Prenylated Flavanones from <i>Monotes engleri</i>: On‐line Structure Elucidation by LC/UV/NMR

Garo, Eliane; Wolfender, Jean‐Luc; Hostettmann, Kurt; Hiller, Wolf; Antus, Sándor; Mavi, S.

doi:10.1002/hlca.19980810325

Cited by 48 publications

(41 citation statements)

References 10 publications

(8 reference statements)

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“…The 1 H NMR (Table I) (Table I) and 13 C NMR data (Table II) quiritigenin and so compound 1 had the same configuration as liquiritigenin previously published in the literature (8). Flavanones with a 2S configuration and having a C-2 equatorial aryl group are known to be laevorotatory (9). The C-2 aryl substituent was in the equatorial orientation, as evident from the large J 2,3ax (13.0 Hz).…”

Section: Chemistrysupporting

confidence: 61%

The isolation of bioactive flavonoids from Jacaranda obtusifolia H. B. K. ssp. rhombifolia (G. F. W. Meijer) Gentry

Khamsan¹,

Liawruangrath²,

Teerawutkulrag³

et al. 2012

Acta Pharmaceutica

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Jacaranda is one of the genera of Bignoniaceae endemic to South America and is now widely distributed in the tropical and subtropical areas of the world. Some species are used in traditional medicine in various countries for the treatment of wounds, rheumatism, colds and skin diseases (1). More recently, a review of the ethnobotanical and pharmacological uses of Jacaranda species has pointed out its interesting phytochemical constituents and biological activities such as anti-dyspeptic, cytotoxic, anti-malarial and lipooxygenase inhibitory activity as well as antimicrobial activities (2). Jacaranda obtu-

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Section: Chemistrysupporting

confidence: 61%

The isolation of bioactive flavonoids from Jacaranda obtusifolia H. B. K. ssp. rhombifolia (G. F. W. Meijer) Gentry

Khamsan¹,

Liawruangrath²,

Teerawutkulrag³

et al. 2012

Acta Pharmaceutica

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“…In complement to LC/MS/MS other hyphenated techniques such as LC/UV-DAD, with post-column addition of UV shift reagents, [16] or LC/NMR have proven to be very valuable for the screening of these constituents [17,18].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Q-TOF-MS/MS and multiple stage IT-MSⁿ for the dereplication of flavonoids and related compounds in crude plant extracts

Wolfender¹,

Waridel²,

Ndjoko³

et al. 2000

Analusis

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“…5) Selinone (1c) (naringenin prenylated at C-4′) was first isolated by Seshadri and Sood from Selinum vaginatum CLARKE, an endemic high-altitude Indian medicinal plant of the Umbelliferae family, locally known as "Bhootkeshi." 6) Later, it was also isolated from Monotes engleri, 7) a plant of the Dipterocarpaceae family in Zimbabwe, and showed antifungal activity against Candida albicans (Chart 1).…”

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confidence: 99%

Simple Synthesis of Sakuranetin and Selinone <i>via</i> a Common Intermediate, Utilizing Complementary Regioselectivity in the Deacetylation of Naringenin Triacetate

