Terpenoids as Models for New Agrochemicals

Elakovich, Stella D.

doi:10.1021/bk-1988-0380.ch016

Cited by 26 publications

(18 citation statements)

References 19 publications

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“…Calcd. for C 22 H 30 O 5 : C, 70.56; H, 8.07; Found: C, 70.90; H, 8.01; IR n max /cm -1 3490, 3475, 2975, 2925, 2855, 1730, 1500, 1460, 1430, 1365, 1300, 1155, 1020, 715; 1 H NMR d 7.26 (d,3 J = 2.0 Hz, 1H, H-16), 6.18 (d, 3 J = 2.0 Hz, 1H, H-15), 4.15-4.30 (m, 2H, CH 2 -1'), 3.90 (dd, 3 J = 10.3 and 1.1 Hz, 1H, H-7), 3.59 (ddd, 3 J = 8.9, 2.9 and 1.7 Hz, 1H, H-14), 2.75 (ddd, 2 J = 16.3 Hz, 3 J = 5.8 and 1.7 Hz, 1H, H-11b), 2.50 (ddd, 2 J = 16.3 Hz, 3 J = 11.2 and 2.9 Hz, 1H, H-11a), 2.42 (ddd, 3 J = 12.2, 10.3 and 8.9 Hz, 1H, H-8), 2.17 (s, 1H, H-5), 1.96 (ddd, 3 J = 12.2, 11.2 and 5.8 Hz, 1H, H-9), 1.80 (dtd, 2 J = 13.2 Hz, 3 J = 3.2 Hz, 4 J = 0.9 Hz, 1H, H-1b), 1,64 (qt, 2 J = 13.2 Hz, 3 J = 13.2 and 3.2 Hz, 1H, H-2a), 1.55 (dqui, 2 J = 13.2 Hz, 3 J = 3.2 Hz, 1H, H-2b), 1.40 (dtd, 2 J = 13.2 Hz, 2 J = 3.2 Hz, 4 J = 0.9 Hz, 1H, H-3b), 1.32 (s, 3H, CH 3 -19), 1.29 (t, 3 J = 7.2 Hz, 3H, CH 3 -2'), 1.22 (td, 2 J = 13.2 Hz, 3 J = 13.2 and 3.2 Hz, 1H, H-1a), 1.10 (td, 1H, 2 J = 13.2 Hz, 3 J = 13.2 and 3.2 Hz, H-3a), 0.97 (s, 3H, CH 3 -18), 0.91 (s, 3H, CH 3 -20); 13 C NMR d 209.Propyl 7b-hydroxy-6-oxovouacapan-17b-oate (6): (171 mg, 88 %); white solid; m.p. 84.6-86.2 °C; Anal.…”

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Synthesis and phytotoxicity evaluation of novel 6α,7β-dihydroxyvouacapan-17β-oic acid derivatives

Castelo-Branco

Rubinger

Resende

et al. 2006

Journal of Chemical Research

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The 6a,7b-dihydroxyvouacapan-17b-oic acid (1) isolated from Pterodon polygalaeflorus Benth has shown allelopathic and plant growth regulatory properties. Six novel esters of (1) were prepared and their effects on the radical growth of Sorghum bicolor L. and Cucumis sativus L. were evaluated.The natural product 6a,7b-dihydroxyvouacapan-17b-oic acid (1) and the lactone 2 (Scheme 1), exhibit anti-inflammatory, analgesic activities, 1 and allelopathic activity. 2 Several terpenoids are involved in plant allelopathic interactions but little is known about the effects of diterpenes on plant growth regulation. 3,4 Some derivatives of 1 have been prepared for biological evaluation. 2,5,6 Here we report the preparation of the esters 4-9 (Scheme 1), and an evaluation of their phytotoxic properties.The acid (1) was isolated from the P. polygalaeflorus Benth fruits. 7 The d-hydroxy-lactone 2 5 and d-keto-lactone 3 8 were prepared as shown in Scheme 1. The novel compounds 4-9 were prepared in good yields (77-89 %) using catalytic amounts of NaOH. The lactone 3 is not very soluble in the alcohols. Thence the end of the reaction could be observed by TLC and by the total disappearance of the solid phase.The esters 4-9 were characterised by elemental analysis, IR and NMR spectroscopy. The IR spectra of all the esters 4-9 showed a hydroxyl absorption between 3495 and 3465 cm -1 and strong C=O stretching bands in the 1735-1709 cm -1 range due to the ester and ketone groups. In the 13 C NMR spectra, the carbonyl signals were observed around d C 174 (ester) and d C 209 (ketone). The 1 H NMR signals due to the furanditerpene backbone hydrogens of the esters 4-9 are very similar to those observed in the spectrum of the parent lactone 3. 8 It is interesting to note the multiplicity of the signal at d H 1.70 in the 1 H NMR spectrum of 6 which is a sextet assigned to H-2', indicating non-resolvable coupling constants (J 7.3 Hz)with the theoretically non-equivalent hydrogens H-1' and H-3'. Other features worth mentioning are the nonequivalence of the H-1' methylenic hydrogens revealed by the double doublets observed in the 1 H NMR spectrum of compound 9 at d H 4.61 and 4.71 with Jgem 12.2 Hz and Jvic 7.2 Hz with H-2'. The remaining signals were in accordance with the proposed structures.It was previously reported that 1 at 100 ppm inhibited the root growth of Sorghum bicolor L. (30-40 %) and stimulated Cucumis sativus L. (5-10 %). 2 Recently it was shown that lactones 2 and 3 inhibited the uncoupled noncyclic electron transport and ATP synthesis, behaving as Hill reaction inhibitors, and the carbonyl at C-6 of 3 affected the photophosphorylation. 2,8 Compounds 1-9 were evaluated in vitro against S. bicolor and C. sativus using a different methodology. 9 As the compounds were not soluble in the usual formulations, 9 an aqueous solution of a triblock copolymer and DMSO was used instead. Table 1 shows the radical lengths. Under these conditions, the novel compounds and the parent lactones did not significantly affect the growth of S. bicolor.

