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Klika K.D.,German Cancer Research Center | Khallouki F.,Natural Substances Biochemistry Laboratory | Owen R.W.,German Cancer Research Center
Zeitschrift fur Naturforschung - Section C Journal of Biosciences | Year: 2014

A new phenolic-type compound containing a nitrogenous, heterocyclic-fused ring from the fruit of the argan tree, Argania spinosa (Skeels L.), is described. This and another already known compound also isolated in the course of the work belong to an obscure and rare class of natural products, the amino phenolics. © 2014 Verlag der Zeitschrift für Naturforschung, Tübingen. Source


Khallouki F.,German Cancer Research Center | Khallouki F.,Natural Substances Biochemistry Laboratory | Haubner R.,German Cancer Research Center | Ulrich C.M.,German Cancer Research Center | Owen R.W.,German Cancer Research Center
Journal of Medicinal Food | Year: 2011

The root bark of Annona cuneata Oliv. is traditionally used in the Democratic Republic of Congo to treat several debilitating conditions, such as hernia, female sterility, sexual asthenia, and parasitic infections. However, little is known about the composition of the secondary plant substances, which may contribute to these traditional medicinal effects. We conducted an ethnobotanical study and then evaluated the composition of the secondary plant substances in extracts of the root bark by using spectroscopic methods. After delipidation, the root bark was lixiviated in methanol, and components in the extract were studied by gas chromatography-mass spectometry, high-performance liquid chromatography (HPLC)-electrospray ionization-MS and nano-electrospray ionization-MS-MS. These methods identified 13 secondary plant substances (almost exclusively phenolic compounds): p-hydroxybenzaldehyde (I), vanillin (II), tyrosol (III), 3,4-dihydroxybenzaldehyde (IV), p-hydroxybenzoic acid (V), vanillyl alcohol (VI), syringaldehyde (VII), 4-hydroxy-3-methoxyphenylethanol (VIII), vanillic acid (IX), 3,4-dihydroxybenzoic acid (X), syringic acid (XI), and ferulic acid (XII), along with the phytosterol squalene (XIII). In the HPLC-based hypoxanthine/xanthine oxidase antioxidant assay system, the methanolic extract exhibited potent antioxidant capacity, with a 50% inhibitory concentration of 72μL, equivalent to 1.38mg/mL of raw extract. Thus, a methanol extract of A. cuneata Oliv. contained a range of polyphenolic compounds, which may be partly responsible for its known traditional medicinal effects. More detailed studies on the phytochemistry of this important plant species are therefore warranted. © Copyright 2011, Mary Ann Liebert, Inc. and Korean Society of Food Science and Nutrition 2011. Source


Khallouki F.,German Cancer Research Center | Khallouki F.,Natural Substances Biochemistry Laboratory | Haubner R.,German Cancer Research Center | Ricarte I.,German Cancer Research Center | And 4 more authors.
Food Chemistry | Year: 2015

High performance liquid chromatography coupled with negative electrospray ionization (HPLC-ESI) along with fragmentation patterns generated by nano-electrospray ionization (nano-ESI-MS-MS) and NMR techniques were utilized for the identification of phenolic compounds in Argan fruits. A total of 15.4 g/kg was determined represented by catechins (39%), flavonoids (28%), procyanidins (26%), free phenolic acids (6%) and phenolic acid glycosides (1%). Twenty-one phenolic compounds were identified for the first time in Argan fruits namely III. epicatechin-(4β → 8)-catechin dimer (procyanidin B1), IV. p-coumaric acid glycoside, VI. epicatechin-(4β → 8)-epicatechin dimer (procyanidin B2), VIII. caffeic acid glycoside, XIX. epicatechin-(4β → 8)-epicatechin-(4β → 8)-epicatechin trimer (procyanidin C1), X. p-hydroxybenzaldehyde XI. ferulic acid glycoside, XII. vanillic acid, XIII. sinapic acid glycoside, XVI. p-coumaric acid, XVII. ferulic acid, XVIII. sinapic acid, XIX. rutin pentoside, XX. quercetin glycopentoside, XXI. 4,4′-dihydroxy-3,3′-imino-di-benzoic acid, XXV. quercetin-3-O-rhamnogalactoside, XXVII. quercetin glycohydroxybenzoate, XXVIII. quercetin glycocaffeate, XXIX. quercetin glycosinapate, XXX. quercetin glycoferulate and XXXI. quercetin glycocoumarate. © 2015 Elsevier Ltd. All rights reserved. Source


Klika K.D.,German Cancer Research Center | Khallouki F.,Natural Substances Biochemistry Laboratory | Owen R.W.,German Cancer Research Center
Records of Natural Products | Year: 2015

Two new analogs, a carboxy methyl (Argaminolic B) and a carboxy derivative (Argaminolic C), of a recently reported amino phenolic, Argaminolic A, isolated from the fruit of the argan tree, Argania spinosa (Skeels L.), are described. Argaminolic B exhibits facile hydrolysis of its methyl ester to yield Argaminolic C, which then undergoes a remarkably facile decarboxylation to the previously described Argaminolic A. © 2015 ACG Publications. All rights reserved. Source


Khallouki F.,University Paul Sabatier | Khallouki F.,Institute Claudius Regaud | Khallouki F.,Natural Substances Biochemistry Laboratory | De Medina P.,University Paul Sabatier | And 9 more authors.
Frontiers in Oncology | Year: 2016

Tocols are vitamin E compounds that include tocopherols (TPs) and tocotrienols (TTs). These lipophilic compounds are phenolic antioxidants and are reportedly able to modulate estrogen receptor β (ERβ). We investigated the molecular determinants that control their estrogenicity and effects on the proliferation of breast cancer cells. Docking experiments highlighted the importance of the tocol phenolic groups for their interaction with the ERs. Binding experiments confirmed that they directly interact with both ERα and ERβ with their isoforms showing potencies in the following order: δ-tocols > γ-tocols > α-tocols. We also found that tocols activated the transcription of an estrogen-responsive reporter gene that had been stably transfected into cells expressing either ERα or ERβ. The role of the phenolic group in tocol-ER interaction was further established using δ-tocopherylquinone, the oxidized form of δ-TP, which had no ER affinity and did not induce ER-dependent transcriptional modulation. Tocol activity also required the AF1 transactivation domain of ER. We found that both δ-TP and δ-TT stimulated the expression of endogenous ER-dependent genes. However, whereas δ-TP induced the proliferation of ER-positive breast cancer cells but not ER-negative breast cancer cells, δ-TT inhibited the proliferation of both ER-positive and ER-negative breast cancer cells. These effects of δ-TT were found to act through the down regulation of HMG-CoA reductase (HMGR) activity, establishing that ERs are not involved in this effect. Altogether, these data show that the reduced form of δ-TP has estrogenic properties which are lost when it is oxidized, highlighting the importance of the redox status in its estrogenicity. Moreover, we have shown that δ-TT has antiproliferative effects on breast cancer cells independently of their ER status through the inhibition of HMGR. These data clearly show that TPs can be discriminated from TTs according to their structure. © 2016 Khallouki, de Medina, Caze-Subra, Bystricky, Balaguer, Poirot and Silvente-Poirot. Source

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