2 Such biomolecular damage by C59 in vitro free radicals leads to many pathological diseases such as cancer, inflammation, and atherosclerosis.3 Antioxidants from various sources, especially those of plant origin, reduce the adverse effects of free radicals. They act as scavengers by donating one of their own electrons in order to replace the stolen electron from free radicals.4 Plant-derived bioactive compounds known as phytochemicals are rich in antioxidant and free radical scavenging properties.5 Many research studies have been carried out to identify plants with significant antioxidant and anticancer potential by analysing their cytotoxic, antiproliferative, apoptotic and radical scavenging

activities using both in vitro and in vivo systems. 6 Caesalpinia pulcherrima is one such candidate plant which blooms in three different colours (orange, pink and yellow) with unique long stamens. It is commonly known as peacock flower MAPK Inhibitor Library chemical structure or “Barbados pride” in English and as “Mayil kondrai” in Tamil and belongs to the family Fabaceae. The aerial parts of the plants have been used traditionally for the treatment of various diseases

including asthma, bronchitis, cholera, diarrhoea, dysentery and malarial infection. 7 The flowers of C. pulcherrima have been reported to possess antiviral activity. 8 In recent years, the use of animals in research, teaching and testing has become an important ethical and political issue. Alternative scientific tests are being developed, which are more efficient and reliable than animal tests. Several non-animal tests have been developed that are cost-effective, practical, and expedient.9 The major advantage of using organ slices as in vitro model is that they represent the multicellular, structural and functional features of in vivo tissue. Organ slices have been used extensively as a promising Histone demethylase model for elucidating the mechanism of drug induced organ injury and for characterizing

species susceptibilities. 10 Precision-cut liver slices are widely used to elucidate the pharmacological metabolism and to investigate the toxicology and efficacy of novel substances on primary material under standardized conditions. 11 They also mimic the in vivo situation of the liver due to the presence of the physiological extracellular matrix. 12 Hence in the present study, the goat liver slices were selected as an in vitro model to determine the antioxidant potential of the methanolic extract of the three different flowers of C. pulcherrima (yellow, pink and orange) against H2O2 induced oxidative stress. Fresh flowers of C. pulcherrima ( Fig. 1) were collected from the local areas of Coimbatore. The three different flowers namely yellow, pink and orange were procured. The plant was identified and certified by the Botanical Survey of India, Tamil Nadu Agricultural University, Coimbatore. The voucher specimen was collected and maintained.