In vitro anti-HIV-1 activities of kaempferol and kaempferol-7-O-glucoside isolated from Securigera securidaca

Abstract

Previously, we reported that the kaempferol and kaempferol-7-O-glucoside isolated from Securigera securidaca showed potent anti-HSV activity. In the present study the anti-HIV-1 activities of kaempferol and kaempferol-7-O-glucoside are investigated at different concentrations (100, 50, 25 and 10 μg/ml) using HIV-1 p24 Antigen kit. Real-time Polymerase chain reaction (RT-PCR) assay was also used for quantification of full range of virus load observed in treated and untreated cells. According to the results of RT- PCR, tested compounds at a concentration of 100 μg/ml exerted potent inhibitory effect. Time of drug addition experiments demonstrated that these compounds exerted their inhibitory effects on the early stage of HIV infection. The results also showed potent anti-HIV-1 reverse transcriptase activity. Antiviral activity of kaempferol-7-O-glucoside was more pronounced than that of kaempferol. These findings demonstrate that kaempferol-7-O-glucoside could be considered as a new potential drug candidate for the treatment of HIV infection which requires further assessments.

Keywords: Antiviral activity; Flavonol; HIV-1; Real Time PCR assay.

Fig. 1

Effect of kaempferol and kaempferol-7-O-glucoside isolated from S. securidaca and zidovudine on HIV-1 replication in peripheral blood mononuclear cells. The 50% inhibitory concentration (IC50) of each extract was calculated using regression line. Each bar represents the mean ± SD of three independent experiments.

Fig. 2

Effect of Kaempferol (◊) and Kaempferol-7-O-glucoside (□) on proliferation of lymphocyte

Fig. 3

Time of addition effect of kaempferol (white bar) and kaempferol-7-O-glucoside (gray bar) obtained from S. securidaca on HIV replication in Vero cells. The extracts was added either before (−2 and −4), during (0) and after (2 and 4) virus infection. The extracts added before virus infection was rinsed off prior to the virus exposure. Each value is the result of mean ± SD of three independent experiments. Zidovudine has been used as positive control (hatched bar).

Fig. 4

HIV-1 reverse transcriptase inhibition by kaempferol and kaempferol-7-O-glucoside isolated from S. securigera The data represent the mean HIV-1 reverse transcriptase inhibition of extracts. The reverse transcriptase inhibitions of extracts are the mean of three separate experiments.