Graduate school for International Development and Cooperation, Hiroshima University, Hiroshima 739-8529, Japan.
Agricultural Genetics Institute, Hanoi City 123000, Vietnam.
Molecules. 2019 Feb 2;24(3):546. doi: 10.3390/molecules24030546.
Although many investigations on phytochemicals in rice plant parts and root exudates have been conducted, information on the chemical profile of essential oil (EO) and potent biological activities has been limited. In this study, chemical compositions of rice leaf EO and in vitro biological activities were investigated. From 1.5 kg of fresh rice leaves, an amount of 20 mg EO was obtained by distillation and analyzed by gas chromatography-mass spectrometry (GC-MS), electrospray ionization (ESI), and atmospheric pressure chemical ionization (APCI) to reveal the presence of twelve volatile constituents, of which methyl ricinoleate (27.86%) was the principal compound, followed by palmitic acid (17.34%), and linolenic acid (11.16%), while 2-pentadecanone was the least (2.13%). Two phytoalexin momilactones A and B were first time identified in EO using ultra-performance liquid chromatography coupled with electrospray mass spectrometry (UPLC/ESI-MS) (9.80 and 4.93 ng/g fresh weight, respectively), which accounted for 7.35% and 3.70% of the EO, respectively. The assays of DPPH (IC = 73.1 µg/mL), ABTS (IC = 198.3 µg/mL), FRAP (IC = 700.8 µg/mL) and β-carotene oxidation (LPI = 79%) revealed that EO possessed an excellent antioxidant activity. The xanthine oxidase assay indicated that the anti-hyperuricemia potential was in a moderate level (IC = 526 µg/mL) as compared with the standard allopurinol. The EO exerted potent inhibition on growth of , and two noxious weeds , and , but in contrast, the growth of rice seedlings was promoted. Among the examined plants, the growth of the root was the most inhibited, proposing that constituents found in EO may have potential for the control of the problematic paddy weed . It was found that the EO of rice leaves contained rich phytochemicals, which were potent in antioxidants and gout treatment, as well as weed management. Findings of this study highlighted the potential value of rice leaves, which may provide extra benefits for rice farmers.
尽管已经对水稻植物部分和根分泌物中的植物化学物质进行了许多研究，但有关精油（EO）的化学组成和潜在生物活性的信息却很有限。在这项研究中，我们研究了水稻叶精油的化学成分和体外生物活性。从 1.5 公斤新鲜的水稻叶片中，通过蒸馏获得了 20 毫克的精油，并通过气相色谱-质谱联用（GC-MS）、电喷雾电离（ESI）和大气压化学电离（APCI）进行了分析，以揭示存在 12 种挥发性成分，其中，甲基蓖麻酸（27.86％）是主要化合物，其次是棕榈酸（17.34％）和亚油酸（11.16％），而 2-十五烷酮则最少（2.13％）。使用超高效液相色谱-电喷雾质谱联用（UPLC/ESI-MS）首次在精油中鉴定出两种植物抗毒素 momilactones A 和 B（分别为 9.80 和 4.93 ng/g 鲜重），分别占精油的 7.35％和 3.70％。DPPH（IC = 73.1 µg/mL）、ABTS（IC = 198.3 µg/mL）、FRAP（IC = 700.8 µg/mL）和β-胡萝卜素氧化（LPI = 79％）的测定表明，精油具有出色的抗氧化活性。黄嘌呤氧化酶测定表明，与标准药物别嘌呤醇相比，其抗高尿酸血症的潜力处于中等水平（IC = 526 µg/mL）。精油对两种有害杂草 和 的生长具有很强的抑制作用，而对水稻幼苗的生长则有促进作用。在所检查的植物中， 的根生长受抑制最为明显，这表明精油中的成分可能具有控制稻田杂草的潜力。研究发现，水稻叶片中的精油含有丰富的植物化学物质，具有抗氧化和治疗痛风以及杂草管理的潜力。本研究的结果强调了水稻叶片的潜在价值，这可能为水稻种植者带来额外的好处。
