Journal of Ethnopharmacology 122 (2009) 60–67
Contents lists available at ScienceDirect
Journal of Ethnopharmacology
journal homepage: www.elsevier.com/locate/jethpharm
Cultural significance of medicinal plant families and species among Quechua
farmers in Apillapampa, Bolivia
Evert Thomas a,∗ , Ina Vandebroek b , Sabino Sanca c , Patrick Van Damme a
a
b
c
Laboratory of Tropical and Subtropical Agriculture and Ethnobotany, Ghent University, Coupure links 653, B-9000 Ghent, Belgium
Institute of Economic Botany, The New York Botanical Garden, 2900 Southern Boulevard, NY 10458, USA
Asociación de Jampiris de Apillapampa, Apillapampa, Bolivia
a r t i c l e
i n f o
Article history:
Received 16 August 2008
Received in revised form 5 October 2008
Accepted 26 November 2008
Available online 3 December 2008
Keywords:
Informant consensus
Emic perception of efficacy
Use quality
Andes
Quantitative ethnobotany
Cultural importance indices
a b s t r a c t
Ethnopharmacological relevance: Medicinal plant use was investigated in Apillapampa, a community of
subsistence farmers located in the semi-arid Bolivian Andes.
Aim of the study: The main objectives were to identify the culturally most significant medicinal plant
families and species in Apillapampa.
Materials and methods: A total of 341 medicinal plant species was inventoried during guided fieldtrips
and transect sampling. Data on medicinal uses were obtained from fifteen local Quechua participants,
eight of them being traditional healers.
Results: Contingency table and binomial analyses of medicinal plants used versus the total number of
inventoried species per family showed that Solanaceae is significantly overused in traditional medicine,
whereas Poaceae is underused. Also plants with a shrubby habitat are significantly overrepresented in the
medicinal plant inventory, which most likely relates to their year-round availability to people as compared
to most annual plants that disappear in the dry season. Our ranking of medicinal species according to
cultural importance is based upon the Quality Use Agreement Value (QUAV) index we developed. This
index takes into account (1) the average number of medicinal uses reported for each plant species by
participants; (2) the perceived quality of those medicinal uses; and (3) participant consensus.
Conclusions: According to the results, the QUAV index provides an easily derived and valid appraisal of a
medicinal plant’s cultural significance.
© 2008 Elsevier Ireland Ltd. All rights reserved.
1. Introduction
The taxonomic classification of plants at the family level is an
important factor in determining the usefulness of plant species to
local people. Some plant families are clearly more useful in certain
use categories than others (Phillips and Gentry, 1993a,b; Moerman,
1996; Moerman et al., 1999; Byg et al., 2006). The same reasoning
holds true for individual plant species (Prance et al., 1987; Byg et
al., 2006). Determining the usefulness of plant families generally
pertains to the domain of scientific researchers (e.g. Moerman,
1996; Treyvaud Amiguet et al., 2006; Bennett and Husby, 2008),
whereas local people are ideally placed to assess the usefulness
of particular plant species for particular applications, as the latter
can rely on empirical knowledge accumulated over several years
to generations of practice.
Resource use preference by local people is often linked to
purpose-specific characteristics of plants, such as durability and
∗ Corresponding author. Tel.: +32 92646093; fax: +32 92646241.
E-mail address: [email protected] (E. Thomas).
0378-8741/$ – see front matter © 2008 Elsevier Ireland Ltd. All rights reserved.
doi:10.1016/j.jep.2008.11.021
ease of handling for roof thatch, strength of stems used in house
construction, efficacy to correct harmful symptoms or to eliminate causal factors associated with particular health conditions, etc.
(Casagrande, 2002; Byg et al., 2006). The concept of incorporating
use quality in ethnobotanical indices was first proposed by Turner
(1988) who assigned qualities a priori, with the specific use type
as the only criterion. For example, food uses received a score of
5 since they were considered more important by the author than
medicinal uses that were assigned a quality score of 3. Other authors
offered similar approaches to address the use preference of plants
(e.g. Pieroni, 2001; Garibay-Orijel et al., 2007). Also, Prance et al.
(1987) indirectly included the quality of uses in their calculations
of species’ use values by subjectively assigning a value of 1 to each
major use and a value of 0.5 to minor uses.
However, since these methods rely at least partly on subjective decisions of researcher(s), it is unlikely that they are applied
consistently by different researchers (Phillips, 1996). Therefore,
an approach whereby participants themselves are encouraged to
assess individual plant use qualities seems better suited. Carretero
(2005) calculated ‘multiple values’ for Bolivian palm species by
combining use quality and use frequency explicitly assigned by
E. Thomas et al. / Journal of Ethnopharmacology 122 (2009) 60–67
local participants and not by researchers. Also, Stagegaard et al.
