catechol- and pyrogallol-type catechins, provides only a low yield. In the present study, we found that a 1-octanol/buffer biphasic system improved the yield of theaflavin 3-gallate in a tyrosinase-catalyzed synthetic reaction with (−)-epicatechin and (−)-epigallocatechin gallate. When the enzymatic reaction proceeded in a buffer solution, oxidized (−)-epigallocatechin gallate was preferentially used for self-dimerization. However, self-dimerization was suppressed in the octanol phase, allowing oxidized (−)-epigallocatechin gallate to participate in coupling with (−)-epicatechin quinone, leading to effective production of theaflavin 3-gallate. Furthermore, the preferential localization of theaflavin...
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Efficient Synthesis of Theaflavin 3-Gallate by a Tyrosinase-Catalyzed Reaction with (−)-Epicatechin and (−)-Epigallocatechin Gallate in a 1-Octanol/Buffer Biphasic System
Journal of agricultural and food chemistry, 2018Co-Authors: Asako Narai-kanayama, Yoshinori Uekusa, Fumiyuki Kiuchi, Tsutomu NakayamaAbstract:Theaflavins, the orange-red pigments contained in black tea, have attracted attention as a result of their health-promoting effects. However, their synthetic preparation, in which the enzymatic oxidation of catechol-type catechin is followed by the quinone-induced oxidative dimerization of selectively combined catechol- and pyrogallol-type catechins, provides only a low yield. In the present study, we found that a 1-octanol/buffer biphasic system improved the yield of theaflavin 3-gallate in a tyrosinase-catalyzed synthetic reaction with (-)-epicatechin and (-)-epigallocatechin gallate. When the enzymatic reaction proceeded in a buffer solution, oxidized (-)-epigallocatechin gallate was preferentially used for self-dimerization. However, self-dimerization was suppressed in the octanol phase, allowing oxidized (-)-epigallocatechin gallate to participate in coupling with (-)-epicatechin quinone, leading to effective production of theaflavin 3-gallate. Furthermore, the preferential localization of theaflavin 3-gallate in the octanol phase prevented (-)-epicatechin-quinone-induced degradation.
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efficient synthesis of theaflavin 3 gallate by a tyrosinase catalyzed reaction with epicatechin and epigallocatechin gallate in a 1 octanol buffer biphasic system
Journal of Agricultural and Food Chemistry, 2018Co-Authors: Asako Naraikanayama, Yoshinori Uekusa, Fumiyuki Kiuchi, Tsutomu NakayamaAbstract:Theaflavins, the orange-red pigments contained in black tea, have attracted attention as a result of their health-promoting effects. However, their synthetic preparation, in which the enzymatic oxidation of catechol-type catechin is followed by the quinone-induced oxidative dimerization of selectively combined catechol- and pyrogallol-type catechins, provides only a low yield. In the present study, we found that a 1-octanol/buffer biphasic system improved the yield of theaflavin 3-gallate in a tyrosinase-catalyzed synthetic reaction with (-)-epicatechin and (-)-epigallocatechin gallate. When the enzymatic reaction proceeded in a buffer solution, oxidized (-)-epigallocatechin gallate was preferentially used for self-dimerization. However, self-dimerization was suppressed in the octanol phase, allowing oxidized (-)-epigallocatechin gallate to participate in coupling with (-)-epicatechin quinone, leading to effective production of theaflavin 3-gallate. Furthermore, the preferential localization of theaflavin 3-gallate in the octanol phase prevented (-)-epicatechin-quinone-induced degradation.
