Antognoni Fabiana, Zheng Suiping, Pagnucco Cristina, Baraldi Rita, Poli Ferruccio, Biondi Stefania
Department of Biology, University of Bologna, Bologna, Italy.
Fitoterapia. 2007 Jul;78(5):345-52. doi: 10.1016/j.fitote.2007.02.001. Epub 2007 Apr 11.
Callus cultures from several species of Passiflora were initiated in vitro, and their capacity to produce four glycosyl flavonoids (orientin, isoorientin, vitexin, isovitexin) was analysed. The aim of the present work was to examine the possible role of UV-B irradiation and elicitation with methyl jasmonate (MJ) on the production of these compounds in callus cultures. All the species tested (P. incarnata, P. quadrangularis, P. edulis) formed friable callus from leaf explants after 4 weeks on medium supplemented with kinetin and 2,4-dichlorophenoxyacetic acid. Among them, P. quadrangularis turned out to have a faster growth rate and a more friable texture, and was therefore chosen for experiments with elicitors. In callus cultures only small amounts of isoorientin were found, while the concentration of the other flavonoids was below the detection limit. UV-B irradiation of calluses was able to increase the production of all four glycosyl flavonoids. After a 7-day exposure of cultures to UV-B light, the production of isoorientin reached concentrations similar to those found in fresh leaves from glasshouse-grown plants. Elicitation with methyl jasmonate also enhanced orientin, vitexin and isovitexin concentrations, even though the stimulation was about 6-fold weaker for orientin and vitexin and about 40-fold for isovitexin, than that exerted by UV-B treatment. Callus cultures treated with the UV-B dose which most enhanced flavonoid production showed a higher antioxidant activity compared to untreated calluses, with an increase ranging from 28% to 76%. Results show that the secondary metabolite biosynthetic capacity of Passiflora tissue cultures can be enhanced by appropriate forms of elicitation.
启动了几种西番莲属植物的愈伤组织培养，并分析了它们产生四种糖基黄酮（荭草苷、异荭草苷、牡荆素、异牡荆素）的能力。本研究的目的是研究紫外线B（UV-B）照射和茉莉酸甲酯（MJ）诱导对愈伤组织培养中这些化合物产生的可能作用。在添加了激动素和2,4-二氯苯氧乙酸的培养基上培养4周后，所有测试物种（ incarnata西番莲、P. quadrangularis西番莲、P. edulis西番莲）的叶片外植体均形成了易碎的愈伤组织。其中，P. quadrangularis西番莲的生长速度更快，质地更易碎，因此被选用于诱导剂实验。在愈伤组织培养物中，仅发现少量异荭草苷，而其他黄酮类化合物的浓度低于检测限。对愈伤组织进行UV-B照射能够增加所有四种糖基黄酮的产量。在将培养物暴露于UV-B光7天后，异荭草苷的产量达到了与温室种植植物新鲜叶片中相似的浓度。用茉莉酸甲酯诱导也提高了荭草苷、牡荆素和异牡荆素的浓度，尽管与UV-B处理相比，对荭草苷和牡荆素的刺激作用弱约6倍，对异牡荆素的刺激作用弱约40倍。与未处理的愈伤组织相比，用最能提高黄酮类化合物产量的UV-B剂量处理的愈伤组织培养物表现出更高的抗氧化活性，增幅在28%至76%之间。结果表明，通过适当的诱导形式可以提高西番莲组织培养物中次生代谢物的生物合成能力。
