Michella DAWRA

Dr. Michella DAWRA


Research Focus & Metrics

Academic Career Length

4Years (2023-Present)

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

Representative Publications

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7 March 2023 in Molecules
Verified
Journal Article
Open access
PDF file
MDMichella DAWRA
Michella DAWRA
Jalloul BouajilaJalloul Bouajila
Jalloul Bouajila
MBMarc El Beyrouthy
Marc El Beyrouthy
AAAlain Abi-Rizk
Alain Abi-Rizk
PTpatricia taillandier
patricia taillandier
YRYoussef El Rayess
Youssef El Rayess
The Salvia fruticosa (Mill.) is the most medicinal plant used in Lebanon. The aim of this study is to investigate the phytochemical composition and the biological activities (in vitro) of its extracts. The plant was extracted by cold maceration with four solvents presenting an increasing polarity: cyclohexane (CHX), dichloromethane (DCM), ethyl acetate (EtOAc) and methanol (MeOH). The extracts were screened for their chemical composition by a HPLC-DAD detector for phenolic compounds identification and quantification and by GC-MS for volatile compounds detection. The antioxidant capacity (DPPH inhibition) was tested. Biological activities, mainly anti-Alzheimer activity (acetylcholinesterase inhibition), the antiproliferation of two human colon cancer cell lines (HCT-116 and Caco-2 cells) and antibacterial activity, were evaluated. Ten aromatic compounds were quantified by HPLC-DAD analysis. A total of 123 compounds were detected by GC-MS analysis. The MeOH extract showed a very interesting antioxidant activity with an inhibition percentage (IP) of 76.1% and an IC50 of 19.4 μg/mL. The EtOAc extract exhibited the strongest inhibition against the acetylcholinesterase activity (IP = 60.6%) at 50 μg/mL. It also strongly inhibited the proliferation of the HCT-116 cells (IP = 87.5%), whereas the DCM extract gave the best result with the Caco-2 cells (IP = 72.3%). The best antibacterial activity was obtained with the MeOH extract against Staphylococcus aureus (MIC = 1.2 μg/mL) and with the EtOAc extract against Escherichia coli (MIC = 2.4 μg/mL). This study highlights the chemical composition and therapeutic potential of S. fruticosa. It is important to mention that the following chemical compounds were identified for the first time in plant extracts: 2,6,11,15-tetramethyl-hexadeca-2,6,8,10,14-pentaene; 4,5,6,7-tetrahydroxy-1,8,8,9-tetramethyl-8,9-dihydrophenaleno [1,2-b]furan-3-one; podocarpa-1,8,11,13-tetraen-3-one,14-isopropyl-1,13-dimethoxy; podocarpa-8,11,13-trien-3-one,12-hydroxy-13-isopropyl-,acetate; 3′,8,8′-trimethoxy-3-piperidin-1-yl-2,2′-binaphthyl-1,1′,4,4′-tetrone; and 2,3-dehydroferruginol, thus underlining the originality of this study.

3 January 2024 in Plants
Verified
Journal Article
Open access
PDF file
MDMichella DAWRA
Michella DAWRA
Jalloul BouajilaJalloul Bouajila
Jalloul Bouajila
MBmarc beyrouthy
marc beyrouthy
PTpatricia taillandier
patricia taillandier
NNNancy Nehme
Nancy Nehme
YRYoussef El Rayess
Youssef El Rayess
Indigenous to Lebanon, Origanum syriacum L. and Cousinia libanotica D.C. are notable plants in the Middle East, with O. syriacum known for its aromatic qualities and C. libanotica being less explored. Both plants have a significant role in traditional medicine for treating various ailments. This study aimed to evaluate the phytochemical composition and biological properties of the extracts from these plants. The extracts were obtained through cold maceration with solvents of increasing polarity. The ethyl acetate extract of O. syriacum exhibited the highest total polyphenol content. High-performance liquid chromatography (HPLC) identified fifteen compounds in both C. libanotica and O. syriacum extracts, whereas gas chromatography–mass spectrometry (GC-MS) analysis unveiled 179 volatile compounds. Notably, the O. syriacum-MeOH extract showed moderate antioxidant activity. Both plants’ methanolic extracts demonstrated significant anti-Alzheimer’s potential. The O. syriacum-dichloromethane and C. libanotica-cyclohexane extracts displayed the highest cytotoxicities against the HCT-116 cell line. For anti-proliferative activity against the Caco-2 cell line, the O. syriacum-methanol and C. libanotica-cyclohexane extracts were the most effective. This study provides valuable insights into the phytochemistry and potential therapeutic applications of extracts from these two oriental plant species.

16 May 2023 in Plants
Verified
Journal Article
Open access
PDF file
MDMichella DAWRA
Michella DAWRA
NNNancy Nehme
Nancy Nehme
MBMarc El Beyrouthy
Marc El Beyrouthy
AAAlain Abi-Rizk
Alain Abi-Rizk
PTpatricia taillandier
patricia taillandier
YRYoussef El Rayess
Youssef El Rayess
Berberis libanotica Ehrenb. ex C.K. Schneider of the Berberidaceae family is an endemic Lebanese plant and is widely used in folk medicine. This study highlights the phytochemical composition and biological activities (in vitro) of fruit and leaf extracts. The two organs were extracted by cold maceration with four solvents of increasing polarity: cyclohexane, dichloromethane, ethyl acetate and methanol. The extracts were screened for their chemical composition by HPLC-DAD to identify and quantify the phenolic compounds. Volatile compounds were detected by GC-MS. The antioxidant capacity through DPPH inhibition was tested. The anti-acetylcholinesterase, antibacterial and anti-proliferative activities were evaluated. Thirteen compounds, including 12 phenolics, were detected in the fruits, whereas 8 phenolic compounds were identified in the leaves. A total of 137 volatile compounds were identified in both organs. At 50 μg/mL, the methanolic leaf extract presented the highest antioxidant capacity, with an inhibition percentage of 54.9%. The dichloromethane fruit extract reduced the acetylcholinesterase activity by 65.3%. The cyclohexane leaf extract reduced the proliferation of the HCT-116 cells by 54.8%, while the dichloromethane fruit extract exhibited the best inhibition against the Caco-2 cells (54%). Interestingly, the minimum inhibitory concentration (MIC) value of the cyclohexane fruit extract against Salmonella enterica serovar Kentucky was 2.4 μg/mL, and the MIC value of the cyclohexane leaf extract against E. coli was 9.7 μg/mL.