Hamdan I. Almohammed

Hamdan I. Almohammed

*This is an algorithmically generated author record based on publicly available information.

Current Organizations / Institutes

The organizations/institutes from the scholar's latest article

Previous Organizations / Institutes

The organizations / institutes from the scholar's other articles in the past ten years


Hamdan I. Almohammed has a total of 36 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Open Access

    Potent In Vitro and In Vivo Effects of Stachys lavandulifolia Methanolic Extract against Toxoplasma gondii Infection

    by Abdullah D. Alanazi, Qais A. H. Majeed, Sultan F. Alnomasy, Hamdan I. Almohammed

    The present study aimed to evaluate the in vitro, in vivo, and safety of Stachys lavandulifolia Vahl. methanolic extract (SLME) against acute toxoplasmosis caused by Toxoplasma gondii RH strain in mice. Methods: MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was used to evaluate the in vitro effect of the SLME on T. gondii tachyzoites. Totally, 72 male BALB/c mice (40 mice for in vivo evaluation of SLME and 32 mice for its toxicity effects on liver and kidney serum enzymes) were used for the present investigation. At first, 40 mice were orally pre-treated with the SLME at doses of 25, 50, and 75 mg/kg/day for two weeks. Mice were checked daily, and the rate of survival and the mean number of tachyzoites were recorded. Liver lipid peroxidation (LPO) and nitric oxide (NO) levels, the effects on kidney and liver function, as well as the expression level of the proinflammatory cytokines such as interleukin-1β (IL-1β) and interferon-γ (IFN-γ), were studied by the quantitative real-time PCR. Flow cytometry analysis was performed on the effects of SLME on the detection of apoptotic and necrotic cells in T. gondii tachyzoites. Results: The SLME at the concentrations 75 and 150 µg/mL completely killed the tachyzoites after 2 hr of incubation. SLME at 25, 50, and 75 mg/kg/day increased the survival rate of infected mice by the sixth, seventh, and eighth days, respectively. SLME also significantly (p < 0.05) decreased the LPO and NO levels and upregulated the IL-1β and IFN-γ mRNA gene expression levels, whereas no considerable change was observed in the serum level of kidney and liver enzymes. Flow cytometry analysis revealed the prompted early and late apoptosis after exposure to T. gondii tachyzoites with various concentrations of SLME. Conclusion: We found the relevant in vitro anti-Toxoplasma effects of SLME against T. gondii. Moreover, the results confirmed the promising in vivo prophylactic effects of SLME. SLME provokes the innate immune system, induces apoptosis, modulates the proinflammatory cytokines, and inhibits hepatic injury in infected mice. With all these descriptions, further surveys are required to support these findings and elucidate this plant’s possible mechanisms of action.


  • Open Access

    Therapeutic Potential and Safety of the Cinnamomum zeylanicum Methanolic Extract Against Chronic Toxoplasma gondii Infection in Mice

    by Abdullah D. Alanazi, Hamdan I. Almohammed

    Background: This experimental study determined the in vitro, in vivo, and toxicity effects of Cinnamomum zeylanicum methanolic extract (CZME) against Toxoplasma gondii infection.Methods: The in vitro activity of CZME T. gondii tachyzoites was studied by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Infected mice were treated with CZME for two weeks at doses of 20, 40, and 60 mg/kg/day. Then, the therapeutic effects of CZME were evaluated by assessing the mean number and mean size of T. gondii tissue cysts, oxidant-antioxidant enzymes, pro-inflammatory cytokines, and mRNA expression levels of bradyzoite surface antigen 1 (BAG1) by real-time PCR.Results: CZME significantly (p <0.001) increased the mortality rate of parasites in a dose- and time-dependent response. The mean number of intracellular tachyzoites was significantly reduced after CZME therapy. The treatment of infected mice with CZME resulted in a significant (p <0.001) downregulation of BAG1 and the level of lipid peroxidation (LPO) and nitric oxide (NO) as oxidative stress markers. However, a considerable rise (p <0.05) was found in the levels of antioxidant markers such as glutathione peroxidase (GPx), catalase enzyme (CAT), and superoxide dismutase enzyme activity (SOD). In a dose-dependent response, after treatment of infected mice with CZME, the level of pro-inflammatory cytokines of IFN-γ, IL-1β, and IL-12 was considerably elevated. CZME had no significant cytotoxicity on Vero cells, with a 50% cytotoxic concentration of 169.5 ± 5.66 μg/ml.Conclusion: The findings confirmed the promising therapeutic effects of CZME on chronic toxoplasmosis in mice. Nevertheless, further investigations must confirm these results, elucidate its precise mechanisms, and examine its effectiveness in human volunteers.