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Efficient Synthesis of Theaflavin 3‑Gallate by a Tyrosinase-Catalyzed Reaction with (−)-Epicatechin and (−)-Epigallocatechin Gallate in a 1‑Octanol/Buffer Biphasic System
2018Co-Authors: Asako Narai-kanayama, Yoshinori Uekusa, Fumiyuki Kiuchi, Tsutomu NakayamaAbstract:Theaflavins, the orange–red pigments contained in black tea, have attracted attention as a result of their health-promoting effects. However, their synthetic preparation, in which the enzymatic oxidation of catechol-type catechin is followed by the quinone-induced oxidative dimerization of selectively combined catechol- and pyrogallol-type catechins, provides only a low yield. In the present study, we found that a 1-octanol/buffer biphasic system improved the yield of theaflavin 3-gallate in a tyrosinase-catalyzed synthetic reaction with (−)-epicatechin and (−)-epigallocatechin gallate. When the enzymatic reaction proceeded in a buffer solution, oxidized (−)-epigallocatechin gallate was preferentially used for self-dimerization. However, self-dimerization was suppressed in the octanol phase, allowing oxidized (−)-epigallocatechin gallate to participate in coupling with (−)-epicatechin quinone, leading to effective production of theaflavin 3-gallate. Furthermore, the preferential localization of theaflavin 3-gallate in the octanol phase prevented (−)-epicatechin-quinone-induced degradation
Hyungkyoon Choi - One of the best experts on this subject based on the ideXlab platform.
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volatiles and key odorants in the pileus and stipe of pine mushroom tricholoma matsutake sing
Food Chemistry, 2008Co-Authors: H J Namgung, Hyungkyoon ChoiAbstract:Abstract The pileus and stipe of pine-mushroom ( Tricholoma matsutake Sing.) were compared for differences in their profiles of volatiles and key odorants. We identified 24 and 21 volatile components in the pileus and in the stipe of pine-mushrooms, of which 3-phenyl-2-propenoic acid methyl ester (methyl cinnamate) and 1-octen-3-ol were most abundant, respectively. The C 8 components, such as 1-octen-3-ol, 3-Octanol, and ( E )-2-octen-1-ol, were more prevalent in the stipe than in the pileus. On the other hand, 1-octen-3-one (mushroom-like) was the most potent key odorant in both the pileus and the stipe. The flavor dilution (FD) factors of 1-octen-3-ol (mushroom-like), 3-Octanol (mushroom-like/buttery), ( E )-2-octen-1-ol (mushroom-like), and 3-octanone (mushroom-like/buttery), exhibiting the typical fungal odor note, were higher in the stipe than in the pileus. In contrast, the FD factors of odorants possessing sweet, floral, green, and citrus odor descriptions, such as linalool (sweet and citrus), 2-methyl-butanoic acid ethyl ester (sweet and floral), 2-methyl-3-buten-2-ol (fresh green), α-terpineol (pine-tree-like), and ( E )-2-decenal (orange-like and fatty), were higher in the pileus than in the stipe.
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Difference in the volatile composition of pine-mushrooms (Tricholoma matsutake Sing.) according to their grades.
Journal of agricultural and food chemistry, 2006Co-Authors: In Hee Cho, Hyungkyoon Choi, Young-suk KimAbstract:The differences in volatile components of pine-mushrooms (Tricholoma matsutake Sing.) according to their grades were observed by applying multivariate statistical methods to GC-MS data sets. A total of 35 and 37 volatile components were identified in raw and cooked pine-mushrooms, respectively. The volatile components in pine-mushrooms were primarily composed of C8 species, such as 3-Octanol, 1-octen-3-ol, 1-octanol, (E)-2-octen-1-ol, 3-octanone, 1-octen-3-one, (E)-2-octenal, and octanoic acid. The levels of ethyl octanoate, junipene, and 3-methyl-3-buten-2-one were much higher in raw pine-mushroom of higher grades, whereas the reverse was true for C8 components. On the other hand, furfuryl alcohol, benzyl alcohol, phenylethyl alcohol, dihydro-5-methyl-2(3H)-furanone, 2(5H)-furanone, (E)-2-methyl-2-butenal, furfural, phenylacetaldehyde, benzoic acid methyl ester, camphene, and beta-pinene were the major components of cooked mushrooms. These volatile components formed by various thermal reactions could be mainly responsible for the difference in volatile components of cooked pine-mushrooms according to their grades.
