Anti-herpes Simplex Virus Type 1 Activity of Kaempferia parviflora Extract

Abstract

This research aims to evaluate the anti-herpes simplex virus type-1 (anti-HSV-1) activity of K. parviflora extracts using an in vitro model. The plant extracts were prepared from dried rhizome using different extraction solvents such as methanol, ethanol, acetone, ethyl acetate, dichloromethane and hexane. For phylogenetic identification of K. parviflora, two non-coding regions in chloroplast DNA, including trnL intron and trnL-F intergenic spacer (IGS) were evaluated by polymerase chain reaction and direct nucleotide sequencing. The results showed that PCR products of approximately 600 and 400 bp in trnL intron and trnL-F IGS were observed, respectively. The nucleotide sequence analysis of K. parviflora showed 99.82% and 99.45% homology with reference sequences of K. parviflora in GenBank database in trnL intron and trnL-F IGS, respectively. Furthermore, K. parviflora CMU01 showed 98.98% and 98.72% homology with Curcuma longa in trnL intron and trnL-F IGS, respectively. For total polyphenol and flavonoid contents of K. parvifora extracts, the hexane extract had the highest amount of total polyphenol contents (153.39 : 13. 14 ug GAE/g extract). The methanolic extract was the highest amount of total flavonoid contents (176.81 士 4.22 ug QE/g extract). For the cytotoxicity of K. parviflora extracts on normal mouse fibroblast cell lines (L929) and African green monkey kidney cell line (Vero cells), the methanolic extract showed the lowest cytotoxic on L929 cell lines with a CCso value of 25.27 + 2.54 ug/mL. In addition, the hexane extract showed the lowest cytotoxic on Vero cells with a CCso value of 41.77 = 5.62 ug/mL. For the anti-HSV-1 of K. parviflora extract, the results revealed that the ethanolic extract had the highest percentage of inhibition of 52.57% after 72 h of treatment at the concentration of 6.0 pg/mL when compared with other solvents extraction, the ECso values and TI values of ethanolic extract were 4.49 + 1.00 and 6.59, respectively. The results showed that the highly polar solvent extracts include the ethanolic extract showed potent anti-HSV-1 activity. It could be the most anti-HSV-1 active compounds were extracted in polar solvents, such as flavonoid compounds. The results were corresponded with the total flavonoid contents of ethanolic extract, which the total flavonoid contents of ethanolic extract were higher than non-polar solvent extracts. The mechanism of function of K. parviflora extract on anti-HSV activity could be interfered with the HSV-1 protein expression. In addition, the ECso value and TI value of acyclovir were 0.11 t 0.02 ug/mL and 1103.00, respectively. These results indicated that acyclovir had low cytotoxic on Vero cells and highly inhibit HSV-1 replication.