2013 ASHS Annual Conference

Antioxidants neutralize free radicals before they can damage cellular structures, including DNA, proteins, and membrane lipids. In humans, the consequences of low antioxidant levels include obesity, cardiovascular disease, and poor immune function, but consumption of fruits and vegetables can prevent certain chronic diseases. Recent studies showed that people who consumed more fruits and vegetables had reduced risks of cancer, stroke, and heart disease. Citrus fruits have long been valued as part of a nutritious and tasty diet and contain many antioxidants. For example, Vitamin C, an essential water-soluble nutrient, acts as an antioxidant by donating electrons to free radicals to form a stable end product. The present study examined the free radical scavenging activities of citrus fruit extracts using different in vitro methods. 'Marrs' sweet oranges were extracted with five different solvents in the Soxhlet apparatus; extracts were dried and used to determine antioxidant activities. Free radical diphenyl-1-picry hydrazyl (DPPH) scavenging activity was measured for five extracts. Chloroform extract had the highest DPPH activity and methanol extracts had the lowest activity whereas in case of 2,2’-azino-bis (3-ethyl benzthiazoline-6-sulfonic acid) (ABTS) assay water extract had highest activity. Furthermore, antioxidant capacity was also determined using the phosphomolybdenum method. Antioxidant capacity of the extracts as equivalent to ascorbic acid (μmole/g of the extract) was in the order of water > acetone acetate > methanol >chloroform. Indeed, extract made with water had the highest antioxidant capacity and hexane extract had the lowest capacity as measured by this assay. Further experiments are needed to gather more data on how antioxidants affect our daily lives.