Antioxidant, antibacterial and antiviral properties of Goniothalamus umbrosus leaves methanolic extract

Abstract

The antioxidant, antibacterial, and antiviral effects of crude methanol extract from the leaves of Goniothalamus umbrosus were studied. Good free radical scavenging activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay was shown by the extract at EC50 of 0.263 mg/ml compared to 0.01 mg/ml for trolox as the positive control. The extract showed greater antibacterial activity against Gram-positive bacteria than Gram-negative with methicillin resistant Staphylococcus aureus (MRSA) isolates were more sensitive than methicillin sensitive S. aureus. Cytotoxicity testing of the leaf extract and goniothalamin a styrylpyrone derivative (SPD) as a lead compound found mostly in the genus Goniothalamus was performed on Vero cells. From the test, the CC50 value for the extract was 125 µg/ml and for SPD 31.25 µg/mL (1.563x10-7 µM). Antiviral test was carried out against Herpes Simplex virus type 1 infected to Vero cells. The results showed that G. umbrosus leaf methanol extract was effective in showing the antiviral activity in all three treatments but SPD is effective only in the first treatment; 1) (C+V)+E, extract and SPD were able to control virus post-infection 2) (C+E)+V: the extract has prophylactic activity implied by treatment of cells with the extract for one day before viral infection and 3) C+(V+E) refers to the ability of extract to control viral infectivity when extract and virus was added simultaneously to cell. This study showed the potential of non-cytotoxic G. umbrosus leaf methanol extract as herbal alternative against MRSA and herpes simplexviruse (HSV) -1.