Pusat Pengajian Sains Kesihatan - Tesis
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- PublicationThe effect of CRX-527 on pro-inflammatory cytokine production against mycobacterium bovis BCG clone expressing the c-terminus of merozoite surface protein-1 of plasmodium falciparum(2021-10)Yusoff, Wan Raihan WanMalaria infection is a leading cause of mortality and morbidity in African and Southeast Asian countries. TLR-4 has been shown to be important in malaria immunity and can be possibly use as an adjuvant to enhance the long-lasting immune response against BCG-MSP1C. This research was conducted to determine the effects of toll-like receptor 4 (TLR-4) agonist, CRX527, on cellular and humoral immune response against Mycobacterium bovis bacille Calmette-Guérin (BCG) expressing the C-terminus of merozoite surface protein-1 of Plasmodium falciparum (BCG-MSP1C). In this study six groups of mice (n=6 per group) were injected with 200 μl intraperitoneal phosphate buffered saline T80 (PBS-T80), 200 μl of PBS-T80 containing 2 x 106 cfu/ml of BCG or rBCG in the presence or absence of CRX527. Blood was collected from the tail veins of the mice before the start of the immunisation and 4 weeks after each immunisation. Enzyme linked immunosorbent assay (ELISA) was carried out to measure the production of TNF-α and IL-12 in the sera of the immunized mice. The findings showed that the sera of rBCG without CRX immunised group yielding the most increase in IL-12 followed by the mice injected with rBCG with CRX. In contrast, the entire mice immunised groups showed decrease production for TNF-α after the immunisation. Therefore, this combination of rBCG with TLR4 agonist can be used to create a vaccine that capable of inducing a strong and long-lasting immunity to allow the immune system to be prepared for the emergence of multidrug-resistant strains of malaria diseases.
- PublicationElucidation of the vasorelaxation mechanisms induced by syzygium polyanthum leaves aqueous extract(2021-08)Hairul, Nuriana MunirahPrevious studies have demonstrated that aqueous extract of Syzygium polyanthum leaves (AESP) has vasorelaxation activity. However, there is still very little information on its mechanism of action on direct vasorelaxation activity. Therefore, the present study was designed to determine endothelium-dependant relaxation of the AESP and investigated the mechanism of vasorelaxation. The in vitro method was utilised, mounting the aortic ring into myograph, precontracted with phenylephrine (1 μM) and studied based on the agonist-antagonist inhibition protocols. The endothelium-dependant was studied on endothelium intact and denuded thoracic arterial ring isolated from Wistar-Kyoto (WKY) rats. The vasorelaxation mechanisms of AESP were evaluated on the endothelial-intact aortic rings. This study shown that the AESP relaxation was endothelium-dependant. The vasorelaxant effect of AESP was attenuated by L-NAME (endothelial nitric oxide synthase/eNOS inhibitor, 100 μM) and ODQ (soluble guanylate cyclase/sGC inhibitor, 10 μM). However, methylene blue (cyclic guanosine monophosphate/cGMP lowering agent, 10 μM) and indomethacin (non-selective COX inhibitor, 10 μM) did not produce significant inhibition on the AESP relaxation. Taken together, the findings indicated that vasorelaxation of AESP was endothelium-dependent, through NO/eNOS and sGC pathways.
