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20121
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Subject: Chemistry × Author: Gunjan × Start date: 2010 × Type: Thesis × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Studies on chemical composition and antioxidant activity of amla (phyllanthus emblica L.) and jamun [syzygium cumini (L.) skeels] fruits
    (CCSHAU, 2012) Gunjan; Madan, V.K.
    Oxidants and antioxidants in humans beings are maintained properly in a normal physiological state, and overproduction of oxidants in certain conditions such as smoking, hazardous environmental exposure or infectious diseases can cause oxidative stress leading to oxidative damage to biomolecules and cells. The indigenous tropical fruits of India like Amla (Phyllanthus emblica L). and Jamun [Syzygium cumini (L.) Skeels] are rich in nutritional and medicinal properties which play an essential role in prevention of diseases. In our present studies, total phenols, flavonoids and ascorbic acid in amla and jamun fruits were estimated using acetone, ethanol and distilled water as solvents. Total phenols were estimated by Folin Cio-calteu method, flavonoids by aluminium chloride colorimetric method and ascorbic acid by titrimetric method which is based on the reduction of 2,6-dichlorophenol indophenol (2,6-DCPIP). The antioxidant activity of different extracts of these fruits was evaluated by two different methods viz; 2, 2’-Diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging method and β-carotene bleaching method (BCBT). Highest amount of phenols on fresh weight basis (f.w.b) was found in acetone extracts (39.05 mg GAE/g f.w.b.) followed by ethanol extracts (24.39 mg GAE/g f.w.b.) and water extracts (18.54 mg GAE/g f.w.b.). Flavonoids content was highest in water extracts (1.24 mg CE/g f.w.b.) followed by ethanol extracts (0.92 mg CE/g f.w.b.) and acetone extracts (0.83 mg CE/g f.w.b.). Like flavonoids, ascorbic acid content was also highest in water extracts (69.87 mg/100g f.w.b.) followed by ethanol extracts (65.60 mg/100g f.w.b.) and acetone extracts (39.56 mg/100g f.w.b.). Similar trends were observed for total phenols, flavonoids and ascorbic acid on dry weight basis (d.w.b.). Free radical scavenging activity by DPPH method was observed to be highest in ethanol extracts i.e. 88.27 % followed by 81.60 % in acetone extracts and 62.97 % in water extracts. Similarly, antioxidant activity shown by β-carotene bleaching method was highest in ethanol extracts i.e. 76.71 % followed by 67.45 % in acetone extracts and 55.00 % in water extracts. Amongst two methods used for evaluating antioxidant activity, it was observed that DPPH free radical scavenging activity of various extracts of amla and jamun fruits ranged from 74.43 – 80.90 % and antioxidant activity by β-carotene bleaching method was lower in comparison to DPPH free radical scavenging activity and it ranged from 61.06 – 71.01 %. From the present studies, it was found that DPPH free radical scavenging method is more efficient in comparison to β-carotene bleaching method for evaluating antioxidant activity. Amongst amla and jamun, amla contained higher amounts of total phenols, flavonoids and ascorbic acid and also showed higher antioxidant activity. Hence, amla can be used as a better source of antioxidants.