Evaluation of Biological Activities of Rice Husk Extracts

Abstract

This study was conducted to determine the biological activities of 70% ethanol extracts from rice husks of nine rice cultivars in Korea. The relative antioxidant activities of rice husk extracts were evaluated by determining DPPH, ABTS radical scavenging activity and reducing power. The contents of total polyphenol, flavonoid and r-oryzanol were measured by spectrophotometric methods. Among the extracts of rice husks, Nokmi rice husks tended to have the most effective antioxidant activities compared to other rice husk varieties. Seolgaeng rice husk extract showed anti-proliferative activity against cancer cell lines (MCF7 and NCI-H460), and Hongjinju rice husk extract significantly exhibited mitogenic activity.

By-products of Rice Processing: An Overview of Health Benefits and Applications

“…Phenolic compounds from methanol extracts of rice husks have been shown to exert high antioxidant activities against scavengers of singlet oxygen and to inhibit high hydrogen peroxideinduced damage to DNA in human lymphocytes [53]. These data are also supported by the findings of Kim et al [54], who showed that Nokmi rice husk extracts have effective antioxidant activities.…”

Antioxidant property of solvent extract and acid/alkali hydrolysates from rice hulls

“…4. The DPPH radical scavenging activity of solvent extract (26%) was found to be lower when compared to earlier report on Thai rice husk (42%) (Butsat & Siriamornpun, 2010) and comparable to that of Korean rice cultivar (27%) (Kim et al, 2011). Both acid (76%) and alkali (79%) hydrolysates exhibited remarkably higher radical scavenging activity when compared to solvent extract (25%).…”

“…3. The solvent extract revealed reducing power of 0.3 Abs at 700 nm and it is found to be higher when compared earlier report on rice husk of nine different Korean cultivars (0.05-0.22 Abs units) (Kim et al, 2011). The alkali hydrolysate exhibited maximum ferric reducing power (0.739 Abs units), which is followed by acid hydrolysate (0.687 Abs units) and then solvent extract (0.313 Abs units).…”