Evaluation of antiangiogenic potential of Psidium guajava leaves using In-Ovo chick chorioallantoic membrane assay

Background: Angiogenesis is the process of formation of new blood vessels from the existing one. Pathological angiogenesis is widely implicated in many diseases, including cancer, diabetic neuropathy, retinopathy, obesity, and arthritis. Objective: The present study was aimed to evaluate the in vitro antioxidant and in ovo antiangiogenic activity of aqueous extract of Psidium guajava leaves (AEPG). Materials and Methods: Psidium guajava commonly known as guava reported to contain polyphenols and flavonoids such as gallic acid, epigallocatechin, catechin, rutin, and quercetin in glycosidic forms in its leaves. The antioxidant activity was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS), nitric oxide, hydrogen peroxide, hydroxyl, and superoxide radical scavenging assays (RSAs) and antiangiogenic activity was evaluated using vascular endothelial growth factor (VEGF)-induced chick chorioallantoic membrane (CAM).The correlation between the antioxidant and antiangiogenic activity was correlated with total phenolic content (TPC) of AEPG. Results: The TPC of AEPG was found to be 493.8 ± 8.9 mg of GAE/g. The total flavonoid content of AEPG was found to be 254.9 ± 13.7 mg of CE/g. In vitro antioxidant activity of AEPG showed IC 50 values of 19.4 ± 1.9, 25.5 ± 0.2, 4.9 ± 0.5, 29.9 ± 2.06, 39.5 ± 2.07, and 29.9 ± 0.9 μg/ml, respectively, for DPPH, ABTS, nitric oxide, hydrogen peroxide, hydroxyl, and superoxide RSAs. Significant reduction in angiogenesis in the AEPG treated groups when compared to untreated VEGF groups and the Pearson's correlation coefficient between TPC of AEPG and total length, area, branches of blood vessels and CAM thickness were −0.9261, −0.9807, −0.9637, and −0.9597, respectively. Conclusion: The results revealed potent antiangiogenic activity of AEPG leaves and exhibit significant correlation between the antioxidant and antiangiogenic activity of AEPG and its TPC. Abbreviations used: EGF: Epidermal growth factor; FGF: Fibroblast growth factor; G-CSF: Granulocyte colony stimulating factor; IL: Interleukin; INF: Interferon; MMP: Matrix metalloproteinases; NOS: Nitric oxide synthase; PAF: Platelet-activating factor; PAI: Plasminogen activator inhibitor; PDGF: Platelet-derived growth factor; PG-E: Prostaglandin E; RSA: Radical scavenging assay; TFC: Total flavonoid content; TPC: Total Phenolic content; TIMP: Tissue inhibitors of metalloproteinases; TNF-α: Tumor necrosis factor alpha; VEGF: Vascular endothelial growth factor.