Demography of informants

A total of 155 informants were interviewed. Out of these, 42 (27.1%) were male and 113 (72.9%) were female. The informants were categorized into five different age groups, as documented in Table 3.

Table 3 Demographic characteristics of informantsMode of preparation

The most frequently used mode of preparation was as an infusion (50.0%) followed by processed (12.9%), fresh (direct utilization) (10.1%), tincture (4.7%), balm (4.4%) and so on (Tables 4, 5 and 6 and Additional file 1: Table 1), which was also reported by ethnobotanical studies performed in the closest neighborhood regions [13, 15, 18]. The most used plant part (Additional file 1: Table 2) was the leaf (44.7%).

Table 4 Medical uses of plant species of the Aleksinac and Bor districts of eastern SerbiaTable 5 Human and domestic animal nutrition and veterinary medicine use of plant species of the Aleksinac and Bor districtsTable 6 Folk and religious rituals and ethnoculture, and other purposes of plant species of the Aleksinac and Bor districtsQuantitative ethnobotanical analysis

The results of the study (Tables 4, 5 and 6) provide information on the use of 114 wild and few domesticated (but still wild growing) plant species quoted by respondents from East Serbia. Recorded plants belong to 97 genera and 47 families, of which the Asteraceae (14.0%), Rosaceae (13.2%), Lamiaceae (7.9%) and Fabaceae (7.9%) were the most represented, similarly to other ethnobotanical studies conducted in Serbia and the Balkans [12, 17, 21].

Use-reports

Out of the total of 2333 reports on the use of plants obtained by respondents, 1653 reports were given for medical purposes, 496 for human nutrition, 26 for animal nutrition, 38 for veterinary purposes, 57 for folk and religious rituals and ethnoculture and 63 for other purposes. Out of a total of 155 informants, 113 women gave 1834 use-reports, while 42 men gave 499. There were no differences between statements provided by men and women with exception for notes on the herbal micellar water and herbal medicinal syrup which were stated specifically by women. There were no differences between men and women regarding the curative and prophylactic use of plants for certain illnesses and disorders. In regard to traditional knowledge on the use of the wild plants for nutrition, religious and other traditional customs and for other purposes, both genders gave more–less similar information. Statements related to ethnoveterinary purposes are more frequently given by men than women.

Out of 2333 use-reports, 1180 (50.6%) were provided by inhabitants from the cities, while 1153 (49.4%) were provided by village inhabitants. There were no statistically significant differences between data on the traditional use of plants between inhabitants from cities and from villages concerning plant part in use and disorders treated by herbs. This is mainly due to the fact that inhabitants of these small semi-urban areas are usually tightly stuck to surrounding rural places, still performing some farming or horticulture for their own needs. However, there were some differences related to the traditional use of plants. Much more statements on animal nutrition, veterinary purposes, folk and religious rituals and ethnoculture, as well as for some less frequent uses, were obtained from inhabitants settled in the villages. Utilization of plant species for certain handicraft uses, as well as the note on common chicory (Cichorium intybus L.) as a coffee substitute, was mentioned only by respondents settled in the villages.

Frequency of citation (FC), relative frequency of citation (RFC) and relative importance index (RI)

In the present study, FC values ranged from 0.05 to 13.1 (Additional file 1: Tables 3 and 4). The highest FC values are recorded for Hypericum perforatum (13.1), followed by Urtica dioica (9.0) and Plantago major (5.1). RFC values ranged from 0.001 to 0.2 (Additional file 1: Tables 3 and 4). The highest RFC was recorded for Hypericum perforatum (0.2) and Urtica dioica (0.2) followed by Plantago major (0.1). As can be seen, the ethnomedicinal plants having high RFC values indicated their abundant use and widespread knowledge among the local communities. RI values ranged from 0.1 to 1 (Additional file 1: Tables 3 and 4). The highest RI values were calculated for Urtica dioica (1.0), followed by Hypericum perforatum (0.7) and Rosa canina (0.7).

All these plants are among the most frequently reported in several neighboring regions, i.e., studied sites from southeast and south Serbia and from Kosovo [12, 17,18,19, 21].

