Screening of the crude acetone extracts of toona ciliata, seriphium plumosum and schkuhria pinnata for their potential anticancer activities against hela cervical cancer cells

Abstract

Cervical cancer is the fourth most common cancer in females, and the seventh of all cancer types in both genders, with an estimated 500,000 new cases each year. As with liver cancer, a large majority (around 85%) of the global burden occurs in the less developed regions, where it accounts for almost 12% of all female cancers. About 90% of cervical cases are associated with human papillomavirus (HPV) as a causative agent and this virus is frequently transmitted through sexual contact involving exchange of fluids (Walboomers et al., 1997). Due to the ineffectiveness, undesirable side effects and costly treatment for the disease the current study was aimed at determining the anti-proliferative effects of extracts of selected medicinal plants for their anticancer activity on HeLa cell line invitro. In order to accomplish the outcome of this research study, medicinal plants (Toona cilliata, Seriphium plumosum and Schkuhria pinnata) from Limpopo Province (South Africa) with history of traditional use on cervical cancer-associated patients were selected. The Toona cilliata plant leaves were collected from Tzaneen, area while Seriphium plumosum and Schkuhria pinnata leaves were collected from Mankweng area. The dried leaves were grounded into powder and extracted using acetone. Thereafter, extracted leaf materials of selected plants were subjected to fingerprint profiling using TLC silicon coated plates immersed in tanks with different mobile phases (TEA, CEF and EMW) of various increasing polarities since. The plates were sprayed with vanillin/H2SO4, dried and visualised under UV light. Scavenging ability of the plant extracts was determined through investigating the presence of antioxidant activities using 0.2% of the 2,2- diphenyl-1- picrylhydrazyl (DPPH) indicator. The quantitative presence of total phenolic and flavonoids contents was also determined using garlic and quercetin as standards, respectively. Quantitative antioxidant scavenging activities were also determined and ascorbic acid was used as a positive control. This was followed by quantitative determination of ferric reducing power and thereafter the EC50 values of the extracts were determined by linear regression. Cell proliferation or viability was determined using the 3[4, 5 dimethylthiazol-2-yl]-2-5 diphenyltetrazolium (MTT) assay with actinomycin as a xv

positive control and untreated cells as the negative control. Apoptotic effects of the extracts were determined using the Annexin V Fluos staining kit. This was followed by determining whether apoptosis was calcium dependent or independent using a calorimetric assay. In comparing the acetone extract yield per 10 g leaves of plants, Toona cilliata leaves exhibited the highest yield followed by Seriphium plumosum and with the least yield from Schkuhria pinnata. The finger print profile showed the prominent separation and was achieved from all the plants when using the non-polar TEA solvent. All plants were shown to contain extracts with varying levels of antioxidant activity especially when using CEF and EMW mobile phases. When evaluating the total phenolic and flavonoids contents all plant extracts exhibited presence of phenolic compounds with high presence observed in Seriphium plumosum and Toona cilliata. Extracts from Seriphium plumosum and Toona cilliata showed to have higher concentrations of phytochemicals that may be of a benefit in antioxidant activities as compared to Schkuhria pinnata in relation to the positive control and a similar trend were observed in the ferric reducing power assay. Extracts from Seriphium plumosum were shown to have the best IC50 scavenging values followed by Toona cilliata and Schkuhria pinnata respectively. All the plants exhibited free radical scavenging abilities with Seriphium plumosum shown to possess higher activities in comparison with the positive control. All the plants exhibited a dose-dependent cytotoxicity activity against the HeLa cervical cell line. Evidence of induced apoptotic activity was observed in HeLa cells when using extracts from Seriphium plumosum and Toona cilliata. Induction of apoptosis by plant extracts was shown to be calcium dependent as there was a decrease in calcium concentration with a decrease in the number of viable cells. In conclusion, the leaf extracts from Toona cilliata, Seriphium plumosum and Schkuhria pinnata contain compounds of various polarities with freeradical, antioxidant and anti-cancerous activities that may be beneficial if further studies are conducted to identify chemical compounds that may inhibit anticervical cancer activities.