South African Herbs Used for Cancer Therapy in Rural Areas

Abstract

South Africa is a rich country in topography and herbs used by traditional healers for the treatment of many infections. Many African ethnic groups use different herbs that are used based on their forebears’ cultures and customs. Most of these plants grow none domestically and are harvested by these traditional healers and treat their patients according to their spiritual revelations and indigenous knowledge. In this chapter herbs will be grouped and comprehensibly discussed on how each tribe uses it according to their diverse cultures, customs, and beliefs. The chapter will also tap into the scientific discovery to document their toxicity for safety. Then a conclusion will be drawn combining the indigenous knowledge, culture, and scientific discovery to guide reader for potential plants.

1. Introduction

Over the past decades, herbs have become the global topic owing to recurring, (re)emerging pandemics and epidemics. In the past 2 years (2020 and 2021) medicinal plants have gained too much interest because of COVID-19 and most South African relied on concoctions for survival due to majority not affording western medication and all restricted measures of movement. Other countries also showed overwhelming trust in medicinal plants and herbs to aid in circumventing pandemic. It would have been the biggest mistake if the focus was only on the pandemic and forgetting treatment of other deadly diseases like Human Immunodeficiency Virus (HIV), tuberculosis (TB), diabetes and cancer to mention a few.

Cancer remains one of the leading causes of death globally and in sub-Saharan countries including South Africa. In the middle of the pandemic traditional healers continued to use ancestral calling guidance, culture, customs, and indigenous knowledge in the treatment of cancer and cancer related signs and symptoms. This chapter will bring most of the plants used by diverse Africans living in rural areas, highlight the scientific discoveries in relation to toxicity and impart a consolidated guidance on which plants to select hereof to avoid exposing their patients to possible toxic mixtures or concoctions.

2. Richness of south African diverse population in herbs using for cancer

South Africa have nine provinces (Figure 1) with a population of almost 60million, 11 spoken official languages (Figure 2) across with English and Afrikaans spoken by many, high unemployment rate that was escalated by the global pandemic, that encouraged traditional people to even rely on and practice the use of medicinal plants [1, 2]. Indigenous knowledge played a major role for many decades for alleviation of the diseases [3]; however, less was known to the effect that some of this herb’s extracts does to the human body as most patients where happy to see the reduction to clearing of infections and the clinical symptoms possible linked to the disease at that time. This chapter will bring the documented herbs and report on the different studies done in assessing the safeness of these extracts and a conclusion will be drawn as an awareness for which plants should our people practicing tradition medicine should be aware of. Scopus, Google Scholar, Web of Science, ScienceDirect, PubMed, and books, as well as local reports and thesis submissions, were used to conduct a broad literature search.

Figure 1.

Map of South Africa showing the different 9 provinces-https://za.pinterest.com/pin/314689092704490764/.

Figure 2.

Distribution pattern of south African 11 languages-https://southafrica-info.com/arts-culture/11-languages-south-africa/ (permission granted by Mary Alexander).

3. Herbs used by the diverse African south African ethnic groups in traditional practices and their scientific safeness discoveries

3.1 Agapanthus-africanus (L.)

Agapanthus-africanus belonging to the family Agapanthaceae which is found in the Western cape Province mostly from Cape Peninsula towards Swellendam during the favored by the winter rainfall area [4].

The leaves are suberect, strap shaped with flowers deep blue, thick textured and broadly funnel shape (Figure 3) [4]. The plant vernacular names used in in the country included Sotho (leta-la-phofu), Zulu (mathunga, icakathi), Xhosa (isilakati), Afrikaans (Haakleli) and English (blue lily). (L.) Hoff manns [4, 5].

Figure 3.

Agapanthusafricanus-http://pza.sanbi.org/agapanthus-africanus.

Traditionally healers collect and dry the roots of this plant in the sun, once they are dry then that will be followed by extraction method of continuous boiling water until a color change is observed, the aqueous infusion will be orally for the treatment of cancer until the patient is cured [5].

There is no scientific evidence reported on the high toxicity of this plant, the studies have shown low poisonous severity except where other studies have proven parts of the plant like leaves to be poisonous [4, 6].