Informant consensus factor

The documented uses of plants in folk medicine refer to the treatment of 15 different groups of disorders. The ICF values ranged from 0.0 to 100.0% and 36.4% to 88.5% for Aleksinac and Bor districts, respectively. The highest ICF value found for the Aleksinac district was related to endocrine system disorders followed by skin-related disorders (79.7%) and circulatory system disorders (69.4%), while the lowest ICF value was found for antiseptic activity and metabolic disorders (0.0%). On the other hand, the highest ICF value for the Bor district was determined for skin disorders (88.5%), followed by digestive system disorders (83.5%) and respiratory system disorders (81.4%), while the lowest ICF value was 36.4% for antiseptic activity (Additional file 1: Table 5). A large number of species described by respondents of Bor district are used for the prevention and healing of digestive and respiratory system disorders. Such a fact might be related to very expressed air and soil pollution, as a consequence of mining and severe dust emission [49]. For the two studied regions considered together, the ICF values ranged from 33.3% to 88.9%. The highest ICF value was determined for skin disorders, followed by respiratory system disorders (82.1%) and digestive system disorders (82.1%), while the lowest ICF value was found for reproductive system disorders (51.4%) and antiseptic activity (33.3%) (Additional file 1: Table 6).

The ICF values ranged from 0.0% to 100.0% and 0.0% to 100.0% for men and women in the Aleksinac district, respectively. The highest ICF value found for men was related to endocrine system disorders followed by skin-related disorders (71.4%) and circulatory system disorders (50.0%), while the lowest was found for metabolic disorders, musculoskeletal system disorders, sensory system disorders, tumor ailments and urinary system disorders (0.0%). On the other hand, the highest ICF value for women was determined for endocrine system disorders and tumor ailments, followed by skin-related disorders (78.4%), while the lowest was recorded for musculoskeletal and sensory system disorders (0.0%) (Additional file 1: Table 7). When it comes to Bor district, the ICF values ranged from 0.0 to 85.7% and 30.0% to 86.9% for men and women, respectively. The highest ICF value found for men was related to sensory system disorders followed by skin (77.8%) and immune system disorders (63.0%), while the lowest was recorded for metabolic disorders (0.0%). On the other hand, the highest ICF value for women was determined for skin system disorders and digestive system disorders (82.8%) followed by immune system disorders (81.5%), while the lowest was recorded for antiseptic activity (Additional file 1: Table 8). In both districts together, the ICF values ranged from 0.0 to 100.0% and 27.3 to 88.0% for men and women, respectively. The highest ICF value found for men was related to endocrine system disorders followed by skin system disorders (79.6%) and immune system disorders (69.4%), while the lowest was recorded for metabolic disorders (0.0%). On the other hand, the highest ICF value for women was determined for skin-related disorders, followed by immune system disorders (82.8%) and respiratory system disorders (80.1%), while the lowest was recorded for antiseptic activity (27.3%) (Additional file 1: Table 9).

Regarding differences recorded in the city and surrounding villages, it was shown that the ICF values ranged from 0.0 to 100.0% in Aleksinac district. The highest ICF value found for both, citizens from the town and citizens from surrounding villages, was related to endocrine system disorders followed by skin system disorders (66.7% and 80.4%, respectively), while the lowest was recorded for musculoskeletal, reproductive, respiratory, sensory, urinary system disorders and musculoskeletal system disorders, respectively (Additional file 1: Table 10). When it comes to Bor district the ICF values ranged from 29.2 to 80.0% and 0.0 to 87.5% for citizens from the town and citizens from surrounding villages, respectively. The highest ICF value found for citizens from town was related to skin system disorders followed by digestive system disorders (74.4%), while the lowest was recorded for general health (29.2%). On the other hand, the highest ICF value for citizens from surrounding villages was determined for sensory system disorders, followed by skin (82.4%) and respiratory system disorders (77.3%), while the lowest was recorded for metabolic disorders (0.0%) (Additional file 1: Table 11). In both districts, the ICF values ranged from 28.0 to 82.5% and 0.0 to 100.0% for citizens from the town and citizens from surrounding villages, respectively. The highest ICF value found for citizens from town was related to skin system disorders followed by digestive (75.1%) and respiratory system disorders (74.8%), while the lowest was recorded for general health (28.0%). On the other hand, the highest ICF value for citizens from surrounding villages was determined for endocrine system disorders followed by skin (86.8%) and immune system disorders (79.2%), while the lowest was recorded for antiseptic activity (0.0%) (Additional file 1: Table 12).

