To seek out a cheap source of dietary polyphenols and antioxidants along with anti-amylase and anti-glucosidase activities, ethanol extracts of eleven cheap Bangladeshi fruits were investigated. The extracts were also examined for anti-allergic activity using rat peritoneal exudate cells exposed to the calcium ionophore A23187.
Phyllanthus emblica (emblic myrobalan) had the highest total polyphenol content (339 mg gallic acid equivalent (GAE)/g), followed by
Syzygium cumini (Indian blackberry; 192.3 mg GAE/g), and
Aegle marmelos (wood apple; 53.7 mg GAE/g).
P. emblica, and
S. cumini also exhibited the most potent DPPH radical scavenging activity, with an IC
50 of 2.1 and 8.6 μg/mL respectively. These extracts also showed promising reducing powers with
P. emblica having the greatest such activity (optical density (O.D.) 1.66), followed by
S. cumini (O.D. 1.34), at a concentration of 0.2 mg/mL. The extracts of
Artocarpus heterophyllus (jackfruit) and
S. cumini showed promising chelating activities. At a concentration of 1 mg/mL,
Dillenia indica (chalta) showed the highest inhibition of α-amylase activity (60%), and
A. marmelos,
D. indica,
P. emblica,
Spondias dulcis (hog-plum) &
S. cumini completely inhibited α-glucosidase activity (100%). Apart from
A. heterophyllus,
D. indica and
Phyllanthus acidus (star-gooseberry), all other extracts inhibited the release of histamine from the peritoneal exudate cells, with
S. cumini having the strongest effect. These fruits therefore have activities beneficial to physiological health.
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