Planta Med 2016; 82(S 01): S1-S381
DOI: 10.1055/s-0036-1596314
Abstracts
Georg Thieme Verlag KG Stuttgart · New York

Cytotoxicity of Grewia tenax on A375 human melanoma cells, and its antimelanogenesis and antioxidant activities

AJ AlQathama
1  Department of Pharmaceutical and Biological Chemistry, University College London School of Pharmacy, 29 – 39 Brunswick Square, WC1N 1AX London, United Kingdom
2  School of Pharmacy, Umm-al-Quran University, Makkah, Kingdom of Saudi Arabia
,
AR Yonbawi
1  Department of Pharmaceutical and Biological Chemistry, University College London School of Pharmacy, 29 – 39 Brunswick Square, WC1N 1AX London, United Kingdom
,
A Bader
2  School of Pharmacy, Umm-al-Quran University, Makkah, Kingdom of Saudi Arabia
,
S Gibbons
1  Department of Pharmaceutical and Biological Chemistry, University College London School of Pharmacy, 29 – 39 Brunswick Square, WC1N 1AX London, United Kingdom
,
JM Prieto
1  Department of Pharmaceutical and Biological Chemistry, University College London School of Pharmacy, 29 – 39 Brunswick Square, WC1N 1AX London, United Kingdom
› Author Affiliations
Further Information

Publication History

Publication Date:
14 December 2016 (online)

 

As part of our continuous efforts in screening the bioactivities of Saudi Arabian plants, we here characterize the in vitro cytotoxicity of Grewia tenax (Forssk.) Fiori on the human melanoma A375 cell line with the SRB [1] and Alamar Blue [2] methods, its inhibition of melanogenesis by mushroom tyrosinase enzyme [3] and its free radical scavenging activity against the synthetic stable radical DPPH [4]. The active secondary metabolites were dereplicated by means of HPTLC analyses. Only the chloroform extract of G. tenax had significant inhibitory effects on the cytotoxicity assays (IC50= 45 – 83 µg/ml). Cell cycle analyses showed that this extract arrested the cell cycle at S phase as well as inducing the activity of caspases 3/7. The inhibitory activity upon tyrosinase enzyme was restricted to one of the fractions of the hexane extract (IC50 = 59 µg/ml). HPTLC analyses confirmed that it contained lupeol (main component) and beta-sitosterol (minor amounts). Lupeol is here described in this plant species for the first time and is already a known inhibitor of this enzyme5. Based on the results of the DPPH assay the hexane and chloroform fractions were devoid of any radical scavenging activity and only one of the fractions of the methanol extract demonstrated a significant activity (EC50 = 10 µg/ml). Further studies are carried out to identify further active principles and opportunities for the use of this popular herbal medicinal plant in the context of this research.

Acknowledgements: AA and AY were sponsored by The Ministry of Higher Education and are thankful to the Arabian Cultural Bureau.

Keywords: Cytotoxicity, tyrosinase, melanoma, antioxidant activity, natural product.

References:

[1] Houghton P, Fang R, Techatanawat I, Steventon G, Hylands PJ, Lee CC. The sulphorhodamine (SRB) assay and other approaches to testing plant extracts and derived compounds for activities related to reputed anticancer activity. Methods 2007; 42: 377 – 387

[2] Rampersad SN. Multiple applications of Alamar Blue as an indicator of metabolic function and cellular health in cell viability bioassays. Sensors 2012; 12: 12347 – 12360

[3] Masuda T, Yamashita D, Takeda Y, Yonemori S. Screening for tyrosinase inhibitors among extracts of seashore plants and identification of potent inhibitors from Garcinia subelliptica. Biosci Biotechnol Biochem. 2005; 69:197 – 201

[4] Hevesi BT, Houghton PJ, Habtemariam S, Kéry A. Antioxidant and antiinflammatory effect of Epilobium parviflorum Schreb. Phytother Res 2009; 23: 719 – 724

[5] Azizuddin, Khan AM, Choudhary MI. Tyrosinase inhibitory potential of natural products isolated from various medicinal plants. Nat Prod Res 2011; 25: 750 – 753