#TITLE_ALTERNATIVE#

• Main Author: SYIFA PERMATA SARI NIM : 10714033, FADHILA
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/27054
• Institution: Institut Teknologi Bandung

The oxidation reaction in the body can produce free radicals that are unstable and reactive atom or <br /> <br /> molecule because it contains one or more unpaired electron in the outermost orbital shells, so the <br /> <br /> molecule is searching dan pulling electron from another coumpund for neutralizing itself. Free radicals in <br /> <br /> normal amounts could kill intracelullar bacteria, but in excess amounts it could attack human cells, causing <br /> <br /> damage to these cells and it become one of the main causes of aging and degenerative disease such as <br /> <br /> cancer, cardiovascular disease, cataracts, decreased immune system, and brain dysfunction. Antioxidants <br /> <br /> are able to stabilize or eliminate free radicals before they attack the cells. Antioxidant compounds such as <br /> <br /> flavonoid substances are essential for maintaining optimum cellular work. Phenol and flavonoid <br /> <br /> compounds are widely contained in plants, included in strawberry (Fragaria ananassa). The objectives of <br /> <br /> this research were to study antioxidant activity of leaves, fruit and stems of strawberry by determining <br /> <br /> IC50 of DPPH (2,2-diphenyl-1-picrylhydrazyl) and EC50 of CUPRAC (Cupric Reducing Antioxidant Capacity); <br /> <br /> total phenolic and flavonoid content; analyze the correlation between total phenolic and flavonoid with <br /> <br /> their IC50 DPPH and EC50 CUPRAC, also analyze the correlation between DPPH and CUPRAC in sample <br /> <br /> extracts. Extraction was performed by reflux using gradient polarity solvents. Determination of IC50 DPPH, <br /> <br /> EC50 CUPRAC, total phenolic and flavonoid content of each extract were performed by spectrophotometry <br /> <br /> ultraviolet-visible and correlation of total phenolic and flavonoid content with their IC50 of DPPH and EC50 <br /> <br /> of CUPRAC activities, also correlation between two antioxidant testing method were analyzed by <br /> <br /> Pearson’s method. Antioxdant activities of leaves, stems and fruits of strawberry revealed that all extracts <br /> <br /> gave IC50 DPPH value in the range of 0.22 - 10.14 µg/mL. The highest total phenolic content was given by <br /> <br /> the ethanolic stem extract of strawberry (18.67 g GAE/100 g), while the ethyl acetate leaves extract of <br /> <br /> strawberry showed the highest total flavonoid content (7.4 g QE/100 g). All organ extracts of strawberry <br /> <br /> were categorized as very strong antioxidant by DPPH method, hence it was potential to be developed as <br /> <br /> source of natural antioxidant. Phenolic compounds were the major contributor in antioxidant activities of <br /> <br /> fruit, leaves and stem of strawberry by DPPH assay. Only strawberry leaves extract showed linear results <br /> <br /> in DPPH and CUPRAC assays. <br />