Background

The use of natural resources, especially plant material, for skin diseases and cosmeceutical purposes, is an ancient practice in many cultures globally [1]. Natural resources refer to substances that occur naturally and include plants, animals and micro-organisms. Plant derived-extracts are more common than animal derived-extracts as a source of cosmeceuticals [2]. Despite the continuous neglect of folk cosmeceuticals in favour of the synthetic ones, natural resources are still utilised for skin health in many rural areas [1, 3,4,5]. The ease of access and belief in the efficacy of indigenous knowledge are common reasons for the continuous dependence on these natural resources.

The bio-compounds from natural resources have been successfully used in skin-care treatment due to their effectiveness and safety. Martins et al. [6] emphasised that the suppliers of the cosmetic industry are embracing the need to include extracts from natural resources because they contain essential vitamins and minerals that exert ultraviolet and anti-oxidant protection and general anti-aging benefits. Recently, the pharmaceutical industry is embracing the ideal of incorporating antioxidants derived from natural resources into their products because they contain chemicals that are valuable in cosmeceuticals [7]. Furthermore, natural antioxidants provide health benefits such as anti-aging, anti-inflammatory, and anti-microbial properties that are suitable for cosmetic purposes [8].

The demand for natural resources for cosmeceuticals is increasing globally. The use of plant-based remedies remains entrenched in the healing practices of developing countries [9]. According to Statistics South Africa [10], South Africans consult both public health facilities and traditional practitioners for rememdies against common illnesses including skin diseases. Even though several ethnobotanical studies have been conducted in Limpopo province, including Vhembe district [11,12,13,14,15,16,17], specific attention on natural resources utilised as cosmeceuticals for skin diseases remains understudied. While Mabogo [16] documented 44 plants with cosmeceutical potential, Mahwasane et al. [11] and Magwede et al. [13] recorded 2 and 13 plants, respectively. A recent study by Constant and Tshisikhawe [12] did not highlight any plant with cosmeceutical value. Ndhlovu et al. [17] focused on plants used for cosmetic and cosmeceutical purposes by the Vhavenda women. Thus, the current study aims at documenting natural resources used as folk cosmeceuticals among households in rural communities located in Vhembe district.

Methods

Study area

The study was conducted in six villages situated on the northern side of Limpopo province, South Africa (Fig. 1). Vhembe district has a population of 1,393,949 with 382,346 households and mainly dominated by the Vhavenda and VaTsongas [18]. It comprises of four local municipalities namely Thulamela, Collins Chabane, Makhado, and Musina. The district municipality is predominantly rural, with more than 85% of its population living in tribal settlements and farms, and only 5% living in urban areas [19]. Vhembe district is mainly covered with the vegetation of Savannah biome and topography and is characterised by Soutpansberg (“Salt Pan Mountain”).

Fig. 1
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Location of the selected villages in Vhembe district municipality, Limpopo province, South Africa. (Luvhimbi = Masikhwa). The map was drawn by S.K. Bett using ArcMap 10.3.1 software

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Ethnopharmacognostic survey

The survey involved 71 participants who were knowledgeable about natural resources utilised for folk cosmeceuticals. The participants included herbalists, traditional practitioners and laypeople. Convenient sampling was used to get the participants. The households were randomly chosen using every fifth (5th) house in the community because all the possible samples that were chosen came from the population that had the same probability to belong to the sample. The convenient sampling was used by asking questions from household members that were willing to participate. This sampling method was adopted to provide the community members the freedom to choose whether to participate or otherwise. In fact, those who were not interested in participating in the study referred the researcher to the people who were known to have the required knowledge.

Semi-structured questionnaires were used to collect data from the participants. The questionnaire was divided into four categories. Category A entailed the interview log that requested information about the name of the community, date of data collection, local municipality and demography of participants. Category B comprised inquiries about natural resources utilised for folk cosmeceuticals, method of preparations and administration and part used. Category C consisted of indigenous knowledge and practices involved in the formulation and use of folk cosmeceuticals, and lastly Category D comprised questions about the factors influencing the use of folk cosmeceuticals. The interview was conducted in Tshivenda and Xitsonga with the assistance of two translators. Some of the interviews were conducted in an informal gathering, although the original intention of the researcher was to interview one person at a time. Interviewing participants that gathered informally contributed a lot to the study. It was observed that some of the participants would only contribute their knowledge when they were in a group which benefited the researcher in saving time and helping to gather more data.

