Anticancer Activity of Certain Herbs and Spices on the Cervical Epithelial Carcinoma (HeLa) Cell Line Danielle Berrington and Namrita Lall
Department of Plant Sciences, University of Pretoria, Pretoria 0002, South Africa
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 (IC50) of 3.48 +/- 0.218 μg/mL and 10.84 +/- 0.125 ug/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 IC50 of 34.46 μg/mL and 0.48 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.
Conclusion In this study common herbs and spices were chosen to determine their anticancer activity. Herbs and spices were chosen due to their bioactive components which have the ability to reduce the risk of cancer through their antimicrobial, antioxidant, and antitumourogenic activity . The rosemary species were found to have the highest antioxidant content which could be attributed to the high content of polyphenolic compounds. Therefore the rosemary species possess potential chemopreventive properties. After performing the XTT cytotoxicity assay it was hypothesized that Laurus nobilis, with an SI of 3.61, and Oregano vulgare, with an SI of 1.30, were the best candidates for further investigation. Both these extracts were further investigated to determine their mechanism of cell death by observing them under light microscopy and confocal microscopy. From the microscopy images it was observed that in both cell lines morphological changes did appear after exposure to various concentrations of the acetone extracts. Although these microscopy images were in agreement with one another that apoptosis was the possible mechanism of cell death, as seen by the characteristic features of hypercondensed chromatin (mostly in HeLa cells) and cellular debris (seen only in Vero cells), they are not sufficient enough to definitely confirm that apoptosis is taking place and therefore more sensitive assays such as flow cytometry need to Be used to confirm that apoptosis is taking place. However Laurus nobilis did show promising results as an anticancer agent due to its relatively high toxicity on the HeLa cell line and at this same concentration a low toxicity on the Vero cell line.