Ethnobotanical study of curative plants used by traditional healers to treat rhinitis in the Limpopo Province, South Africa

Background Studies focusing on plants used medicinally to heal and manage rhinitis are very scarce in Africa and elsewhere. Objectives To document plants used by traditional healers (THs) in the treatment and management of rhinitis and related symptoms in the Limpopo Province of South Africa. Methods Data was gathered using a semi structured interviews with 105 THs in the Limpopo Province, supplemented by field expeditions for plant specimen collection and observation. Results 63 plant species from 59 genera distributed across 40 botanical families, mainly the Asteraceae (7 spp.) and Euphorbiaceae (6 spp.) were therapeutically used by THs. Overall, 77 herbal recipes (87%=mono and 12.9%=poly), mainly prepared from roots (55.5%) and leaves (19%) were recorded. Most of these recipes were processed via pounding (59.7%) and boiling (20.7%). Oral (44.1%) and nasal (33.7%) was the preferred modes of dispensing remedies by THs. Artemisia afra, Clerodendrum ternatum, Cryptocarya transvaalensis, Enicostema axillare, Kalanchoe brachyloba, Lasiosiphon caffer, Lippia javanica, Schkuhria pinnata, Securidaca longepedunculata, Spirostachys africana, Stylochaeton natalensis and Zanthoxylum capense were the most widely used and preferred species for treatment of rhinitis and/or related symptom by all questioned THs. Conclusion This study is the first to document plants used traditionally to treat rhinitis in Africa. Therefore, it provides a baseline data on the plants used to heal rhinitis in the Limpopo Province. Finding of this study can be used as apedestal for further investigation in to effective plant-based anti-rhinitis drugs.


Introduction
Rhinitis is a respiratory affliction that is characterised by inflammation of the nasal mucosa 1 . This complaint can either be allergic and non-allergic. Overall, rhinitis is a significant cause of both the widespread morbidity and medical treatment costs in many countries worldwide. It is estimated that over 400 million people inhabiting both developed and developing countries are diagnosed with this condition 2 . For instance, up to 40% of children, and approximately 20% of the adult population in the United States of America were previously reported to suffer from rhinitis 3 . The latter occurrence is lower compared to 29.8% noted by Morais-Almeida et al. 4 amongst the adult subjects residing in Portugal. Eriksson 5 reported 26.9% prevalence of rhinitis amid the West Swedenees population.
Incidence of rhinitis is also common in Africa, and here it varies according to the geographical location as well as age group. In Nigeria the prevalence of 29.6% amongst adults aged between 18 and 45 years was previously registered 6 . The occurrence of rhinitis in this age brackets was 10.4% in Cameroon 7 . This respiratory infection affected at least 15.3% of Egyptian population aged [11][12][13][14][15] year olds 8 . In South Africa, there are extremely few epidemiological studies that addressed the prevalent of rhinitis. However, available study; Zar et al. 9 , was conducted in two phases carried out seven years apart, amongst the [13][14] year olds adolescents in randomly selected South African schools. The outcomes of this surveys indicated that the incidence of rhinitis amongst these subjects had increased significantly between two time points. For instance, in phase I of the investigation, conducted in 1995, the prevalence was 30.4%, and by phase II in 2003, the occurrence had gone up to 38.5%. The possible reasons for this drastic increase in the incidence of rhinitis could be attributed to the increasing prevalence of contributing factors.
Although sometimes rhinitis is mistakenly viewed as a trivial disease, its symptoms may significantly affect a patient's quality of life 10 . Different disorders that are associated to this respiratory infection include bronchial asthma, sinusitis, otitis media, nasosinusal polyposis, respiratory infections and alterations in dental occlusion 11 . In addition, conditions such as headache, cognitive impairment, nasal obstruction, nasal itching, sneezing and watery rhinorrhoea are also common in rhinitis suffer 12 . Therefore, appropriate management of this respiratory affliction may be an important component in effective management of all the above stated coexisting or complicating respiratory ailments.
According to DeGuzman et al. 13 , management approaches of rhinitis by western health care professionals in Africa and elsewhere include educating patients about the various strategies to avoid risk factors such as animals and insect allergens, house dust mites, molds and pollens, amongst other factors. Therapeutic options or pharmacological agents such as anti-H1 antihistamines, intranasal corticosteroids, topical anticholinergic, topical or oral vasoconstrictors and sodium cromoglycate are also prescribed by these professionals as part of rhinitis treatment and management 14 . Despite the evidence indicating prevalence of rhinitis and its management approaches employed by western health professionals; little is still known about the herbal medications implicated by the aboriginal health care providers as treatment of this affliction. However, few attempts to address this gap in knowledge have been made in countries such as Turkey 15 and India 16 . In Africa as a continent wherein over 80% of the population relies on traditional medicines and healers' health care services either as the only option or the preferred option 17 , ethnobotanical studies focusing on the treatment of rhinitis are lacking. The aim of the present study is therefore, to investigate the therapeutic plants implicated by traditional healers in the Limpopo Province against rhinitis.

