URSOLIC ACID AND CIS-TILIROSIDE PRODUCED BY Merremia tomentosa AFFECT OVIPOSITION OF Leucoptera coffeella ON COFFEE PLANTS

Abstract

publicado na web em 18/01/2018To contribute to the development of new products to control the coffee leaf miner (Leucoptera coffeella), which is a major pest for coffee plants, this work aimed to select plant species able to produce substances active against this insect and to identify the active substances in the selected plant and their protein targets in the insect. Among the extracts of nineteen plant species, only that from leaves of Merremia tomentosa (Choisy) Hall. f. (Convolvulaceae) reduced the oviposition of L. coffeella on leaves of coffee plants. This extract was submitted to successive fractionation steps to achieve the isolation and identification of two active substances, ursolic acid (UA) and cis-tiliroside (CT). An in silico study showed that UA inhibits glycogen phosphorylases (GP) by binding to their allosteric site, while CT probably inhibits xanthine dehydrogenases (XT). As both GP and XT appear to be essential enzymes for insects, these results suggest that, during evolution, L. coffeella learned to identify plants producing inhibitors of these enzymes to avoid oviposition on such plants. Thus, both UA and CT have potential to be used as lead compounds in the development of new products for the control of the coffee leaf miner.

Research Progression of the Genus Merremia: A Comprehensive Review on the Nutritional Value, Ethnomedicinal Uses, Phytochemistry, Pharmacology, and Toxicity

“…Using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and reverse phase-high performance liquid chromatography (RP-HPLC), Angappan et al [79] identified chlorogenic acid (41) in the aqueous leaf extract of M. emarginata, which was attributed to the diuretic activity of the extract. In another study, Santos et al [80] isolated ursolic acid (59) and cis-tiliroside (2) from M. tomentosa leaf extract, and these compounds were thought to be responsible for the insecticidal activity of the extract. The medicinal characteristic of the species of Merremia and other medicinal plants depends on the structure, quantity, and quality of the phytochemical constituents.…”

“…A study was carried out by Santos et al [80] on the control of coffee plants pest, Leucoptera coffeella, by oviposition reduction using methanol leaf extracts of 19 plants, including M. tomentosa (8.9 mg mL −1 ). The authors also assessed the effect of three isolated compounds (cis-tiliroside (2), trans-tiliroside, and ursolic acid ( 59)) from M. tomentosa leaves; Tween 80 and chlorpyrifos served as negative and positive controls.…”

Ursolic and Oleanolic Acids: Plant Metabolites with Neuromodulatory Potential

“…OA co-occurs with UA in numerous plant species, including many food, aromatic and medicinal plants [10,17,18,25,26] and UA is usually more abundant than OA (Table 1). Both triterpenoids are often found in the epicuticular waxes and they perform important functions, namely, prevent water loss, serve as a first defence barrier against pathogens and protect from herbivores [26][27][28]. For instance, OA is present as almost pure crystals on the surface of olive leaves and forms a physical barrier against fungal infection [29].…”