Spectrophotometric zinc(II) based determination of quercetin in pharmaceutical formulations
Апстракт
Flavonoids are a group of polyphenolic compounds widely present in the herbal world
representing an important part of human diet. Quercetin, which is a flavanol, makes 70% of total daily
intake of flavonoids. Because of the characteristic chemical structure, quercetin has the ability of
complexing metals and antioxidative ability.
Using equimolar solution variation method it was determined that quercetin makes a complex
with zinc(II)-ion in acidic environment (pH 5.25), in stoichiometric relation quercetin:zinc(II)-ion =
2:1, with absorption maximum on λmax=363 nm. The ability of quercetin to make complex
compounds with zinc(II)-ion was used to develop simple, precise and accurate assay to determine the
content of quercetin in various samples of heterogeneous composition.
The proposed indirect spectrophotometric method can selectively determine quercetin in
concentrations ranging from 0.1 to 6.0 mg/L. LOD and LOQ were derived from the calibration curve
and estimated as 0.03 ...mg/L and 0.1 mg/L respectively. Developed method is reproductive and
accurate, as indicated by high value of correlation coefficient R=0.99996 and low value of
SD=0.00122. Method was successfully used to determine quercetin content in dietary supplement
tablets. Dietary supplements, proscribed for therapeutic and/or profilactic pruposes, usualy content
quercetin combined with other flavonoids and ascorbic acid. Therefore, it was necessary to test the
selectivity of proposed method.
The reliability of the method was checked out by newly developed RP-HPLC/UV method for
capsules with direct determination of quercetin after separation. The good agreement between the two
methods indicates the applicability of the proposed spectrophotometric method for quercetin
determination in dietary supplement tablets with high reproducibility, and enables direct and simple
determination without its prior extraction from samples.
In addition, the antioxidative ability of quecetin and zinc(II)-quercetin complex was
determined using oxidation-reduction standardized methods DPPH and FRAP. The same samples
were tested for antimicrobial activity against seven laboratory control strains of bacteria and one
yeast. As a result of those tests, there are no obstacles to combine quercetin and zinc in the same
formulation.
Кључне речи:
quercetin / complex / zinc(II)-ion / antioxidative ability / spectrophotometryИзвор:
25th Congress of Chemists and Technologists of Macedonia, 19–22 September 2018, Ohrid, R. Macedonia, 2018, 119-119Издавач:
- Society of Chemists and Technologists of Macedonia
Финансирање / пројекти:
- Електропроводни и редокс-активни полимери и олигомери: синтеза, структура, својства и примена (RS-MESTD-Basic Research (BR or ON)-172043)
- Синтеза, моделовање, физичко-хемијске и биолошке особине органских једињења и одговарајућих комплекса метала (RS-MESTD-Basic Research (BR or ON)-172016)
Институција/група
PharmacyTY - CONF AU - Pavun, Leposava AU - Ćirić, Andrija AU - Milenković, Marina AU - Uskoković-Marković, Snežana PY - 2018 UR - https://farfar.pharmacy.bg.ac.rs/handle/123456789/5220 AB - Flavonoids are a group of polyphenolic compounds widely present in the herbal world representing an important part of human diet. Quercetin, which is a flavanol, makes 70% of total daily intake of flavonoids. Because of the characteristic chemical structure, quercetin has the ability of complexing metals and antioxidative ability. Using equimolar solution variation method it was determined that quercetin makes a complex with zinc(II)-ion in acidic environment (pH 5.25), in stoichiometric relation quercetin:zinc(II)-ion = 2:1, with absorption maximum on λmax=363 nm. The ability of quercetin to make complex compounds with zinc(II)-ion was used to develop simple, precise and accurate assay to determine the content of quercetin in various samples of heterogeneous composition. The proposed indirect spectrophotometric method can selectively determine quercetin in concentrations ranging from 0.1 to 6.0 mg/L. LOD and LOQ were derived from the calibration curve and estimated as 0.03 mg/L and 0.1 mg/L respectively. Developed method is reproductive and accurate, as indicated by high value of correlation coefficient R=0.99996 and low value of SD=0.00122. Method was successfully used to determine quercetin content in dietary supplement tablets. Dietary supplements, proscribed for therapeutic and/or profilactic pruposes, usualy content quercetin combined with other flavonoids and ascorbic acid. Therefore, it was necessary to test the selectivity of proposed method. The reliability of the method was checked out by newly developed RP-HPLC/UV method for capsules with direct determination of quercetin after separation. The good