Use value (UV)

In the present study, the UV (Additional file 1: Table 13) in Aleksinac district ranged between 0.02 and 0.8. Based on UV data, the five most commonly used ethnomedicinal plant species were Hypericum perforatum (0.8), Urtica dioica (0.6), Plantago major (0.3), Sambucus nigra (0.3) and Achillea millefolium (0.3). The UV (Additional file 1: Table 14) in Bor district ranged between 0.01 and 1.4. The five most commonly used ethnomedicinal plant species in Bor district were Urtica dioica (1.4), Hypericum perforatum (1.3), Sambucus nigra (1.1), Rosa canina (0.9) and Rubus plicatus (0.7). These species were used for diverse purposes which are indicated in Tables 4, 5 and 6.

Fidelity level

Fidelity level (FL) value in Aleksinac district ranged from 21 to 100%. The highest FL of 100% was recorded for Allium ursinum and Crataegus monogyna (circulatory system disorders), Althaea officinalis and Hedera helix (respiratory system disorders) and Betula pendula (urinary system disorders) (Additional file 1: Table 15). Further results showed that FL value in Bor district ranged from 22 to 100%. The highest FL of 100% was recorded for Alchemilla vulgaris (reproductive system disorders), Melilotus albus (circulatory system disorders) and Rumex patientia (digestive system disorders) (Additional file 1: Table 16). In addition, the results for the entire studied area showed that FL values range from 25 to 100%. The highest FL of 100% was recorded for Alchemilla vulgaris (reproductive system disorders), Crataegus monogyna and Melilotus albus (circulatory system disorders) and Rumex patientia (digestive system disorders) (Additional file 1: Table 17). FL values indicate that respondents from Aleksinac district mostly use plants for skin system disorders (five species), while respondents from Bor district mostly use plants typical for the treatment of digestive system disorders (13 species).

Based on use-records given by men and women, FL values, in Aleksinac district, ranged from 75 to 100% and 33.3 to 100.0%, respectively. The highest FL of 100% according to men uses was recorded for Juglans regia (endocrine system disorders) (Additional file 1: Table 18), while for women was recorded for Betula pendula (urinary system disorders), Crataegus monogyna (circulatory system disorders) and Hedera helix (respiratory system disorders) (Additional file 1: Table 19). On the other hand, FL values in Bor district ranged from 30.8 to 88.9% (based on man uses) and 20.0 to 100.0% (based on women uses). The highest FL according to men uses was recorded for Melissa officinalis (nervous system disorders) (Additional file 1: Table 20), while for women was recorded for Alchemilla vulgaris (reproductive system disorders), Epilobium parviflorum (urinary system disorders), Euphrasia officinalis (sensory system disorders), Melilotus albus (circulatory system disorders) and Mentha longifolia and Rumex patientia (digestive system disorders) (Additional file 1: Table 21). In addition, the results for the entire studied area showed that FL value ranged from 27.8% to 100% (man uses) and 20.0% to 100% (women uses). The highest FL based on men use-records was recorded for Juglans regia (endocrine system disorders), Pulmonaria officinalis (respiratory system disorders) and Sambucus nigra (immune system disorders) (Additional file 1: Table 22). The highest FL based on women use-records was recorded for Alchemilla vulgaris (reproductive system disorders), Betula pendula and Epilobium parviflorum (urinary system disorders), Crataegus monogyna and Melilotus albus (circulatory system disorders), Euphrasia officinalis (sensory system disorders) and Mentha longifolia and Rumex patientia (digestive system disorders) (Additional file 1: Table 23). FL values indicate that men from Aleksinac district mostly use plants for skin system disorders (two species), while men from Bor district mostly use plants typical for the treatment of digestive system disorders (five species). FL values indicate that women from Aleksinac district mostly use plants for skin system disorders (five species), while women from Bor district mostly use plants typical for the treatment of digestive system disorders (12 species).

