Search

Ethnopharmacology Relevance: GB-2a is a I3-naringenin-II8-eriodictyol compound isolated from Garcinia gardneriana (Planchon & Triana) Zappi, a plant used in folk medicine for the treatment of skin disorders., Aim of Study: In the search for new depigmenting agents, this study was carried out to investigate the in vitro effects of GB-2a isolated from G. gardneriana (Planchon & Triana) Zappi in B16F10 melanoma cells., Materials and Methods: The effects of GB-2a were evaluated through determination of melanin biosynthesis in B16F10 melanoma cells in comparison with the reference drug kojic acid (500µM). In parallel, the GB-2a effect was assessed in a cell viability assay. Mushroom tyrosinase activity assays were conducted to verify the effect of this enzyme. In order to ascertain the nature of enzyme inhibition on tyrosinase, kinetics analysis of the GB-2a was performed with L-tyrosine and L-3,4-dihydroxyphenylalanine (L-DOPA) substrates., Results: The results showed that GB-2a biflavonoid significantly inhibited the melanin content, without reducing cell viability. GB-2a also showed a strong antityrosinase activity in the mushroom tyrosinase assay. GB-2a inhibited the tyrosinase activity, exerting a mixed inhibition. For the L-tyrosine substrate the inhibition was in non-competitive mode and for L-DOPA it was in uncompetitive mode., Conclusion: GB-2a biflavonoid promoted inhibition on tyrosinase activity and reduced melanin biosynthesis in B16F10 cells, which suggests great potential for medical and cosmetic uses as a depigmenting agent., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Ethnopharmacological Relevance: Synadenium grantii Hook f. has traditionally been used to treat various neoplastic diseases in southern Brazil., Aim of Study: Evaluation of the antitumoural potential of Synadenium grantii latex against B16F10 melanoma cell line using in vitro and in vivo models, as well as a phytochemical study of the latex., Materials and Methods: The in vitro antitumoural activity was performed using MTT and trypan blue assays with different latex concentrations (1.7 µg-7.0 µg/well and 1.22 mg-4.88 mg/well). Flow cytometry was used to determine the progression of the cell cycle. The in vivo activity was performed by subcutaneously injecting melanoma cells in the dorsum of C57BL6 mice, followed by treating the mice with a popular form of use of the latex (garrafada) administered orally. After sacrificing the animals, histological analysis of the organs was performed by hematoxylin-eosin staining. The phytochemical study of the latex was performed by NMR and chromatographic procedures and the extracts and isolated substances were evaluated by IR, 1D and 2D NMR analysis., Results: The Synadenium grantii latex exhibited decreased cell viability of the melanoma line in a concentration and time-dependent manner, and also cell cycle arrest in the S-G2/M phase. The latex caused a 40% reduction in the volume of tumours of the mice with melanomas. Histological examination of the organs of these animals showed no differences between groups. The phytochemical investigation resulted in the isolation and identification of triterpene euphol and the steroid citrostadienol, which were tested against the strain of melanoma. Euphol showed no antitumoural activity, while the steroid citrostadienol showed reduced cytotoxic activity., Conclusion: The Synadenium grantii latex presented in vitro and in vivo cytotoxic effects with antitumoural activity against B16F10 melanoma cells., (© 2013 Elsevier Ireland Ltd. All rights reserved.)