agreement between the two methods indicates the applicability of the proposed spectrophotometric method for quercetin determination in dietary supplement tablets with high reproducibility, and enables direct and simple determination without its prior extraction from samples. In addition, the antioxidative ability of quecetin and zinc(II)-quercetin complex was determined using oxidation-reduction standardized methods DPPH and FRAP. The same samples were tested for antimicrobial activity against seven laboratory control strains of bacteria and one yeast. As a result of those tests, there are no obstacles to combine quercetin and zinc in the same formulation. PB - Society of Chemists and Technologists of Macedonia C3 - 25th Congress of Chemists and Technologists of Macedonia, 19–22 September 2018, Ohrid, R. Macedonia T1 - Spectrophotometric zinc(II) based determination of quercetin in pharmaceutical formulations SP - 119 EP - 119 UR - https://hdl.handle.net/21.15107/rcub_farfar_5220 ER -
@conference{ author = "Pavun, Leposava and Ćirić, Andrija and Milenković, Marina and Uskoković-Marković, Snežana", year = "2018", abstract = "Flavonoids are a group of polyphenolic compounds widely present in the herbal world representing an important part of human diet. Quercetin, which is a flavanol, makes 70% of total daily intake of flavonoids. Because of the characteristic chemical structure, quercetin has the ability of complexing metals and antioxidative ability. Using equimolar solution variation method it was determined that quercetin makes a complex with zinc(II)-ion in acidic environment (pH 5.25), in stoichiometric relation quercetin:zinc(II)-ion = 2:1, with absorption maximum on λmax=363 nm. The ability of quercetin to make complex compounds with zinc(II)-ion was used to develop simple, precise and accurate assay to determine the content of quercetin in various samples of heterogeneous composition. The proposed indirect spectrophotometric method can selectively determine quercetin in concentrations ranging from 0.1 to 6.0 mg/L. LOD and LOQ were derived from the calibration curve and estimated as 0.03 mg/L and 0.1 mg/L respectively. Developed method is reproductive and accurate, as indicated by high value of correlation coefficient R=0.99996 and low value of SD=0.00122. Method was successfully used to determine quercetin content in dietary supplement tablets. Dietary supplements, proscribed for therapeutic and/or profilactic pruposes, usualy content quercetin combined with other flavonoids and ascorbic acid. Therefore, it was necessary to test the selectivity of proposed method. The reliability of the method was checked out by newly developed RP-HPLC/UV method for capsules with direct determination of quercetin after separation. The good agreement between the two methods indicates the applicability of the proposed spectrophotometric method for quercetin determination in dietary supplement tablets with high reproducibility, and enables direct and simple determination without its prior extraction from samples. In addition, the antioxidative ability of quecetin and zinc(II)-quercetin complex was determined using oxidation-reduction standardized methods DPPH and FRAP. The same samples were tested for antimicrobial activity against seven laboratory control strains of bacteria and one yeast. As a result of those tests, there are no obstacles to combine quercetin and zinc in the same formulation.", publisher = "Society of Chemists and Technologists of Macedonia", journal = "25th Congress of Chemists and Technologists of Macedonia, 19–22 September 2018, Ohrid, R. Macedonia", title = "Spectrophotometric zinc(II) based determination of quercetin in pharmaceutical formulations", pages = "119-119", url = "https://hdl.handle.net/21.15107/rcub_farfar_5220" }
Pavun, L., Ćirić, A., Milenković, M.,& Uskoković-Marković, S.. (2018). Spectrophotometric zinc(II) based determination of quercetin in pharmaceutical formulations. in 25th Congress of Chemists and Technologists of Macedonia, 19–22 September 2018, Ohrid, R. Macedonia Society of Chemists and Technologists of Macedonia., 119-119. https://hdl.handle.net/21.15107/rcub_farfar_5220
Pavun L, Ćirić A, Milenković M, Uskoković-Marković S. Spectrophotometric zinc(II) based determination of quercetin in pharmaceutical formulations. in 25th Congress of Chemists and Technologists of Macedonia, 19–22 September 2018, Ohrid, R. Macedonia. 2018;:119-119. https://hdl.handle.net/21.15107/rcub_farfar_5220 .
Pavun, Leposava, Ćirić, Andrija, Milenković, Marina, Uskoković-Marković, Snežana, "Spectrophotometric zinc(II) based determination of quercetin in pharmaceutical formulations" in 25th Congress of Chemists and Technologists of Macedonia, 19–22 September 2018, Ohrid, R. Macedonia (2018):119-119, https://hdl.handle.net/21.15107/rcub_farfar_5220 .