et al. 2016

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Sakuranetin and selinone were successfully synthesized utilizing the regioselective deacetylation of naringenin triacetate. Deacetylation of the latter at C-7 with imidazole in 1,4-dioxane at 40°C furnished the corresponding diacetate in 80% yield. Methylation of the obtained free hydroxy group and subsequent removal of the remaining two acetyl groups gave sakuranetin, which was previously isolated as a phytoalexin against rice blast disease fungus, Pyricularia oryzae, in 71% overall yield. The same intermediate, naringenin triacetate, was subjected to transesterification with 2-propanol in tetrahydrofuran, catalyzed by Candida antarctica lipase B. A contrasting regioselective preference for C-4′ deacetylation was observed, giving an isomeric diacetate in 82% yield. Prenylation of the free hydroxy group under Mitsunobu conditions and subsequent deprotection furnished selinone, which was previously isolated from Monotes engleri and exhibits antifungal activity against Candida albicans, in 55% overall yield. Key words flavanone; regioselective deprotection; lipase-catalyzed transesterificationPartially alkylated forms of flavanones are widespread in plants. Among them, sakuranetin (1b) (naringenin (1a) methylated at C-7) was first isolated from cherry tree bark as a sakuranin aglycone by Asahina in 1908, 1) and its antifungal activity was reported later.2) Recently, its additional antimutagenic 3) and antiinflammatory activities 4) were also demonstrated. Agricultural biology and chemistry constitute other fields for the application of 1b. Kodama et al. isolated 1b from UV-irradiated rice leaves as a phytoalexin against the pathogenic fungus Pyricularia oryzae, which causes rice blast disease, and also detected 1b in rice leaves infected with P. oryzae. 5)Selinone (1c) (naringenin prenylated at C-4′) was first isolated by Seshadri and Sood from Selinum vaginatum CLARKE, an endemic high-altitude Indian medicinal plant of the Umbelliferae family, locally known as "Bhootkeshi." 6)Later, it was also isolated from Monotes engleri, 7) a plant of the Dipterocarpaceae family in Zimbabwe, and showed antifungal activity against Candida albicans (Chart 1).Sakuranetin (1b) has previously been synthesized by methylation of naringenin (1a), as shown in Chart 2. The formation of 1b in 87% yield by methylation of 1a with dimethyl sulfate in acetone was reported.8) The formation of the regioisomeric monoether 1d under the above condition was also reported. 9)These results suggest that sakuranetin (1b) was isolated from a mixture of mono-and dimethylated products by silica gel column chromatography. Furthermore, it was shown that methylation of 1a by treatment with 1.5 eq of methyl iodide in N, N-dimethylformamide (DMF) led to the formation of not only 1b (76%) but also dimethyl ether 1e (3%).10) To selectively methylate the C-7 hydroxy group, which is the most acidic of the three, 1a was treated with diazomethane solution in diethyl ether under almost neutral conditions, to give 1b in 75% yield after silica gel column chromatog...

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Prenylated Flavanones from Monotes engleri: On‐line Structure Elucidation by LC/UV/NMR

Abstract: The CH,CI, extract of Monores engleri GILG. (Dipterocarpaceae) showed antifungal activity against the yeast Cundidu u1bicun.s in our bioautographic TLC assays. After a first fractionation of the crude extract, the bioactivity was located in one of the fractions.

Cited by 48 publications

References 10 publications

The isolation of bioactive flavonoids from Jacaranda obtusifolia H. B. K. ssp. rhombifolia (G. F. W. Meijer) Gentry

The isolation of bioactive flavonoids from Jacaranda obtusifolia H. B. K. ssp. rhombifolia (G. F. W. Meijer) Gentry

Evaluation of Q-TOF-MS/MS and multiple stage IT-MSⁿ for the dereplication of flavonoids and related compounds in crude plant extracts

Simple Synthesis of Sakuranetin and Selinone <i>via</i> a Common Intermediate, Utilizing Complementary Regioselectivity in the Deacetylation of Naringenin Triacetate

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Prenylated Flavanones from Monotes engleri: On‐line Structure Elucidation by LC/UV/NMR

Abstract: The CH,CI, extract of Monores engleri GILG. (Dipterocarpaceae) showed antifungal activity against the yeast Cundidu u1bicun.s in our bioautographic TLC assays. After a first fractionation of the crude extract, the bioactivity was located in one of the fractions.

Cited by 48 publications

References 10 publications

The isolation of bioactive flavonoids from Jacaranda obtusifolia H. B. K. ssp. rhombifolia (G. F. W. Meijer) Gentry

The isolation of bioactive flavonoids from Jacaranda obtusifolia H. B. K. ssp. rhombifolia (G. F. W. Meijer) Gentry

Evaluation of Q-TOF-MS/MS and multiple stage IT-MSn for the dereplication of flavonoids and related compounds in crude plant extracts

Simple Synthesis of Sakuranetin and Selinone <i>via</i> a Common Intermediate, Utilizing Complementary Regioselectivity in the Deacetylation of Naringenin Triacetate

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Resources

About

Evaluation of Q-TOF-MS/MS and multiple stage IT-MSⁿ for the dereplication of flavonoids and related compounds in crude plant extracts