Methanolic extract of Crocus sativus flowers was prepared, and its antioxidant activity
evaluated by total phenolic contents (TPC), 1,1-diphenyl-2-picrylhydrazyl (DPPH)
radical scavenging activity, 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) radical
scavenging activity (ABTS) and the reducing power. The results showed that TPC was
86.65 mg/g gallic acid equivalents, while DPPH and ABTS for 1 mg/mL concentration
were 92.41 and 86.87, respectively. In the reducing power experiment, the IC50 value
was 231.75, about 11 times lower than that of ascorbic acid. The extract showed a
significant inhibitory effect on tyrosinase activity of 28.22%.
During normal metabolic processes or due to the exogenous factors and agents, reactive
oxygen species (ROS) in the forms of superoxide anion radical (·O2−), hydroxyl radical
(·OH), hydrogen peroxide (H2O2) may be generated. Formation of ROS can cause
oxidative damage to human cells, leading to various diseases such as cancer,
cardiovascular disease, osteoporosis, and degenerative diseases (1). Some compounds
known as antioxidants are able to delay or inhibit the initiation or propagation of
oxidative chain reaction and thus prevent or repair oxidative damage done to the body's
cells by oxygen (2). During the last few decades, some synthetic antioxidants such as
butylated hydroxyanisol (BHA) and butylated hydroxy toluene (BHT) have been used or
suggested as additives in food industry. However, due to their synthetic origin, these
antioxidants may induce carcinogenesis by mutagenicity and toxicity against human
enzymes and lipids (3). However, antioxidants derived from natural sources have
attracted many interests for use in foods or pharmaceutical preparations. Particularly,
much study is focused on natural products including vegetables and wild plant sources
(4).