Study area and population
The area selected for survey was the municipalities of Capricorn, Sekhukhune and Waterberg districts, in the Limpopo Province, South Africa ( Figure 1). Five villages from each municipality were selected as study sites. Generally, most of these settlements are poorly developed and lack basic infrastructures such as sanitations, roads and healthcare facilities. The populace of the sampled districts comprised of different ethnic groups, with Bapedi who speak Sepedi language being the largest group, comprising about 50% of the entire population 18 .

Ethnobotanical survey and data collection
The ethical approval to conduct the present study was obtained from the Ethical Review Committee of the University of Fort Hare (Ref: MAR001SSEMO1). Prior to the field survey, permission to conduct an investigation was sought from the local tribal leaders of each sampled village, and subsequently THs were requested to take part in this study. Both the local community leaders and all the THs were informed about the purpose of the survey. Traditional healers who agreed to participate in the study were asked to sign a consent form before being questioned.
Data was collected from May 2017 to October 2017 using semi structure questionnaires during face-to-face interview with 105 THs who were conveniently chosen (i.e., with the help of local leaders and THs). The questionnaire was designed to captured information on the local name of used medicinal plants by THs to treat rhinitis, used plant part/s, mode of herbal preparation, administration and dosage prescription. Interviews were conducted by researchers, independently for each traditional healer in Sepedi language.
The data obtained from questionnaire guides was supplemented by independent field walk with each traditional healer for the practical identification of used medicinal plants and direct observations on their characteristics. During field trips plants were initially pointed-out by THs via vernacular names and subsequently researchers collected the voucher specimens. The collected plant samples were prepared (i.e., numbered, pressed and dried) and deposited at the Larry Leach Herbarium (University of Limpopo) for scientific identification by a trained taxonomist.

Data analysis Micro Soft Excel and Statistical Package for the Social Sciences (SPSS)
Data from ethnobotanical surveys was analysed using Microsoft Excel 2000 and SPSS programmes by means of descriptive statistics. These programmes were used to identify proportions of plant families, habits, used species and their parts, condition of medicinal plant part/s use (fresh/dried), mode of remedies preparations and administration, amongst the other information.

Fidelity level (FL)
The FL was employed to quantify the percentages of THs claiming the use of a certain plant for rhinitis and/ related symptom/s. This was determined following the method of Al-Quran 19 : Where Np was the number of THs who independently used a particular plant species to treat rhinitis and/or related symptom, and N was the total number of THs who reported the plant as a medicine to treat any given disease (rhinitis or related symptom/s). The FL index shows the degree of homogeneity on the informant's knowledge regarding the medical application of a particular medicinal plant species against a specific ailment 19 , therefore it reveals the most utilised and avoided species.

Use value (UV)
Use value provides a good measure to estimate all the possible uses of an individual plant species. An individual plant-disease-use combination mentioned by Bapedi THs for rhinitis and related symptoms was evaluated using the formula outlined below 20 : Where U was the number of citations per species, and was N the total number of questioned THs. Generally, UV for a plant is high when there are corresponding broad therapeutic applications coupled with a relatively high use mentioned (UM) by participants 20 .

Diversity of used plant species
In the present study a total of 63 plant species (55 indigenous and 8 exotics) from 59 genera distributed across 40 botanical families, mainly the Asteraceae (7 spp.), Euphorbiaceae (6 spp.) and Malvaceae (4 spp.) were used by 105 Bapedi THs to treat rhinitis and various symptoms they perceived as related to this respiratory infection (
Dosage strength of all herbal preparation documented in the present study was determined. In general, consistencies amongst THs with regards to this were only noted for boiled liquid medicine taken orally. For instance, a metal cup (500ml) was prescribed by all Bapedi THs three times a day (morning,midday and evening). However, dosage regimes of the rest of the herbal recipes made by these THs was not standardised, and depended on an individual healers' experience.