  • Retracted
    Open Access

    Role of Aromatherapy as a Natural Complementary and Alternative Therapy in Cardiovascular Disease: A Comprehensive Systematic Review

    by Hamdan I AlMohammed, Nada A Alanazi, Esraa Fahad Maghrabi, Manar A Alotaibi

    Background. The purpose of this study was a comprehensive review of studies on the effect of aromatherapy with plant essential oils on the improvement of some conditions, for example, anxiety, stress, sleep quality, fatigue, and pain in people with cardiovascular disease. Materials and Methods. We carried out this systematic review based on the instructions of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Ethical agreement was not necessary as main data have not been collected. During March 2022, we searched the main English databases, for example, Google Scholar, Web of Sciences, EMBASE, EBSCO, ScienceDirect, Scopus, and PubMed/MEDLINE, with limitation to human clinical trials. For this study, no time limit was applied for the publication of articles. Results. Out of 1380 papers, 52 papers up to March 2022 were eligible for review in this systematic review. Based on the obtained results, the most widely used medicinal plants for aromatherapy in patients with cardiovascular diseases were Lavandula angustifolia (lavender, 55.7), Rosa damascena (Damask rose, 11.5), and Mentha piperita (peppermint, 5.8), respectively. Most studies have been performed on the effect of aromatherapy on coronary angiography (21 papers, 40.4), followed by artery bypass graft surgery (14 studies, 26.9), and cardiac patients (5 studies, 9.6). Most studies on the effect of aromatherapy in cardiovascular diseases were performed on anxiety (31 papers, 59.6), sleep quality (8 studies, 15.4), and hemodynamic parameters (6 studies, 11.5), respectively. Conclusion. This study systematically reviewed the effects of aromatherapy in patients with cardiovascular diseases. The review of studies showed that lavender, Damask rose, and peppermint are the most frequents plants used for aromatherapy, whereas they significantly improved some illnesses and conditions, especially anxiety and sleep quality. Therefore, it can be concluded that cardiologist can used aromatherapy as a natural complementary and alternative therapy particularly with lavender, Damask rose, and peppermint to improve quality of life and some conditions such as anxiety and sleep quality.


  • Open Access

    Antibacterial, Cytotoxic, and Cellular Mechanisms of Green Synthesized Silver Nanoparticles against Some Cariogenic Bacteria (Streptococcus mutans and Actinomyces viscosus)

    by Hanaa Ghabban, Sultan F. Alnomasy, Hamdan Almohammed, Ohoud M. Al Idriss, Sameh Rabea, Yasir Eltahir

    Background. The present study focused on the green synthesis of silver nanoparticles (AgNPs) using the Astragalus spinosus Forssk. aqueous extract. In addition, we evaluated the antibacterial activity of AgNPs as well as some cellular mechanisms against Actinomyces viscosus and Streptococcus mutans as the most causative agents of tooth decay. Methods. In this study, AgNPs were green synthesized by the precipitation method based on the reduction of silver ions (AgNO3) by A. spinosus extract. Antibacterial effects of the green synthesized AgNPs were performed by measuring the minimum inhibitory concentration (MIC) and minimum bactericidal concentrations (MBC) through micro broth dilution method. In addition, we evaluated the reactive oxygen species (ROS) production, nucleic acid leakage, and protein leakage as the main antibacterial mechanisms of the green synthesized AgNPs against A. viscosus and S. mutans. The cytotoxicity effects of AgNPs against on human normal (NOF18 cells) and oral cancer (SCC4 cells) cell lines were also evaluated using MTT assay. Results. The green synthesized AgNPs have a spherical shape and are relatively uniform in size in the range of 30‐40 nm. The MIC values for S. mutans and A. viscosus of the green synthesized AgNPs were 10.6 and 13.3 μg/ml, respectively, whereas the MBC values for S. mutans and A. viscosus of the green synthesized AgNPs were 21.3 and 26.6 μg/ml. The findings exhibited that ROS production, nucleic acid leakage, and protein leakage were increased after treatment of A. viscosus and S. mutans by the green synthesized AgNPs. The results demonstrated that the 50% inhibitory concertation (IC50) values of AgNPs on NOF18 and SCC4 cells were 93.3 μg/ml and 41.2 μg/ml, respectively. Conclusion. Overall, the results of this study showed that A. spinosus extract has a good ability to produce silver nanoparticles. The AgNPs produced have significant antibacterial effects against some tooth decay bacteria. Our results also revealed that the green synthesized AgNPs are more cytotoxic against cancerous cell line than normal cell line. Further in vivo studies are required to investigate the side effects and to evaluate the effectiveness of these bacteria.


