Smaili Amal, Mazoir Noureddine, Rifai Lalla Aicha, Koussa Tayeb, Makroum Kacem, Kabil El Mostafa, Benharref Ahmed, Faize Mohamed
Laboratory of Plant Biotechnology and Ecosystem Valorisation, Faculty of Sciences, University Chouaib Doukkali, El Jadida, Morocco.
Department of Chemistry, Faculty of Sciences El Jadida, Chouaib Doukkali University, P.O. Box 20, 24000 El Jadida, Morocco; Laboratory of Biomolecular Chemistry, Natural Substances and Reactivity, URAC 16, Faculty of Sciences Semlalia, Cadi Ayyad University, P.O. Box 2390, Marrakech, Morocco.
Phytochemistry. 2017 Mar;135:169-180. doi: 10.1016/j.phytochem.2016.12.017. Epub 2016 Dec 24.
Oxidation of α-euphorbol and 31-norlanostenol, two triterpenic compounds isolated from the latex of Euphorbia resinifera and Euphorbia officinarum respectively, yielded four products named 3β-tosyloxy-4α,14α-dimethyl-5α-cholesta-7,9-diene; 4α,14α-dimethyl-5α-cholesta-7,9-dien-3β-ol; 24-methylen-elemo-lanosta-8,24-dien-3-one and elemo-lanost-8-en-3,11,24-trione. They were evaluated for protection of tomato plants against Verticillium dahliae in a greenhouse. The four semisynthesized products were phytotoxic at higher concentrations as they completely inhibited tomato germination at 100 and 500 μg/ml. However at lower concentrations (10 and 50 μg/ml) germination and root length were not affected. Disease resistance against Verticillium wilt was assessed in tomato plants derived from seeds that germinated in the presence of 10 and 50 μg/ml of the four products. All of them were able to reduce significantly disease severity, with 10 μg/ml being more effective than 50 μg/ml. Reduction of leaf alteration index and of stunting index ranged from 52 to 68% and from 43 to 67%, respectively, while vessel discoloration was reduced by at least 95%. The compounds were also able to elicit HO accumulation before and after fungal inoculation and to significantly enhance peroxidase and polyphenol oxidase activities. These results suggest that the hemisynthetized triterpenes can be used as elicitors of disease resistance.
分别从树脂大戟和药用大戟的乳胶中分离得到的两种三萜类化合物α-大戟醇和31-降羊毛甾烯醇，经氧化后得到四种产物，分别命名为3β-对甲苯磺酰氧基-4α,14α-二甲基-5α-胆甾-7,9-二烯；4α,14α-二甲基-5α-胆甾-7,9-二烯-3β-醇；24-亚甲基-榄香-羊毛甾-8,24-二烯-3-酮和榄香-羊毛甾-8-烯-3,11,24-三酮。在温室中对它们保护番茄植株免受大丽轮枝菌侵害的能力进行了评估。这四种半合成产物在较高浓度时具有植物毒性，因为它们在100和500μg/ml时能完全抑制番茄种子萌发。然而，在较低浓度（10和50μg/ml）下，种子萌发和根长不受影响。对在10和50μg/ml这四种产物存在下萌发的种子所培育出的番茄植株进行了抗黄萎病能力评估。所有这些产物都能显著降低病害严重程度，10μg/ml比50μg/ml更有效。叶片病变指数和矮化指数的降低幅度分别为52%至68%和43%至67%，而维管束变色至少降低了95%。这些化合物还能够在真菌接种前后引发H₂O₂积累，并显著提高过氧化物酶和多酚氧化酶的活性。这些结果表明，半合成三萜类化合物可作为抗病诱导剂。
