Khaled A Nematallah

Dr. Khaled A Nematallah


Research Focus & Metrics

Academic Career Length

6Years (2021-Present)

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

Representative Publications

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22 December 2021 in Nutrients
Verified
Journal Article
Open access
PDF file
NANahla Ayoub
Nahla Ayoub
NBNadia Badr
Nadia Badr
SASaeed Al-Ghamdi
Saeed Al-Ghamdi
SASafaa Alsanosi
Safaa Alsanosi
AAAbdullah R Alzahrani
Abdullah R Alzahrani
NSNoha Swilam
Noha Swilam
Salvadora persica L. (S. persica, Siwak) is an ethnic plant that is widely used for improving oral hygiene. This study aimed to provide a phytochemical profiling of S. persica ethyl acetate fraction (SPEAF) and to evaluate the healing activity of a muco-adhesive formula of the fraction against acetic acid-induced oral ulcers in rats. HPLC-ESI-QTOF-MS-MS analysis of SPEAF resulted in the tentative identification of 56 metabolites containing fatty acids (23%), urea derivatives (10.5%) and sulphur compounds (10%), in addition to several amides, polyphenols and organic acids (6.5%, 5% and 2%, respectively). For the first time, 19 compounds were identified from S. persica. In vitro and in vivo experiments indicated that the extract is non-toxic. SPEAF exhibited superior healing activities compared to both the negative and positive control groups on days 7 and 14 of tongue ulcer induction. This was confirmed by histopathological examinations of haematoxylin and eosin-stained (H&E) and Masson’s trichrome-stained tongue sections. Moreover, SPEAF showed potent anti-inflammatory activities, as evidenced by the inhibited expression of interleukin-6 (IL-6) and tumour necrosis alpha (TNF-α). Moreover, SPEAF exhibited potent antioxidant activity, as it prevented malondialdehyde (MDA) accumulation, reduced glutathione (GSH) depletion and superoxide dismutase (SOD) exhaustion. SPEAF significantly enhanced hydroxyproline tongue content and upregulated collagen type I alpha 1 (Col1A1) mRNA expression. SPEAF also improved angiogenesis, as shown by the increased mRNA expression of the angiopoietin-1 (Ang-1). In conclusion, S. persica has a wide range of secondary metabolites and ameliorates acetic acid-induced tongue ulcers in rats. This can be attributed, at least partly, to its anti-inflammatory, antioxidant, procollagen and angiogenic activities. These findings provide support and validity for the use of S. persica as a traditional and conventional treatment for oral disorders.

1 June 2022 in ACS Omega
Verified
Journal Article
Open access
Sherif Ashraf FahmySherif Ashraf Fahmy
Sherif Ashraf Fahmy
KNKhaled A Nematallah
Khaled A Nematallah
NMNoha Khalil Mahdy
Noha Khalil Mahdy
HEHesham I. El-Askary
Hesham I. El-Askary
MMMeselhy Ragab Meselhy
Meselhy Ragab Meselhy
Hassan AzzazyHassan Azzazy
Hassan Azzazy
Egyptian rice bran was fermented with baker's yeast, and released phenolics were extracted with aqueous methanol to give fermented rice bran extract (FRBE). The analysis of the FRBE with ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry revealed 21 compounds, mainly phenolic acids and flavonoids. The FRBE was then complexed with (2-hydroxypropyl)-β-cyclodextrin (HPβCD) via noncovalent host-guest inclusion complexation using the thin-film hydration technique to improve the hydrophilicity and bioactivity of the FRBE. The formation of the inclusion complex was confirmed using HPLC, 1H NMR, FT-IR, and a phase solubility study. In addition, the biological activities of the complex were investigated. The FRBE/HPβCD inclusion complex had more pronounced antioxidant, antiviral, and anticancer activities compared to free FRBE. These findings warrant the future investigation of potential medical applications of FRBE.

24 February 2022 in ACS Omega
Verified
Journal Article
Open access
KNKhaled A Nematallah
Khaled A Nematallah
SESahar El-mekkawy
Sahar El-mekkawy
MAMaha R. A. Abdollah
Maha R. A. Abdollah
MEMohey M. Elmazar
Mohey M. Elmazar
Essam Abdel-SattarEssam Abdel-Sattar
Essam Abdel-Sattar
MMMeselhy Ragab Meselhy
Meselhy Ragab Meselhy
Natural products are considered as a good source of antifibrotic agents, but identifying and isolating bioactive molecule(s) is still challenging. Fortunately, numerous computational techniques have evolved to save time and efforts in this field. The aim of the current study was to utilize several cheminformatics software to study the chemical and biological features of the bark of Eucalyptus globulus cultivated in Egypt. Sirius software, with the aid of online databases, was used to process liquid chromatography–mass spectrometry (LC–MS) chemical profiling and predict precise molecular formulae, chemical classes, and structures. Accordingly, 37 compounds were tentatively identified, including 15 reported here for the first time from this species. Also, the BioTransformer tool was successfully applied for in silico virtual study of the human metabolism of these compounds, and 1960 different products were obtained through various metabolic pathways. Finally, an electronic library of the identified compounds and their metabolites were developed and docked in silico against eight different protein targets that are involved in the liver fibrosis process. The results revealed that the extract may have a potential hepatoprotective effect through several mechanisms and that the metabolites have the highest binding affinities to the relevant enzymes than their parent compounds. The extract was found to show potent cytotoxic activity against the liver cancer cell lines HEPG2 and HUH-7, and its absorption was enhanced through nanoformulation, as proved using the ex vivo everted gut sac method.