Plant collections and identification

Plants were collected both from home gardens and natural vegetation during the fieldwork with the assistance of knowledge holders and translators. The permission to collect the required specimens was granted by the Department of Environmental Affairs, Limpopo Province and the tribal authority. Voucher specimens of the plants were deposited at the herbarium of the South African National Biodiversity Institute (SANBI), Pretoria for identification. Plants were also identified with the relevant books and with the assistance of an expert (Botanist).

Ethics approval and consent to participate

The current study was approved (ethical clearance no: NWU-07740-17-A9) was by the research ethics committee of North-West University, Mmabatho, South Africa. Permission letter to access and conduct research in six communities was granted by the traditional leaders. Data were collected with full agreement with the participants and consent form was issued to them which clearly stated and explained that the participants were volunteering and the details of the study which included aim, objectives and how data were going to be collected.

Data analysis

The data analysis was carried out using both descriptive and inferential statistics utilizing percentage and frequency. Data from the questionnaire were analysed using IBM SPSS analytical tool, Microsoft Excel 2016. Ethnobotanical indices such as frequency of mention (F), use-value (UV) and Relative frequency of citation (RFC) were calculated as detailed previously [20].

Results

Socio-demographic characteristics of participants

In the current survey, the 71 participants that were interviewed had diverse demographic characteristics (Table 1). Most of the participants involved in the survey were from Shigalo and Tshakuma communities. The majority (76%) of the participants were females and the dominating (35%) age group was those individuals older than 70 years. The majority of the participants belonged to the Venda tribe (66%) and most of the participants lacked formal employment.

Table 1 Demographic characteristics of participants in the study area
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Plant and non-plant resources used for cosmeceuticals

In total, 52 plants from 27 families were cited as being used as folk cosmeceuticals in the study area (Table 2; Fig. 2). As shown in Fig. 2, most of the plants belong to the following families: Leguminosae/Fabaceae (6), Ebenaceae (4), Poaceae (4), Euphorbiaceae (4), Anacardiaceae (3), Compositae/Asteraceae (3) and Rutaceae (3). In terms of frequency, the most cited plants were Dicerocaryum zanguebarium, Ricinus communis, Helinus integrifolius, Zea mays and Annona senegalensis. Shrubs and trees constituted the most (71%) occurring plant life-forms while the proportion of herbs and grasses were 21 and 8%, respectively (Fig. 3). Even though diverse plant parts were used as cosmeceuticals, the leaves (32%), fruit (18%) and roots (13%) were the most utilised plant parts (Fig. 4). Plants with the highest UV were Aloe vera (0.084), Euclea divinorum (0.084), Bauhinia thonningii (0.070) and Citrus limon (0.056) (Table 2).

Table 2 Plants used as folk cosmeceuticals among rural communities in Vhembe district municipality, Limpopo province, South Africa
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Fig. 2
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Frequency of plant families used as folk cosmeceuticals among rural communities in Vhembe district municipality, Limpopo province, South Africa

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Fig. 3
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Frequency of plant life-forms used as folk cosmeceuticals among rural communities in Vhembe district municipality, Limpopo province, South Africa

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Fig. 4
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Distribution (%) of plant parts used for preparing folk cosmeceutical remedies among rural communities in Vhembe district municipality, Limpopo province, South Africa, n = 68

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Twenty-two (22) non-plants materials were recorded as folk cosmeceuticals among rural communities (Table 3). In terms of frequency, the most common (with more than 10 citations) non-plant materials were nguluvhe/honje (pig fats), luvhundi (soil), mafhura tharu/ntlharo (python fat) and wood ashes/coal. In addition, nguluvhe/honje, wood, ashes/coal, soil and sandy soil had the highest (0.042–0.056) UV among the non-plant resources (Table 3).

