Anticancer Activity of Certain Herbs and Spices on the Cervical Epithelial Carcinoma (HeLa) Cell Line

Abstract

Acetone extracts of selected plant species were evaluated for their in vitro cytotoxicity against a noncancerous African green monkey kidney (Vero) cell line and an adenocarcinoma cervical cancer (HeLa) cell line. The plants studied were Origanum vulgare L. (Oregano), Rosmarinus officinalis L. (Upright and ground cove rosemary), Lavandula spica L. (Lavender), Laurus nobilis L. (Bay leaf), Thymus vulgaris L. (Thyme), Lavandula x intermedia L. (Margaret Roberts Lavender), Petroselinum crispum Mill. (Curly leaved parsley), Foeniculum vulgare Mill. (Fennel), and Capsicum annuum L. (Paprika). Antioxidant activity was determined using a quantitative DPPH (1,1-diphenyl-2-picryl hydrazyl) assay. The rosemary species exhibited effective radical scavenging capacity with 50% inhibitory concentration (IC(50)) of 3.48 ± 0.218 μg/mL and 10.84 ± 0.125 μg/mL and vitamin C equivalents of 0.351 g and 1.09 g for McConnell's Blue and Tuscan Blue, respectively. Cytotoxicity was measured using XTT (Sodium 3'-[1-(phenyl amino-carbonyl)-3,4-tetrazolium]-bis-[4-methoxy-6-nitro] benzene sulfonic acid hydrate) colorimetric assay. Only L. nobilis and O. vulgare exhibited pronounced effects on the HeLa cell line. Dose-dependent studies revealed IC(50) of 34.46 ± 0.48 μg/mL and 126.3 ± 1.00 μg/mL on the HeLa cells and on the Vero cells 124.1 μg/mL ± 18.26 and 163.8 μg/mL ± 2.95 for L. nobilis and O. vulgare, respectively. Light (eosin and haematoxylin staining) and confocal microscopy (Hoechst 33342, acridine orange, and propidium iodide staining) were used to evaluate the cytotoxic mechanism of action for L. nobilis and O. vulgare.

Figure 1

Comparison of the IC₅₀ values and the Vitamin C equivalents of the plant extracts.

Figure 2

Haematoxylin and eosin staining of HeLa medium only control cells (a), vehicle-treated control cells (b), 34.46 μg/mL Laurus nobilis treated cells (c), 68.92 μg/mL Laurus nobilis treated cells (d), and 0.05 μg/mL actinomycin D (e), after 72 h of exposure (400x magnification).

Figure 3

Haematoxylin and eosin staining of Vero medium only control cells (a), vehicle-treated control cells (b), 124.1 μg/mL Laurus nobilis treated cells (c), 248.2 μg/mL Laurus nobilis treated cells (d), 34.46 μg/mL Laurus nobilis treated cells (e), and 0.05 μg/mL actinomycin D (f), after 72 h of exposure (400x magnification).

Figure 4

Haematoxylin and eosin staining of HeLa medium only control cells (a), vehicle-treated control cells (b), 126.3 μg/mL Origanum vulgare treated cells (c), 252.6 μg/mL Origanum vulgare treated cells (d), and 0.05 μg/mL actinomycin D (e), after 72 h of exposure (400x magnification).

Figure 5

Haematoxylin and eosin staining of Vero medium only control cells (a), vehicle-treated control cells (b), 163.8 μg/mL Origanum vulgare treated cells (c), 327.6 μg/mL Origanum vulgare treated cells (d), 126.3 μg/mL Origanum vulgare treated cells (e), and 0.05 μg/mL actinomycin D (f), after 72 h of exposure (400x magnification).

Figure 6

Hoechst 33342 and propidium iodide staining of HeLa medium only control cells (a), vehicle-treated control cells (b), 34.46 μg/mL Laurus nobilis treated cells (c), 68.92 μg/mL Laurus nobilis treated cells (d), and 0.05 μg/mL actinomycin D (e), after 72 h of exposure (1000x magnification).

Figure 7

Hoechst 33342 and propidium iodide staining of Vero medium only control cells (a), vehicle-treated control cells (b), 124.1 μg/mL Laurus nobilis treated cells (c), 248.2 μg/mL Laurus nobilis treated cells (d), 34.46 μg/mL Laurus nobilis treated cells (e), and 0.05 μg/mL actinomycin D (f), after 72 h of exposure (1000x magnification).

Figure 8

Hoechst 33342 and propidium staining of HeLa medium only control cells (a), vehicle-treated control cells (b), 126.3 μg/mL Origanum vulgare treated cells (c), 252.6 μg/mL Origanum vulgare treated cells (d), and 0.05 μg/mL actinomycin D (e), after 72 h of exposure (1000x magnification).

Figure 9

Hoechst 33342 and propidium iodide staining of Vero medium only control cells (a), vehicle-treated control cells (b), 163.8 μg/mL Origanum vulgare treated cells (c), 327.6 μg/mL Origanum vulgare treated cells (d), 126.3 μg/mL Origanum vulgare treated cells (e), and 0.05 μg/mL actinomycin D (f), after 72 h of exposure (1000x magnification).