3.2 Solanum aculeastrum Dunal

S. aculeastrum Dunal belong to the family Solanacease, is a small tree or shrub native to tropical Africa south to South Africa, in a wide range of soil, terrain and climatic conditions [7]. This taxon can be found in the southern African countries of Swaziland, KwaZulu-Natal, Mpumalanga, Limpopo, and Mpumalanga. In addition to disturbed areas, S. aculeastrum subsp. aculeastrum grows naturally in grassland, woodland, and forest margin. It is highly branched and reaches 1–5 m high, with numerous sharp hooked brown thorns. The leaves are ovate, up to 15 cm long and 13 cm broad, with lobed margins and a downy underside. Its flowering time is between September to July, peaking from November to March in South Africa climate conditions [7]. This shrub contains small smooth, round berries and fade from green to yellow as they ripen. These berries contain high levels of the poisonous alkaloid solanine [8].

The species name aculeastrum refers to the thorns that adorn most parts of the shrub (Figure 4) (15). Locally the plant is commonly called Zulu (mtuma), Xhosa (umthuma, itunga), Tswana (thola), Venda (murulwa), English (goat bitter-apple, bitter-apple, goat apple, poison apple) and in Afrikaans (bok-bitterappel, bitterappel, bokappel, gifappel) [7].

Figure 4.

Solanum aculeastrum Dunal-http://pza.sanbi.org/solanum aculeastrum Dunal.

The zulu’s traditional healers and other ethnic groups practices use the fruit fresh, boiled, or charred to make herbal medicine in treating a variety of diseases such as toothaches, ringworms, and cancer [7, 9, 10]. In the Eastern Cape, The Xhosa’s, the berries are boiled until this burst into pieces, decoctions prepared from the fruits are taken orally once a day post filtration until the cancer is cured [5, 11].

Scientifically isolated steroid alkaloids from the Solanaum acueastrum have been reported to possess anticancer activity [9, 10]. This exceedingly bitter fruit of S. aculeastrum is used medicinally (fresh, cooked, or burnt) in a variety of methods for both people and domestic animals, according to Hutchings et al. [9]. Leaf and fruit aqueous extracts were found to possess low activity against cancer cells [12]. Care should be taken in the use of fresh, dried, and boiled berry extracts and they were found to affect organs function in a study done by Aboyade et al. [13]. The deadly alkaloid solanine is present in both adult and immature fruits. Botanist have warned about poisonous nature of this shrub, according to Acocks (1988), this species is an unwelcome plant whose population should be decreased by effective veld management shrub due to the presence of poisonous alkaloid solanine. It’s important for traditional healers to take cognisance of this plant and rather use other herbs available at their disposable [14].

3.3 Leonotis leonurus (L.) R. Br

L. leonurus (L.) R. Br. belong to the family Lamiaceae, the wild dagga with soft-woody fast-growing shrub with 1.5 m wide and almost 3 m tall. When L. leonurus (L.) R. Br. leaves are crushed, they release a powerful herby aroma. It consists of flowers varying in color from different shades of orange to vivid orange red, the flower heads are in axillary verticils in clusters of 3–11. The herb has stiff hairs that are prickly when touched. Summer is the season for flowering; in some regions, this occurs from November to January, whereas in others, it occurs from mid-autumn to winter (April to June). There are additional known varieties with apricot, yellow, and white flower (Figure 5) (15).

Figure 5.

Leonotis-leonuru-http://pza.sanbi.org/leonotis-leonurus.

In South African ethnic’s groups, the shrub is common named, Sotho (lebake, levake); Zulu (umfincafincane, umcwili, imunyane, utshwala-bezinyoni, Xhosa (utywala-bengcungcu, umfincafincane, umunyamunya), Shona (ibetshule-badala, ilihambambeba), English (wild dagga, lion’s ear, leonotis) and Afrikaans (wildedagga, duiwelstabak).