Table 3 Non-plant resources used as cosmeceuticals in Vhembe district municipality, Limpopo province, South Africa
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Mode of preparation and administration of folk cosmeceuticals

The natural resources used as folk cosmeceuticals were prepared by diverse means such as infusion, grinding and maceration (Fig. 5). The most common methods of preparation of non-plant natural resources were crushing (33%), while maceration (3.5%) and infusion (3.5%) were the least common methods. These natural resources used for folk cosmeceuticals are applied in the form of powder, poultice, juice and infusion. The majority (88%) of the natural product remedies were applied topically. In terms of the broad categories, the remedies were administered for skin afflictions, cosmetics, anti-oxidants and hair care (Table 4).

Fig. 5
figure 5

Frequency of the preparation methods used as folk cosmeceuticals among rural communities in Vhembe district municipality, Limpopo province, South Africa

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Table 4 Frequency of citations for natural resources used for skin conditions in Vhembe district municipality, Limpopo province, South Africa
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Indigenous knowledge and practices of folk cosmeceuticals

As highlighted by some of the participants, skin diseases are believed to have an underlying spiritual cause. For instance, some skin diseases are believed to be caused by disobeying ancestors, result from misbehaving in a community and evil spells. As a result, rituals are often recommended and performed for the healing of the skin afflictions. Healers are known to perform ‘Gumululo’ which is a ritual used to remove sores from infected skin. Traditional practitioners wash the sores by sprinkling water mixed with the unspecified concoction. Some severe skin diseases require the patient to stay in an isolated area for a certain duration in order to be healed. When it is time for the patient to return home, the family members are given a similar concoction to prevent the same disease. In some instances, patients wash in a lake called ‘Dzivha la fundudzi’ in Venda because it is a sacred river, a river of gods. For them to access the lake to wash away the disease, permission is requested from the priest and traditional practitioner that guard the lake.

Discussion

As emphasized by Fongnzossie et al. [5], there is inadequate documentation of the ethnobotanical knowledge on cosmeceuticals. Furthermore, Lall and Kishore [21] highlighted the existing research gaps that involve both the inadequacies in ethnobotanical documentation and scientific evaluation of the plants used skincare in South Africa. The current ethnopharmacognostic survey indicated that the custodians of knowledge on natural resources with cosmeceutical potential were females and elders (above 70 years). Indigenous knowledge often held by the elders in the communities is transmitted orally from generation to generation but its practice seems to be declining due to the lack of interest by the youth [22].

Diversity of natural resources used for folk cosmeceuticals

The high quantity of natural resources as well as the diversity of flora identified, is an indication that the study area has rich indigenous knowledge on folk cosmeceuticals. As an addition to existing surveys in Vhembe district [11,12,13,14,15,16,17], the current study documented new plants (for e.g. Zea mays, Eugenia natalitia, Salacia rehmannii) for the first time, as natural resources for folk cosmeceuticals. Some of these plants were previously documented as medicine without the details of the diseases in recently study by Magwede et al. [13]. The current study indicated that the natural resources used to treat the same skin problems differ among the rural communities. It was also evident that a single plant is utilised for more than one skin problem; and a single skin problem has more than one natural resource as the recommended remedies.

Some of the plants were used in almost all of the rural communities where the survey was conducted. These plants included Dicerocaryum zanguebarium (Museto), Ricinus communis (Nhlampfurha/mupfure), Zea mays (mavhele), Euclea divinorum (Nhlangula/mutangule) and Diospyros mespiliformis (Musuma). These commonly used plants have been recorded by other authors, which is an indication of their cosmeceutical value. For instance, Chigora et al. [23] stated that the whole plant of Dicerocaryum zanguebarium (Museto) is used to make foam which is inserted into the vagina to dilate the birth canal, in Zimbabwe. The juice from the plant is used as shampoo by people of Gazankulu in Limpopo province [24]. The current study affirmed the use of Dicerocaryum zanguebarium, as the participants indicated the use of the whole plant to wash their hair. Many surveys have identified and documented Ricinus communis, [25,26,27,28], which suggests that the plant has high medicinal and cosmeceutical values. According to Maroyi [29], the roots of Ricinus communis are used indigenously to clean the teeth and to heal tooth-ache. The seeds are used as oil which is applied on sore eyes in Zimbabwe. The leaves are burned, seeds and bark are pulverised and applied as poultices to relieve soreness and inflammation [30]. Similarly, the leaves are mixed with water to wash and cure boils on the skin by the Xhosa people in Eastern Cape, South Africa [31]. The different plant parts used from the same plant for different cosmeceutical purposes is evidence of the variety of indigenous knowledge possessed among different communities and ethnic groups.

