Τετάρτη, 17 Ιουλίου 2013

Chemoprevention potential of plant-derived naphthoquinone derivatives, leaf powder of the medicinal plant Lawsonia inermis L, commonly known as 'henna', was evaluated by its inhibition of the Epstein-Barr virus early antigen (EBV-EA) activation induced by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) in Raji cells.

Anticancer Agents Med Chem. 2013 Jul. [Epub ahead of print]

Chemoprevention of Skin Cancer: Effect of Lawsonia Inermis L. (Henna) Leaf Powder
and its Pigment Artifact, Lawsone in the Epstein- Barr Virus Early Antigen
Activation Assay and in Two-Stage Mouse Skin Carcinogenesis Models.

Kapadia GJ, Rao GS, Sridhar R, Ichiishi E, Takasaki M, Suzuki N, Konoshima T,
Iida A, Tokuda H.

Department of Pharmaceutical Sciences, College of Pharmacy, Howard University,
Washington, DC 20059, USA.

In continuation of our studies with chemoprevention potential of plant-derived
naphthoquinone derivatives, leaf powder of the medicinal plant Lawsonia inermis
L, commonly known as 'henna', was evaluated by its inhibition of the Epstein-Barr
virus early antigen (EBV-EA) activation induced by the tumor promoter
12-O-tetradecanoylphorbol-13-acetate (TPA) in Raji cells. Lawsone
(2-hydroxy-1,4-naphthoquinone), the reddish orange pigment artifact formed during
the extraction or preparation of the dye from henna leaves and believed to be the
active component, was also assessed in this in vitro assay. Both showed a
profound inhibition (>88%) of EBV-EA activation. In the in vivo two-stage mouse
skin carcinogenesis study using UV-B radiation for initiation and TPA for tumor
promotion, oral feeding of henna (0.0025%) in drinking water ad libitum decreased
tumor incidence by 66% and multiplicity by 40% when compared to the positive
control at 10 weeks of treatment. Similarly, in the above mouse model, orally fed
lawsone (0.0025%) decreased tumor incidence by 72% and multiplicity by 50%. The
tumor inhibitory trend continued throughout the 20-week test period. Similar
antitumor activities were observed when henna (0.5 mg/ml) was applied topically
on the back skin in the UV-B initiated, TPA promoted and peroxynitrite initiated,
TPA promoted mouse skin carcinogenesis models. Topically applied lawsone (0.015
mg/ml) also exhibited similar protection against tumor formation in the
7,12-dimtehylbenz(a)anthracene induced and TPA promoted skin cancer in mice.
Also, there was a delay of 1 to 2 weeks in tumor appearance in both henna and
lawsone treated groups compared to control in all three test models. This study
ascertains the skin cancer chemopreventive activity of henna leaf powder and
lawsone when administered by either oral (through drinking water) or topical (by 
application on the back skin) routes. Further, it emphasizes the need for the
evaluation of these henna-derived green chemopreventive candidates in combination
with currently used sunscreen agents for complementary anticancer potential
against UV-induced skin carcinogenesis.

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