The traditional healers prepare at tea from a handful leaves and flowers each morning and night for the treatment of cancer [15]. Another study at the Eastern Cape South African has supported the anticancer activity from the water extract of both the leaf and the flower [16]. The water extract of the leave was scientifically reported to affect the blood system, kidneys and liver function when tested on the rats [17]. The study done by Dlamini in 2005 on toxicity test in the laboratory (in vitro) found the leaf extract to be non-toxic to the human lympocyets [18]. The scientific studies interchangeable show that even though the leaf and flowers possess anticancer activity care should be taken as it can affect the functioning of other organs of the body.

3.4 Hypoxis argentea Harv. Ex baker

Hypoxis argentea Harv. ex Baker belong to the family Hypoxidaceae, grows in the Eastern Cape of South Africa on rocky outcrops and grassy areas. It features tiny yellow flowers and slender, ribbed leaves with silky yellowish hairs. A thin, herbaceous perennial plant called Hypoxis argentea can reach heights of 7 to 10 cm and produces a cluster of four to seven grass-like leaves from a tiny, corm-like tuber. The majority of Hypoxis species are severely harmed or killed by even brief frosts because they are often not extremely cold-tolerant plants. Nearly all the S. African species typically thrive in a Mediterranean environment with little to no frost because they are native to regions with summer rainfall and little to no winter rain (Figure 6) [19, 20].

Figure 6.

Hypoxis argentea Harv. Ex baker - https://www.pacificbulbsociety.org/pbswiki/index.php/Hypoxis#&gid=1&pid=9.

The frequently used name by the different ethnic groups is South Africa are Sesotho (Leihlo-khomo le leholo, Leihlo-la-kxomo-le-leholo, letsikitlane), Xhosa(ixalanxa), Zulu (inongwe), English (small silver starflower). Other subspecies of Hypoxidaceae family usend mostly across the country in rural areas included the following hypoxis colchicifolia Bakr (Zulu-iLabatheka; English-broad-leaves hypoxi), hypoxis hemerocallidea Fisch., C.A. Mey. & Ave-Lall (Sesotho-moli kharatsa, lotsane; Tswana-tshuka; Xhosa-inongwe, ilabatheka, ixhalanxa, ikubalo lezithunzela; Zulu-inkomfe, ilabatheka, inkomfe enkulu; English-star flower, yellow star; and Afrikaans-sterblom, geelsterretjie, gifblom) [5].

The plant is harvested from the wild by traditional healers and ordinary people for medicinal use [21]. An aquest decoctions made from crushed buldis orally taken for the treatment of cancer until the patient is cured [5, 22, 23]. No Scientific report on the toxicity of this plants have been documented.

3.5 Euphorbia ingens E. Mey. Ex Boiss

E. ingens E. Mey. ex Boiss, a member of the Euphorbiaceae family, is a spiny, evergreen, succulent tree with a short trunk [24]. It has a thick bole, gray and coarsely fissured bark, abundant latex, persistent branches from about three meters up, virtually upright, rebranching, and forming a huge, broadly rounded crown [24]. Simple and transitory, the stems’ nearly spine-free, green, cactus-like leaves do most of the photosynthesis instead of the leaves themselves. The plant is distributed across the following provinces of South Africa Gauteng, KwaZulu-Natal, Limpopo, Mpumalanga, and North-West [20]. This tree prefers warm areas and can survive in areas that go through long periods of drought or are generally very dry (Figure 7) [24].

Figure 7.

Euphorbia ingens E. Mey. Ex Boiss-http://pza.sanbi.org/euphorbia-ingens.

The vernacular names of the common tree E. ingens E. Mey. ex Boiss are; Sepedi (Mohlohlo-kgomo, Abaphaphi, Mokgoto, Mokgwakgwatha); Tswana (Monkgôpô, Ngôgô, Nkonde, Nkondze.); Zulu (Abaphaphi, Umahetheni, Umhlondlo, Umhlonhlo, Umphapha Umhlondlo, Umpapa, nkondze); Shona (inkonze, mkonde, mukondwe, mukonde); IsiNdebele (Inkonze); English (Cactus Euphorbia, Candelabra Euphorbia, Candelabra Tree, Common Tree Euphorbia, Tree Euphorbia, Giant Euphorbia, Naboom); Afrikaans (Gewone Melkboom, Gewone Naboom, Gewone Melkboom, Gewone Naboom, Kankerbos, Naboom, Noorsboom, Noorsdoring, Noorsdoringboom, Noorsheuning); Tshivenda (Mukonde). The vilage Naboomspruit (− now Mookgopong), North of Pretoria, took its name from this tree [25].

