Yahya S. Alqahtani

Prof. Yahya S. Alqahtani


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

View All Publications
29 June 2022 in Molecules
Verified
Journal Article
Open access
PDF file
YAYahya S. Alqahtani
Yahya S. Alqahtani
SMSunil S. More
Sunil S. More
KRKeerthana R.
Keerthana R.
Ibrahim Ahmed ShaikhIbrahim Ahmed Shaikh
Ibrahim Ahmed Shaikh
AJAnusha K. J.
Anusha K. J.
AKAejaz Abdullatif Khan
Aejaz Abdullatif Khan
Enzymes that degrade pectin are called pectinases. Pectinases of microbial origin are used in juice clarification as the process is cost-effective. This study screened a pectinase-producing bacterium isolated from soil and identified as Bacillus subtilis 15A B-92 based on the 16S rRNA molecular technique. The purified pectinase from the isolate showed 99.6 U/mg specific activity and 11.6-fold purity. The molecular weight of the purified bacterial pectinase was 14.41 ± 1 kD. Optimum pectinase activity was found at pH 4.5 and 50 °C, and the enzyme was 100% stable for 3.5 h in these conditions. No enzymatic inhibition or activation effect was seen with Fe2+, Ca2+, or Mg2+. However, a slight inhibition was seen with Cu2+, Mn2+, and Zn2+. Tween 20 and 80 slightly inhibited the pectinase, whereas iodoacetic acid (IAA), ethylenediaminetetraacetate (EDTA), urea, and sodium dodecyl sulfate (SDS) showed potent inhibition. The bacterial pectinase degraded citrus pectin (100%); however, it was inactive in the presence of galactose. With citrus pectin as the substrate, the Km and Vmax were calculated as 1.72 mg/mL and 1609 U/g, respectively. The high affinity of pectinase for its substrate makes the process cost-effective when utilized in food industries. The obtained pectinase was able to clarify orange and apple juices, justifying its application in the food industry.

28 October 2022 in Antibiotics
Verified
Journal Article
Open access
PDF file
YAYahya S. Alqahtani
Yahya S. Alqahtani
ABAmal Bahafi
Amal Bahafi
KMKiran K. Mirajkar
Kiran K. Mirajkar
RBRakshith Rudrapura Basavaraju
Rakshith Rudrapura Basavaraju
SMSusweta Mitra
Susweta Mitra
Ibrahim Ahmed ShaikhIbrahim Ahmed Shaikh
Ibrahim Ahmed Shaikh
An estimated 35% of the world’s population depends on wheat as their primary crop. One fifth of the world’s wheat is utilized as animal feed, while more than two thirds are used for human consumption. Each year, 17–18% of the world’s wheat is consumed by China and India. In wheat, spot blotch caused by Bipolaris sorokiniana is one of the major diseases which affects the wheat crop growth and yield in warmer and humid regions of the world. The present work was conducted to evaluate the effect of green synthesized silver nanoparticles on the biochemical constituents of wheat crops infected with spot blotch disease. Silver nanoparticles (AgNPs) were synthesized using Mangifera indica leaf extract and their characterization was performed using UV-visible spectroscopy, SEM, XRD, and PSA. Characterization techniques confirm the presence of crystalline, spherical silver nanoparticles with an average size of 52 nm. The effect of green synthesized nanoparticles on antioxidative enzymes, e.g., Superoxide dismutase (SOD), Catalase (CAT), Glutathione Reductase (GR), Peroxidase (POX), and phytochemical precursor enzyme Phenylalanine Ammonia-Lyase (PAL), and on primary and secondary metabolites, e.g., reducing sugar and total phenol, in Bipolaris sorokiniana infected wheat crop were studied. Inoculation of fungal spores was conducted after 40 days of sowing. Subsequently, diseased plants were treated with silver nanoparticles at different concentrations. Elevation in all biochemical constituents was recorded under silver nanoparticle application. The treatment with a concentration of nanoparticles at 50 pp min diseased plants showed the highest resistance towards the pathogen. The efficacy of the green synthesized AgNPs as antibacterial agents was evaluated against multi drug resistant (MDR) bacteria comprising Gram-negative bacteria Escherichia coli (n = 6) and Klebsiella pneumoniae (n = 7) and Gram-positive bacteria Methicillin resistant Staphylococcus aureus (n = 2). The results show promising antibacterial activity with significant inhibition zones observed with the disc diffusion method, thus indicating green synthesized M. indica AgNPs as an active antibacterial agent against MDR pathogens.

