Antiviral Activity of Dicrocephala Integrifolia (Kuntze) Against Herpes Simplex Type-1 Virus: An in vitro Study

Abstract

At present, acyclovir is commercially available as the drug of choice for managing herpes simplex type I (HSV-1) viral infection. However, terpenoids the aqueous were DI extracts found to was be in present the range in 71.31 the extracts. ± 2.65 to The >100 CC 50 μg/ml values com- of the high prevalence of the infection coupled with the emergence of resistant viral strains has limited its effectiveness. Thus, the development of novel pared the pre-adsorptive to >100 μg/ml phase of acyclovir. of HSV-1 The activity EC 50 values was in of the crude range extracts 54.45±3.45 of DI on to antiviral agents is crucial. Practitioners of herbal medicine in Kenya make >100μg/ml compared to 4.772±7.81μg/ml of acyclovir whilst use of Dicrocephala integrifolia (DI) for the management of several diseases of the crude extracts of DI on the post-adsorptive phase of including viral infections. However, information on the efficacy of this plant against HSV-1 viral infection is not available. The aim of the present study was to determine the in vitro antiviral activity of crude extracts of DI against HSV-1. Methods: Leaves, roots, flowers and stems of DI were extracted using water (W) and methanol (ME) and qualitatively screened to identify the phytoconstituents present. Furthermore, the anti HSV-1 activity of the obtained extracts was evaluated on Vero cell lines using the 3-[4, 5 dimeth- ylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide] assay. The 50% cytotoxic concentration (CC 50 Sample collection Whole plant material of DI (Figure 1) was collected from Mabariri, Nyamira county, Kenya (S 000 31. 367s, E 0340 56. 426s) by Dr. Abdi Hussein Hadun in December 2015. Taxonomic identification was done by Mr. Antony Mutiso, a botanist at the University of Nairobi’s School of Biological Science. A voucher number AHH2015/01 was deposited at the University of Nairobi herbarium for future reference. Sample preparation Plant material was carefully washed and allowed to dry in a clean, well- ventilated room at the Department of Public Health, Pharmacology and Toxicology, University of Nairobi. Dried parts were then ground to a fine powder using an electric grinder and packed in zip-locked plastic bags awaiting further use. Extraction of different plant parts The method of Mwitari et al.13 was used with minor modifications. Briefly, 350g of dry powder material of different parts of DI were accurately weighed on an analytical balance, poured into separate conical flasks and soaked in 1 liter of distilled water and methanol separately for 48 h with frequent shaking. The resultant mixtures were then filtered. The aqueous filtrates were freethe HSV-1 EC 50 activity value was in the range 45.270±4.31 to >100μg/ml compared to >100μg/ml of acyclovir. Conclusion: The results suggest that crude extracts of DI may be a reservoir of phytochemicals with potentially good efficacy against HSV-1. Key words: Dicrocephala integrifolia, Iin vitro, Cytotoxicity, Antiviral activity, HSV-1. ze-dried to a lyophilized powder which was then weighed and transferred into clean sample bottles and stored at -20oC awaiting further use. The organic filtrates were transferred to a rotavapor operating at 40°C to remove residual solvent. The resulting product was then weighed and transferred to clean sample bottles, labelled and stored at -20oc awaiting further use.