The plant is harvested by the Bapedi people who use the freshly squeezed juice from the stem and apply it after bathing on the skin topically for the treatment of breast cancer [26]. The Sotho speaking people apply its latex topically for the external cancer on the skin until cancer is cured [5]. The studies shows that other ethnic groups use it for the treatment of cancer [21]. Traditional healers and traditional medicine practicing people at the rural area should be careful when handling this plant, due to the deadly milky sap or latex [25]. It is exceedingly dangerous to use latex because it can cause allergic reactions, blisters, and even blindness [25]. It is advisable burn this tree first to reduce the impact of the toxic fluid before used as a tradition medicine [24, 25].

3.6 Raphionacme hirsuta (E. Mey.) R.a. dyer

Raphionacme hiesuta (E. Mey.) R.A. Dyer is a member of the Apocynaceae family, a perennial plant that grows to around 200 mm tall, profoundly branched, and has a huge, tuberous rootstock. Its herbaceous, finely hairy stems exude a milky sap. This plant often hibernates during winter and sprouts new growth in the spring. In a grassland, its blue blossoms are frequently missed because they appear at ground level before the leaves emerge. Once observed, something will always be remembered. The leaves are 12–50 6–25 mm, hairy or hairless, and have parallel secondary veins and a conspicuous midvein [27]. It forms a very big underground tuber that has many cultural and medicinal attributes. In savanna and open grassland provinces like Gauteng, Free State, Mpumalanga, KwaZulu-Natal, the Eastern and Northern Cape, North-West, and Limpopo, Raphionacme hirsuta is frequently found on rocky and mountainous terrain (Figure 8) [28].

Figure 8.

Raphionacme hirsuta (E.Mey.) R.a. dyer- http://pza.sanbi.org/raphionacme-hirsuta.

The vernacular names of the common plant Raphionacme hirsuta (E. Mey.) R.A. Dyer are Southern Sotho (Kerentshane), Xhoza (intsema), Zulu (umathanjane, Umathangane), English (false gentian, khadi root), and Afrikaans (Khadiwortel, khadi) [29, 30].

R. hirsuta tubers or roots are traditionally used as a source of yeast to produce beer and as a traditional therapy for maladies and diseases like cancer and chronic ulcers despite being rumored to be poisonous [31, 32]. As early as in the 1960’s the Southern Sotho speaking people were using this plant for the treatment of internal tumors [33].

Scientific study reported that a 50% aqueous methanol was effective to inhibit almost 90% a rodent leukemia (P-388) cancer model [34]. A great caution should be exercised as the roots of this plants are believed to be poisonous [35].

3.7 Lassertia frutescense (L.)

Lassertia frutescense is a fast-growing, hardy shrublet in the fabrica (Fabaceae) family that has been cultivated in gardens for many years. Lessertia frutescens is found in the dry parts of southern Africa. It is found in the Western Cape and up the west coast as far north as Namibia and into Botswana, as well as in the western Karoo and the Eastern Cape including the Mpumalanga and KwaZulu-Natal provices [36]. It is distinguished by its silvery-gray leaves and loose clusters of luminous coral-red pea-shaped flowers that bloom from spring to mid-summer (Figure 9) [37]. It is drought-tolerant and prefers well-drained soil. The shrub is native to South Africa and is used to treat illnesses such as cancer, tuberculosis, diabetes, and associated symptoms of HIV/AIDS [38].

Figure 9.

Lassertia frutescensehttps://candide.com/ZA/plants/eaabf98455d9bdfef9c454fdb2d06f99.

The shrub is commonly called Xhoza (Umnwele), English (cancer bush), and Afrokaans (kanerbossie, eendjies, ganbossie) [5]. Lessertia frutescens (previously Sutherlandia frutescens) is well-known for its medicinal properties, interesting balloon-like fruit capsules and incredibly bitter taste. The shrub became famously known as the ‘cancer bush’ alludes to its reputation as a potential cure for cancer in South Africa. Although there was no scientific report to support for Lessertia as a cure for cancer as alluded by traditional healers, later there was a proven to boost the immune system and activate the body’s resources to combat disease and mental and physical stress of daily life [37].