In addition, based on use-records given by citizens from the town and citizens from surrounding villages FL values in Aleksinac district ranged from 55.6 to 100% and 42.9 to 100.0%, respectively. The highest FL (citizens from town) was recorded for Paliurus spina-christi (digestive system disorders) (Additional file 1: Table 24), while the highest FL (citizens from surrounding villages) was recorded for Althaea officinalis (respiratory system disorders), Betula pendula (urinary system disorders), Crataegus monogyna (circulatory system disorders), Hedera helix and Pinus nigra (respiratory system disorders) (Additional file 1: Table 25). On the other hand, FL values in Bor district ranged from 50.0% to 100.0% (citizens from town) and 18.2 to 100.0% (citizens from surrounding villages). The highest FL (citizens from town) was recorded for Cichorium intybus (digestive system disorders) and Sambucus nigra (respiratory system disorders) (Additional file 1: Table 26), while the highest FL (citizens from surrounding villages) was recorded for Alchemilla vulgaris (reproductive system disorders), Epilobium parviflorum (urinary system disorders), Euphrasia officinalis (sensory system disorders), Humulus lupulus (nervous system disorders), Melilotus albus (circulatory system disorders) and Mentha longifolia and Rumex patientia (digestive system disorders) (Additional file 1: Table 27). In addition, the results for the entire studied area showed that FL values ranged from 23.1% to 100% (citizens from town) and 25.0% to 100% (citizens from surrounding villages). The highest FL (citizens from town) was recorded for Alchemilla vulgaris (reproductive system disorders), Euphrasia officinalis (sensory system disorders), Melilotus albus (circulatory system disorders), Paliurus spina-christi and Rumex patientia (digestive system disorders) and Valeriana officinalis (nervous system disorders) (Additional file 1: Table 28), while the highest FL (citizens from surrounding villages) was recorded for Althaea officinalis (respiratory system disorders), Betula pendula (urinary system disorders), Crataegus monogyna (circulatory system disorders), Pinus nigra and Pulmonaria officinalis (respiratory system disorders) and Rumex patientia (digestive system disorders) (Additional file 1: Supplementary Table 29).

FL values indicate that citizens from Aleksinac town mostly use plants for skin system disorders (two species), while citizens from Bor town mostly use plants typical for the treatment of immune system disorders (three species). FL values indicate that citizens from surrounding villages in Aleksinac district mostly use plants for skin system disorders (four species) and respiratory system disorders (four species), while citizens from surrounding villages in Bor district mostly use plants typical for the treatment of digestive system disorders (14 species).

Obtained results point to the fact that although citizens from these districts rely on the official health care system, still medicinal plants have significant value in everyday life for these people.

Multivariate analysis

A scatter plot from principal coordinate analysis (PCoA) showed the formation of three distinct homogeneous groups (Fig. 1). The first group consisted of seven species (Rumex acetosa, Xanthium spinosum, Sambucus ebulus, Rumex patientia, Potentilla reptans, Paliurus spina-christi and Cydonia oblonga). All these species are grouped in relation to one variable, i.e., the effects on digestive system disorders. The second group was formed from five species (Melilotus albus, Loranthus europaeus, Allium ursinum, Crataegus monogyna and Viola odorata) acting mainly for circulatory system disorders, according to information from respondents. The third group consisted of five species (Petasites albus, Asparagus officinalis, Equisetum telmateia, Hieracium pilosella and Pyrus pyraster) which were mentioned for urinary system disorders application.

Fig. 1

Principal coordinate analysis of plants used in traditional human medicine in surveyed area in East Serbia

Traditional preparations and remedies

Out of 114 reported species, 101 (88.6%) are used for medical purposes (Table 4). Plants are the most commonly used to treat digestive system disorders (49.1%), circulatory system disorders (41.2%) and respiratory system disorders (35.1%). These findings on a wide use of plants for digestive and respiratory system conditions are in accordance with other ethnobotanical studies in Serbia [17, 18, 21]. Concerning plants used for medicinal purposes, 33 species are included in the European Pharmacopoeia 8.0. [50] (marked with ♦  in Table 4). Plant parts, i.e., plant drugs which differ from citations provided in European Pharmacopoeia 8.0. [50], are marked with hash (#) Table 4. Some interesting traditional remedies were recorded, which haven’t been so far indicated in previous ethnopharmacological studies in the Balkans.

