Kim Min-Ji, Son Su-Young, Jeon Su-Gyeong, Kim Jeong-Gu, Lee Choong-Hwan
Department of Bioscience and Biotechnology, Konkuk University, Seoul 05029, Korea.
Insititute for Bioresources Research, Gyeongsangbuk-do Agricultural Research and Extension Services, Andong 36614, Korea.
Plants (Basel). 2021 Aug 23;10(8):1751. doi: 10.3390/plants10081751.
Yams ( spp.) are cultivated and consumed as edible tubers, while their leaves are discarded as waste or burned with negative environmental impact. Herein, the metabolites of two yam species (Danma, DAN; Dunggeunma, DUN), harvested in June, July, and August, were profiled using GC-TOF-MS and UHPLC-LTQ-Orbitrap-MS/MS and the antioxidant activity of the extracts was evaluated to stimulate the utilization of yam leaves as a by-product. We observed that the relative levels of amino acids, organic acids, sugars, and saponins decreased linearly with prolonged harvest time, while fatty acid, phenanthrene, and flavonoid levels gradually increased. Furthermore, the leaf extracts obtained in August exhibited the highest antioxidant activity. To determine the antioxidant-contributing metabolites, OPLS-DA was performed for the leaf metabolites of DAN and DUN leaves harvested in August. Hydroxytyrosol-glucoside, apigenin-rhamnoside, and rutin were more abundant in DUN, while luteolin, phenanthrene derivatives, epicatechin, and kaempferide were relatively higher in DAN and their respective metabolites were positively correlated with the antioxidant activity. Moreover, secondary metabolites were more abundant in the leaves than in the roots, and consequently, the antioxidant activity of the former was also higher. Overall, the potential value of yam leaves as a renewable source of bioactive compounds is proposed.
山药(薯蓣属)作为可食用块茎进行种植和食用,而其叶子则作为废弃物被丢弃或焚烧,对环境产生负面影响。在此,对6月、7月和8月收获的两种山药品种(丹麻,DAN;墩根麻,DUN)的代谢产物进行了气相色谱-飞行时间质谱(GC-TOF-MS)和超高效液相色谱-线性离子阱-轨道阱质谱/质谱(UHPLC-LTQ-Orbitrap-MS/MS)分析,并评估了提取物的抗氧化活性,以促进将山药叶作为副产品加以利用。我们观察到,随着收获时间延长,氨基酸、有机酸、糖类和皂苷的相对含量呈线性下降,而脂肪酸、菲和黄酮类化合物的含量则逐渐增加。此外,8月获得的叶提取物表现出最高的抗氧化活性。为了确定具有抗氧化作用的代谢产物,对8月收获的DAN和DUN叶的代谢产物进行了正交偏最小二乘法判别分析(OPLS-DA)。羟基酪醇葡萄糖苷、芹菜素鼠李糖苷和芦丁在DUN中含量更高,而木犀草素、菲衍生物、表儿茶素和山柰酚苷元在DAN中相对较高,它们各自的代谢产物与抗氧化活性呈正相关。此外,叶中的次生代谢产物比根中更丰富,因此,叶的抗氧化活性也更高。总体而言,提出了山药叶作为生物活性化合物可再生来源的潜在价值。