Traditional healers collect stems, leaves, flowers, and seeds which are then dried, then decoctions from each is administered orally to treat internal cancers. In the case of external cancers decoctions prepared from this shrub are applied topically until the patient is cured [5]. Other traditional healers collect fresh plant materials, dry them, and then stamp or mash them into powder between two stones, as this tradition is practiced by various ethnic groups. The preparation is then typically infused in hot or boiling water, allowed to cool before being administered to the sick person [15, 39, 40].

There is scientific evidence that the phenolic, flavonoid, alkaloid, and saponin contents of extracts of in vitro leaves, field leaves, and seeds of the leguminous plant L. frutescens were quantified using spectrophotometric and gravimetric methods. Saponins were found to be more abundant in in vitro leaves than in field leaves and seeds, followed by phenolics, flavonoids, and alkaloids. The extracts were also qualitatively examined to determine the presence of additional phytochemicals of medicinal interest. Tannins, phlobatannins, and cardiac glycosides were found in this qualitative analysis [39]. This study clarified and added to the body of knowledge because it is critical for our traditional healers to understand which parts of the shrub contain a variety of ingredients. Another scientific study discovered that our forefathers could even distinguish which decoctions to prepare based on the type of disease indicated by the patient [15]. Other studies reported that the traditional healers prepare this shrub by using its leaves, flowers, stems, and roots to treat various ailments [40]. Furthermore, more studies done globally supported the benefit of this plant in the treatment of cancer and most importantly it was found to induce cell death (apoptosis) and was also reported nontoxic by the different scientific [41, 42, 43, 44, 45, 46, 47, 48, 49, 50]. Both the sciences and indigenous knowledge contributed to the identification an honored this plant by calling it cancer bush.

3.8 Pittosporum viridiflorum Sims

P. viridiflorum, a Pittosporaceae family member, is found throughout the eastern half of South Africa (Eastern, P. viridiflorum, a Pittosporaceae family member, is found throughout the eastern half of South Africa (Eastern), from the Western Cape up into tropical Africa and beyond to Arabia and India [51]. P. viridiflorum can grow from a small shrub to a large forest tree up to 30 m tall. The bark is pale brown to grayish, with distinct white dots (lenticels). It has glossy, dark green leaves that are typically wider above the center. In early summer (November to December), small, greenish white, sweetly scented flowers bloom [51]. Following them are small yellow-brown seed capsules. When the capsules are broken open, a slew of small, shiny, orange-red seeds emerge, each encased in a sticky, resinous exudate (Figure 10). This cheese wood is frequently confused with white milkwood [51].

Figure 10.

Pittosporum viridiflorum Sims - http://pza.sanbi.org/pittosporum-viridiflorum.

The vernacular plant among South African ethnic groups are Southern Sotho (Sesotho) (Mosetlela), Afrikaans (Witboekenhout, Kaarsuur, Bosbeukenhout, Bosboekenhout Kersuurboom, Kasuur), English (cheesewood, Umkwenkwe, White Cape Beech), Northern Sotho (Kgalagangwe), Tswana (Mpustinya-poqo, Nkasur), Venda (Mulondwane, Mutanzwakhamelo), Zulu (umfusamvu, Umkhwenkwe, Umphushamvu Umphushane, Umvusamvu), Xhoza (Umgqwengqwe, Umkhwenkwe [52].

Traditionally the root or bark decoctions are administered orally in the Eastern Cape province [5]. Another scientific study has reported that the bitter taste and strong resinous or liquorice smell bark is used medicinally, and it possess positive anticancer activity against human prostate cancer [53]. Dried, powdered root or bark is sometimes added to beer as an aphrodisiac [5]. Traditional healers should practice great caution when using this plant, P. viridiflorum has been scientifically found to have moderate to significant toxicity against cancer cells in the laboratory [54, 55, 56]. A similar kind of toxicity was observed scientifically when tested Swiss mice study which ranged from low toxicity on bark to killing of the mices in 24 hours by leaf extract [56, 57].

