Protective effect of Ocimum sanctum on 3-methylcholanthrene, 7,12-dimethylbenz(a)anthracene and aflatoxin B1 induced skin tumorigenesis in mice
Authors: Bhola N Paul
Subhash K Khanna
D Kar Chowdhuri
Yogeshwer Shukla
Shipra Rastogi
Mukul Das
Journal: Toxicology and Applied Pharmacology (2007)
Discipline: PHARMACOLOGY & TOXICOLOGY
Keywords: Ocimum sanctum; skin tumorigenesis; alcoholic extract; mouse model; MCA
Affiliations: Industrial Toxicology Research Centre, Mahatma Gandhi Marg, P.O. Box 80, Lucknow-226001, India.

Abstract:  A study on the protective effect of alcoholic extract of the leaves of Ocimum sanctum on 3-methylcholanthrene (MCA), 7,12-dimethylbenzanthracene (DMBA) and aflatoxin B1 (AFB1) induced skin tumorigenesis in a mouse model has been investigated. The study involved pretreatment of mice with the leaf extract prior to either MCA application or tetradecanoyl phorbol acetate (TPA) treatment in a two-stage tumor protocol viz a viz, DMBA/TPA and AFB1/TPA. The results of the present study indicate that the pretreatment with alcoholic extract of the leaves of O. sanctum decreased the number of tumors in MCA, DMBA/TPA and AFB1/TPA treated mice. The skin tumor induced animals pretreated with alcoholic extract led to a decrease in the expression of cutaneous gamma-glutamyl transpeptidase (GGT) and glutathione-S-transferase-P (GST-P) protein. The histopathological examination of skin tumors treated with leaf extract showed increased infiltration of polymorphonuclear, mononuclear and lymphocytic cells, decreased ornithine decarboxylase activity with concomitant enhancement of interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) in the serum, implying the in vivo antiproliferative and immunomodulatory activity of leaf extract. The decrease in cutaneous phase I enzymes and elevation of phase II enzymes in response to topical application of leaf extract prior to MCA, AFB1, DMBA/TPA and AFB1/TPA treatment indicate the possibility of impairment in reactive metabolite(s) formation and thereby reducing skin carcinogenicity. Furthermore, pretreatment of leaf extract in the carcinogen induced animals resulted in elevation of glutathione levels and decrease in lipid peroxidation along with heat shock protein expression, indicating a scavenging or antioxidant potential of the extract during chemical carcinogenesis. Thus it can be concluded that leaf extract of O. sanctum provides protection against chemical carcinogenesis in one or more of the following mechanisms: (i) by acting as an antioxidant; (ii) by modulating phase I and II enzymes; (iii) by exhibiting antiproliferative activity. 

Retracted: No

PubPeer comments:
  Fig. 8. Heat shock protein (HSP70) expression in carcinogen induced mice pretreated with and without leaf extract of O. sanctum. [...] (B) SDSu2013PAGE, note the equal intensity of each protein band appearing on the CBB stained gel. Ten micrograms of each protein sample loaded on a 12.5% SDSu2013PAGE and stained with CBB. Lane 1u2014control; lane 2u2014leaf extract treated; lane 3u2014MCA treated; lane 4, MCA +leaf extract treated; lane 5u2014 DMBA TPA treated; lane 6u2014 DMBA TPA +leaf extract treated; lane 7u2014 AFB1 TPA treated; and lane 8u2014 AFB1 TPA +leaf extract treated; lane M is indicated as standard marker proteins Three pairs of duplicated lanes, as marked. The identity between lanes 2 and 4 is not entirely obvious due to what may be retouching, so I include an increased-contrast version where it is clearer.  ,