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difference in the volatile composition of pine mushrooms tricholoma matsutake sing according to their grades
Journal of Agricultural and Food Chemistry, 2006Co-Authors: Hyungkyoon ChoiAbstract:The differences in volatile components of pine-mushrooms (Tricholoma matsutake Sing.) according to their grades were observed by applying multivariate statistical methods to GC−MS data sets. A total of 35 and 37 volatile components were identified in raw and cooked pine-mushrooms, respectively. The volatile components in pine-mushrooms were primarily composed of C8 species, such as 3-Octanol, 1-octen-3-ol, 1-octanol, (E)-2-octen-1-ol, 3-octanone, 1-octen-3-one, (E)-2-octenal, and octanoic acid. The levels of ethyl octanoate, junipene, and 3-methyl-3-buten-2-one were much higher in raw pine-mushroom of higher grades, whereas the reverse was true for C8 components. On the other hand, furfuryl alcohol, benzyl alcohol, phenylethyl alcohol, dihydro-5-methyl-2(3H)-furanone, 2(5H)-furanone, (E)-2-methyl-2-butenal, furfural, phenylacetaldehyde, benzoic acid methyl ester, camphene, and β-pinene were the major components of cooked mushrooms. These volatile components formed by various thermal reactions could be mai...
Yoshinori Uekusa - One of the best experts on this subject based on the ideXlab platform.
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Efficient Synthesis of Theaflavin 3-Gallate by a Tyrosinase-Catalyzed Reaction with (−)-Epicatechin and (−)-Epigallocatechin Gallate in a 1-Octanol/Buffer Biphasic System
Journal of Agricultural and Food Chemistry, 2018Co-Authors: Asako Narai-kanayama, Yoshinori Uekusa, Fumiyuki Kiuchi, Tsutomu NakayamaAbstract:Theaflavins, the orange–red pigments contained in black tea, have attracted attention as a result of their health-promoting effects. However, their synthetic preparation, in which the enzymatic oxidation of catechol-type catechin is followed by the quinone-induced oxidative dimerization of selectively combined catechol- and pyrogallol-type catechins, provides only a low yield. In the present study, we found that a 1-octanol/buffer biphasic system improved the yield of theaflavin 3-gallate in a tyrosinase-catalyzed synthetic reaction with (−)-epicatechin and (−)-epigallocatechin gallate. When the enzymatic reaction proceeded in a buffer solution, oxidized (−)-epigallocatechin gallate was preferentially used for self-dimerization. However, self-dimerization was suppressed in the octanol phase, allowing oxidized (−)-epigallocatechin gallate to participate in coupling with (−)-epicatechin quinone, leading to effective production of theaflavin 3-gallate. Furthermore, the preferential localization of theaflavin...
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Efficient Synthesis of Theaflavin 3-Gallate by a Tyrosinase-Catalyzed Reaction with (−)-Epicatechin and (−)-Epigallocatechin Gallate in a 1-Octanol/Buffer Biphasic System
Journal of agricultural and food chemistry, 2018Co-Authors: Asako Narai-kanayama, Yoshinori Uekusa, Fumiyuki Kiuchi, Tsutomu NakayamaAbstract:Theaflavins, the orange-red pigments contained in black tea, have attracted attention as a result of their health-promoting effects. However, their synthetic preparation, in which the enzymatic oxidation of catechol-type catechin is followed by the quinone-induced oxidative dimerization of selectively combined catechol- and pyrogallol-type catechins, provides only a low yield. In the present study, we found that a 1-octanol/buffer biphasic system improved the yield of theaflavin 3-gallate in a tyrosinase-catalyzed synthetic reaction with (-)-epicatechin and (-)-epigallocatechin gallate. When the enzymatic reaction proceeded in a buffer solution, oxidized (-)-epigallocatechin gallate was preferentially used for self-dimerization. However, self-dimerization was suppressed in the octanol phase, allowing oxidized (-)-epigallocatechin gallate to participate in coupling with (-)-epicatechin quinone, leading to effective production of theaflavin 3-gallate. Furthermore, the preferential localization of theaflavin 3-gallate in the octanol phase prevented (-)-epicatechin-quinone-induced degradation.
