dc.description.abstract | Bitter melon (Momordica charantia L.) is common and familiar plant widely
utilized for food and medicine. Research of Horax, 2005 shows that bitter melon extract
contains flavonoids are potent as antioxidants. Some flavonoid known have potent antifree radicals or antioxidants. This study aims to determine the antioxidant activity from
bitter melon extract using variation concentration of ethanol in solvent and to know the
relationship between levels of total flavonoids with antioxidant activity. Determination
of antioxidant activity was evaluated from the scavenging free radical DPPH (2,2-
diphenyl-1-pikrilhidrazil) spectrophotometrically. This study used variation of solvent is
ethanol 50%, 70%, and 90% in order to determine antioxidant activity of each
concentration and vitamin C as comparison, Increased concentrations of extract and
vitamin C resulted in the reduction of free radicals are also getting bigger. The value
reduction of free radical DPPH was calculated based on it absorbance, measured at λ
517,6 nm. From linear regression result show that IC50 of 50 % ethanol extract are 24,25
ppm, 70% ethanol extract are 43,02 ppm, 90% ethanol extract are 49,94 ppm, and
vitamin C (comparison) are 69,54 ppm. These results showed that anti radical activity
ethanol extract of bitter melon is higher than vitamin C. The bigger total flavonoids
present by 50 % ethanol extract. IC50 value is inversely proportional with total
flavonoids, the high flavonoid content is more potential as an antioxidant therefore
concentration required to eliminate 50 % of scavenging free radicals activity more
smaller. The correlation of total flavonoid with antioxidant activity is directly
proportional and inversely proportional to the IC50 | en_US |