Determination of antioxidant activity of antibiotics by HPLC-DPPH method

Budući da bakterijske rezistencije ugrožava status antibiotika kao iznimno djelotvornih lijekova u borbi protiv patogena, racionalna primjena antibiotika postala je nužna. Danas se u kliničkoj praksi primjenjuje mnoštvo različitih antibiotika, stoga dobro poznavanje farmakokinetičkih i farmakodinamičkih svojstava može biti od velike pomoći pri odabiru najprikladnijeg lijeka. Antioksidativno djelovanje antibiotika može pridonijeti smanjenju oksidativnog stresa koji može nastati tijekom infekcije zbog mogućeg poremećaja ravnoteže slobodnih radikala i antioksidansa. Posljedično dolazi do oštećenja tkiva slobodnim radikalima što može dovesti do razvoja niza različitih bolesti. Antioksidativni učinak nekim antibioticima može dati prednost pri odabiru zbog smanjenja oštećenja organizma ili čak povećanja osjetljivosti bakterija na antibiotike. Cilj ovog rada bio je ispitati antioksidativni učinak 12 antibiotika mjereći njihovu sposobnost hvatanja slobodnog DPPH radikala. Antioksidativna aktivnost mjerena je HPLC-DPPH metodom. Korištene su 1mM otopine antibiotika uz dodatak otopine DPPH radikala pri čemu dolazi do smanjenja površine pika. Dobiveni rezultati pokazali su kako antioksidativna aktivnost ispitivanih antibiotika varira u rasponu od 0,037 mM (azitromicin) do 0,302 mM (doksiciklin) TEAC. Na temelju dobivenih rezultata izraženu antioksidativnu aktivnost u in vitro uvjetima pokazali su: cefradin, cefaleksin, ciprofloksacin, oksitetraciklin, doksiciklin i rifampicin te se korištena metoda pokazala brzom i učinkovitom za određivanje antioksidativne aktivnosti antibiotika.Since bacterial resistance compromises the status of antibiotics as potent drugs in the fight against pathogens and rational administration of antibiotics is necessary. Many different antibiotics are used in clinical practice today, therefore a good knowledge of pharmacokinetic and pharmacodynamic properties can be of great help in selecting the most appropriate drugs. The antioxidant activity of antibiotics can contribute to the reduction of oxidative stress that can occur during infection due to the possible disruption of the balance of free radicals and antioxidants. As a result, tissue damage to free radicals can occur which can lead to various diseases. The antioxidant properties of some antibiotics may be advantageous in selection because of reducing damage or even increasing bacterial susceptibility to antibiotics. The aim of this work was to investigate the antioxidant activity of 12 antibiotics by measuring its ability to trap free DPPH radical. Antioxidant activity was measured by the HPLC-DPPH method. A 1mM solution of antibiotics was used with the addition of a DPPH radical solution reducing the peak area. The results are expressed in TROLOX equivalents. The results obtained showed that the antioxidant activity of the investigated antibiotics varied from 0.037 mM (azithromycin) to 0.302 mM (doxycycline) TEAC. Based on the results obtained, it can be concluded the antioxidant activity was demonstrated by cefradine, cephalexin, ciprofloxacin, oxytetracycline, doxycycline and rifampicin. Also, HPLC-DPPH method has been proved to be rapid and efficient for determination of antioxidative activity of antibiotics