(2002) encouraged participants to rate the usefulness of plants as
either “usable but sub-optimal” (0.5), “suitable” (1.0) or “near optimal” (1.5) for five use categories. However, the downside of the
latter method is that it does not allow for more than one quality assessment per use category. For example, according to the
methodology of Stagegaard et al. (2002), a particular plant species
that is reported to be a good remedy for treating three different
health conditions will receive an identical quality assessment for
the medicinal use category as a plant that is a good remedy for treating just one health condition. In this paper we therefore propose an
alternative method, specifically for assessing local people’s perception of a medicinal plant’s efficacy to correct deleterious symptoms.
The overall goal of the present study is to identify the most
important medicinal families and species for Apillapampa, a community of subsistence farmers from the Bolivian Andes. The
importance of medicinal plant families was assessed by means of
contingency table and binomial analyses as proposed by Bennett
and Husby (2008). To quantify the cultural significance of medicinal plant species in Apillapampa, an index was developed that is
based on an adaptation and combination of existing ethnobotanical
indices.
2. Methodology
2.1. Research area
Apillapampa is located at about 3250 m.a.s.l. and 17◦ 51 S,
66◦ 15 W, along the road connecting Capinota with Arampampa
(Fig. 1). No on-site climate data are available, but the nearest
village of Capinota (2400 m.a.s.l.) is characterized by a semi-arid
bioclimate with a pronounced dry season with 6–8 arid months
and a mean annual temperature and precipitation of 17.8 ◦ C and
447 mm (Navarro, 2002). A somewhat lower temperature and
higher precipitation can be expected in Apillapampa due to the
higher altitude. At the time of research, Apillapampa consisted
of about 430 households (2600 inhabitants) of Quechua-speaking
subsistence farmers (Fepade, 1998). The main economic activity of
most Apillapampeños is agriculture for domestic use. The vegetation consists of mainly xerophytic shrubs and small trees, which are
supplemented with annual herbs during the rainy season (Navarro,
2002; Thomas, 2008). A more detailed description of the ethnographic and geographical background of the study area is provided
in Vandebroek et al. (2003, 2004a,b, 2008).
2.2. Data collection
The results presented in this paper were collected in two studies
as described below.
Fig. 1. Location of the study area within Bolivia, the Department of Cochabamba
and Capinota Province (map elaborated with DIVA-GIS (www.diva-gis.org)).
61
I. Between July 2000 and April 2001 a project on medicinal plant
use in Apillapampa was carried out in collaboration with eight
traditional healers from the semi-formal healers’ association
called “Asociación de Jampiris de Apillapampa”. Methodological
details of this study are provided in Vandebroek et al. (2003,
2004a,b, 2008).
II. The second study, conducted between December 2002 and
November 2003, focused on a comprehensive quantitative ethnobotanical inventory of all useful plant species in Apillapampa.
Plant species were collected in transects, homegardens, and during numerous fieldtrips. Thirty-six transects of 50 m × 2 m were
installed such that they represented the vegetation occurring in
the study area. In these transects, all plants with a mature growth
height ≥0.1 m were sampled (Thomas et al., 2008). Ethnobotanical information about 387 of the sampled plant species was
gathered ex situ between December 2002 and December 2003 by
means of semi-structured interviews with 8 male and 5 female
inhabitants (age range 14–66 years). Only six of the eight traditional healers who participated in the first study (Vandebroek et
al., 2003) were involved in both investigations, as two of them
no longer lived in Apillapampa at the time the second study
was carried out. Other participants were selected through peer
recommendations as described by Davis and Wagner (2003).
In both studies, interviews were conducted individually and
included questions about local plant name(s), use(s), and preparation methods of plant species. Voucher specimens were used
as a prop during interviewing (cf. Thomas et al., 2007). The total
number of collected species that were presented to participants
during ethnobotanical interviews amounted to 441. Ethnopharmacological data of most species mentioned in this paper are listed
in Vandebroek et al. (2003). Voucher specimens (ET1-600, IV1188, JBC1-63 and TC500-650) were identified and deposited in the
Bolivian herbaria of Cochabamba (BOLV) and La Paz (LPB).
Acceptance of both projects by the Apillapampa community
council (Subcentral), the local healers’ association Asociación de
Jampiris de Apillapampa, and other participating community members was formalized by written agreements between researchers,
indigenous representatives and the Centro de Biodiversidad y
Genética from the Universidad Mayor de San Simon, Cochabamba.