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efficient synthesis of theaflavin 3 gallate by a tyrosinase catalyzed reaction with epicatechin and epigallocatechin gallate in a 1 octanol buffer biphasic system
Journal of Agricultural and Food Chemistry, 2018Co-Authors: Asako Naraikanayama, Yoshinori Uekusa, Fumiyuki Kiuchi, Tsutomu NakayamaAbstract:Theaflavins, the orange-red pigments contained in black tea, have attracted attention as a result of their health-promoting effects. However, their synthetic preparation, in which the enzymatic oxidation of catechol-type catechin is followed by the quinone-induced oxidative dimerization of selectively combined catechol- and pyrogallol-type catechins, provides only a low yield. In the present study, we found that a 1-octanol/buffer biphasic system improved the yield of theaflavin 3-gallate in a tyrosinase-catalyzed synthetic reaction with (-)-epicatechin and (-)-epigallocatechin gallate. When the enzymatic reaction proceeded in a buffer solution, oxidized (-)-epigallocatechin gallate was preferentially used for self-dimerization. However, self-dimerization was suppressed in the octanol phase, allowing oxidized (-)-epigallocatechin gallate to participate in coupling with (-)-epicatechin quinone, leading to effective production of theaflavin 3-gallate. Furthermore, the preferential localization of theaflavin 3-gallate in the octanol phase prevented (-)-epicatechin-quinone-induced degradation.
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Efficient Synthesis of Theaflavin 3‑Gallate by a Tyrosinase-Catalyzed Reaction with (−)-Epicatechin and (−)-Epigallocatechin Gallate in a 1‑Octanol/Buffer Biphasic System
2018Co-Authors: Asako Narai-kanayama, Yoshinori Uekusa, Fumiyuki Kiuchi, Tsutomu NakayamaAbstract:Theaflavins, the orange–red pigments contained in black tea, have attracted attention as a result of their health-promoting effects. However, their synthetic preparation, in which the enzymatic oxidation of catechol-type catechin is followed by the quinone-induced oxidative dimerization of selectively combined catechol- and pyrogallol-type catechins, provides only a low yield. In the present study, we found that a 1-octanol/buffer biphasic system improved the yield of theaflavin 3-gallate in a tyrosinase-catalyzed synthetic reaction with (−)-epicatechin and (−)-epigallocatechin gallate. When the enzymatic reaction proceeded in a buffer solution, oxidized (−)-epigallocatechin gallate was preferentially used for self-dimerization. However, self-dimerization was suppressed in the octanol phase, allowing oxidized (−)-epigallocatechin gallate to participate in coupling with (−)-epicatechin quinone, leading to effective production of theaflavin 3-gallate. Furthermore, the preferential localization of theaflavin 3-gallate in the octanol phase prevented (−)-epicatechin-quinone-induced degradation
Fumiyuki Kiuchi - One of the best experts on this subject based on the ideXlab platform.
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Efficient Synthesis of Theaflavin 3-Gallate by a Tyrosinase-Catalyzed Reaction with (−)-Epicatechin and (−)-Epigallocatechin Gallate in a 1-Octanol/Buffer Biphasic System
Journal of Agricultural and Food Chemistry, 2018Co-Authors: Asako Narai-kanayama, Yoshinori Uekusa, Fumiyuki Kiuchi, Tsutomu NakayamaAbstract:Theaflavins, the orange–red pigments contained in black tea, have attracted attention as a result of their health-promoting effects. However, their synthetic preparation, in which the enzymatic oxidation of catechol-type catechin is followed by the quinone-induced oxidative dimerization of selectively combined catechol- and pyrogallol-type catechins, provides only a low yield. In the present study, we found that a 1-octanol/buffer biphasic system improved the yield of theaflavin 3-gallate in a tyrosinase-catalyzed synthetic reaction with (−)-epicatechin and (−)-epigallocatechin gallate. When the enzymatic reaction proceeded in a buffer solution, oxidized (−)-epigallocatechin gallate was preferentially used for self-dimerization. However, self-dimerization was suppressed in the octanol phase, allowing oxidized (−)-epigallocatechin gallate to participate in coupling with (−)-epicatechin quinone, leading to effective production of theaflavin 3-gallate. Furthermore, the preferential localization of theaflavin...