3.9 Knowltonia capensis (L.) Huth

Knowltonia capensis (L.) Huth is a slow-growing, stemless perennial herb that grows between 300 and 500 mm tall and belongs to the Ranunculaceae family. Flowers are made up of colored sepals rather than petals (this distinguishes it from Ranunculus). In winter and spring, it has a 450 mm long flowering stem with a compound umbel of creamy-green flowers (from June to September). These are followed by fruits, which are small, fleshy berries in dense clusters that are green when ripe and turn black when fully ripe. There is a short rhizome with fleshy roots (Figure 11). The tooth-edged, basal leaves are distinctive, being tough, coarse, and leathery in texture. They are usually trifoliately compound, that is, divided into three distinct leaflets, with the middle leaflet being slightly larger than the two on the side. Anemone knowltonia is found in coastal bush and forested kloofs and grows along forest margins. This plant is most common in East London, from which it spreads eastward to the KwaZulu-Natal midlands and westward to the Cape Peninsula. Because it has a rhizome, it will most likely be able to withstand frost, and due to its wide distribution range, it can withstand both high and low rainfall [58].

Figure 11.

Knowltonia capensis (L.) Huth-http://pza.sanbi.org/knowltonia-capensis-0.

Traditionally healers collect and dry the corms, this normally followed by crushing the corms which will be taken orally with water to treat cancer or in the form of decoction until the patient is cured [5]. There is no scientific study reported toxicity related to cancer cells on this plant thus far.

3.10 Celtis Africana Burm.f

Agapanthus-africanus Celtis Africana is a deciduous shrub or a tree with a spreading crown belong to the family Ulmacea. It can grow up to 30 metres tall, rarely to 40 metres. The straight, cylindrical bole can be free of branches for up to 15 metres, though it is often low branching. It is up to 90 cm in diameter, often slightly fluted but usually without buttresses (Figure 12) [59].

Figure 12.

Celtis Africana Burm.f-http://pza.sanbi.org/celtis-africana.

The common ethnic groups once included Sesotho (modutu, mohatakhomo, modutu, mothibadifate, Northern Sotho (mothibadifate), English (White Stinkwood), Afrikaans (Witstinkhout), Xhosa (umthuma, itunga, mumvumvu), Zulu (Usinga, lwesalukazi), Venda (mpopano), Tswana (modutu) [5].

Traditionally healers collect roots of this plants and sun-dry them, upon confirmation of dryness the aqueous or milk infusion is prepared for the patient can drink until cancer is cure [5]. Studies done on toxicity in the laboratory (in-vitro) showed low toxicity to be in general of this plant and no animals (in-vivo) reports found in general of this plant.

3.11 Recommended daily use, risk and contraindication of the following herbs used in rural area of South Africa

Most of these plants’ extracts are traditionally used daily ranging from 4 teaspoons every morning, a ¼ cup and a 1 cup daily depending on what the traditional healer recommends. There is no specific rule and concentration determined as most are prepared by boiling to a color change in 2 liters of water [59].

3.11.1 Agapanthus-africanus (L)

South African Xhosa tribes revere the Agapanthus-africanus for its magical powers according to their indigenous knowledge. Agapanthus-africanus is brewed and consumed by pregnant women in their third trimester to help with birth, in the belief that this will make the child strong and healthy, the newborn is further bathed in a similar concoction on the first day.

The Zulu nation, culturally use Agapanthus-africanus to treat flue, paralysis, heart conditions, coughs, chest problems (such as tightness or pains), tired feet (when the plaited leaves are applied as a bandage to the feet) and colds. Significantly, the Agapanthus-africanus (including the roots) is considered poisonous to humans, making all these applications rather intriguing given the associated risk [60].

If the clear sticky sap is ingested, symptoms may include nausea, vomiting, abdominal pain, and diarrhea, as well as severe mouth ulceration. When the sap comes into contact with your skin, it can cause burning, irritation, and rashes [61].

3.11.2 Solanum aculeastrum Dunal

S. aculeastrum. Dunal (Solanaceae) is used in traditional medicine to treat various human and animal diseases, specifically stomach disorders and various cancers, in the Eastern Cape, South Africa [11].

