Tetrahydroberberine (THB), otherwise known as canadine, is a natural alkaloid showing significant pharmacological properties and antioxidant protection against oxidative damage. Herein, we synthetized structurally complex THB analogues, namely pyrrolino-tetrahydroberberines (PTHBs) 4a-g, containing the pyrrolino[2,3-b]pyridine system, by means of the reactions of 1,2-diaza-1,3-dienes and 7,8-dihydroberberine. Aim of the study was to explore the in vitro antioxidant properties of PTHBs in comparison to THB thus to identify the most effective against free radical-induced oxidative injury, by using three different antioxidant tests: the ORAC method, the DNA nicking assay, and the DCFH-DA cellular assay. As a result, PTHB 4d emerged among the other THB analogues by exhibiting the best antioxidant properties. First, it was the only compound having an ORAC value completely comparable to that of THB, indicating the same ability to neutralize peroxyl radicals. Secondly, 4d showed an even better antioxidant capacity than THB in protecting DNA against ferrous ion-induced strand breaks. These observations were also confirmed in NCTC-2544 human keratinocytes exposed to hydrogen peroxide. Indeed, 4d protected cells against oxidation more efficiently than THB both in the short (1 and 3 h) and long (24 h) period of incubation, possibly suggesting increased cell membrane permeability and/or intracellular stability of 4d as compared to THB.

Synthesis and biological evaluation of novel heteroring-annulated pyrrolino-tetrahydroberberine analogues as antioxidant agents.

Giacomo Mari;Simona Catalani;Elena Antonini;Lucia De Crescentini;Fabio Mantellini;Stefania Santeusanio;Antonella Amicucci;Serafina Battistelli;Serena Benedetti
;
Francesco Palma
2018

Abstract

Tetrahydroberberine (THB), otherwise known as canadine, is a natural alkaloid showing significant pharmacological properties and antioxidant protection against oxidative damage. Herein, we synthetized structurally complex THB analogues, namely pyrrolino-tetrahydroberberines (PTHBs) 4a-g, containing the pyrrolino[2,3-b]pyridine system, by means of the reactions of 1,2-diaza-1,3-dienes and 7,8-dihydroberberine. Aim of the study was to explore the in vitro antioxidant properties of PTHBs in comparison to THB thus to identify the most effective against free radical-induced oxidative injury, by using three different antioxidant tests: the ORAC method, the DNA nicking assay, and the DCFH-DA cellular assay. As a result, PTHB 4d emerged among the other THB analogues by exhibiting the best antioxidant properties. First, it was the only compound having an ORAC value completely comparable to that of THB, indicating the same ability to neutralize peroxyl radicals. Secondly, 4d showed an even better antioxidant capacity than THB in protecting DNA against ferrous ion-induced strand breaks. These observations were also confirmed in NCTC-2544 human keratinocytes exposed to hydrogen peroxide. Indeed, 4d protected cells against oxidation more efficiently than THB both in the short (1 and 3 h) and long (24 h) period of incubation, possibly suggesting increased cell membrane permeability and/or intracellular stability of 4d as compared to THB.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11576/2661469
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 7
  • ???jsp.display-item.citation.isi??? 6
social impact