H. perforatum is reported as an herbal remedy effective against every disorder (medical panacea) which is in agreement with some earlier investigation. Although spatially distant, in the Arribes del Duero (Spain), the cultural importance of H. perforatum oil is unquestionable. It is also cited, literally translated, that “What Hypericum doesn’t cure the doctor certainly won’t” [51]. Many previous studies on the Balkans documented its usage against diseases of different organ systems [52,53,54,55].

It is claimed that the best herbal medicines, with the most healing properties, are made if this plant is collected on July 7 (St. John’s Day). It is even stated that flowers smell different on that day. Flowers are collected, basted with sunflower or olive oil, and left in the sunlight for 40 days. On the 40th day, oil extract is brought into the home. Similar methods for preparation are noted in earlier studies both on Serbian territory [12] and in the region [21, 56,57,58]. Oil extract is used externally for skin ailments, hemorrhoids and gynecological problems. Živković and colleagues (2020) reported the same type of preparation against skin complaints and hemorrhoids [19], while Varga and collaborators (2019) reported the usage of infusion against gynecological diseases [59]. Internally, it is applied for digestive ailments and improving general health conditions.

Informants are also knowledgeable on the toxicity of certain medicinal plants, as well as their side effects when combined with medicinal drugs. For example, they stated that H. perforatum tea should not be used together with drugs used in the treatment of malignant diseases because it can “completely reverse the effect of the drug.” Also, tea should not be drunk for more than seven days in a row.

When it comes to medicinal herbs, the so-called Ciklus svetojovanskog bilja (lit. Cycle of St. John’s herbs) is also mentioned. It encompasses the period from June 28 (Vidovdan; lit. St. Vitus day) to July 7 (Ivanjdan; St. John’s Day) when it is most desirable to collect certain medicinal herbs (Achillea millefolium, Melissa officinalis and Hypericum perforatum).

It is not unusual for some traditional receipts in Serbia to be prepared during the 40 days. It is possible that roots of the method of preparation lie down in the Christian religion where the number 40 has a particular meaning. Christians believe souls need 40 days after death to leave the Earth, in the Bible it is mentioned that the great flood lasted 40 days and nights [60], Moses spent 40 days and nights in Mount Sinai, the same number of days Jesus fasted and was tempted in the wilderness [61]. We assume that it is easier for people to remember and pass on the knowledge related to the preparation if there is some universally known fact.

Traditional tinctures

Homemade tinctures are usually prepared with the fruit spirit (`rakija` in Serbian). Among the most used, there are the tinctures made of a single herb, such as wild thyme, nettle or marigold, or those prepared of mixture herbs.

Tincture for a massage, circulation improvement and thrombosis prevention is made of hundreds of marigold flowers (Calendula officinalis) put in a liter of “rakija”. The usage of this herb as a tincture also was noted in the research conducted in southwestern Serbia [14]. The comfrey (Symphytum officinale) tincture is made in a similar way (one mature root is put in one liter of rakija), or the drug is mixed with five wild chestnut fruits and one rosemary branch in half a liter of spirit for healing of leg pains and varicose veins. One ethnobotanical investigation previously published, conducted in the northeastern part of Croatia, reported the traditional use of comfrey’s roots as tincture against cardiovascular disorders [62].

Syrups and honey

Few informants mentioned preparation of homemade syrup for strengthening immunity, which was especially recommended to children. The syrup is made from Pinus nigra shoots, Plantago lanceolata leaves, Sambucus nigra flowers, Thymus serpyllum aerial parts and Tussilago farfara leaves. The preparation is made by boiling of sugar (3 kg) for 10 min and thereafter adding 300 g of each plant drug to cook for an additional 9 min exactly. In the final step, 15 g of commercial citric acid is added, and the mixture is cooked for one more minute.

