Assessment of Antiviral Activity of Curcuma longa on Two RNA Viruses

Major pandemics and seasonal epidemics that have ravaged the world in the past and even at present, are mostly caused by RNA viruses. This has necessitated the need for continuous research to identify important natural products, with antiviral potentials, which can be harnessed for use in the prevention and treatment of viral infections. This study therefore, evaluated the antiviral property of Curcuma longa on two important RNA viruses of public health importance, namely polio and measles viruses. Extraction of active ingredients from turmeric rhizomes was done with the use of Analar grade methanol and concentrated using rotary evaporator. Polio and measles viruses were isolated from their respective vaccines using Reed-Muench method. Infective doses of the viruses and toxicity profile of extract were determined. Confluent Vero cells were inoculated with the viruses at different dilutions of the extract, incubated and observed for 7 days. Methanol extract of Curcuma longa inhibited polio virus at the maximum non-toxic concentration (MNTC) of 0.031μg μL-1 and inhibitory concentration (IC50) of 0.067 μg μL-1 with selectivity index of 2.16. Inhibition by the extract was observed prior to infection with the viruses. Phytochemical analysis of the extract showed presence of terpenes, saponins, alkaloids, flavonoids, tannins, cardiac glycosides and phenol as the bioactive phytochemicals. This study has shown that curcuma longa has potent inhibitory activity, hence can be harnessed in the development of an effective antiviral agent against polio and measles viruses.