Cytotoxic and antioxidant properties of phenolic compounds from Tagetes patula flower

Abstract

Context: Tagetes patula Linn. (Asteraceae) (French Marigold) flowers are used by local practitioners for cancer treatment; however, it lacks scientific justification.

Objective: Identification of bioactive compounds in T. patula flower for cytotoxic and growth inhibition in human cancer cell lines along with its antioxidant properties using chemical and cell based systems.

Materials and methods: The T. patula flower methanol extract, its seven fractions, and three phenolic compounds including methyl protocatechuate (1), patuletin (2), and patulitrin (3) were evaluated using sulforhodamine-B assay against HeLa, HT-144, NCI-H460, MCF-7, PC-3, and SF-268 human cancer cell lines. In parallel, antioxidant activity was evaluated using chemical (DPPH^·, deoxyribose, and lipid peroxidation assays) and cell-based chemiluminescence systems (human neutrophils and mice macrophages).

Results: The methanol extract and ethyl acetate insoluble fraction exhibited cytotoxic and growth inhibitory effects against HeLa in which 2 exhibited highest cell growth inhibition (GI₅₀: 0.6 ± 0.1 µg/ml) and cytotoxicity (LC₅₀: 2.5 ± 0.1 µg/ml). It also scavenged LOO^· (IC₅₀: 6.5 ± 0.7 µg/ml) and (IC₅₀: 27.5 ± 1.3 μg/ml) in chemical systems and human neutrophils, respectively. However, 1 preferably scavenged H₂O₂–Cl⁻ (IC₅₀: 0.5 ± 0.01 μg/ml) in mice macrophages.

Discussion and conclusion: Compound 2 from T. patula flower exhibited both growth inhibitory and cytotoxic properties while 1 and 3 were only growth inhibitory against HeLa. 1–3 also displayed antioxidant properties implying its probable role in growth inhibition/cytotoxic action. The present study provides scientific evidence for the use of T. patula flower in cancer treatment by traditional healer.

• Antiproliferative
• free radical scavenger
• French marigold
• HeLa cell line
• patuletin

Acknowledgements

We are thankful to the National Cancer Institute, Frederick, MD, for providing us cell lines under a Material Transfer Agreement.

Declaration of interest

The authors declare that there are no conflicts of interest. Ms. Samina Bano was financially supported through funds provided by Higher Education Commission, Islamabad, Pakistan, through the “Indigenous 5000 Fellowship Program”.