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Article

Synthesis, Spectroscopic Study and Radical Scavenging Activity of Kaempferol Derivatives: Enhanced Water Solubility and Antioxidant Activity

1
Department of Chemistry, Jinan University, Guangzhou 510632, China
2
State Key Laboratory of Quality Research in Chinese Medicines, Macau University of Science and Technology, Macau 000853, China
*
Author to whom correspondence should be addressed.
These authors contributed equally to this work.
Int. J. Mol. Sci. 2019, 20(4), 975; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms20040975
Received: 29 December 2018 / Revised: 13 February 2019 / Accepted: 19 February 2019 / Published: 23 February 2019
(This article belongs to the Section Physical Chemistry and Chemical Physics)
Kaempferol (Kae) is a natural flavonoid with potent antioxidant activity, but its therapeutic use is limited by its low aqueous solubility. Here, a series of Kae derivatives were synthesized to improve Kae dissolution property in water and antioxidant activity. These compounds included sulfonated Kae (Kae-SO3), gallium (Ga) complexes with Kae (Kae-Ga) and Kae-SO3 (Kae-SO3-Ga). The compound structures were characterized by high-resolution mass spectrometry (HRMS), nuclear magnetic resonance (NMR) spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy and thermal methods (TG/DSC). The results showed that a sulfonic group (-SO3) was successfully tethered on the C3’ of Kae to form Kae-SO3. And in the metal complexation, 4-CO and 3-OH of the ligand participated in the coordination with Ga(III). The metal-to-ligand ratio 1:2 was suggested for both complexes. Interestingly, Kae-SO3-Ga was obviously superior to other compounds in terms of overcoming the poor water-solubility of free Kae, and the solubility of Kae-SO3-Ga was about 300-fold higher than that of Kae-Ga. Furthermore, the evaluation of antioxidant activities in vitro was carried out for Kae derivatives by using α,α-diphenyl-β-picrylhydrazyl (DPPH) and 2,2’-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) diammonium salt (ABTS) free radical scavenging. The results showed that Kae-SO3-Ga was also optimal for scavenging free radicals in a dose-dependent manner. These data demonstrate that sulfonate kaempferol-gallium complex has a promising future as a potential antioxidant and as a potential therapeutic agent for further biomedical studies. View Full-Text
Keywords: kaempferol; gallium complex; water solubility; antioxidant activity; flavonoid kaempferol; gallium complex; water solubility; antioxidant activity; flavonoid
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MDPI and ACS Style

Deng, S.-P.; Yang, Y.-L.; Cheng, X.-X.; Li, W.-R.; Cai, J.-Y. Synthesis, Spectroscopic Study and Radical Scavenging Activity of Kaempferol Derivatives: Enhanced Water Solubility and Antioxidant Activity. Int. J. Mol. Sci. 2019, 20, 975. https://0-doi-org.brum.beds.ac.uk/10.3390/ijms20040975

AMA Style

Deng S-P, Yang Y-L, Cheng X-X, Li W-R, Cai J-Y. Synthesis, Spectroscopic Study and Radical Scavenging Activity of Kaempferol Derivatives: Enhanced Water Solubility and Antioxidant Activity. International Journal of Molecular Sciences. 2019; 20(4):975. https://0-doi-org.brum.beds.ac.uk/10.3390/ijms20040975

Chicago/Turabian Style

Deng, Sui-Ping, Yi-Li Yang, Xing-Xing Cheng, Wen-Rong Li, and Ji-Ye Cai. 2019. "Synthesis, Spectroscopic Study and Radical Scavenging Activity of Kaempferol Derivatives: Enhanced Water Solubility and Antioxidant Activity" International Journal of Molecular Sciences 20, no. 4: 975. https://0-doi-org.brum.beds.ac.uk/10.3390/ijms20040975

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