Physiological Free Radicals Scavenging Potential of Brans of Selected Sri Lankan Traditional Red Rice (Oryza sativa L.): an In Vitro Antioxidant Activity Study

Objectives: To evaluate the effect of brans of selected Sri Lankan traditional red rice varieties on physiological free radicals scavenging potential using in vitro antioxidant assays.
Materials and Methods: Freeze dried 70% ethanolic extracts of brans of four traditional red rice varieties namely Sudu Heeneti, Goda Heeneti, Dik Wee and Masuran were used. Antioxidant activities were evaluated using superoxide radical scavenging activity (SRSA), nitric oxide radical scavenging activity (NORSA) and oxygen radical absorbance capacity: ORAC (measure of peroxyl radical scavenging activity) in vitro antioxidant assays (n=3 each).
Results and Discussion: Brans of all the selected varieties showed SRSA, NORSA and ORAC. The observed antioxidant activities varied significantly (P<0.05) among varieties. SRSA and NORSA were significantly high (P<0.05) in brans of Masuran and Sudu Heeneti respectively. For ORAC, brans of Sudu Heeneti and Goda Heeneti showed comparable and significantly high (P<0.05) activities compared to the rest of the varieties. The order of potency of brans of selected varieties for SRSA, NORSA and ORAC were Masuran>Sudu Heeneti=Dik Wee>Goda Heeneti, Sudu Heeneti>Dik Wee=Goda Heeneti>Masuran and Sudu Heeneti=Goda Heeneti>Dik Wee=Masuran respectively.
Conclusion: It is concluded that brans of all the selected Sri Lankan traditional red rice varieties had physiological free radicals scavenging activities with varying degrees of potentials. This is the 1st study to report such biological activities for any variety of rice in Sri Lanka and indicates its potential as a functional food ingredient in the health food industry.

Author(s): Abeysekera WKSM, Abeysekera WPKM,Premakumara GAS and Ratnasooriya WD

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