A scientific study found that the medicinal use of these plant, on the other hand, poses significant health risks [62]. Berry extracts were nephrotoxic, hepatotoxic, haematotoxic, and fatal at higher doses, according to research into the plant’s safety. Another source of concern about the plant’s safety is its extracts’ non-selectivity in inhibiting carcinoma, actively dividing and un-dividing cells [62, 63]. The effect of processing on the efficacy and safety of the berry as a herbal IV remedy yielded conflicting results [62, 63]. The extract’s anti-inflammatory and analgesic activity appeared to improve with processing while its cytotoxic potential appeared to decrease. However, processed extracts were found to be less toxic than fresh extracts. Effect of processing on the efficacy and safety of Solanum Aculeastrum Dunal berries [62, 63].

Another study performed on the risk assessment found that the overall changes in biochemical parameters caused by the various extracts of S. aculeastrum berries at the different doses suggested that the normal functioning of these organs may be compromised. However, drying and boiling the berries may reduce their toxicity [13]. That is why is important for the indigenous knowledge people need to improve their understanding on the safeness of this plant and it less toxic dose.

3.11.3 Leonotis leonurus (L.) R. Br

The study done on male rats as part of the clinical trisls found that the effects of the aqueous extract of L. leonurus leaves on hematological, liver, and kidney functional indices suggest that the extract has parameter and dose-selective effects and will have consequences on the normal functioning of the animals’ blood system, kidney, and liver [17]. When consumed daily for 21 days at the low doses, the extract is also unlikely to predispose the animals to cardiovascular risk. As a result, the aqueous extract of L. leonurus leaves was not ‘safe’ as an oral remedy in male rats [17]. High level of caution should be practised when traditional healers used and recommend this herb to their people.

3.11.4 Hypoxis argentea Harv. Ex baker

The study done on Hypoxis argentea Harv. ex Baker found that the acclaimed anti-diabetic effects of H. argentea could be mediated by its promotion of glucose utilization and preservation of pancreatic beta cell populations while preventing fat accumulation in adipocytes [64].

3.11.5 Euphorbia ingens E. Mey. Ex Boiss

If the latex from this tree is consumed, it can cause severe skin irritation, blindness, and severe illness in both humans and animals. If used correctly, it can be used as a purgative or to treat ulcers. The Basotho and Venda people in South Africa are said to use it as a cancer cure [65].

3.11.6 Raphionacme hirsuta (E. Mey.) R.a. dyer

Raphionacme hirsuta (E. Mey.) R.A. Dyer and Cheilanthes contracta have been used in African anticancer medicines. In some rodent test-systems, extracts of these plants demonstrated antitumor activity [32]. While the tuberous roots are used in the production of alcoholic beverages, the plant is also said to be poisonous [66].

3.11.7 Lassertia frutescense (L.)

Traditionally, S. frutescens has been used to treat fever, wounds, cancer, diabetes, kidney and liver problems, rheumatism, and stomach ailments [67].Sutherlandia capsules are commercially available and have been used with apparent positive clinical results in two health facilities in Kwazulu-Natal and the Northern Cape for outpatients living with AIDS [68].

The safety efficacy of Lassertia frutescense was tested on healthy adults, and the results revealed no significant differences in general adverse events, cardiovascular, central nervous system, gastrointestinal tracts, infection, allergy, malaise, or most physical, hematological, biochemical, or physiological parameters (P > 0.05). Subjects who consumed L. frutescens, on the other hand, reported greater appetite than those in the placebo group (P0.01). Although the treatment group had a lower respiratory rate (P0.04), a higher platelet count (P0.03), MCH (P0.01), MCHC (P0.02), total protein (P0.03), and albumin levels (P0.03) than the placebo group, these differences were within the normal physiological range and were not clinically significant [69]. Canavanine, an L. frutescens biomarker, was undetectable in subject plasma. In general, healthy adults tolerated 800 mg/day L. frutescens leaf powder capsules well [69]. This indicate that Lassertia frutescense can be safely used for human consumption with no adverse events on the patients.