Nettle (Urtica dioica) syrup is considered as the best medicine for strengthening the immune system in patients with anemia. Firstly, red wine is cooked with yellow sugar. When it comes to boiling, 50 young apical parts of nettle are added, and it is cooked for 2–3 min. Every morning before breakfast, a small glass of preparation should be consumed.

To the best of our knowledge, these receipts are mentioned for the first time on the Balkan Peninsula.

The honey is often mixed with herbs for different treatments. For example, there is a recipe quoting that two tablespoons of the black pine (Pinus nigra) pollen, locally known as “flower powder” (in Serbian, “cvetni prah”) are mixed with 200–300 g of meadow honey. It is believed that this remedy improves respiratory ailments. These results are similar to those obtained from the Kopaonik mountain where buds and needles of P. sylvestris are also mixed with honey in the final part of the preparation of medicine against chronic bronchitis [12] Mustafa and colleagues (2012b, 2020) reported mixing cones of Pinus spp. with honey to treat respiratory system ailments, which is partially in agreement with the results of the current study [56, 63]. The arum is also mixed with honey: one kilogram of Arum maculatum rhizome is combined with a kilogram of honey. The mixture is consumed 2–3 times a day before a meal for digestion and hemorrhoids treatment. A particular product is made of dandelion flowers (Taraxacum officinale). It is called “dandelion honey.” Dandelion flowers are collected and cooked together with water and sugar until the flowers are completely cooked in the mixture. This product is frequently prepared and consumed in the Balkans, according to some previous ethnobotanical studies [56, 64].

Ointment for skin diseases

Ointment is prepared with a hundred of marigold petals fried with a tablespoon of homemade grease and it is used cold for the treatment of urticaria. Our results are congruent with some previous studies [16], which mentioned the similar use of these flowers against different skin injuries [12,13,14, 19]. Twigs of elder (Sambucus nigra) are used for preparing balm for burns therapy and insect and spider bites treatment. Twigs are grated and mixed with plant wax, honey, the incense and chopped yarrow (Achillea millefolium) leaves. The mixture is filtered and stored in a cold place.

Decoction for urinary diseases

Aerial parts of Equisetum telmateia are mixed with young corn cobs and corn silk (elongated stigmas) and cooked in water. The mixture is cooked until the volume of water drops to a third of the initial volume, and the color becomes red. The decoction is used against urinary problems.

Wild herbs for human nutrition

There were 37 (32.5%) plant species recorded for human nutrition (Table 5). Out of 37 species used for nourishment, 35 species are simultaneously used for medical treatments. The plant drugs are used fresh, dry and processed. Homemade food and beverage products made from or with the addition of wild plants include juices, jams, compotes, wine and Serbian traditional sweet dish “slatko” [65]. Fresh and dried herbs are often used for seasoning, i.e., as spices, either single or in mixtures (e.g., Achillea millefolium, Allium ursinum, Melissa officinalis, Origanum vulgare, Satureja subspicata, Thymus serpyllum, and Urtica dioica). Salad used for nutrition, additionally providing health benefits, especially for stomach ailments regulation is prepared as a mixture of leaves of five species: Fragaria vesca, Plantago major, Rubus plicatus, Rumex acetosa and Urtica dioica.

For the preparation of the sweet delicacy “slatko” the petals of the dog rose (Rosa canina) are used. Firstly, the petals are mixed with water and sugar and the mixture is boiled for at least half an hour. In the next step, a few drops of lemon juice are added to restore a petal color (should remain as gently reddish).

Traditional and beloved herbal beverages in Balkans mainly refer to those made of elder flowers, which has been already reported in some former studies [16]. The new information obtained in our research is related to the note about potential negative effects on men's fertility if it is overused. Elder fruits are used either fresh or processed, mostly for preparing a fruit wine. Fruits of elder are cooked for 15 min at 80 °C with water and sugar (half of the quantity of used fruits), and left for fermentation. Similar use of elder is already known in Europe [66].

Replacement for traditional coffee drink is made of dried and grinded chicory (Cichorium intybus) roots mixed with Turkey oak (Quercus cerris) acorn for nicer flavor.

Overlap of medicinal and food plants

In our study, nearly 100% plant species overlap as food and medicine. This finding is in agreement with another study conducted in Negotin, the very near region [