Utilisation of photolysis of neutral red for analysis of antioxidant capacity in various flowers of medicinal plants from Bosnia

The objective of the study was to investigate the antioxidant capacity (AC) in various flowers of medicinal plants from Bosnia such as: Rosa centifolia, Rosa polyantha, Dianthus armeria, Cichorium intybus, Petunia hybrida, Paeonia officinalis, Viola tricolor, Hesperis matronalis, Chaenomeles japonica, Malva silvestris, Ajuga reptans, Wistaria sinensis. Method: Measurement of the AC is based on the photolysis of Neutral Red (NR). Photolysis of coloured NR solution is followed by decrease in absorbance at 532nm. The decrease in absorbance can be affected by interaction with antioxidants [1]. Results: The absorbance of pure NR solutions (8.66µM) at 532nm, at initial time and after 3.8 and 24 hours during irradiation with VIS and UV, and the absorbances of NR solutions in which either added 100µL supernatant flowers were measured. Difference of absorbance between photolysed pure NR and absorbance of NR solution with different supernatants describes AC. Antioxidant effect of these supernatants was, after 24 hours, during VIS irradiation in the order: Wistaria sinensis (70%) >Malva silvestris (64%) >Paeonia officinalis (62%) >Cichorium intybus (58%) >Rosa centifolia (52%) >Viola tricolor (44%) >Rosa polyantha (43%) >Hesperis matronalis (40%) >Petunia hybrida (39%) >Dianthus armeria and Ajuga reptans (36%) >Chaenomeles japonica (32%). Results showed that antioxidants contents in 100µL supernatants Wistaria sinensis, had higher antioxidant effects (70%) against NR^+·. Conclusions: This method can be particularly useful for nutritional and scientifical studies.

References: 1. Rimpapa, Z. (2006), Photolysis of neutral red and its inhibition by different antioxidants. PhD thesis, University of Sarajevo.