Octanol

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Tsutomu Nakayama - One of the best experts on this subject based on the ideXlab platform.

  • 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, 2018
    Co-Authors: Asako Naraikanayama, Yoshinori Uekusa, Fumiyuki Kiuchi, Tsutomu Nakayama
    Abstract:

    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.

  • Efficient Synthesis of Theaflavin 3‑Gallate by a Tyrosinase-Catalyzed Reaction with (−)-Epicatechin and (−)-Epigallocatechin Gallate in a 1‑Octanol/Buffer Biphasic System
    2018
    Co-Authors: Asako Narai-kanayama, Yoshinori Uekusa, Fumiyuki Kiuchi, Tsutomu Nakayama
    Abstract:

    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 Naraikanayama - One of the best experts on this subject based on the ideXlab platform.

  • 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, 2018
    Co-Authors: Asako Naraikanayama, Yoshinori Uekusa, Fumiyuki Kiuchi, Tsutomu Nakayama
    Abstract:

    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.

Frank Wania - One of the best experts on this subject based on the ideXlab platform.

  • critical review and recommended values for the physical chemical property data of 15 polycyclic aromatic hydrocarbons at 25 c
    Journal of Chemical & Engineering Data, 2010
    Co-Authors: Hang Xiao, Frank Wania, Wenhua Wang
    Abstract:

    Accurate physical-chemical properties are of fundamental importance for interpreting and simulating the environmental fate and transport behavior of polycyclic aromatic hydrocarbons (PAHs). A complete set of thermodynamically consistent property data (vapor pressure, aqueous solubility, Octanol solubility, Octanol−water partition coefficient, Octanol−air partition coefficient, and air−water partition coefficient) for 15 PAHs [naphthalene (Nap), acenaphthylene (Acy), acenaphthene (Ace), fluorene (Fluo), phenanthrene (Phe), anthracene (Ant), fluoranthene (Flu), pyrene (Pyr), chrysene (Chry), benzo[a]anthracene (BaA), benzo[b]fluoranthene (BbF), benzo[k]fluoranthene (BkF), benzo[a]pyrene (BaP), dibenzo[a,h]anthracene (DBA), indeno[1,2,3-c,d]pyrene (IP), and benzo[g,h,i]perylene (BghiP)] is derived from measured data reported in the literature. First, literature-derived values (LDVs) at 25 °C for each property and compound are obtained by averaging, regression, and extrapolation. Then the LDVs for each compou...

  • compilation evaluation and selection of physical chemical property data for organochlorine pesticides
    Journal of Chemical & Engineering Data, 2005
    Co-Authors: Frank Wania
    Abstract:

    Accurate physical−chemical properties (aqueous solubility SW, Octanol−water partition coefficient KOW, vapor pressure P, Henry's law constant H, Octanol−air partition coefficient KOA, Octanol solubility SO) and their temperature dependence are of fundamental importance for interpreting and simulating the environmental fate and transport of organochlorine pesticides (OCPs). A complete set of property data for 14 organochlorine chemicals is derived by evaluating, averaging, and regressing all measured values reported in the literature. The 14 chemicals are hexachlorobenzene (HCB), pentachlorobenzene (PeCB), cis-chlordane, trans-chlordane, 1,1,1-trichloro-2,2-bis-4-chlorophenyl-ethane (p,p‘-DDT) and its metabolites 1,1-dichloro-2,2-bis-4-chlorophenyl-ethene (p,p‘-DDE) and 1,1-dichloro-2,2-bis-4-chlorophenyl-ethylene (p,p‘-DDD), heptachlor and its metabolite heptachlor epoxide, aldrin, dieldrin, endrin, α-endosulfan, and β-endosulfan. Properties for each individual chemical are adjusted to ensure thermodynami...

  • compilation evaluation and selection of physical chemical property data for α β and γ hexachlorocyclohexane
    Journal of Chemical & Engineering Data, 2004
    Co-Authors: Hang Xiao, And Nanqin Li, Frank Wania
    Abstract:

    A complete set of temperature-dependent physical-chemical property data (aqueous solubility (SW), Octanol−water partition coefficient (KOW), vapor pressure (P), Henry's law constant (H), Octanol−air partition coefficient (KOA), and Octanol solubility (SO)) for α-, β-, and γ-hexachlorocyclohexane (HCH) is derived by evaluating, averaging, and regressing all experimentally obtained values reported in the literature. Properties for each isomer are adjusted slightly to ensure thermodynamic consistency. That adjustment is sized according to, and is smaller than, the uncertainty apparent from the range of reported experimental values. The data analysis confirms that an unsually high KOA and an unusually low H reported for β-HCH are in agreement with the measured SW and P values when these are converted to the liquid state. Linear solvation energy relationships fail to predict the observed differences in the partitioning behaviors of the three isomers.

Fumiyuki Kiuchi - One of the best experts on this subject based on the ideXlab platform.

  • 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, 2018
    Co-Authors: Asako Naraikanayama, Yoshinori Uekusa, Fumiyuki Kiuchi, Tsutomu Nakayama
    Abstract:

    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.

  • Efficient Synthesis of Theaflavin 3‑Gallate by a Tyrosinase-Catalyzed Reaction with (−)-Epicatechin and (−)-Epigallocatechin Gallate in a 1‑Octanol/Buffer Biphasic System
    2018
    Co-Authors: Asako Narai-kanayama, Yoshinori Uekusa, Fumiyuki Kiuchi, Tsutomu Nakayama
    Abstract:

    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

Yoshinori Uekusa - One of the best experts on this subject based on the ideXlab platform.

  • 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, 2018
    Co-Authors: Asako Naraikanayama, Yoshinori Uekusa, Fumiyuki Kiuchi, Tsutomu Nakayama
    Abstract:

    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.

  • Efficient Synthesis of Theaflavin 3‑Gallate by a Tyrosinase-Catalyzed Reaction with (−)-Epicatechin and (−)-Epigallocatechin Gallate in a 1‑Octanol/Buffer Biphasic System
    2018
    Co-Authors: Asako Narai-kanayama, Yoshinori Uekusa, Fumiyuki Kiuchi, Tsutomu Nakayama
    Abstract:

    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