Inhibitory Effect of Rose Hip (Rosa caninaL.) on Melanogenesis in Mouse Melanoma Cells and on Pigmentation in Brown Guinea Pigs

SummaryThe differences among human, rabbit and guinea-pig platelet adhesiveness as for inhibitions by adenosine, dipyridamole, chlorpromazine and acetylsalicylic acid are described, and the influence of measurement conditions on platelet adhesiveness is also reported. Platelet adhesiveness of human and animal species decreased with an increase of heparin concentrations and an increase of flow rate of blood passing through a glass bead column. Human and rabbit platelet adhesiveness was inhibited in vitro by adenosine, dipyridamole and chlorpromazine, but not by acetylsalicylic acid. On the other hand, guinea-pig platelet adhesiveness was inhibited by the four drugs including acetylsalicylic acid. In in vivo study, adenosine, dipyridamole and chlorpromazine inhibited platelet adhesiveness in rabbits and guinea-pigs. Acetylsalicylic acid showed the inhibitory effect in guinea-pigs, but not in rabbits.

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Delta-Tocotrienol Causes Decrease of Melanin Content in Mouse Melanoma Cells

JOURNAL OF HEALTH SCIENCE ◽

10.1248/jhs.55.314 ◽

2009 ◽

Vol 55 (2) ◽

pp. 314-318 ◽

Cited By ~ 8

Author(s):

Akihiro Michihara ◽

Sachiyo Morita ◽

Yae Hirokawa ◽

Saya Ago ◽

Kenji Akasaki ◽

...

Keyword(s):

Melanoma Cells ◽

Melanin Content ◽

Mouse Melanoma

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Novel Chemically Modified Curcumin (CMC) Derivatives Inhibit Tyrosinase Activity and Melanin Synthesis in B16F10 Mouse Melanoma Cells

Biomolecules ◽

10.3390/biom11050674 ◽

2021 ◽

Vol 11 (5) ◽

pp. 674

Author(s):

Shilpi Goenka ◽

Francis Johnson ◽

Sanford R. Simon

Keyword(s):

Enzyme Activity ◽

Parent Compound ◽

Radical Scavenging ◽

Melanoma Cells ◽

Tyrosinase Activity ◽

Partial Recovery ◽

Tyrosinase Inhibitor ◽

Pyrocatechol Violet ◽

Mouse Melanoma ◽

Chemically Modified

Skin hyperpigmentation disorders arise due to excessive production of the macromolecular pigment melanin catalyzed by the enzyme tyrosinase. Recently, the therapeutic use of curcumin for inhibiting tyrosinase activity and production of melanin have been recognized, but poor stability and solubility have limited its use, which has inspired synthesis of curcumin analogs. Here, we investigated four novel chemically modified curcumin (CMC) derivatives (CMC2.14, CMC2.5, CMC2.23 and CMC2.24) and compared them to the parent compound curcumin (PC) for inhibition of in vitro tyrosinase activity using two substrates for monophenolase and diphenolase activities of the enzyme and for diminution of cellular melanogenesis. Enzyme kinetics were analyzed using Lineweaver-Burk and Dixon plots and nonlinear curve-fitting to determine the mechanism for tyrosinase inhibition. Copper chelating activity, using pyrocatechol violet dye indicator assay, and antioxidant activity, using a DPPH radical scavenging assay, were also conducted. Next, the capacity of these derivatives to inhibit tyrosinase-catalyzed melanogenesis was studied in B16F10 mouse melanoma cells and the mechanisms of inhibition were elucidated. Inhibition mechanisms were studied by measuring intracellular tyrosinase activity, cell-free and intracellular α-glucosidase enzyme activity, and effects on MITF protein level and cAMP maturation factor. Our results showed that CMC2.24 showed the greatest efficacy as a tyrosinase inhibitor of all the CMCs and was better than PC as well as a popular tyrosinase inhibitor-kojic acid. Both CMC2.24 and CMC2.23 inhibited tyrosinase enzyme activity by a mixed mode of inhibition with a predominant competitive mode. In addition, CMC2.24 as well as CMC2.23 showed a comparable robust efficacy in inhibiting melanogenesis in cultured melanocytes. Furthermore, after removal of CMC2.24 or CMC2.23 from the medium, we could demonstrate a partial recovery of the suppressed intracellular tyrosinase activity in the melanocytes. Our results provide a proof-of-principle for the novel use of the CMCs that shows them to be far superior to the parent compound, curcumin, for skin depigmentation.

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Treatment with Uncaria tomentosa Promotes Apoptosis in B16-BL6 Mouse Melanoma Cells and Inhibits the Growth of B16-BL6 Tumours

Molecules ◽

10.3390/molecules26041066 ◽

2021 ◽

Vol 26 (4) ◽

pp. 1066

Author(s):

Ali Zari ◽

Hajer Alfarteesh ◽

Carly Buckner ◽

Robert Lafrenie

Keyword(s):

Tumour Size ◽

Melanoma Cells ◽

Tunel Staining ◽

Aqueous Extracts ◽

Ki 67 ◽

Uncaria Tomentosa ◽

Mouse Melanoma ◽

Anti Cancer

Uncaria tomentosa is a medicinal plant native to Peru that has been traditionally used in the treatment of various inflammatory disorders. In this study, the effectiveness of U. tomentosa as an anti-cancer agent was assessed using the growth and survival of B16-BL6 mouse melanoma cells. B16-BL6 cell cultures treated with both ethanol and phosphate-buffered saline (PBS) extracts of U. tomentosa displayed up to 80% lower levels of growth and increased apoptosis compared to vehicle controls. Treatment with ethanolic extracts of Uncaria tomentosa were much more effective than treatment with aqueous extracts. U. tomentosa was also shown to inhibit B16-BL6 cell growth in C57/bl mice in vivo. Mice injected with both the ethanolic and aqueous extracts of U. tomentosa showed a 59 ± 13% decrease in B16-BL6 tumour weight and a 40 ± 9% decrease in tumour size. Histochemical analysis of the B16-BL6 tumours showed a strong reduction in the Ki-67 cell proliferation marker in U. tomentosa-treated mice and a small, but insignificant increase in terminal transferase dUTP nick labelling (TUNEL) staining. Furthermore, U. tomentosa extracts reduced angiogenic markers and reduced the infiltration of T cells into the tumours. Collectively, the results in this study concluded that U. tomentosa has potent anti-cancer activity that significantly inhibited cancer cells in vitro and in vivo.

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