METHODS: Anti-plasmodium effect of andrographolide against Plasmodium falciparum strains was screened using the conventional malaria drug sensitivity assay. The drug was incubated with uninfected RBCs to monitor its effect on their morphology, integrity and osmotic fragility. It was incubated with the plasmodium infected RBCs to monitor its effect on the parasite induced permeation pathways. Its effect on the potential of merozoites to invade new RBCs was tested using merozoite invasion assay.
RESULTS: It showed that at andrographolide was innocuous to RBCs at concentrations approach its therapeutic level against plasmodia. Nevertheless, this inertness was dwindled at higher concentrations.
CONCLUSIONS: In spite of its success to inhibit plasmodium induced permeation pathway and the potential of merozoites to invade new RBCs, its anti-plasmodium effect can't be attributed to these functions as they were attained at concentrations higher than what is required to eradicate the parasite. Consequently, other mechanisms may be associated with its claimed actions.
MATERIALS AND METHOD: In this experiment, the potential of embelin, isolated from Embelia ribes, to inhibit the growth and sensitize CQ action was screened using SYBRE-green-I based drug sensitivity and isobologram assays, respectively. Its effect on red blood cells stability was screened to assess its safety. To explore its molecular mechanism, its effect on plasmodial Hemozoin and the in vitro β-hematin formation was screened as well. Furthermore, its anti-oxidant activity was measured using the conventional in vitro tests and its molecular characters were obtained using Molispiration program.
RESULTS: The results showed that its anti-plasmodial effect was weaker than CQ but synergism was obtained when they were combined at ratios lower than 5:5 CQ/embelin. Furthermore, β-hematin formation was inhibited by embelin without showing any synergism after mixing with CQ.
CONCLUSION: Overall, embelin is not ideal to be suggested as a conventional antiplasmodium but it has a potential to ameliorate CQ resistance. Furthermore, its action is not related to its impact on hemozoin formation. Further, investigations are recommended to illustrate its detailed mechanism of action. Abbreviation used: CQ-DV-PBS-HEPES: Chloroquine-Digestive vacuole-Phosphate-buffer-saline-4-(2-hydroxyethyl-1-piperazin-ethan-sulphoni-acid), EDTA: Ethylen-diamin-tetra-acetic-acid, g.m.wt: Gram molecular weight, cMCM: Complete-malaria-culture-medium, Hct: Hematocrite, PRBCs: Parasitized-redblood-cells, nRBCs: Normal-red-blood-cells, RT: Room temperature, IC: Inhibitory concentration, FIC: Fractional inhibitory concentration, iCM: Incomplete-culturemedium, BSA: Bovin serum albumin, MTT: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, DPPH: 2,2-diphenyl-1- picrylhydrazy, BHT: Butylatedhydroxyl-toleuen, PSA: Polar surface area, ClogP: Log partition coefficient (octanol/water), GPCR: G-protein-coupled-receptors, DMSO: Dimethylsulphoxide, NaOH: Sodium hydroxide.
MATERIALS AND METHODS: A total of 333 patients from the Family Medicine Specialist Clinic at Hospital Sultan Abdul Aziz Shah were recruited between March 2022 and February 2023. Blood samples were taken after a 12-hour fasting period, and levels of fasting blood sugar (FBS), triglycerides (TG), total cholesterol (TC), HDL cholesterol, and LDL cholesterol were measured. 150 plasma samples were randomly selected for cytokine analysis of CCL2 and TNF-α using the Human Magnetic Luminex Assay. Patients' cardiovascular risk was assessed using the FRS calculator. The Kruskal-Wallis test was used to analyze the relationship between cytokine levels and FRS categories, followed by a post hoc test with Bonferroni correction. A logistic regression model was implemented to assess the independent effects of these variables.
RESULTS: The results demonstrated a significant association between the level of chemokines CCL2 and proinflammatory TNF-α, and FRS categories (low-risk, moderate-risk, and high-risk). CCL2 levels were notably higher in the high-risk group, as were TNF-α levels, with both biomarkers showing increasing trends with higher risk categories, (p<0.001, effect size=0.32) and (p<0.001, effect size-0.29), respectively. Multiple logistic regression analysis showed that dyslipidaemia, FBS, and TNF-α remained significant after adjusting for other variables. Specifically, dyslipidaemia had lower odds of being in the high-risk group (AOR: 0.04), while FBS (AOR: 3.19) and TNF-α (AOR: 1.18).
CONCLUSION: This study highlights the potential of CCL2 and TNF-α as biomarkers for CVDs risk assessment. Integrating these biomarkers into CVDs risk prediction models may enhance the precision of identifying individuals at elevated risk. However, the study's cross-sectional design and small sample size for cytokine analysis constrain the findings. Future research should explore the long-term predictive value of these cytokines in larger, longitudinal cohorts and explore more advanced techniques for improving CHD risk prediction models.