3.11.8 Pittosporum viridiflorum Sims

P. viridiflorum Sims was discovered in a scientific study to be used in traditional medicine to treat tuberculosis, inflammatory disorders, wounds, veterinary ailments, gastrointestinal, sexually transmitted diseases, kidney, circulatory, and malaria. [70]. Toxicological effects have also been reported from this species, that’s why safety should be carefully considered when using this herb. Compound(s) with antimalarial, anticancer and acaricidal properties have been isolated from P. viridiflorum [70]. There is enough scientific evidence on pharmacological and phytochemical properties of P. viridiflorum which gives credibility to the use of this plant species against various diseases in African traditional medicine [70].

3.11.9 Knowltonia capensis (L.) Huth

It was found that when fresh leaves and roots are eaten, a white crystalline compound which is enzymatically changed to a highly toxic oil with an acrid taste that produces the blistering [71]. Traditionally the smoke from burning leaves is inhaled for headaches [71]. These plants’ leaf poultices are commonly used in traditional medicine to treat wounds, external cancers, and rheumatism. To relieve toothache, the roots of Anemone knowltonia can be applied directly [71].

3.11.10 Celtis Africana Burm.f

The bark extracts of Celtis Africana Burm.f have been used as pain-killers, fabrifuges, and during malnutrition, while the leaf extracts was used for the treatment of the eyes infection and pulmonary troubles [72].

Medicinal plant remedies play an important role not only in the treatment of cancer, but also in the treatment of chronic ailments such as hypertension and many others by lay people in rural South Africa. A clear scientific report suggests that there must be awareness on the risks associated with the concurrent use of conventional medication and medicinal plants. Even though this chapter brought both sciences and tradition knowledge together, there is a clear need to educate health practitioners and patients about the potential risks of using both prescribed western drugs and medicinal plants to avid contraindication [73].

4. Conclusions

This chapter brings together traditional knowledge and science to discuss how indigenous plants are widely utilized in South Africa to treat cancer and diseases associated to cancer. The chapter acknowledges the contribution of indigenous knowledge to the body of knowledge to dispel the misconception that African epistemologies are less developed. When the hard sciences and soft social indigenous knowledges are combined, the vertical and horizontal knowledge become less mysterious and less colonized. The plants are common in the many climatic regions of the nation; some are drought-resistant plants that thrive in the provinces of the Western, Eastern, and Northern Cape as well as some parts of KwaZulu-Natal, with differing chemical and genetic compositions in each of these geographical locations. Extensive scientific research is being conducted on the safety, quality, and efficacy of this medicinal plant to validate traditional claims, identify bioactive constituents, and conduct clinical trials. This has created a unique situation in which traditional knowledge and science meet to provide insight into these popular plants as well as safety advice to traditional healers. The chapter demonstrated the relationship between science and indigenous knowledge of traditional healers, local knowledge of people who care for the sick, product development, and the global innovation agenda as it relates to these plants. This chapter demonstrates that there is a growing understanding of phytomedicine and traditional medicines that can potentially be used to treat cancer patients. In selecting plants for cancer treatment, our forefathers’ innate knowledge demonstrated true predictions, and our traditional healers should also understand that not all plants and plant parts are safe for human consumption. This chapter demonstrated how a convergence of vertical hardcore sciences and horizontal non formal curriculum indigenous knowledge can contribute to a new decolonized world in which African pedagogies and transformation discourse in society will be permitted. Collaboration between traditional healers and scientists clearly improved understanding of the use, preparation, therapeutic potential, and pharmaceutical make-up of these medicinal plants in the treatment of cancer. In this way, traditional knowledge, and science meet in novel and unexpected ways.

Acknowledgments

I would like to acknowledge the Central University of Technology-Research Office UCDP Grant-for funding the publication.

The CUT Faculty of Health and Environmental Sciences assistance Dean’s office: Prof T Makhafola for financial assistance.

The Family, colleagues, and Friends for encouragement.

Thanks to Dr. LF Mogongoa, SD Mokgawa, DE Rampana-Moleleki, D Mathiase, Dr. I Manduna, B Nakedi, A Molelekoa and M Motaung for proof-reading the manuscript and provide constructive comments.

Conflict of interest

The author declares no conflict of interest.