METHODS: Geraniin was prepared from Nephelium lappaceum rind by reverse phase C-18 column chromatography. Cytotoxicity of geraniin towards Vero cells was evaluated using MTT assay while IC50 value was determined by plaque reduction assay. The mode-of-action of geraniin was characterized using the virucidal, attachment, penetration and the time-of-addition assays'. Docking experiments with geraniin molecule and the DENV envelope (E) protein was also performed. Finally, recombinant E Domain III (rE-DIII) protein was produced to physiologically test the binding of geraniin to DENV-2 E-DIII protein, through ELISA competitive binding assay.
RESULTS: Cytotoxicity assay confirmed that geraniin was not toxic to Vero cells, even at the highest concentration tested. The compound exhibited DENV-2 plaque formation inhibition, with an IC50 of 1.75 μM. We further revealed that geraniin reduced viral infectivity and inhibited DENV-2 from attaching to the cells but had little effect on its penetration. Geraniin was observed to be most effective when added at the early stage of DENV-2 infection. Docking experiments showed that geraniin binds to DENV E protein, specifically at the DIII region, while the ELISA competitive binding assay confirmed geraniin's interaction with rE-DIII with high affinity.
CONCLUSIONS: Geraniin from the rind of Nephelium lappaceum has antiviral activity against DENV-2. It is postulated that the compound inhibits viral attachment by binding to the E-DIII protein and interferes with the initial cell-virus interaction. Our results demonstrate that geraniin has the potential to be developed into an effective antiviral treatment, particularly for early phase dengue viral infection.
Method: The English version of the 5D-IS was translated into Malay according to International Guidelines. Face and content validity was determined by an expert panel and pilot tested in patients with end-stage renal disease (ESRD). The M5D-IS was then validated in a tertiary hospital in Malaysia from May to June 2016. We recruited patients with (i.e., patients with ESRD) and without pruritus (i.e., patients with stage 1-3 CKD) (to determine if the M5D-IS could discriminate between the two groups), and administered the M5D-IS at baseline and 2 weeks later. Exploratory factor analysis was used to examine the construct validity. Internal consistency was assessed using Cronbach's alpha and intraclass correlation coefficient was calculated to assess the reliability of the instrument.
Results: A total of 70 participants were recruited (response rate = 100%). The majority were males (51.4%) and Malay (67.1%). Exploratory factor analysis revealed that the 5D-IS had 2-factor loadings: "daily routine activity" and "pattern of itching," which explained 77.7% of the variance. The overall score of the M5D-IS, as well as for each domain, was significantly worse in participants with pruritus (9.83 ± 0.35), compared to those without pruritus (5.51 ± 0.93, p