Growth Inhibition and Cytotoxicity in Human Lung and Cervical Cancer Cell Lines and Glutathione S-Transferase Inhibitory Activity of Selected Sri Lankan Traditional Red Rice (Oryza Sativa L.) Brans

Abstract

Extracts, fractions and gastrointestinal-resistant protein hydrolysates (GRPH) from rice bran (RB) of four Sri Lankan traditional varieties were studied for growth inhibition (GI) and cytotoxicity against human lung cancer (NCI-H460), cervical cancer (HeLa) cell lines and effect on glutathione S-transferase (GST) in vitro. RB extracts showed significantly high (P < 0.05) GI (GI50 μg/mL: HeLa: 19.24 ± 3.47 to 112.58 ± 0.05; NCI-H460: 54.63 ± 4.89 to 170.31 ± 4.71) and cytotoxicity (LC50 μg/mL: HeLa: 240.12 ± 9.23 to 476.22 ± 0.05; NCI-H460: 255.36 ± 1.81 to 412.07 ± 17.73) compared with GRPH. Highest GI (GI50: 30.63 ± 9.19 to 44.40 ± 5.34 μg/mL) and cytotoxicity (LC50: 141.31 ± 14.47 to 169.51 ± 2.04 μg/mL) was evident in nonpolar fractions (dichloromethane: Goda Heeneti and Sudu Heeneti; hexane: Dik Wee and Sudu Heeneti). No cytotoxicity was evident to normal cells. All RB extracts had high GST inhibition. Properties observed indicate its usefulness in managing lung and cervical cancers. PRACTICAL APPLICATIONSLung and cervical cancers are two of the most commonly diagnosed cancers in men and women, respectively, and leading causes of mortality. Although numerous potent chemotherapeutic drugs are available for management, most of these drugs are very expensive and are associated with numerous side effects. Further, anticancer drugs containing electrophilic centers can easily form a conjugate with glutathione, which is facilitated by glutathione S-transferase (GST) and excreted from the body resulting in lower efficacy. Therefore, GST inhibitors are used as adjuvants during cancer chemotherapy. The selected rice varieties in this study claimed to possess health-enhancing properties according to Sri Lankan ethnomedicine. The findings of this study clearly showed that bran extracts, fractions and gastrointestinal-resistant protein hydrolysates of selected rice varieties had growth inhibition and cytotoxicity against both lung and cervical cancers. Further, all of these selected varieties had high GST inhibition. Therefore, selected rice brans may be useful in the management of lung and cervical cancers.

Antioxidant potential of brans of twenty-nine red and white rice (Oryza sativa L.) varieties of Sri Lanka

“…Traditional red grain varieties had long been consumed in some Asian countries including Sri Lanka [13,26] and claimed for its superior nutritional quality and enhanced health benefits [14,16]. Findings from the present study and our previous studies were able to prove such traditional health claims scientifically [15,16,27,28]. Further, this is the first study to demonstrate differences in antioxidant properties of large set of NI rice varieties in comparison to OI and traditional rice varieties of Sri Lanka.…”

Physicochemical and nutritional properties of twenty three traditional rice (Oryza sativa L.) varieties of Sri Lanka

“…Colored or pigmented rices are popular in some countries and are reported as special rices. Such rices are reported to have variety of health benefits compared to non-pigmented rices [6,7,[19][20][21][22]29]. Our previous researches on health benefits of traditional rice varieties of Sri Lanka showed high antioxidant, anti-diabetic, anti-inflammatory and cytotoxic effects on human cancer cell lines in brans of red rices in contrast to brans of white rices [19][20][21][22].…”

“…These varieties were selected based on the health claims in the Sri Lankan traditional knowledge and the findings of our previous researches [17,[19][20][21][22]. Physicochemical properties of the rice grain are important rice grain quality attributes which influence the consumers' acceptance [1,2,4,5].…”

“…However, among these thousands of traditional rice varieties, some had been cultivated widely than the other varieties because of their health benefits, adaptability to problematic soils and resistance to different abiotic stress conditions [17,19]. Recent research conducted in the country scientifically showed range of medically important health benefits of some Sri Lankan traditional rice varieties [19][20][21][22]. These findings were able to uplift the traditional rice industry in the country immensely.…”

Nutritional and antioxidant properties of selected traditional rice (Oryza sativa L.) varieties of Sri Lanka

“…Some of these varieties were claimed to have medicinal properties according to the Sri Lankan ethno medicine and folklore (Dharmasena, 2010;Abeysekera & Premakumara, 2016). These health claims including some nutritional and antioxidant properties were scientifically proven in recent studies (Premakumara et al, 2013;Abeysekera et al, 2015a;Abeysekera et al, 2015b;Abeysekera & Premakumara, 2016) and thus such traditional rice varieties currently have a good market value (Wickramasinghe & Noda, 2008;Suriyagoda et al, 2011). However, there are numerous varieties yet to be studied.…”