An ethnobotanical survey of medicinal plants used by traditional healers for the treatment of cancer in Hammanskraal and Winterveld, Tshwane Metropolitan Municipality, South Africa

Background Knowledge of medicinal plants used by the traditional healers are mostly confined among the locals and the adherents, hence, proper enquiry and documentation can help the ever dynamic scientific world to find permanent cure to the menace of such deadly diseases such as cancer. This study aimed at (1) specifically recording medicinal plants traditionally used for the treatment of cancer in Hammanskraal and Winterveld, South Africa, and (2) documenting the different methods of preparation and administration of those medicinal plants as recorded during the study. Method An open-ended semi-structured questionnaire was administered to 90 willing traditional healers in Hammanskraal and Winterveld area, Tshwane Municipality, South Africa to document plants used for cancer treatments. The study was conducted over a period of six months (July – December, 2018). Descriptive statistics was used to present the obtained data. Results The study recorded twenty-eight plant species belonging to 18 families for the treatment of different types of cancer. Plant species in the Fabaceae family particularly Lessertia frutescens (L.) Goldblatt and J.C. Manning, Senna italica Mill and Trifolium pratense L. were the most prominently mentioned (highest citation frequency) by the traditional healers for lung, and skin cancer treatment. Based on the citation frequency, the most treated cancer by the traditional healers is in the order: skin cancer > lung cancer > breast cancer > prostate cancer > cervical cancer. The method of preparation included decoction (32.3%), infusion (29%), paste (16.1%) and maceration (22.6%). Conclusion In addition to the documentation of indigenous knowledge related to the use of medicinal plants in the traditional management of cancer in South Africa, this study opens a vista for investigations into the phytochemical and pharmacological properties of the documented plants.


Introduction
Cancer is a serious health challenge rated as the second leading cause of death worldwide next to cardiovascular diseases 1 . The International Agency for Research on Cancer indicated that there were 18.1 million new cases and 9.6 million deaths in 2018, up from the estimated 14.1 million new cancer cases and 8.2 million cancer-related deaths in 2012 2 . Projections based on the Global Burden of Cancer study indicate a substantive increase to over 29 million new cancer cases by year 2040, due to population growth and other social and economic factors 3 . Torre et al. 4 stated that out of all the new cancer cases globally, over 55% were from developing countries. This scenario plays out because of the low quality of healthcare management system and lack of resources to combat the incidences 5 . Herbal medicines are prepared using plant parts such as the root, stems, barks, leaves, flowers, fruits or the seeds, harvested from the wild or conservation parks. Africa's richness in cultural and floral diversity provides the necessary recipe for development of new drugs either traditionally or by modern medicine 6 . Conservatively, about 90% of the African population particularly the rural dwellers are still dependent on traditional medicine 7 and Southern Africa is known to have a large number of indigenous and useful medicinal plants, which have ben used as alternative medicine for many decades 8 . World Health Organization (WHO) shows a livid desire and encourages the documentation of medicinal plants used in treating diseases by natives from different parts of the world 9 . Despite the long history of cancer treatment using herbal remedies in South Africa, there is scarcity of information recording these medicinal plants in Hammanskraal and Winterveld area of Tshwane Metropolitan district. Therefore, documenting these plants becomes imperative so as not to lose vital information resulting from the demise of the traditional healers and also to ignite further scientific exploration.
In this study, we documented the plant species (indigenous and alien) used in the treatment of cancer by traditional healers specifically, Tswana speaking population that resides in Hammanskraal and Winterveld, Tshwane Metropolitan Municipality, South Africa with a view to providing baseline data for future studies into the phytochemical and pharmacological potential of these plants in relation to the management of cancer. The main objectives were to (1) specifically investigate and record medicinal plants used for the treatment of cancer in Hammanskraal and Winterveld, and (2) document the methods of preparation and administration of these medicinal plants during the treatment of different types of cancer.

Methodology Study Area
This study was done in Hammanskraal and Winterveld, Tshwane Metropolitan Municipality, South Africa. Hammanskraal is situated in the northern part of the Gauteng Province, which lies in the latitude 25° 41'' S and longitude 28° 26'' E. Hammanskraal is a large rural area dominated by farms and small holdings with settlers from different Provinces but largely Tswana speaking 10 . On the other hand, Winterveld is located in northwest part of Pretoria and forms part of the Tshwane Metropolitan Municipality. Winterveld lies in the latitude 25° 42'' S and longitude 27° 95'' E10. Winterveld was designated as an apartheid relocation settlement for Bophuthatswana population of South Africa 10 . The study was conducted over a period of six months (July -December, 2018).

