DefinePK

Research Objective

To assess the chemomodulatory potential of the n-hexane extract of Conyza bonariensis (CB) against skin carcinogenesis induced by DMBA and Croton oil in mice, and to evaluate its cytotoxic properties against human skin carcinoma cell line (SCC-13) and human peripheral blood mononuclear cells (PBMC) in vitro.

Methodology

The study involved in vitro and in vivo experiments. In vitro, the cytotoxic effects of CB n-hexane extract were tested on SCC-13 and PBMC cell lines using the MTT assay. In vivo, a two-stage skin carcinogenesis model was induced in Swiss albino mice using 7-12-dimethylbenz(a)anthracene (DMBA) and Croton oil. Mice were treated orally or topically with CB n-hexane extract at different doses. Various parameters were measured, including tumor incidence, tumor volume, tumor weight, body weight, and biochemical markers of oxidative stress (GSH, GSHPx, SOD, Catalase, MDA). Histopathological studies were also conducted. HPLC was used to identify active constituents.

Methodology Flowchart

                        graph TD
    A["Plant Collection and Extraction n-hexane"] --> B["In Vitro Cytotoxicity Assay on SCC-13 & PBMC"];
    B --> C["Determine IC50 & Selectivity Index"];
    A --> D["In Vivo Carcinogenesis Model Induction - DMBA/Croton Oil"];
    D --> E["Treatment with CB n-hexane Extract - Oral/Topical"];
    E --> F["Observation & Measurement: Tumor incidence, volume, weight, body weight"];
    E --> G["Biochemical Analysis: Antioxidant markers, lipid peroxidation"];
    E --> H["Histopathological Examination"];
    F --> I["Data Analysis"];
    G --> I;
    H --> I;
    I --> J["Conclusion & Interpretation"];                    

Discussion

The findings suggest that the n-hexane extract of Conyza bonariensis possesses significant chemopreventive activity against skin carcinogenesis. Its cytotoxic and antioxidant effects are attributed to its triterpenoid constituents and flavonoids like quercetin. The extract's ability to modulate oxidative stress markers and reduce lipid peroxidation indicates its potential to protect against carcinogen-induced damage. The study validates traditional claims regarding the use of Conyza bonariensis for cancer treatment.

Key Findings

The CB n-hexane extract exhibited selective cytotoxicity against SCC-13 cells (IC50=7.5 µM) with a selectivity index of 4.05 compared to PBMC (IC50=30.4 µM). In vivo, oral and topical administration of CB n-hexane extract significantly reduced the number and incidence of skin papillomas. The extract also augmented the actions of catalase and superoxide dismutase, increased glutathione content, and reduced skin lipid peroxidation levels in a dose-dependent manner. Histopathological analysis showed that the extract restored normal skin structure and architecture.

Conclusion

The n-hexane extract of Conyza bonariensis demonstrates significant chemomodulatory potential against DMBA/Croton oil-induced skin carcinogenesis in mice. It exhibits selective cytotoxicity in vitro and effectively reduces tumor development and oxidative stress in vivo, supporting its traditional use and suggesting its promise as a source for novel chemopreventive agents.

Fact Check

1. IC50 values: The study reported an IC50 of 7.5 µM for CB n-hexane against SCC-13 cells and 30.4 µM against PBMC.
2. Duration of study: The in vivo experiment was conducted for 16 weeks.
3. Carcinogens used: The skin carcinogenesis was induced by 7-12-dimethylbenz(a)anthracene (DMBA) and Croton oil.

Mind Map