  • Open Access

    Molecular Epidemiology of Theileria annulata in Cattle from Two Districts in Punjab (Pakistan)

    by Asia Parveen, Abeer Mousa Alkhaibari, Muhammad Asif, Hamdan I. Almohammed, Zahra Naqvi, Adil Khan, Munir Aktas, Sezayi Ozubek, Muhammad Farooq, Furhan Iqbal

    The present study was designed to report the molecular prevalence of T. annulata in cattle blood samples collected from Punjab in Pakistan. A total of 428 cattle blood samples were collected from Districts Lodhran (n = 218) and Dera Ghazi Khan (n = 210). The prevalence of T. annulata was determined by the amplification of a fragment from its cytochrome b gene and parasite prevalence was significantly higher (p = 0.03) in the blood samples of cattle collected from Dera Ghazi Khan (70/210; 33%) as compared to Lodhran (52/218; 24%). Presence of T. annulata was also confirmed by the amplification of a fragment from their 30 kDa gene. The amplified PCR products of both genes were confirmed by DNA sequencing and these partial DNA sequences were submitted to GenBank. Phylogenetic analysis revealed that amplified partial gene sequences resembled previously reported T. annulata sequences in cattle from India, China, Iran, Tunisia, Turkey and Egypt. The incidence of T. annulata infection was higher in Sahiwal cattle (p = 0.04) than the other enrolled cattle breed from Dera Ghazi Khan. Female cattle from Lodhran (p = 0.02), while males (p = 0.02), animals housed in close compounds (p = 0.04), animals with a tick burden (p = 0.005) and farms with only cattle (p = 0.01) in Dear Ghazi Khan were found to be more susceptible to T. annulata infection. We recommend that large-scale tick and tick-borne disease control strategies be implemented in both districts under investigation, especially in Dera Ghazi Khan.


  • Open Access

    Molecular detection and risk factors for Anaplasma platys infection in dogs from Egypt

    by Abdelfattah Selim, Hamdan Almohammed, Abdelhamed Abdelhady, Abdulaziz Alouffi, Fahdah Ayed Alshammari

    Background: Anaplasma platys is a tick-borne bacterium which infects blood platelets of dogs, causing canine cyclic thrombocytopenia. The disease is distributed worldwide, particularly in the tropics and subtropics, but information on the epidemiology of A. platys infection in dogs is fragmentary in many countries, including Egypt. In this study, we investigated the prevalence and risk factors associated with A. platys infection in dogs from Egypt. Methods: A conventional PCR targeting a fragment of the 16S rRNA gene of A. platys was used to screen 500 dogs from five North Egyptian governorates. DNA sequencing and phylogenetic analysis were performed for one of the positive samples. Results: The overall prevalence of A. platys in the studied dogs was 6.4%. Females of the German shepherd breed without veterinary care had higher odds for A. platys positivity. High tick infestation and lack of anti-tick treatment were also identified as risk factors for A. platys infection. Phylogenetic analysis revealed that the sequence obtained herein was closely related to sequences from Egypt, South Africa and Uruguay. Conclusions: This is the first large-scale epidemiological study of A. platys in Egypt, where female German shepherd dogs without veterinary care, as well as dogs with high tick infestation and without anti-tick treatment are at a higher risk of infection. Graphical