21 September 2024 in Journal of Functional Foods
Verified
Journal Article
Open access
KNKhaled A Nematallah
Khaled A Nematallah
AAAmgad Albohy
Amgad Albohy
NSNoha Swilam
Noha Swilam

1 July 2026 in Nutrients
Verified
Journal Article
Open access
PDF file
NSNoha Swilam
Noha Swilam
KNKhaled A Nematallah
Khaled A Nematallah
AAAmgad Albohy
Amgad Albohy
NBNoha M. Badawi
Noha M. Badawi
Sameh GadSameh Gad
Sameh Gad
NANahla Ayoub
Nahla Ayoub
Background: Skin aging is driven by oxidative stress and ultraviolet (UV) exposure, leading to extracellular matrix degradation and loss of skin elasticity. This study aimed to identify the most biologically active Citrus species using a bioassay-guided approach and evaluate its potential for dermal applications. Methods: Hydroalcohol extracts and ethyl acetate fractions of Citrus sinensis, Citrus aurantifolia, and Citrus reticulata leaves were screened for antioxidant, enzyme-inhibitory, and polyphenol content. The most active fraction was characterized by UPLC-PDA and LC–MS/MS, formulated into Span-based nanovesicles, and evaluated for physicochemical properties and drug release. Biological activity was assessed using an in vitro scratch wound-healing assay on human dermal fibroblasts and a UVA-induced photoaging mouse model, supported by molecular dynamics simulations. Results: The ethyl acetate fraction of C. aurantifolia (CAE) exhibited the highest biological activity among the tested samples. This fraction showed potent antioxidant activity (DPPH IC50 = 3.53 ± 0.05 µg/mL), marked inhibition of elastase (91.3%), collagenase (92.0%), and tyrosinase (80.2%), and a high total flavonoid content (110.49 mg rutin equivalents/g). Phytochemical profiling of CAE tentatively identified fourteen compounds, predominantly flavonoids, with hesperidin (30.4 mg/g) as a major constituent. The optimized nanovesicles (184 ± 0.9 nm, PDI 0.10, EE% 75.0%) enabled sustained hesperidin release. CAE and CAEnp enhanced fibroblast migration and accelerated wound closure at 24 h (p < 0.05). In vivo, CAEnp improved UVA-induced histopathological alterations and modulated oxidative stress-related markers by reducing p62/SQSTM1 by 28.7%, Keap1 expression to 21% compared with the CAE-treated group, and enhancing Nrf2, ARE, and NQO1 expression by 54.1%, 28.3%, and 57%, respectively. Molecular dynamics simulations supported stable hesperidin binding to elastase and suggested possible modulation of collagenase flexibility. Conclusions: The polyphenol-rich leaf fraction from C. aurantifolia, identified through comparative bioassay-guided fractionation, demonstrated antioxidant, enzyme-inhibitory, wound-healing, and photoprotective effects, particularly after nanoformulation. These findings support its potential for further development as a natural topical anti-aging candidate.

29 September 2025 in Egyptian Journal of Chemistry
Verified
Journal Article
Closed access
NFNariman N Fouad
Nariman N Fouad
KNKhaled A Nematallah
Khaled A Nematallah
MIMarwa Yousry Issa
Marwa Yousry Issa
MMMeselhy R Meselhy
Meselhy R Meselhy
The genus Hypoestes comprises around 150 species of herbs and shrubs native to the tropical regions of Asia and Africa. Plants from this genus are rich in alkaloids, lignans, diterpenes, and triterpenes. Extracts and compounds from various Hypoestes species, including Hypoestes aristata, Hypoestes forskaolii, Hypoestes phyllostachya (rosea), Hypoestes pubescens, Hypoestes purpurea, and Hypoestes verticillaris, have shown significant cytotoxicity against several cancer cell lines and demonstrated promising antiproliferative effects in vitro and in vivo. This review comprehensively summarizes the key findings from cytotoxicity studies on various Hypoestes species. However, further studies are required to identify the cytotoxic activity of the promising phytochemicals, clarify their mechanism of actions, and evaluate their potential as novel anticancer agents.