Plant Anatomy Laboratory, Botanical Department, Biology Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
Federal Institute of Education, Science and Technology, Campos dos Goytacazes, Brazil.
J Photochem Photobiol B. 2015 Jul;148:73-81. doi: 10.1016/j.jphotobiol.2015.03.011. Epub 2015 Apr 4.
Ultraviolet-B radiation is an important abiotic factor that can stimulate the production of secondary metabolites, including polyphenolic compounds. Kalanchoe pinnata (Crassulaceae) is a medicinal plant popularly used in Brazil for treating wounds and inflammation. This species is rich in phenolic compounds, which could account for some of its biological activities, including antileishmanial, antihypertensive and antibacterial properties. We investigated the effects of supplemental UV-B radiation on the phenolic profile, antioxidant activity and total flavonoid content of leaves of K. pinnata. Plants were grown under white light (W - control) and supplemental UV-B radiation (W+UVB). Supplemental UV-B radiation enhanced the total flavonoid content of the leaf extracts, without affecting the antioxidant activity or yield of extracts. Analysis by TLC and HPLC of W and W+UVB leaf extracts revealed quantitative and qualitative differences in their phenolic profiles. W+UVB extracts contained a higher diversity of phenolic compounds and a larger amount of quercitrin, an important bioactive flavonoid of this species. This is the first report of the use of ImageJ® program to analyze a TLC visualized by spraying with NP-PEG reagent. UV-B radiation is proposed as a supplemental light source in K. pinnata cultivation in order to improve its flavonoid composition.
紫外-B 辐射是一种重要的非生物因素，能刺激次生代谢产物的产生，包括多酚类化合物。长寿花（景天科）是一种药用植物，在巴西被广泛用于治疗伤口和炎症。该物种富含酚类化合物，这可能是其部分生物活性的原因，包括抗利什曼原虫、抗高血压和抗菌特性。我们研究了补充紫外-B 辐射对长寿花叶片中酚类物质组成、抗氧化活性和总黄酮含量的影响。植物在白光（W-对照）和补充紫外-B 辐射（W+UVB）下生长。补充紫外-B 辐射增强了叶片提取物的总黄酮含量，而不影响提取物的抗氧化活性或产率。通过 TLC 和 HPLC 对 W 和 W+UVB 叶片提取物的分析显示，它们的酚类物质组成存在定量和定性的差异。W+UVB 提取物含有更多种类的酚类化合物和更多的槲皮素，槲皮素是该物种的一种重要生物活性类黄酮。这是首次使用 ImageJ®程序分析用 NP-PEG 试剂喷雾可视化的 TLC。紫外-B 辐射被提议作为长寿花培养的补充光源，以改善其类黄酮组成。