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confidence: 99%

Synthesis and phytotoxicity evaluation of novel 6α,7β-dihydroxyvouacapan-17β-oic acid derivatives

Castelo-Branco

Rubinger

Resende

et al. 2006

Journal of Chemical Research

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“…Coumarins are known to inhibit photosynthetic phosphorylation, glycolysis and oxidative phosphorylation. A study showed that coumarins caused significant reduction of growth of some herbs including velvetleaf, pigweed and prosomillet and of another weed Amaranthus retroflexus . Inhibition of growth of some weeds including pigweed, coffeweed and barnyard grass was also induced by saponins in another sudy .…”

Section: Resultsmentioning

confidence: 99%

Aqueous extract from leaves of Ludwigia hyssopifolia (G. Don) Exell as potential bioherbicide

et al. 2019

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BACKGROUND: Ludwigia hyssopifolia (G. Don) Exell, one of the problem weeds in some rice-producing countries, was studied to determine its allelopathic potential based on the effects of aqueous extracts of its tissues (leaves, roots and stem) on seedling growth of selected weeds and rice. The major phenolic compound of its leaves was also isolated and characterized. RESULTS: L. hyssopifolia aqueous leaf extract showed significant inhibition of shoot growth and biomass accumulation of weeds (Amaranthus spinosus L., Dactyloctenium aegyptium L., Cyperus iria L.) while maintaining less adverse effects on rice (crop) compared to other aqueous extracts of roots and stem. Phytochemical screening showed that phenols, tannins, flavonoids, terpenoids, saponins and coumarins are found in its leaf aqueous extract. The Folin-Ciocalteu method revealed that its leaves contain 26.66 ± 0.30 mg GAE g −1 leaf. The extract was then acid-hydrolyzed to liberate the phenolics (25 mg phenolics g −1 leaf). The major compound was isolated via preparative thin-layer chromatography using formic acid-ethyl acetate-n-hexane (0.05:4:6) solvent system. It had maximum UV absorption at 272 nm while its Fourier transform infrared spectrum revealed phenol, carboxylic acid and ether functionalities. This also had similar chromatographic mobility when run together with syringic acid in two-dimensional paper chromatography and thin-layer chromatography. CONCLUSIONS: L. hyssopifolia has potential allelopathic activity and its leaf aqueous extract showed the highest phytotoxic activity (P ≤ 0.05) indicating its potential as a bioherbicide. The most probable identity of the major phenolic compound is syringic acid.

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“…A wide range of secondary metabolites produced by plants, such as essential oils are endowed with antimicrobial, allelopathic, antioxidant and bioregulatory molecules (French, 1985;Elakovich, 1988). Many of the essential oils and their constituents are commonly used as culinary herbs and spices (Isman, 2000).…”

Section: Discussionmentioning

confidence: 99%

Evaluation of plant oils for suppression of crown rot disease and improvement of shelf life of banana (Musa spp. AAA subgroup, cv. Robusta)

Ganesan¹,

Thangavelu²,

Rani³

2010

Int J of Food Sci Tech

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Fourteen plant oils were evaluated to control the crown rot disease caused by Lasiodiplodia theobromae and Colletotrichum musae. Five of these, viz. Ocimum sanctum, Cymbopogan citratus, C. martinii, C. nardus and Pelargonium graveolens oils completely arrested the mycelial growth of both test pathogens at their lowest concentration compared to other oils. Besides, these plant oils have also inhibited the activity of cellulolytic and pectinolytic enzymes produced by these pathogens effectively under in vitro condition. The treatment of banana fruit var. Robusta (Cavendish-AAA) with oils of O. sanctum, C. citratus, C. nardus and C. martinii not only reduced the crown rot severity significantly, but also increased the shelf life of banana fruits. However, under low-temperature storage (14°C) condition, O. sanctum oil increased the shelf life of banana fruits up to 48 days without affecting their organoleptic properties. Hence, O. sanctum oil could be used as an alternative to chemical fungicides for the management of crown rot disease.

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Terpenoids as Models for New Agrochemicals

Cited by 26 publications

References 19 publications

Synthesis and phytotoxicity evaluation of novel 6α,7β-dihydroxyvouacapan-17β-oic acid derivatives

Synthesis and phytotoxicity evaluation of novel 6α,7β-dihydroxyvouacapan-17β-oic acid derivatives

Aqueous extract from leaves of Ludwigia hyssopifolia (G. Don) Exell as potential bioherbicide

Evaluation of plant oils for suppression of crown rot disease and improvement of shelf life of banana (Musa spp. AAA subgroup, cv. Robusta)

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