  • Open Access

    Determination of Seroprevalence of Contagious Caprine Pleuropneumonia and Associated Risk Factors in Goats and Sheep Using Classification and Regression Tree

    by Abdelfattah Selim, Ameer Megahed, Sahar Kandeel, Abdullah D. Alanazi, Hamdan I. Almohammed

    Classification and Regression Tree (CART) analysis is a potentially powerful tool for identifying risk factors associated with contagious caprine pleuropneumonia (CCPP) and the important interactions between them. Our objective was therefore to determine the seroprevalence and identify the risk factors associated with CCPP using CART data mining modeling in the most densely sheep- and goat-populated governorates. A cross-sectional study was conducted on 620 animals (390 sheep, 230 goats) distributed over four governorates in the Nile Delta of Egypt in 2019. The randomly selected sheep and goats from different geographical study areas were serologically tested for CCPP, and the animals’ information was obtained from flock men and farm owners. Six variables (geographic location, species, flock size, age, gender, and communal feeding and watering) were used for risk analysis. Multiple stepwise logistic regression and CART modeling were used for data analysis. A total of 124 (20%) serum samples were serologically positive for CCPP. The highest prevalence of CCPP was between aged animals (>4 y; 48.7%) raised in a flock size ≥200 (100%) having communal feeding and watering (28.2%). Based on logistic regression modeling (area under the curve, AUC = 0.89; 95% CI 0.86 to 0.91), communal feeding and watering showed the highest prevalence odds ratios (POR) of CCPP (POR = 3.7, 95% CI 1.9 to 7.3), followed by age (POR = 2.1, 95% CI 1.6 to 2.8) and flock size (POR = 1.1, 95% CI 1.0 to 1.2). However, higher-accuracy CART modeling (AUC = 0.92, 95% CI 0.90 to 0.95) showed that a flock size >100 animals is the most important risk factor (importance score = 8.9), followed by age >4 y (5.3) followed by communal feeding and watering (3.1). Our results strongly suggest that the CCPP is most likely to be found in animals raised in a flock size >100 animals and with age >4 y having communal feeding and watering. Additionally, sheep seem to have an important role in the CCPP epidemiology. The CART data mining modeling showed better accuracy than the traditional logistic regression.


  • Open Access

    MOLECULAR EPIDEMIOLOGICAL STUDIES ON TRYPANOSOMA EVANSI TYPE A AND TYPE B IN CAMELS (CAMELUS DROMEDARIES) FROM FIVE DIFFERENT REGIONS OF SAUDI ARABIA USING THE ITS1 RDNA AND ROTAT 1.2 VSG GENE

    by Abdullah D. Alanazi, R. Puschendorf, Mohamed S. Alyousif, Mohamed S. Al-Khalifa, Samir A. Alharbi, Zafer S. AL Shehri, Ashraf E. Said, Ibrahim O. Alanazi, Hamdan I. Al-Mohammed

    Trypanosoma evansi is the most widespread of the pathogenic salivarian trypanosomes and cause a serious disease called (surra) that is affect the domestic animals such camels and horses in Tropical and subtropical countries and often leads to reduced productivity and economic losses. Therefore, the objectives of the present study were to determine the prevalence rates of trypanosomiasis using polymerase chain reaction (PCR) among camels from five different regions of Saudi Arabia and to sequence and characterized the T. evansi from these animals. In the current study, 832 camel blood samples collected from five different regions of Saudi Arabia for detecting T. evansi. A generic ITS1-PCR and RoTat 1.2 VSG gene were applied in this study to analyze camels’ blood samples. Molecular analysis was performed using ITS1-PCRwhich showed that the highest prevalence of trypanosomes was observed in Al-Qaseem province (50.1%) followed Riyadh province (49%), whereas in Hail and the Northern Borders, there were fewer infections with trypanosomes (28.4% &17.6%), respectively. PCR amplification was carried out targeting RoTat 1.2 VSG gene on TS1-positive samples and some of them were negative for RoTat1.2. The test negative in RoTat 1.2 PCR but ITS1 PCR positive could suggest T. evansi type B. Presence of T. evansi type B is interest to the international community, as this has a message to redesign the existing molecular and serological diagnostic markers. However, to our knowledge this the first study demonstrating T. evansi type B out of Africa.