Contents of the total polyphenols and flavonoids in the dietary fiber from tubers and stalks of domestic sweet potatoes were investigated. In addition, their antioxidant activity as well as the potent anti-cancer effects through the growth inhibition in human colon cancer cells (HT-29) in vitro were tested. The total flavonoids as naringin equivalents in dietary fiber from tubers and stalks of sweet potatoes were 0.5 ± 0.001 naringin/g extract and 2.0 ± 0.008 mg naringin/g extract dry basis, respectively. The amounts of the total polyphenols as gallic acid equivalents were 2.8 ± 0.01 mg gallic acid/g dry basis and 6.3 ± 0.03 mg gallic acid/g dry basis, respectively. 1,2-Diphenyi-1-picrylhydrazyl (DPPH) radical-scavenging activity of the dietary fiber from stalks was 2.4 times higher than that of the dietary fiber from tubers. Interestingly, a strong growth inhibition on HT-29 cells was observed in both dietary fibers originated from stalks and tubers of sweet potato in a dose-dependent manner. In addition, we found that the dietary fiber from tubers and stalks of sweet potato increased the gene expression of tumor suppressor p53. The great potential value in the prevention of various diseases including cancer the potential value could be confirmed through effects of the dietary fiber from tubers and stalks of sweet potato on antioxidant activity and anticancer in human colon cancer.

본 연구에서는 국내 고구마 괴근과 잎자루로부터 분리한 식이섬유의 총 폴리페놀, 플라보노이드의 양을 측정하고, 이들로 인한 항산화 효과와 HT-29 대장암 세포에서의 증식억제를 통한 항암 효과를 확인하였다. 고구마 잎자루와 괴근 식이섬유의 총 플라보노이드 함량은 각각 0.5 ± 0.001 mg naringin/g dry basis와 2.0 ± 0.008 mg naringin/g dry basis이었고, 총 폴리페놀 함량은 각각 2.8 ± 0.01 mg gallic acid/g dry basis와 6.3 ± 0.03 mg gallic acid/g dry basis이었다. DPPH 라디칼 소거능 측정에서 잎자루 식이섬유가 괴근 식이섬유에 비해 2.4배 높게 나타남을 확인할 수 있었다. 대장암 세포주의 세포사멸효과를 측정한 결과, 두 경우 모두 식이섬유 첨가량에 대해서 농도의존적 세포 증식 억제를 보여 주었다. 또한 잎자루와 괴근 식이섬유는 종양억제 p53 유전자 발현을 증가시키는 것으로 확인되었다. 이에 고구마 괴근과 잎자루로부터 분리한 식이섬유의 항산화 및 대장암에서의 항암 효과를 통해 암을 비롯한 다양한 질병의 예방에 있어 잠재적인 가치를 확인할 수 있었다.