- PublicationEvaluation of Hibiscus Sabdariffa L. calyx as cardioprotective agents(2021-10)Asri, Nur Ain MohdCardiovascular diseases (CVD), particularly Myocardial Infarction (MI), are the leading cause of mortality and morbidity worldwide. Hypercholesterolaemia increased the risk of developing CVD. Hibiscus sabdariffa L. (Roselle) has been used traditionally to reduce cholesterol levels. However, there is limited evidence of the plant's cardioprotective effects. The present study evaluated the effects of the aqueous extract of H. sabdariffa calyx (AEHS) on hypercholesterolaemia-myocardial infarction (HC-MI) rats. The proximate analysis was conducted to determine the nutritional composition of a self-made high-cholesterol diet (HCD). There are three phases in the animal study. The first phase (induction phase) was aim to develop an HC rat model using HCD for 6 weeks. The second phase (intervention phase) was to evaluate the effects of 30 days of AEHS treatment on body mass index (BMI), fasting blood sugar (FBS), fasting cholesterol (FC) and systolic blood pressure (SBP) in the rat. The third phase is where isoprenaline induced the myocardial infarction in rats (HC-MI) at day- 29 and 30. Although the cholesterol level was normal in HC-MI rats, there was a fatty change in the liver (steatosis). The HC-MI rat was also established based on raised cardiac troponin T level and the necrotic changes on the left ventricle tissue. However, AEHS did not significantly improve the parameters in the intervention phase. Moreover, AEHS did not reduce the cardiac troponin T significantly compared to the untreated-HC-MI, which is concurrent with the histology of the left ventricle. However, RFT and LFT were normal in AEHS-treated HC-MI. Collectively, further studies are needed to elucidate H. sabdariffa as a cardioprotective agent.
- PublicationDevelopment and optimization of rapid resolution liquid chromatography (RRLC) method following solid-phase extraction for determination of anthocyanin in rat plasma(2021-08)Sauji, Nadiratul AsyikinThe growing interest of anthocyanins in roselle has brought upon the importance of the compound’s analysis to investigate its pharmacological properties. Sensitive and specific analytical methods are required to accurately analyse the anthocyanin present in the sample. In this study, rapid resolution liquid chromatography (RRLC) was used to analyse cyanidin-3-O-glucoside chloride, one of the anthocyanins found in roselle. Spectrophotometric analysis and optimization of chromatographic conditions were performed to develop a suitable and precise RRLC method for the determination of the selected anthocyanin. Both liquid-liquid extraction (LLE) and solid-phase extraction (SPE) method were performed to evaluate the best extraction method of anthocyanin in the rat plasma sample. The optimised chromatographic method demonstrated that the mobile phase composition of 0.1% trifluoroacetic acid aqueous solution and acetonitrile in the ratio of 81:19, respectively with a flow rate of 0.5 mL/min, at 30°C column temperature and detection wavelength of 525 nm were suitable for RRLC analysis of cyanidin-3-O-glucoside chloride. SPE was chosen as the final extraction method in the study as it produced better peaks in the chromatogram compared to LLE. In conclusion, the developed RRLC method in this study can be used to determine anthocyanins in the future pharmacokinetic study of roselle.
- PublicationEvaluation of the male reproductive toxicity of the anthocyanin-rich standardized extract of hibiscus sabdariffa L.loaded niosomes in sprague dawley rats(2021-08)Ghazali, Mohamad Luqman HanafiHibiscus sabdariffa has long been widely utilised for medicinal purposes. Aqueous extract of H. sabdariffa encapsulated in niosome (AEHS-Nio) was formulated to improve the effectiveness of this plant extract. It was administered to forty male Sprague Dawley rats at four different dosages 0 (control), 250, 500, and 1000 mg/kg/day by oral gavage for 63 days to evaluate the potential effects of AESHNio on the male reproductive system. A substantial number of parameters were evaluated throughout the treatment period that was comprised of three phases; premating, mating, and post-mating. Results obtained demonstrated that the effects of AEHS-Nio on the male rat reproductive system were slightly significant for certain doses. No mortality and any signs of physical toxicity were observed. The mating performance was also not affected. However, due to the established anti-obesity effects of H. sabdariffa extract, the bodyweight of rats were considerably changed. As a consequence, the reproductive organ weights were found to be statistically different. Furthermore, AEHS-Nio increased the testosterone levels and sperm counts of the 250 and 1000 mg/kg dose groups, while the 500 mg/kg dose group showed considerably low levels for both parameters. The 500 mg/kg dose group was detected to exhibit inconsistent data for certain parameters when compared to other groups, which might be caused by confounding factors instead of AEHS-Nio. Therefore, the current data suggest that AEHS-Nio did not toxic to the reproductive system of male rats. Nevertheless, AEHS-Nio should be consumed with caution as long as the dose administered does not exceed 250 mg/kg of bodyweight a day.The human risk on male reproductive parameters associated with its use should also be reasonably estimated.