Discussion
To the best of our knowledge, the present study is the first in South Africa and Africa as a continent to investigate plants used traditionally by THs or lay people to treat rhinitis and related symptoms, thus there is a dearth of comparative data against which to evaluate our findings. As a matter of fact, there is generally a scanty of information regarding the use of herbal remedies to treat these conditions worldwide. However, few attempts to address this gap in knowledge have been made in countries such as Turkey 15 and India 16 . Comparison of medicinal plants documented in these two studies with ours is divergent, probably due to the fact that diverse cultures of the world possess their own specific knowledge of plant use and tradition 21 . We documented 63 plant species belonging to 40 botanical families, mainly the Asteraceae, Euphorbiaceae and Malvaceae used by Bapedi THs to treat rhinitis and related symptoms. Kanakavalli et al. 16 reported the dominant of Fabaceae, and Sayin et al. 15 found that all the botanical families in their study were each equally represented by a single species. The dominance of Asteracea, Malvaceae and Euphorbiaceae in our study could be attributed to their wider distribution across the studied sites, which in turn afforded local THs with higher diversity of plants to explore healing potential, and subsequently experiment against various human ailments including rhinitis. The remaining families recorded in this study were represented with less than three species used to heal rhinitis and related symptoms, thus correspondingly suggesting that their members are less popular amongst the interviewed Bapedi THs as treatment of these diseases. Overall higher number of taxa and associated botanical families documented in this study shows that Bapedi THs are knowledgeable about diversity of plants useful for rhinitis and related conditions. Also such high diversity to some extent is a good indicator that the studied areas harbour diverse habitats which supports a rich curative floristic wealth useful for these illnesses. is an indication that they do take this respiratory infection serious, and thus investigation of the efficacy of these plants should be conducted. Effective herbal treatments of these symptoms are equally imperative in achieving the best outcomes of diagnosed patients. This is because it might assist in eliminating both occurrences and associated health impact of such symptoms that might affect quality.
Our study revealed that THs mainly prefer herbaceous and tree species for the preparation of herbal medicine to heal and manage rhinitis and related symptoms. Their distinct preferences of herbaceous species could be attributed to the fact that they are abundant at close proximity and are easy to harvest with less effort, both compared to trees and shrubs. On the other hand, utilisation of these two growth forms might be due to their ease of identification in the wild, high adaptability as well as capacity to proliferate in various seasons, thus available throughout the year. In general, the above recorded habits might be a reflection of the curative plant community structure across the studied areas.
Plant species which scored the highest FL as treatments of rhinitis and related symptoms in this study indicate greater agreement among the THs regarding their phyto-therapeutic use/s which might be attributed to efficacy, hence their strong selectivity over the others. Thus, such species should be prioritised for phytochemistry and pharmacological properties studies. Similar attention must be given to species such as Z. capense (headache and rhinitis therapies), S. longepedunculata (headache and rhinitis), A. afra, C. ternatum, C. transvaalensis, E. axillare, L. caffer, L. javanica, S. natalensis (rhinitis), K. brachyloba and S. africana (headache, for each) and S. pinnata (painful eyes) with the highest UV index. However, the high UVs of these species also indicates the need to promote their sustainable utilisations and harvesting.
Roots and leaves were mostly used plant parts in this study. On contrary, Kanakavalli et al. 16 reported leaf, rhizome and whole plant as equally favoured medicinal plant parts for preparation of rhinitis remedies. The observed discrepancies might be due to the larger number (n=63) of plant recorded in our study compared to just nine species noted by this authors. Larger number of plant parts in our study was prepared by THs in their dry) state than when they are still fresh, thus suggesting that few species are grown in home gardens or available in close vicinity for instance use as medicines. Not surprising, about 87% of herbal recipes was made from a single plant part, perhaps due to the ease of preparation compared to poly-recipes. Overall, diverse procedures of herbal preparing medicines recorded in this study might be attributed to THs' preferences or is a reflection of an old tradition amid these THs observed from various mentors. Different route of administering remedies such as burning and inhalation, rubbing between hands for inhalation of vapour and snuffing might be effective for treatment and management of rhinitis, mainly due to the fact that prescriptions go directly to the nasal membranes, thus might act on various components of the nasal inflammatory process reducing inflammatory cell numbers.

Conclusion
Our study is the first to document plants used traditionally to treat rhinitis and related symptoms in South Africa and Africa at large. Therefore, it is not surprising that all species used by interviewed Bapedi THs are recorded in this survey for the first time as rhinitis cure. On the other hand, high usage of some of the plant species implicated by these THs in the treatments of symptoms they perceived as allied to rhinitis across the studied district and municipalities, confirm the authenticity of data gathered and importance of such species. Overall, the medicated claims of the species inventoried in the study need to be evaluated through phytochemical and pharmacological investigations. Scanty of ethnobotanical information focusing on treatment of rhinitis and related symptoms in South Africa and Africa as a continent call for an urgent need to record such valuable data before it becomes inaccessible or vanishes together with its holders.