Gac fruit extracts ameliorate proliferation and modulate angiogenic markers of human retinal pigment epithelial cells under high glucose conditions

Objective: To investigate the impact of the extracts of Gac fruit parts(peel, pulp, seed, and aril) on the cell viability and angiogenesis markers of human retinal pigment epithelial(ARPE-19) cells under high glucose conditions. Methods: The effect of the extracts of Gac fruit peel, pulp, seed and aril on the ARPE-19 cells was determined using MTT viability assay, Trypan blue dye and morphological changes were observed using light microscopy. Enzyme-linked immunosorbent-based assay was performed to evaluate the effect of Gac fruit parts on the reactive oxygen species(ROS), vascular endothelial growth factor(VEGF) and pigmented epithelium-derived factor(PEDF) secretions. Results: High glucose(HG) at 30 mmol/L increased ARPE-19 cell viability and ROS and VEGF secretions. While, the exposure of ARPE-19 cells in high glucose condition to Gac fruit extracts led to inhibition of cell viability, induced morphological changes, decreased ROS and VEGF secretions, and increased PEDF level. Gac pulp, seed, and aril at 1 000 μg/mL showed significant inhibition activities [(7.5 ± 5.1)%,(2.7 ± 0.5)%,(3.2 ± 1.1)%, respectively] against HG-induced ARPE-19 cell viability. The findings also demonstrated that Gac aril at 250 μg/mL significantly decreased ROS and VEGF levels [(40.6 ± 3.3) pg/mL,(107.4 ± 48.3) pg/mL, respectively] compared to ROS [(71.7 ± 2.9) pg/mL ] and VEGF [(606.9 ± 81.1) pg/mL] in HG untreated cells. Moreover, 250 μg/mL of Gac peel dramatically increased PEDF level [(18.2 ± 0.3) ng/mL] compared to that in HG untreated cells [(0.48 ± 0.39) ng/mL]. Conclusions: This study indicates that the extracts of Gac peel, pulp, seed and aril reduced cell viability, minimized ROS generations and showed angiogenic activities. Therefore, our findings open new insights into the potentiality of Gac fruit against HG-related diabetic retinopathy disease.

Antioxidant compounds and capacities of Gac (Momordica cochinchinensis Spreng) fruits

Objective: To identify and determine the composition of antioxidant compounds, and to evaluate the antioxidant abilities of Gac fruit parts(peel, pulp, seed and aril) grown in Malaysia. Methods: LC-MS/MS was used for identification of antioxidant compounds and UV-Vis for estimation of the contents of phenolics, flavonoids, and carotenoids. Lycopene and β-carotene were quantified using high-performance liquid chromatography. DPPH(2, 2-diphenyl-1-picrylhydrazyl) and ferric reducing antioxidant power assays were employed to evaluate antioxidant capacities. Results: Phytochemicals were found amongst all the fruit parts. Notably, significant amounts of carotenoids [(107.4 ± 4.5),(85.7 ± 4.4),(110.6 ± 2.1) mg/100 g dry weight(DW)], and relatively high levels of both phenolics [(27.3 ± 1.7),(28.9 ± 2.4),(30.8 ± 2.7) mg/100 g DW] and flavonoids [(38.1 ± 2.2),(8.8 ± 1.3),(24.5 ± 3.3) mg/100 g DW] were found in the fruit's peel, pulp and aril, respectively. Seed part also showed a relatively high level of flavonoids [(18.1 ± 2.3) mg/100 g DW]. Lycopene and β-carotene were found to be significantly high(P < 0.05) in aril [(579.3 ± 22.7) and(621.0 ± 35.0) μg/g DW], followed by peel [(51.0 ± 7.5) and(210.0 ± 12.5) μg/g DW] and pulp [(37.6 ± 10.9) and(205.6 ± 22.1) μg/g DW)]. Antioxidant assays revealed that aril possessed the highest scavenging activity(IC_(50) = 865 μg/mL), while the peel possessed the highest ferric reducing power of 140 μmol FeSO4/μg. Conclusions: The current results demonstrate that Gac fruit grown in Malaysia is a rich source of phytochemicals, especially carotenoids, and possesses antioxidant activities. Thus, such findings suggest Gac fruit as a source of an antioxidant plant.