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Efficient Synthesis of Theaflavin 3-Gallate by a Tyrosinase-Catalyzed Reaction with (−)-Epicatechin and (−)-Epigallocatechin Gallate in a 1-Octanol/Buffer Biphasic System
Journal of agricultural and food chemistry, 2018Co-Authors: Asako Narai-kanayama, Yoshinori Uekusa, Fumiyuki Kiuchi, Tsutomu NakayamaAbstract:Theaflavins, the orange-red pigments contained in black tea, have attracted attention as a result of their health-promoting effects. However, their synthetic preparation, in which the enzymatic oxidation of catechol-type catechin is followed by the quinone-induced oxidative dimerization of selectively combined catechol- and pyrogallol-type catechins, provides only a low yield. In the present study, we found that a 1-octanol/buffer biphasic system improved the yield of theaflavin 3-gallate in a tyrosinase-catalyzed synthetic reaction with (-)-epicatechin and (-)-epigallocatechin gallate. When the enzymatic reaction proceeded in a buffer solution, oxidized (-)-epigallocatechin gallate was preferentially used for self-dimerization. However, self-dimerization was suppressed in the octanol phase, allowing oxidized (-)-epigallocatechin gallate to participate in coupling with (-)-epicatechin quinone, leading to effective production of theaflavin 3-gallate. Furthermore, the preferential localization of theaflavin 3-gallate in the octanol phase prevented (-)-epicatechin-quinone-induced degradation.
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efficient synthesis of theaflavin 3 gallate by a tyrosinase catalyzed reaction with epicatechin and epigallocatechin gallate in a 1 octanol buffer biphasic system
Journal of Agricultural and Food Chemistry, 2018Co-Authors: Asako Naraikanayama, Yoshinori Uekusa, Fumiyuki Kiuchi, Tsutomu NakayamaAbstract:Theaflavins, the orange-red pigments contained in black tea, have attracted attention as a result of their health-promoting effects. However, their synthetic preparation, in which the enzymatic oxidation of catechol-type catechin is followed by the quinone-induced oxidative dimerization of selectively combined catechol- and pyrogallol-type catechins, provides only a low yield. In the present study, we found that a 1-octanol/buffer biphasic system improved the yield of theaflavin 3-gallate in a tyrosinase-catalyzed synthetic reaction with (-)-epicatechin and (-)-epigallocatechin gallate. When the enzymatic reaction proceeded in a buffer solution, oxidized (-)-epigallocatechin gallate was preferentially used for self-dimerization. However, self-dimerization was suppressed in the octanol phase, allowing oxidized (-)-epigallocatechin gallate to participate in coupling with (-)-epicatechin quinone, leading to effective production of theaflavin 3-gallate. Furthermore, the preferential localization of theaflavin 3-gallate in the octanol phase prevented (-)-epicatechin-quinone-induced degradation.
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Efficient Synthesis of Theaflavin 3‑Gallate by a Tyrosinase-Catalyzed Reaction with (−)-Epicatechin and (−)-Epigallocatechin Gallate in a 1‑Octanol/Buffer Biphasic System
2018Co-Authors: Asako Narai-kanayama, Yoshinori Uekusa, Fumiyuki Kiuchi, Tsutomu NakayamaAbstract:Theaflavins, the orange–red pigments contained in black tea, have attracted attention as a result of their health-promoting effects. However, their synthetic preparation, in which the enzymatic oxidation of catechol-type catechin is followed by the quinone-induced oxidative dimerization of selectively combined catechol- and pyrogallol-type catechins, provides only a low yield. In the present study, we found that a 1-octanol/buffer biphasic system improved the yield of theaflavin 3-gallate in a tyrosinase-catalyzed synthetic reaction with (−)-epicatechin and (−)-epigallocatechin gallate. When the enzymatic reaction proceeded in a buffer solution, oxidized (−)-epigallocatechin gallate was preferentially used for self-dimerization. However, self-dimerization was suppressed in the octanol phase, allowing oxidized (−)-epigallocatechin gallate to participate in coupling with (−)-epicatechin quinone, leading to effective production of theaflavin 3-gallate. Furthermore, the preferential localization of theaflavin 3-gallate in the octanol phase prevented (−)-epicatechin-quinone-induced degradation
Asako Narai-kanayama - One of the best experts on this subject based on the ideXlab platform.