Copies of these agreements and all details of the projects were sent
to the Bolivian government (Ministerio de Desarrollo Sostenible y
Planificación).
2.3. Informant indexing technique
Various analytical tools can be used to make a quantitative
assessment of the cultural importance of individual plant species.
Recently, Tardío and Pardo-de-Santayana (2008) reviewed quantitative methods in ethnobotany. More specifically, the authors
compared the validity of four indices for ranking plants according to
cultural significance which are based on (i) ‘informant consensus’,
or (ii) a combination of ‘informant consensus’ and the diversity of
reported plant uses. Clearly, all these indices provide scholars with
valuable means to analyse different aspects of plant use data. However, we identify two basic problems with the indices that take into
account both informant consensus and the diversity of reported
plant uses. The first problem is that these indices only consider
whether or not a plant is used within a particular use category and
do not take into account multiple plant uses within different use
categories. Obviously, this leads to the loss of valuable plant use data
that could potentially affect the cultural importance value of plants.
Second, since these indices are based on use categories instead of
individual plant uses, there exists a certain degree of bias depending
on how use categories are defined. Although efforts have been made
to standardize the recording and grouping of ethnobotanical data
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E. Thomas et al. / Journal of Ethnopharmacology 122 (2009) 60–67
(e.g. Cook’s Ethnobotanical Data Collection Standard, 1995), most
scholars keep on using their own subjective classification systems
(Tardío and Pardo-de-Santayana, 2008). Hence, there exist significant differences between various publications in the number of use
categories, but also with respect to the choice of assigning certain
plant uses to one category or another. To complicate matters even
more, subjective allocations of plant uses to categories are hardly
ever detailed or justified in scientific publications. Therefore, these
indices are likely to generate different results, depending on the
researcher who applies them. By contrast, indices based on individual plant uses as provided by respondents are far less prone to
subjectivity because they do not require a classification of primary
data into subjectively assigned categories. That is why in the present
manuscript we used the informant indexing technique proposed by
Phillips and Gentry (1993a). Estimates of the medicinal use value of
each species s were calculated according to the simplified formula
of Phillips and Gentry (1993a):
n
UVs =
i=1
Uis
ns
whereby Uis equals the number of medicinal uses of species s
mentioned by informant i. This approach has the advantage that,
given a sufficient number of informants interviewed, minor uses
or even mistakes will only minimally influence use values (Phillips
and Gentry, 1993a). As such, the UV index provides an objective
assessment of the cultural importance of plants. In their evaluation of three different indices that incorporate both informant
consensus and the diversity of uses, Tardío and Pardo-de-Santayana
(2008) concluded that the cultural importance (CI) index is likely
to be most objective. However, the authors appropriately note that
although both indices are defined in different ways, the CI index
generates identical results as the UV index when based on individual plant uses instead of use categories. In other words, Tardío
and Pardo-de-Santayana (2008) indirectly confirm the advantages
of the UV index as compared to other existing indices.
One important aspect that is overlooked by the technique proposed by Phillips and Gentry (1993a) is the quality of individual
plant uses. For the present study, we “extended” or reinterpreted
the use value index proposed by Phillips and Gentry (1993a) by
incorporating the quality of all individual plant uses. The “quality
use value” of each species s can be defined as:
n
QUVs =
i=1
QUis
ns
whereby (1) QUis equals
Qis , or the sum of the qualities of all
medicinal uses assigned to species s by informant i and (2) ns equals
the number of participants interviewed for species s. This implies
that the quality of each medicinal use mentioned is to be assessed
by each individual participant. In the present investigation, qualities
were appraised on an ordinal scale, choosing between (a) good to
excellent, (b) fair, or (c) bad, to which values of 1, 0.5 and 0.25 were
attributed, respectively.
2.4. Contingency table and binomial analyses
In order to evaluate the local importance of different plant families and growth forms for traditional medicine in Apillapampa,
we used the contingency table and binomial analysis techniques
proposed by Bennett and Husby (2008). Expected numbers of
medicinal species per family, or plant growth form, were calculated
assuming that medicinal and non-medicinal species are allocated
within a family or growth form according to the proportion of
medicinal species in the flora as a whole. Hence, the expected
number of medicinal species in a family or growth form = (total
# of species in a family or growth form × (total # of medicinal
species/total # of species shown to participants)). To assess the
under- or overrepresentation of certain medicinal plant families or
plant growth forms in the flora of Apillapampa, we performed an
exact randomization test for Goodness of Fit (many expected values were smaller than 5 in our sample, ruling out reliable use of
the chi-square Goodness of Fit statistic) (Bennett and Husby, 2008).
