Abstract

The fruit and hulls of the water caltrop (Trapa taiwanensis Nakai) are used as hepatoprotective herbal tea ingredients in Taiwan. The stability of hydrolysable tannins in herbal drinks has rarely been reported. In the present study, two hydrolysable tannins, tellimagrandin II (TGII) and 1,2,3,4,6-pentagalloylglucopyranose (PGG), were isolated from water caltrop hulls. The stability of the two compounds was evaluated by treatment with various pH buffer solutions, simulated gastric fluid and intestinal fluid, different temperatures, and photo-irradiation at 352 nm in different solvents. Results showed that TGII and PGG were more stable in a pH 2.0 buffer solution (with 91.88% remaining) and in a water solution with 352 nm irradiation (with 95% remaining). TGII and PGG were more stable in methanol or ethanol solutions (with >93.69% remaining) than in an aqueous solution (with <43.52% remaining) at 100 C. In simulated gastric fluid, more than 96% of the hydrolysable tannins remained after incubation at 37 C for 4 h. However, these hydrolysable tannins were unstable in simulated intestinal fluid, as after incubation at 37 C for 9 h, the content of TGII had decreased to 31.40% and of PGG to 12.46%. The synthetic antioxidants, butyl hydroxy anisole (BHA), di-butyl hydroxy toluene (BHT), and propyl gallate, did not exhibit photoprotective effects on these hydrolysable tannins. However, catechin, a natural antioxidant, displayed a weak photoprotective effect. Ascorbic acid had a short-term thermal-protective effect but not a long-term protective effect. The different stability properties of hydrolysable tannins in solutions can be used in the development of related herbal teas in the future.

Original languageEnglish
Article number365
JournalMolecules
Volume24
Issue number2
DOIs
Publication statusPublished - Jan 21 2019

Fingerprint

Hydrolyzable Tannins
fluids
antioxidants
Fluids
buffers
Water
Stomach
water
Buffers
gallates
anisole
Antioxidants
Propyl Gallate
irradiation
Irradiation
fruits
ascorbic acid
Taiwan
Catechin
ingredients

Keywords

  • Ellagitannin
  • Gallotannin
  • Hydrolysable tannin
  • Stability
  • Trapa taiwanensis Nakai

ASJC Scopus subject areas

  • Analytical Chemistry
  • Chemistry (miscellaneous)
  • Molecular Medicine
  • Pharmaceutical Science
  • Drug Discovery
  • Physical and Theoretical Chemistry
  • Organic Chemistry

Cite this

Stability of Principal Hydrolysable Tannins from Trapa taiwanensis Hulls. / Wang, Ching Chiung; Chen, Hsyeh Fang; Wu, Jin Yi; Chen, Lih Geeng.

In: Molecules, Vol. 24, No. 2, 365, 21.01.2019.

Research output: Contribution to journalArticle

Wang, Ching Chiung ; Chen, Hsyeh Fang ; Wu, Jin Yi ; Chen, Lih Geeng. / Stability of Principal Hydrolysable Tannins from Trapa taiwanensis Hulls. In: Molecules. 2019 ; Vol. 24, No. 2.
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abstract = "The fruit and hulls of the water caltrop (Trapa taiwanensis Nakai) are used as hepatoprotective herbal tea ingredients in Taiwan. The stability of hydrolysable tannins in herbal drinks has rarely been reported. In the present study, two hydrolysable tannins, tellimagrandin II (TGII) and 1,2,3,4,6-pentagalloylglucopyranose (PGG), were isolated from water caltrop hulls. The stability of the two compounds was evaluated by treatment with various pH buffer solutions, simulated gastric fluid and intestinal fluid, different temperatures, and photo-irradiation at 352 nm in different solvents. Results showed that TGII and PGG were more stable in a pH 2.0 buffer solution (with 91.88{\%} remaining) and in a water solution with 352 nm irradiation (with 95{\%} remaining). TGII and PGG were more stable in methanol or ethanol solutions (with >93.69{\%} remaining) than in an aqueous solution (with <43.52{\%} remaining) at 100 ◦C. In simulated gastric fluid, more than 96{\%} of the hydrolysable tannins remained after incubation at 37 ◦C for 4 h. However, these hydrolysable tannins were unstable in simulated intestinal fluid, as after incubation at 37 ◦C for 9 h, the content of TGII had decreased to 31.40{\%} and of PGG to 12.46{\%}. The synthetic antioxidants, butyl hydroxy anisole (BHA), di-butyl hydroxy toluene (BHT), and propyl gallate, did not exhibit photoprotective effects on these hydrolysable tannins. However, catechin, a natural antioxidant, displayed a weak photoprotective effect. Ascorbic acid had a short-term thermal-protective effect but not a long-term protective effect. The different stability properties of hydrolysable tannins in solutions can be used in the development of related herbal teas in the future.",
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AB - The fruit and hulls of the water caltrop (Trapa taiwanensis Nakai) are used as hepatoprotective herbal tea ingredients in Taiwan. The stability of hydrolysable tannins in herbal drinks has rarely been reported. In the present study, two hydrolysable tannins, tellimagrandin II (TGII) and 1,2,3,4,6-pentagalloylglucopyranose (PGG), were isolated from water caltrop hulls. The stability of the two compounds was evaluated by treatment with various pH buffer solutions, simulated gastric fluid and intestinal fluid, different temperatures, and photo-irradiation at 352 nm in different solvents. Results showed that TGII and PGG were more stable in a pH 2.0 buffer solution (with 91.88% remaining) and in a water solution with 352 nm irradiation (with 95% remaining). TGII and PGG were more stable in methanol or ethanol solutions (with >93.69% remaining) than in an aqueous solution (with <43.52% remaining) at 100 ◦C. In simulated gastric fluid, more than 96% of the hydrolysable tannins remained after incubation at 37 ◦C for 4 h. However, these hydrolysable tannins were unstable in simulated intestinal fluid, as after incubation at 37 ◦C for 9 h, the content of TGII had decreased to 31.40% and of PGG to 12.46%. The synthetic antioxidants, butyl hydroxy anisole (BHA), di-butyl hydroxy toluene (BHT), and propyl gallate, did not exhibit photoprotective effects on these hydrolysable tannins. However, catechin, a natural antioxidant, displayed a weak photoprotective effect. Ascorbic acid had a short-term thermal-protective effect but not a long-term protective effect. The different stability properties of hydrolysable tannins in solutions can be used in the development of related herbal teas in the future.

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