Phytochemical screening and potential antioxidant, antibacterial and anti-melanoma activities of <i>Rollinia dolabripetala</i> leaves

Plants are an important source of natural compounds used for medicine. The Annonaceae family exhibits a cytotoxic effect on different tumor strains and on several bacterial strains. This unprecedented study investigates the antioxidant, anti-melanoma, anti-staphylococcal and anti-streptococcal potential of hydroalcoholic extracts of <i>Rollinia dolabripetala</i> leaves and of 1.7 -dihydroxyxanthone and xanthone phytocompounds. The determination of the antioxidant capacity was performed by the DPPH and lipid peroxidation methods. Isolated phytochemicals xanthone and 1.7-dihydroxyxanthone were also included in cytotoxicity and antimicrobial tests. Assays for antitumor leaf potential were performed on melanoma carcinogenic cells and assays for antibacterial potential were performed on Gram-positive <i>Staphylococcus aureus</i> 29213 (SA13), <i>S. aureus</i> 4075 (SA75) and <i>Streptococcus bovis</i>-01 (SB01) strains. The phytochemical prospection revealed the presence of flavonols, tannins and xanthones. Halo inhibition (mm) of Gram-positive SA13 was 7.00 ± 0.38. There was no inhibitory effect on SA75 and SB01 strains. The antitumor activity, expressed in the minimum lethal concentration (GI₅₀) was in μg/mL: <i>R. dolabripetala</i>: 47.04, 1.7-dihydroxyxanthone: 0.98, Xanthone: 3.38, and 5-Fluorouracil: 0.24. When comparing treatments with 5-Fluorouracil, the best correlation between dosage and the inhibition rate occurs with 1.7-dihydroxy-xanthone followed by <i>R. dolabripetala</i> treatment. In conclusion, <i>R. dolabripetala</i> exhibits antioxidant, anti-staphylococcal and anti-melanoma bioactivities with 1.7-dihydroxy-xanthone exhibiting the best correlation between dosage and inhibition rate. Phytochemicals such as, flavonols, tannins and xanthone reinforce the biological results obtained. The seasonal factor in the collection of plant samples may explain the discrepancies in the phytochemical data of <i>R. dolabripetala</i> compared to other species of the genus.