The commonly used non-plant resources included wood ashes, pig fat, stones, ochre (Luvhundi soil) and soot (Tshinyae). Ochre is commonly used in initiation schools in South Africa. As stated by the participants, it is used for skin protection from sun and insect bites. The cosmeceutical value of ochre has been recorded in several studies [32, 33]. In Western Sahara, Volpato et al. [34] indicated that Sahrawi refugees apply red ochre around their eyes to reduce solar radiance. The participants mentioned that the wood ashes are utilised to dye hair and make it soft, darken their eyebrows as make-up and for teeth whitening. As part of the remedies for healing skin diseases in the inland Marches, Central-Eastern Italy, Pieroni et al., (2004) indicated that the mixture of ashes and water is used to soften the hair. As indicated by Zhang et al. [35], the people of Bulang, China used soot to blacken their teeth to ensure health of the teeth.

Distribution of plant families, life-forms and plant parts

The documented plants belong to 27 families and the dominant family was Fabaceae. This plant family was also the most dominant among the study areas in South West Nigeria [36]. On the other hand, Afolayan et al. [37] indicated that Fabaceae is the third most common family after Solanaceae and Asteraceae, among plant families used by the Xhosas for skin diseases. Generally, the Fabaceae is regarded as one of the families with diverse economic and medicinal value [38]. The life-form that dominated was woody plants (trees and shrubs) and most of the remedies were prepared using the leaves. Similarly, high utilisation of the leaves was recorded as folklore phytocosmetics among the communities of South West Nigeria [36]. The use of leaves as folk cosmeceutical emboldens conservation practices, unlike using roots and bark which may cause the death of plants when done indiscriminately. According to Mathabe et al. [39], remedies were commonly prepared from bark collected at any time and though, in some instances, some plants were not collected because the formulation requires the use of the roots be collected.

Cosmeceutical applications, method of preparation and administration

Skin-related diseases are diverse and occur without any discrimination relating to the age, gender or social status of an individual. As shown in Table 4, the highest cosmeceutical application mentioned by the participants was wounds (27) and body creams (16). The current study revealed that natural resources are popular remedies for diverse skin diseases among the local communities. Thus, ethnopharmacological information from surveys remains a valuable source to explore for potential cosmeceutical products that may possess commercial value [40].

The natural resources are prepared as single component remedies or in combination with other natural resources. The study shows that both plants and non-plants are mostly mixed with water and oil to enhance their penetration across the skin layers. The non-plant materials such as urine and cow dung are mixed with the other plant materials to potentiate its effect [15]. Crushing was the most dominating preparation method and these remedies are mostly applied topically as pastes directly on the skin. Based on existing literature on medicinal plants used for skin problems, the method of administrations includes powder, paste, ointment, poultice and infusion [25, 37, 41, 42]. These aforementioned studies indicated that the majority of administration methods are similar to the current study. Mongalo and Makhafola [14] investigated the ethno-botanical knowledge of laymen in Blouberg (Pedi tribe), Limpopo and indicated that the medicinal plants are applied topically on the skin while others are used to wash and rinse the infected body part(s).

Potential of documented plants with high use-value

Plants with high UV included Aloe vera and Euclea divinorum, Bauhinia thonningii and Citrus limon. These aforementioned plants are known for their diverse therapeutic values. Aloe vera is an ancient medicinal plant that is used externally for different skin problems. In the current study, the gel of the plant is used to moisturise the skin, remove stretch marks, wounds, ringworm and rash as well as to heal burned skin. Likewise in India, Bhowmik [43] indicated that Aloe vera is a ‘miracle’ plant with different cosmeceutical applications (to heal cuts, burns, eczema, inflammation, sunburns and as hair styling gel). Furthermore, Aloe vera is used in many natural products for the skin which include make-up, moisturisers, soaps, sunscreens, shampoos and lotions [43]. Aloe vera is known to be involved in a coordinated cascade of cellular and molecular events that interact with re-epithelialisation and reconstitution processes of the tissue to ensure wound healing [44]. As reviewed by Amoo et al. [45], Aloe species are generally used for skin ailments because they exert pharmacological properties such as antimicrobial, anti-inflammatory, and antioxidant activities.