6 February 2024 in Separations
Verified
Journal Article
Open access
PDF file
UMUday M Muddapur
Uday M Muddapur
SMSamiksha Manjunath
Samiksha Manjunath
YAYahya S. Alqahtani
Yahya S. Alqahtani
Ibrahim Ahmed ShaikhIbrahim Ahmed Shaikh
Ibrahim Ahmed Shaikh
AKAejaz Abdullatif Khan
Aejaz Abdullatif Khan
SMSunil S. More
Sunil S. More
The main objective of this research was to perform Gymnema sylvestre (Asclepiadaceae) extract’s phytochemical screening and identify its therapeutic potential. Using a Soxhlet apparatus, the powdered plant material was extracted using ethyl acetate. The preliminary phytochemical analysis confirmed the presence of alkaloids, flavonoids, phenols, glycosides, and steroids. Gas chromatography–mass spectroscopy analysis of the extract was performed and confirmed the presence of 11 compounds. As per the quantitative analysis, the extract exhibited a phenolic content of 948 µg gallic acid equivalent/g dry weight, a total flavonoid content of 398 µg quercetin equivalent/g dry weight, and an alkaloid content of 487 µg atropine equivalent/g dry weight. As per the in vitro cytotoxicity test using A549 cells, the IC50 (half-maximal inhibitory concentration) value for the extract was found to be 76.06 ± 1.26 µg/mL, indicating its cytotoxic effect on the cells. The ethyl acetate extract showed significant antibacterial efficacy, as evidenced by a zone of clearance measuring 3 mm against Escherichia coli and 6 mm against Bacillus subtilis. For anthelmintic activity, the earthworm paralysis time induced by G. sylvestre extract (10 mg/mL) was 28.13 ± 0.8 min, and the time of death was 68.21 ± 1.72 min. In comparison, the reference drug, piperazine citrate (10 mg/mL), caused paralysis in 22.18 ± 1.02 min and resulted in death at 66.22 ± 2.35 min. Similarly, the coagulation time was notably prolonged, with blood clot formation observed at 1 min and 40 s, at a concentration of 1 mg/mL, which underscores the potential anticoagulant or hemostatic modulation properties of G. sylvestre extract. The test extract showed good inhibition of alpha-amylase activity and exhibited an IC50 value of 15.59 µg/mL. The IC50 value for DPPH (2,2-diphenyl-1-picrylhydrazyl)-scavenging activity for the extract was 19.19 µg/mL. Based on the GCMS results, the compound 2,7-dimethyl-undecane was selected for its anticancer potential. Docking studies were conducted with the epidermal growth factor receptor (EGFR) protein, specifically the 5WB7 variant associated with lung cancer. The docking score was −4.5, indicating a potential interaction. Key interaction residues such as ASN328, VAL350, and THR358 were identified. Overall, this research provides valuable insights into the phytochemical composition and diverse biological activities of G. sylvestre extract, offering a foundation for further exploration of its medicinal and pharmacological potential.

29 December 2021 in Vaccines
Verified
Journal Article
Open access
PDF file
YAYahya S. Alqahtani
Yahya S. Alqahtani
Vaccines afford protection against infectious diseases. However, a sizeable part of the population refuse vaccinations and continue to dispute the evidence supporting vaccinations. The objective of this study was to determine the prevalence of COVID-19 vaccination uptake and its determinants among the Saudi population in the southern region of Saudi Arabia. A cross-sectional survey studied COVID-19 vaccine acceptance in adults in Saudi Arabia, targeting the general population in the southwestern region. Data were collected through an online survey questionnaire tool. All data were analysed using SPSS version 23.0. The majority (57.29%) of the participants were willing to receive the new COVID-19 vaccine, whereas almost 64% believed it is necessary to take the COVID-19 vaccine to protect oneself and that the vaccine is safe, efficient and effective. The data showed that perceived risk of COVID-19 (p = 0.015), history of previous vaccination against seasonal influenza (p = 0.000), and trust in the healthcare system (p = 0.025) were significant predictors for COVID-19 vaccine acceptance. We conclude that participants’ trust in the healthcare system, perceived risk of contracting COVID-19, and history of previous vaccination against seasonal influenza were significant predictors for COVID-19 vaccine acceptance. Knowing the acceptance rates for the COVID-19 vaccination can aid state agencies, medical practitioners, and other entities in reducing the impact of vaccine avoidance.

11 May 2022 in Applied Sciences
Verified
Journal Article
Open access
PDF file
BABandar Alyami
Bandar Alyami
AAAli O. Alqarni
Ali O. Alqarni
YAYahya S. Alqahtani
Yahya S. Alqahtani
MMMater H. Mahnashi
Mater H. Mahnashi
QJQamar Javed
Qamar Javed
Mariusz MojzychMariusz Mojzych
Mariusz Mojzych
The binding of fluoroquinolones, the most commonly prescribed antibiotics, with melanin is well explored. However, their binding patterns and exact mechanism of interaction with tyrosinase, a key enzyme in melanogenesis, are not explored yet. Thus, in the present study, seven fluoroquinolone drugs were selected to characterize their interactions with the tyrosinase enzyme: ciprofloxacin, enoxacin sesquihydrate, ofloxacin, levofloxacin, sparfloxacin, moxifloxacin and gemifloxacin. The results confirmed that all the drugs execute excellent enzyme activity, with an inhibition range from IC50 = 28 ± 4 to 50 ± 1.9 μM, outperforming the standard hydroquinone (IC50 = 170 μM). Later, kinetic studies revealed that all the drugs showed irreversible, but mixed-type, tyrosinase inhibition, with a preferentially competitive mode of action. Further, 2D and 3D docked complexes and binding analyses confirmed their significant interactions in the active region of the target enzyme, sufficient for the downstream signaling responsible for the observed tyrosinase inhibition. Thus, this is the first report demonstrating their mechanism of tyrosinase inhibition, critical for melanin-dependent responses, including toxicity.