Background:The emergence of drug resistance towards Herpes Simplex Virus Type 1 (HSV-1) has encouraged scientists to develop novel lower toxicity and highly effective anti-HSV drugs. Styrylpyrone derivative (SPD) is a bioactive compound isolated from the roots and leaves of Goniothalamus sp. It is believed that this compound possesses antiviral properties against HSV-1. Objective: This paper introduces the interaction of SPD towards HSV-1 through in silico study of molecular docking and molecular dynamic simulation. Materials and Methods: Molecular docking is a computational tool which is used to study the molecular interaction between two or more structures. ADME/T properties of the SPD were generated using the SwissADME online tool in which SPD was found to have a good pharmacokinetic profile. Results: Molecular docking study revealed that SPD has a high docking score of -7.9 Kcal/mol. SPD has a strong affinity with the thymidine kinase (PDB id: 1OF1) producing hydrogen bond and non-polar interaction at the target point of amino acid residue. Conclusion: Molecular docking analysis provides new insight into the structure-based design of SPD compounds with better antiviral activity against HSV-1.

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A study was conducted to investigate the anti-viral effect of a styrylpyrone derivative (SPD) called goniothalamin and the effects on the dengue virus serotype 2 (DENV-2) replication cycle. The SPD was prepared from the root of Goniothalamus umbrosus after purification with petroleum ether. The isolated SPD was then subjected to gas chromatography–mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) analyses for structure validation. The cytotoxicity of the SPD was evaluated using a cell viability assay, while the anti-viral activity of the SPD towards DENV-2 was confirmed by conducting a foci reduction assay which involved virus yield reduction, time-of-addition, and time removal assays. Transcriptomic analysis via quantitative real-time polymerase chain reaction (qRT-PCR) using the DENV-2 E gene was conducted to investigate the level of gene transcript. Immunocytochemistry analysis was used to investigate the effects of SPD treatment on protein E expression. Finally, software molecular docking of the SPD and E protein was also performed. The cytotoxicity assay confirmed that the SPD was not toxic to Vero cells, even at the highest concentration tested. In the time-of-addition assay, more than 80% foci reduction was observed when SPDs were administered at 2 h post-infection (hpi), and the reduction percentage then dropped with the delay of the treatment time, suggesting the inhibition of the early replication cycle. However, the time removal assay showed that more than 80% reduction could only be observed after 96 h post-treatment with the SPD. Treatment with the SPD reduced the progeny infectivity when treated for 24 h and was dose-dependent. The result showed that transcript level of the E gene in infected cells treated with the SPD was reduced compared to infected cells without treatment. In immunocytochemistry analysis, the DENV-2 E protein exhibited similar expression trends, shown by the gene transcription level. Molecular docking showed that the SPD can interact with E protein through hydrogen bonds and other interactions. Overall, this study showed that SPDs have the potential to be anti-DENV-2 via a reduction in viral progeny infectivity and a reduction in the expression of the DENV-2 E gene and protein at different phases of viral replication. SPDs should be further researched to be developed into an effective anti-viral treatment, particularly for early-phase dengue viral infection.

Background and Objectives: Catharanthus roseus is generally used to treat many diseases in folklore remedies. The present study is aimed at determining phytochemical constituents, cytotoxicity and antiviral activities for crude extract of the plant. Materials and Methods: The whole plant of C. roseus was extracted using methanol extraction method. Phytochemical qualitative screening was carried out for C. roseus extract according to standard procedures used to test for the presence of alkaloid, saponin, terpenoid and steroid. Cytotoxicity was assessed using 3-(4,5-dimethylthiazol-2,5-diphenyltetrazolium bromide (MTT) assay. Plaque reduction assays were carried out to evaluate the antiviral activity of C. roseus extract against herpes simplex virus type 1 (HSV-1). These include post-treatment, pre-treatment and virucidal assays. Results: C. roseus extract contain secondary metabolites such as alkaloid, saponin and terpenoid but does not contain steroid. Cytotoxicity screening against Vero cells using MTT assay showed that the CC50 values for crude extract of C. roseus was 0.5 mg/mL. The extract prepared from C. roseus possesses phytochemical compound that was non-cytotoxic to the cell with potential antiviral activity. Plaque reduction assays against herpes simplex virus type 1 (HSV-1) showed that the selective indices (SI = CC50 / EC50) of C. roseus extract in post-treatment, pre-treatment and virucidal assays were 36, 20 and 4.7 respectively. The results revealed that the extract prepared from C. roseus possesses phytochemical compound that was non-cytotoxic to the cell with potential antiviral activity. Conclusion: This study showed that C. roseus extract has promising potential to be explored as anti-HSV-1 agent regardless of the mode of treatment.

Background: Cynometra cauliflora is a species of tree in the family Fabaceae and has been used in folk medicinal preparation. Objectives: In this study, Cynometra cauliflora methanolic leaves extract was tested against clinical isolate herpes simplex virus type-1 (HSV-1). Materials and Methods: The leaves of C. cauliflora plant was extracted using methanol extraction method. Cytotoxicity was assessed using 3-(4,5-dimethylthiazol-2,5-diphenyltetrazolium bromide (MTT) assay. Plaque reduction assays were carried out to evaluate the antiviral activity of C. cauliflora extract against HSV-1. These include post-treatment, pre-treatment and virucidal assays. Results: The value of cytotoxic concentration, CC 50 of C. cauliflora extract was 36 mg/ mL. High antiviral activity was observed in post-treatment. C. cauliflora extract treatment was found to not interfere directly to infectious particle and confer mild protection when given as prophylaxis. Conclusion: This study provides important novel insights on the phytomedicinal properties of C. cauliflora extracts on HSV-1.