Ethnobotanical and Identification Methods
Information was sourced from the traditional healers through oral interview with some structured questions administered as questionnaires after several reconnaissance visits. The total number of traditional healers per study site was 45. The questions focused on medicinal plants used by the local people from the study sites for the treatment of various cancer types and number of years of traditional healing practice by each practitioner. Furthermore, information about the plant parts used, recipe preparation and methods of recipe administration were documented during the study. Informed consent of the traditional healers who participated in the interview was obtained, including the usage of information given with respect to this study. Plants were collected for voucher number assignment after obtaining collecting permit. Plants collection trip involved the research team, traditional healers and Mr Petros (a Botanist) from the University of Pretoria. Voucher number assignment was done by Magda Nel and the voucher specimens deposited at the H.G.W.J. Schweickerdt Herbarium, University of Pretoria.

Statistical analysis
Data were presented using descriptive statistics such as percentages and frequencies. Frequency index of each plant species was calculated using the formula: Where FI is % of frequency of citation for one plant species by respondents (traditional practitioners), FC is the number of traditional practitioners who cited the use of a particular plant species, and N is the number of traditional practitioners 11 .

Results and Discussion Interviews with Traditional Practitioners
A total number of ninety traditional healers (45 per township) who were willing to provide information on their scope of work and ready to share their op-erational methods responded to the questionnaires. Seventy-five percent (75%) of the traditional healers in both locations were females and 25% were males. This is in consonance to the reports of Benarba et al. 12 and Tchicaillat-Landou et al. 13 in their ethnobotanical study on medicinal plants used by traditional healers for the treatment of oxidative stress-related diseases in Congo Basin and Algeria where females dominated the gender of the traditional healers. Sixty-three percent (63%) of the traditional healers in our study were between the ages 40 years and above with over fifteen years' practice experience. Tchicaillat-Landou et al. 13 also reported the ages of the traditional healers interviewed in their ethnobotanical study to be between 40 and 70 years. The ages of the remaining 37% traditional healers were below 40 years with less than 10 years' experience suggesting less interest in traditional practice by the younger generation.

Plant Frequency index, Habits and Parts Mostly Used for Cancer Treatment
Lessertia frutescens (Fabaceae), recorded the highest frequency index i.e. it is the mostly used plant species by the traditional healers in the study locations for skin and lung cancer treatment. It has a long history of usage in the treatment of various diseases according to the folklore medicine 14 . The plants least mentioned were Euphorbia ingens E. Mey. ex Boiss., Justicia sp var. capensis Thunb., and Asparagus laricinus Burch (Table 1). Based on the documented plants and the citation frequency during the study, plants habit was in the order: climber < trees < bulbs < herbs = shrubs. Shrubs and herbs were more favored by the traditional healers over other plant habits, which may be linked to the ever present status of shrubs and herbs throughout the season of the year. In agreement to the above assertion, factors such as availability throughout the season of the year, shape, smell, color and size of plants (shrubs and herbs) were attributed to the choice of plants used for treatment in the study of Maema et al. 15 . The plant parts mostly used in the therapeutic preparations by the traditional practitioners were leaves > roots > bulbs = stems > barks > fruits (Table 1; Figure 1). Several ethnobotanical surveys have reported leaves as the mostly used plant parts for treatment of diseases by locals 13,16 . For example, Tchicaillat-Landou et al. 13 in their survey on treatment of oxidative stress by traditional practitioners in Congo noted the leaves as the mostly used plant part. Similarly, Savikin et al. 16 reported that leaves were the mostly used plant part in their ethnobotanical study in South-western Serbia. Thorns, latex, flowers, and corms were rarely used for recipe during cancer treatment (Figure 1).

Preparation and Administration of Recipe
Decoction (32.3%) was the most preferred method of recipe preparation used by the traditional healers when compared to other three methods namely infusion, maceration and paste ( Figure 2). This finding is in concordance with the report of Raez et al. 17 where decoction was reported as the preferred method of recipe preparation in their study. Oral administration (75%) was the mostly used method by the traditional healers for treatment application as documented in this study ( Figure 3). Maema et al. 15 in their study of invasive plant species used for the treatment of diseases also recorded oral administration as the preferred method of medication on patients during treatment course. According to Yang and Ross 18 in their study on the theories and concepts in the composition of Chinese herbal formulas, decoction with oral administration was reported to be absorbed quickly and have the strongest action among all the traditional types of recipe preparation and administration.

Conclusions
The practice of traditional medicine is an age long practice in South Africa and plays a critical role in healthcare management practices. This study documented plants that have been in use by the traditional healers for different cancer treatments from two areas in Tshwane Metropolitan Municipality. Literature have shown that a number of these documented plants are yet to undergo in vivo evaluation and clinical trials for cancer management. This study therefore increases the archive of documented plants for further in vivo investigation. Further studies on these documented plants are required and this should include research that will investigate the anticancer ability of these plants without compromising the immune system of the individuals when administered. Efficacy of the identified plant species in in vivo assays, followed by clinical trials where there are promising results is further required.