Arafa Hamed

Arafa Hamed


Research Focus & Metrics

Academic Career Length

15Years (2012-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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Verified
Journal Article
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RSRidha Ben SAID
Ridha Ben SAID
AHArafa Hamed
Arafa Hamed
UMUsama Mahalel
Usama Mahalel
AAAbdullah Sulaiman Al-Ayed
Abdullah Sulaiman Al-Ayed
MKMariusz Kowalczyk
Mariusz Kowalczyk
Anna StochmalAnna Stochmal
Anna Stochmal
Phoenix dacylifera is an ancient palm species rich in (poly)phenols. These phenolic compounds were tentatively identified by using liquid chromatography coupled with ion spray mass spectrometry in tandem mode (LC/MS/MS) with negative ion detection. Negative identification of the compounds was based on their retention times and mass spectra in full scan mode (MS), and in different MS/MS modes. For the first time, complete hypothesis, and routs for both p-coumaroylshikimic acids (CoSA) and caffeoylshikimic acids (CSA) were suggested and confirmed by Density Fonctional Theory (DFT) study. Notably, of the 53 compounds characterized, 19 hydroxycinnamates derivatives were tentativelycharacterized in male flowers of date palm and 15 of them were recorded for the first time. In addition, five organic acids, six B-type proanthocyanidins, two anthocyanidin and 21 flavonoid derivatives have been tentatively characterized. Identification of B-type proanthocyanidins were based on the diagnostic ions resulting from heterocyclic ring fission (HRF) and retro-Diels-Alder (RDA) reaction of flavan-3-ol provided information on the hydroxylation pattern and the type of inter-flavan bond proanthocyanidins. The sequence of proanthocyanidins was detected through ions extracted from quinone methide (QM) cleavage of the inter-flavan bond.

20 March 2014 in Journal of Mass Spectrometry
Verified
Journal Article
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AHArafa Hamed
Arafa Hamed
AAAbdulla S. Al‐Ayed
Abdulla S. Al‐Ayed
JMJarosław Mołdoch
Jarosław Mołdoch
SPSonia Piacente
Sonia Piacente
Wieslaw OleszekWieslaw Oleszek
Wieslaw Oleszek
ASAnna Stochmal
Anna Stochmal

4 January 2017 in Natural Product Research
Verified
Journal Article
Closed access
AHArafa Hamed
Arafa Hamed
RSRidha Ben Said
Ridha Ben Said
AAAbdullah S. Al-Ayed
Abdullah S. Al-Ayed
JMJarosław Mołdoch
Jarosław Mołdoch
UMUsama A. Mahalel
Usama A. Mahalel
Anna StochmalAnna Stochmal
Anna Stochmal
A fingerprint of steroid saponins, the major constituent in 80% methanolic fraction from the male flowers of Phoenix dactylifera has been established. Under ESI-MS/MS conditions, the fragmentation patterns of [M − H]− ions exclusively displayed signals corresponding to the cleavage of the glycosidic bonds, thus allowing a rapid identification of 21 steroidal saponins. Moreover, two unique among them conjugated with histidine were detected by LC-ESI (-)-MS and DFT and were given tentative names of 3-o-histidine-26-o-hexosyl-dioscin and 3-o-histidine-26-o-dihexosyl-hydroxydioscin. Their steroidal saponins exhibited a significant improvement of the sperm cells count, motility and viability in male rats. These effects could be attributed to enhancing the levels of sex hormones.

20 April 2012 in Phytochemical Analysis
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Journal Article
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AHArafa Hamed
Arafa Hamed
BJBogdan Janda
Bogdan Janda
UMUsama A. Mahalel
Usama A. Mahalel
ASAnna Stochmal
Anna Stochmal
Wieslaw OleszekWieslaw Oleszek
Wieslaw Oleszek

9 September 2021 in Natural Product Research
Verified
Journal Article
Closed access
RSRidha Ben Said
Ridha Ben Said
MAMohamed Ali Ben Aissa
Mohamed Ali Ben Aissa
SRSeyfeddine Rahali
Seyfeddine Rahali
BTBahoueddine Tangour
Bahoueddine Tangour
MKMariusz Kowalczyk
Mariusz Kowalczyk
AHArafa Hamed
Arafa Hamed
The present study has tentatively elucidated the structure of two acylated polyoxypregnane glycosides from Caralluma quadrangula (Forssk.) N.E.Br. (CQ). The analyses were performed using an electrospray-ionization quadrupole time-of-flight (ESI-Q-TOF) mass spectrometer in positive ionization modes to explore fragmentation pathways. The used ionization mode provided consistent and/or complementary information for most of the pregnane glycosides, their fragmentation sequences, and their aglycones. Presumably, this is due to higher efficiency, sensitivity, and better selectivity of the mass spectrometry-based method. The present experimental and theoretical report deals with the characteristic fragmentation behaviors of two acylated polyoxypregnane glycosides CQ1 and CQ2 from the aerial parts of C. quadrangular. A DFT Study was performed to elucidate the position of ikemoyl, and benzoyl residues in compounds CQ1 and CQ2, respectively. Graphical Abstract

1 May 2012 in Natural Product Communications
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Journal Article
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AHArafa Hamed
Arafa Hamed
MLMichele Leonardi
Michele Leonardi
ASAnna Stochmal
Anna Stochmal
Wieslaw OleszekWieslaw Oleszek
Wieslaw Oleszek
LPLuisa Pistelli
Luisa Pistelli
The fruits of the edible and medicinal Egyptian palm, Medemia argun, were collected from Aswan in Egypt and the essential oil (EO) from fruits and headspace (HS) of the seeds and fleshy mesocarps were analyzed by GC and GC-MS. Results obtained by GC-MS analysis indicated a high variability in the oil and in the headspace from seeds and mesocarps. Sesquiterpene derivatives were the main group of volatiles in the EO from fruits and in the HS from seeds (45.0 and 64.0%, respectively), while oxygenated hydrocarbon derivatives were the main constituents in the HS obtained from fleshy mesocarps (96.5%). The different chemical composition of the headspace obtained from the seeds and mesocarps of M. argun can be correlated with the different roles that the different constituents play in the prevention of dehydration of the fruits in the desert region from where the plant was collected.