Publications by authors named "Abdulaziz Abdulrahman Al-Askar"

4 Publications

  • Page 1 of 1

Green catalyst Cu(II)-enzyme-mediated eco-friendly synthesis of 2-pyrimidinamines as potential larvicides against Culex quinquefasciatus mosquito and toxicity investigation against non-target aquatic species.

Bioorg Chem 2021 Apr 8;109:104697. Epub 2021 Feb 8.

Research Department of Chemistry, Nehru Memorial College (Affiliated to Bharathidasan University), Puthanampatti 621007, Tiruchirappalli District, Tamil Nadu, India. Electronic address:

Novel one-pot multicomponent synthesis of 2-pyrimidinamine derivatives can be achieved via green chemistry, using Cu(II)-tyrosinase enzyme (Cu-Tyr) as a catalyst. This method offers mild reaction conditions and a high yield of derivatives. We synthesised several compounds in this manner and evaluated their larvicidal, and antifeedant activities. Out of the synthesised derivatives, compound 3, with a median lethal dose (LD) of 21.43 µg/mL, was highly active against Culex quinquefasciatus, compared to compounds 1a-m and 2, and the control, hydantocidin. Compounds 1j, 1d, and 1e were low active against C. quinquefasciatus with LD values of 78.46, 78.59, and 79.54 µg/mL, respectively. In antifeedant screening, compounds 1j, 1l, and 2 generated 100% mortality within 24 h against Oreochromis mossambicus at 100 µg/mL, where toxicity was determined as the ratio of the number of dead and live fingerlings (%) at 24 h. In contrast, compounds 1a-f, 1i, 1m, and 3 were less toxic to O. mossambicus as compared to the control, dibromoisophakellin. Therefore, compound 3 had high larvicidal activity against C. quinquefasciatus and was less toxic to non-target aquatic species. Molecular docking studies also supported the finding that compound 3 was an effective larvicide with more inhibition ability than the control hydantocidin (-9.6 vs. -6.1 kcal/mol).
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http://dx.doi.org/10.1016/j.bioorg.2021.104697DOI Listing
April 2021

Anti-saprolegnia potency of some plant extracts against the causative agent of saprolengiasis.

Saudi J Biol Sci 2020 Jun 13;27(6):1482-1487. Epub 2020 Apr 13.

Botany and Microbiology Dept., College of Science, King Saud University, P.O. 2455, Riyadh 11451, Saudi Arabia.

Saprolegnosis of fresh water fishes caused by often results in serious economic losses to fish hatcheries. Despite the proven efficiency of malachite green as a potential fungicide in prevention and control of fish saprolegnosis, there is a strong debate about its safety aspects in use since it was documented to be responsible for many carcinogenic and teratogenic attributes. Bioactivity of four ethanolic plant extracts were assessed to attain a natural alternative to the traditional fungicide currently used in saprolegnosis control. Ethanolic extracts of and exhibited a potential efficacy in suppressing mycelial growth of at concentration of 0.5 mg/ml while extracts of and were not effective respectively. The extract of pomegranate showed the highest antifungal potency with minimum inhibitory concentration (MIC) of 200 ppm while thyme extract was less effective and recorded MIC of 400 ppm against . The acute fish toxicity of the plant extracts indicated the low toxicity of and extracts as no fish mortalities were detected at aquaria containing 200, 400 and 800 ppm of plant extracts respectively. Considering the low toxicity of these plant extracts, it may be concluded that 200 and 400 ppm of pomegranate and thyme extracts which suppressed the mycelial growth of the S. could be safely used for saprolegniasis control. Both of pomegranate and thyme extracts which proved to possess a potential antifungal activity can be considered as a natural alternative fungicides to control saprolegniasis avoiding carcinogenic malachite green application.
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http://dx.doi.org/10.1016/j.sjbs.2020.04.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7254045PMC
June 2020

In vitro anticandidal potency of Syzygium aromaticum (clove) extracts against vaginal candidiasis.

BMC Complement Med Ther 2020 Jan 30;20(1):25. Epub 2020 Jan 30.

Botany and Microbiology Department, College of Science, King Saud University, P.O. 2455, Riyadh, 11451, Saudi Arabia.

Background: Candida vaginitis is a global health hazard that increases morbidity among women of childbearing age. Recent studies have revealed a high incidence of drug-resistant Candida strains. Additionally, treating Candida vulvovaginitis during pregnancy is challenging as antifungal therapy is associated with fetal abnormalities. Hence, it is important to develop novel therapeutic strategies to treat vulvovaginal candidiasis.

Methods: In this study, we used the disc diffusion method to evaluate the anticandidal activity of different Syzygium aromaticum extracts (methanol, ethyl acetate, n-hexane, and diethyl ether) against C. albicans, C. glabrata, and C. tropicalis. Furthermore, gas chromatography-mass spectrometry (GC-MS) analysis of different S. aromaticum extracts was performed to determine active components exhibiting anticandidal activity. Cytotoxicity of different clove extracts against the HUH7 cell line was evaluated.

Results: The ethyl acetate extract exhibited the highest antifungal activity against C. albicans, C. glabrata, and C. tropicalis with inhibition zone diameters of 20.9, 14.9, and 30.7 mm, respectively. The minimum inhibitory concentration of the S. aromaticum ethyl acetate extract was 250 μg/disc against C. tropicalis, and 500 μg/disc against C. albicans and C. glabrata, while the minimum fungicidal concentration was 0.5 mg/disc against C. tropicalis and 1 mg/disc against the C. albicans and C. glabrata. GC-MS analysis of the ethyl acetate extract revealed the main bioactive compound as eugenol (58.88%), followed by eugenyl acetate (23.86%), trans-caryophyllene (14.44%), and α-humulene (1.88%). The cytotoxicity assay indicated that the diethyl ether extract demonstrated the lowest toxicological effect against the HUH7 cell line, with a relative IC of 62.43 μg/ml; the methanolic extract demonstrated a higher toxicity (IC, 24.17 μg/ml).

Conclusion: As the S. aromaticum extract exhibited high antifungal activity at low concentrations, it can be a potential source of natural antifungal drugs.
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http://dx.doi.org/10.1186/s12906-020-2818-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7076834PMC
January 2020

Decolorization and biotransformation pathway of textile dye by Cylindrocephalum aurelium.

Bioprocess Biosyst Eng 2019 Sep 10;42(9):1483-1494. Epub 2019 May 10.

Department of Water and Environmental Engineering, Faculty of Engineering, Universiti Teknologi Malaysia, 81310, Johor Bahru, Johor, Malaysia.

Due to environmental concern, the research to date has tended to focus on how textile dye removal can be carried out in a greener manner. Therefore, this study aims to evaluate the decolorization and biotransformation pathway of Mordant Orange-1 (MO-1) by Cylindrocephalum aurelium RY06 (C. aurelium RY06). Decolorization study was conducted in a batch experiment including the investigation of the effects of physio-chemical parameters. Enzymatic activity of C. aurelium RY06 during the decolorization was also investigated. Moreover, transformation and biodegradation of MO-1 by C. aurelium RY06 were observed using the gas chromatography-mass spectrometry. Manganese peroxidase, lignin peroxidase, laccase, 1,2-dioxygenase, and 2,3-dioxygenase enzymes were detected during the decolorization. In general, the present work concluded that the MO-1 was successfully degraded by C. aurelium RY06 and transformed to be maleic acid and to be isophtalic acid.
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http://dx.doi.org/10.1007/s00449-019-02144-3DOI Listing
September 2019