Mary Jane G. Barluado | Mary Jean M. Lagang | Ivy Faye M. Gordonas | Cybonne Diane B. Bosas
Angiogenesis or the development of blood vessels and oxidation or the radical transformations of cellular substances are two key processes that contribute to cancer progression. This study evaluated the antiangiogenic and antioxidant properties of different concentrations of calamansi (Citrus microcarpa) ethanolic peel extract. Preliminary quantification of active compound phenolic acid in 1 ml of 0.1% extract solution revealed 0.005% phenolic acid content. By chorioallantoic membrane (CAM) assay of 11-day duck embryo, 0.10 g/ ml to 0.30 g/ml extract revealed significantly lower numbers of blood vessels compared to the untreated control (p<0.05), in a concentration-dependent fashion, demonstrating antiangiogenic property of the extract. On the other hand, by 1, 1-Diphenyl-2-picrylhydrazyl (DPPH) assay, 0.10% to 0.50% extract concentrations were tested against DPPH radical using ascorbic acid as positive control. Spectrophotometric analysis revealed significantly stronger inhibition of DPPH radical by the extract than by ascorbic acid (p < .05), demonstrating more powerful antioxidant property of the extract than ascorbic acid. Hence, the study proved that C. microcarpa peel extract exhibits both antiangiogenic and antioxidant properties. Development of anti-cancer therapy envisaged, antiangiogenic and antioxidant bioassays of the extract using tumor-positive animal models are recommended.