Euclea divinorum is a traditional medicine that is used for several ailments, including skin diseases. The current findings also indicated that the plant removes skin irritation, ringworms, rash, pimples and chickenpox. Woldemedhin et al. [46] affirmed the healing property of Euclea divinorum by revealing its usefulness against skin ailments such as inflammation of the skin, eczema and scabies in Ethiopia. A study by Otang and Afolayan [47] affirmed the therapeutic value of Citrus limon for skin diseases based on the antimicrobial efficacy against a panel of microbes. In the Amathole District, Eastern Cape, South Africa, Citrus limon is utilized for diverse purposes. For instance, it is used to reduce skin itching, for skin nourishment, and the pulp left after extraction of the juice is used for the treatment of pimples and wrinkles and to soften facial skin [48]. Similar uses were also recorded in the current study whereby the participants indicated that Citrus limon is used for moisturising the skin, removing wrinkles, scars and pimples. Furthermore, Otang and Afolayan [47] demonstrated that Citrus limon has high anti-oxidant property which is relevant to the effective treatment of skin ailments.

Indigenous knowledge and practices on folk cosmeceuticals used against skin diseases

According to Rankoana et al. [49], some of the indigenous aetiology of disease are ancestral spirits, witches and sorcerers. Shenefelt and Shenefelt [50] affirmed that since ancient times, skin diseases have had spiritual and religious origins. There are several ways that Africans explain and understand the causes of diseases. For instance, evil spirits and disobedience to ancestors are believed to cause different diseases [51, 52]. Good-health and well-being is usually understood in terms of the relationship with one’s ancestors and as a result of good behaviour, i.e. if one lives in accordance with the values and norms of the traditions of the community [51]. Quave et al. [53] affirmed that if diseases are observed as superstitious or spiritualistic, they are treated differently. Some of the manifestations of skin inflammation are believed to be caused by wind illness or dead fire illness which requires the performance of rituals accompanied by natural resources [53]. Hence, Reyes-García [54] asserted that the choice of treatment is often related to an understanding of the cause of disease in African indigenous health systems. African indigenous healing system is addressed via two perspectives, which are the spiritual and physical perspectives [51]. Ethnomedicine practices form the basis of indigenous healthcare across different ethnic groups globally [49, 55,56,57]. The participants stated that their knowledge about folk cosmeceuticals comes from their ancestors, hence, they find it necessary to trust it, otherwise, they will lose their culture and which ultimately will dishonour their ancestors. Furthermore, they mentioned that traditional practitioners use folk cosmeceuticals to honour and obey ancestors. The participants consult traditional practitioners or use folk cosmeceuticals before using western medicine or consulting western practitioners. Some skin diseases cannot be healed by applying conventional cosmeceuticals, hence, indigenous people use folk cosmeceuticals because they believe that folk cosmeceuticals have spiritual modes of action that ensures effectiveness.

Conclusions

This explorative study documented the natural resources (plant and non-plant materials) used for folk cosmeceuticals by six rural communities in Vhembe district municipality, Limpopo province, South Africa. The study identified the natural resources used as folk cosmeceuticals in Vhembe district for future investigation for potential solutions to dermatological problems. In total, 52 plants and 22 non-plant materials were recorded as folk cosmeceuticals. The high number of natural resources is an indication that the area of study is rich in folk cosmeceuticals. As commonly observed with many ethnobotanical surveys, most of the participants were elders. This is an indication that a great deal of effort is needed to document the folk knowledge. However, scientific investigations in terms of the efficacy of natural resources is strongly recommended. For example, toxicity assay of the natural resources will provide insight and understanding of the safety of the folk cosmeceuticals, which may guarantee the safety of local users.