Phytochemical investigation and evaluation of the potential antiviral effect and acute oral toxicity of Scoparia dulcis L. (broom)
Scoparia, medicinal plants, HSV-1, flavonoids and broom.
Scoparia dulcis L. species (Plantaginaceae), commonly known as broom, is popularly used as, anti-inflammatory and in the treatment of gastrointestinal diseases. The presence of several secondary metabolites were until described including terpenes as scopadulcic acids A and B, scopadiol, scopadulciol, scopadulinic, scoparic acids A - C and some flavonoids. Thus, the present study aimed to evaluate the phytochemical profile and the antiviral potential of S. dulcis leaf extract, as well as their toxicity. Hidroethanolic extracts were prepared with samples collected in the urban area of Natal and in the rural area of Serra Caiada-RN, using two different methods and ethanol proportions: maceration 35% and 70%, turbolysis 35% and 70%. Then, phytochemical profile was analyzed by Thin Layer Chromatography and by Liquid Chromatography coupled to a mass spectrometer and the content of flavonoids total phenols were evaluated. The cell viability test in VERO cells was carried out with the extracts produced from the urban area by the MTT test. Then, the antiviral activity of the extracts against herpes virus type I-HSV-1 was evaluated by the tests: virucidal activity, post-infection, concomitant and pre-treatment. Acute oral toxicity was evaluated using only the maceration extract 70 % obtained from the rural area of Serra Caiada in in vivo model, by oral administration of 2000 mg/kg. Through chromatography analysis coupled to a mass spectrometer, 31 substances were identified in S. dulcis leaf extracts, the majority of which were flavonoids as O-glycosides derived from the quercetin nucleus, added to terpenoids such as benzyl alcohol, benzoic acid methyl ester, palmitic acid methyl ester, oleic acid methyl ester, phytol acid methyl ester, stearic acid methyl ester, n-tetracosane and five other unidentifiable compounds. Regarding the content of total phenols and flavonoids, the extracts that presented the highest content were: turbolysis 70% 104.18 ± 0.05 for phenols and 64.06 ± 0.05 for flavonoids and maceration 70% rural area with 98.04 ± 0.03 and 56.75 ± 0.06. Cell viability above 80% was observed for all extracts up to a concentration of 250 μg/ml, except to extract obtained by turbolysis 35% which presented cell viability below 50%. Regarding the antiviral results, extract obtained by turbolysis 70% proved to be the most efficient when compared to the other extracts, promoting a significant inhibition of the HSV-1 virus. In the non-clinical study of acute oral toxicity in vivo of maceration extract 70 % (rural area) no changes were observed in the biochemical, behavioral or hematological parameters, suggesting that the extract is safe in acute administration. Scoparia dulcis showed a potential antiviral effect and safety in vitro and in vivo acute model of toxicity.