A B S T R A C TThe total antioxidant capacity of Pinus gerardania, or Chilgoza and the presence of antioxidant compounds which typically exist in pine nuts were quantified. Oxygen radical absorbance capacity assay, ferric reducing antioxidant power, and the 2, 2-diphenyl-1-picrylhydrazyl (DPPH•) and 2, 2-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS•+) radical cation scavenging assays were conducted on dichloromethane, ethanol, ethyl acetate, hexane, methanol and water extracts of Chilgoza. The water and dichloromethane extracts displayed the highest antioxidant activity across all assays. Antioxidant compounds such as gallocatechin, catechin, lutein, lycopene, caretenoids and tocopherols were present in all extracts.Gallocatechin had the highest presence out of all the compounds. Its amounts present in the water and dichloromethane extracts were 64.9 and 56.9 µg per gram fresh weight (µg/g), respectively. The total carotenoid contents in the water and dichloromethane extracts were 14.72 and 14.26 µg/g, respectively, while the total tocopherol contents were 1.05 and 2.53 µg/g, respectively.

The free radical scavenging activity of Aspalathus linearis (Rooibos tea) and its effect on reactive oxygen species (ROS), catalase (CAT), and superoxide dismutase (SOD) were investigated in two in vitro disease models of cancer and diabetes. Although the antioxidant activity of this tea has been reported in several studies, its effects in disease models of ROS-induced oxidative stress have not been systematically evaluated to date. The oxygen radical absorbance capacity (ORAC) assay was used in this study to quantify the antioxidant capacity of the extract, whereas the ROS scavenging ability in hyperglycemia-induced human umbilical vein endothelial cells (HUVECs) and HeLa cells were investigated. The CAT and SOD assays were also carried out in the two disease models in order to evaluate the effect of the extract in the stimulation of these two enzyme activities. The extract was observed to have reduced ROS in a dose-dependent manner in both HUVECs and HeLa cells. The stimulation of the CAT and SOD enzyme activities were observed to be dose-dependent as well. The high ORAC value of the extract indicated the presence of antioxidant compounds which could directly quench ROS, whereby this mechanism of action could be hypothesized to have been further complemented through the stimulation of CAT and SOD. Overall, the Aspalathus linearis extract was observed to have increased the CAT and SOD activities in two in vitro disease models of cancer and hyperglycemia. Given the correlation between the ORAC values, the increases in CAT and SOD activities and the reduction in ROS in a dose-dependent manner, it could be hypothesized that the extract had a significant therapeutic potential for either the prevention of the onset of the two diseases or their progression because ROS has been identified as their root causes.

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The antioxidant activities of curry leaves, fenugreek seeds, Indian malabar leaves, red silk cotton tree leaves, cowitch leaves, holyfruit tree leaves, and black mustard seeds were compared. Their effects on reactive oxygen species (ROS) and superoxide dismutase (SOD) activity were investigated. The Oxygen Radical Absorbance Capacity (ORAC) assay determined the antioxidant potential of the extracts, while the ROS scavenging ability was explored in hyperglycemia-induced human umbilical vein endothelial cells (HUVECs). The SOD assay determined if the extracts stimulated the enzyme activity in the HUVECs. Curry leaf and fenugreek extracts had high ORAC values and superior free radical scavenging abilities compared with the rest of the extracts. The curry leaf extract had also increased the SOD activity. Fenugreek extract had not increased the SOD activity of the HUVECs. Thus, the two herbs displayed two distinct pathways of action for scavenging of ROS.