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Efficient Synthesis of Theaflavin 3-Gallate by a Tyrosinase-Catalyzed Reaction with (−)-Epicatechin and (−)-Epigallocatechin Gallate in a 1-Octanol/Buffer Biphasic System
Journal of Agricultural and Food Chemistry, 2018Co-Authors: Asako Narai-kanayama, Yoshinori Uekusa, Fumiyuki Kiuchi, Tsutomu NakayamaAbstract:Theaflavins, the orange–red pigments contained in black tea, have attracted attention as a result of their health-promoting effects. However, their synthetic preparation, in which the enzymatic oxidation of catechol-type catechin is followed by the quinone-induced oxidative dimerization of selectively combined catechol- and pyrogallol-type catechins, provides only a low yield. In the present study, we found that a 1-octanol/buffer biphasic system improved the yield of theaflavin 3-gallate in a tyrosinase-catalyzed synthetic reaction with (−)-epicatechin and (−)-epigallocatechin gallate. When the enzymatic reaction proceeded in a buffer solution, oxidized (−)-epigallocatechin gallate was preferentially used for self-dimerization. However, self-dimerization was suppressed in the octanol phase, allowing oxidized (−)-epigallocatechin gallate to participate in coupling with (−)-epicatechin quinone, leading to effective production of theaflavin 3-gallate. Furthermore, the preferential localization of theaflavin...
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Efficient Synthesis of Theaflavin 3-Gallate by a Tyrosinase-Catalyzed Reaction with (−)-Epicatechin and (−)-Epigallocatechin Gallate in a 1-Octanol/Buffer Biphasic System
Journal of agricultural and food chemistry, 2018Co-Authors: Asako Narai-kanayama, Yoshinori Uekusa, Fumiyuki Kiuchi, Tsutomu NakayamaAbstract:Theaflavins, the orange-red pigments contained in black tea, have attracted attention as a result of their health-promoting effects. However, their synthetic preparation, in which the enzymatic oxidation of catechol-type catechin is followed by the quinone-induced oxidative dimerization of selectively combined catechol- and pyrogallol-type catechins, provides only a low yield. In the present study, we found that a 1-octanol/buffer biphasic system improved the yield of theaflavin 3-gallate in a tyrosinase-catalyzed synthetic reaction with (-)-epicatechin and (-)-epigallocatechin gallate. When the enzymatic reaction proceeded in a buffer solution, oxidized (-)-epigallocatechin gallate was preferentially used for self-dimerization. However, self-dimerization was suppressed in the octanol phase, allowing oxidized (-)-epigallocatechin gallate to participate in coupling with (-)-epicatechin quinone, leading to effective production of theaflavin 3-gallate. Furthermore, the preferential localization of theaflavin 3-gallate in the octanol phase prevented (-)-epicatechin-quinone-induced degradation.
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Efficient Synthesis of Theaflavin 3‑Gallate by a Tyrosinase-Catalyzed Reaction with (−)-Epicatechin and (−)-Epigallocatechin Gallate in a 1‑Octanol/Buffer Biphasic System
2018Co-Authors: Asako Narai-kanayama, Yoshinori Uekusa, Fumiyuki Kiuchi, Tsutomu NakayamaAbstract:Theaflavins, the orange–red pigments contained in black tea, have attracted attention as a result of their health-promoting effects. However, their synthetic preparation, in which the enzymatic oxidation of catechol-type catechin is followed by the quinone-induced oxidative dimerization of selectively combined catechol- and pyrogallol-type catechins, provides only a low yield. In the present study, we found that a 1-octanol/buffer biphasic system improved the yield of theaflavin 3-gallate in a tyrosinase-catalyzed synthetic reaction with (−)-epicatechin and (−)-epigallocatechin gallate. When the enzymatic reaction proceeded in a buffer solution, oxidized (−)-epigallocatechin gallate was preferentially used for self-dimerization. However, self-dimerization was suppressed in the octanol phase, allowing oxidized (−)-epigallocatechin gallate to participate in coupling with (−)-epicatechin quinone, leading to effective production of theaflavin 3-gallate. Furthermore, the preferential localization of theaflavin 3-gallate in the octanol phase prevented (−)-epicatechin-quinone-induced degradation