Calculations for the contingency table approach were performed in
the statistical software package R (version 2.6.2, 2008).
In case the number of medicinal plants for the entire flora
departs from the null model, individual families or growth forms
can be examined by means of binomial analysis (Bennett and Husby,
2008). Hereby, the null hypothesis is that species from a particular
family or growth form are no more likely to be used medicinally
than would be the case for the flora as a whole. This means that
the proportion of medicinal plants in a family or growth form
equals the proportion of medicinal plants in the total flora. To test
the significance of individual variation from a uniform proportion
of medicinal plants among families or growth forms, binomial pvalues were calculated for over- and underrepresentation, using
Microsoft Excel’s BINOMDIST function as detailed in Bennett and
Husby (2008). All other statistical calculations were performed in
SPSS 12.0.
3. Results and discussion
3.1. Most important medicinal plant families
A total of 341 medicinal plant species was recorded for Apillapampa: 181 during the first study and 307 during the second,
with 147 species overlapping between both studies. The number
of Quechua participants interviewed per medicinal plant varied
between 1 and 15 with an average of almost 10 (9.5 ± 3.5). In absolute numbers, medicinal plant use in Apillapampa is not unusually
high, since pharmacopoeias of more than 300 species have been
reported for various societies around the world (e.g. Bastien, 1987;
Ankli et al., 1999; Etkin, 2002; Leonti et al., 2003; Shepard, 2004).
However, it is important to note that Apillapampa represents only
one settlement of Quechua people, whereas most of the studies
previously mentioned encompass several communities of people
with a similar ethnical background. Intriguing in this respect are the
Bolivian Kallawayas whose pharmacopoeia is composed of approximately one thousand different medicinal plant species (Bastien,
1987). The Kallawayas follow an Andean pattern of specialization
in their medicinal practices at the community level (Bastien, 1987).
Specialized (Andean) communities are characterized by: (1) availability of specific resources at different ecological levels; (2) skills
acquired by practice and passed along through oral traditions; (3)
a community’s reputation, established by its specialists in traditional medicine; (4) maintenance of this reputation by the elders
of the communities through a network of trust with other communities with whom resources are exchanged; and (5) reciprocity, i.e.
exchange of medicinal resources between specialized communities
(Bastien, 1987). In another paper (Thomas et al., 2008), we discuss
several factors that contibute to explaining the exceptionally high
use of medicinal plants in Apillapampa.
The 341 medicinal plants are distributed over 80 botanical families. One fourth of all species are Asteraceae (85 species; 25%)
followed by Fabaceae (27 species; 8%), Solanaceae (22 species; 6%),
Lamiaceae (14 species; 4%) and Scrophulariaceae (10 species; 3%).
The popularity of Asteraceae has been attributed to the wide array
of bioactive components they contain, as well as to the higher likeliness of people to experiment with members of this family as a
consequence of the typical bitter phytochemicals they often contain (e.g. sesquiterpene lactones) (Heinrich et al., 1998; Casagrande,
2002). However, it is no coincidence that the botanically most
diverse families in Apillapampa (leaded by Asteraceae) also provide
E. Thomas et al. / Journal of Ethnopharmacology 122 (2009) 60–67
the highest numbers of medicinal species. The number of medicinal
plant species in a family correlates positively with the total number
of species inventoried for that family (Kendall’s b = 0.83; p < 0.001).
Still, the exact Goodness of Fit Test on the contingency table for
the Apillapampa flora as a whole revealed that medicinal species
are not evenly distributed among families (p < 0.01). Subsequent
binomial analysis yielded two families that differ significantly from
the null model. Poaceae is underrepresented (p < 0.001) with only
5 medicinal species (while 17 species were inventoried and its predicted species number is 13). By contrast, 22 of 23 Solanaceae
species had a medicinal use according to participants, which
explains their statistical overuse (p = 0.02; expected species number is 18). If the significance level is increased from 0.05 to 0.1,
Convolvulaceae (p = 0.06) and Scrophulariaceae (p = 0.07) would
contain more medicinal species than expected from the null model.
Many studies that identified over/underutilization of certain
plant families for medicinal purposes followed Moerman’s regression residual approach (see Moerman, 1991, 1996). However, the
statistical soundness of this technique has recently been questioned
(Bennett and Husby, 2008). We agree with this critique and therefore used contingency table and binomial analysis instead. Among
the literature sources that applied the regression residual approach,
the most frequently and widely overused medicinal plant family is
the Asteraceae (Moerman, 1996; Moerman et al., 1999; Leonti et al.,
2003; Treyvaud Amiguet et al., 2006). In Apillapampa, Asteraceae
is the most important medicinal family in terms of species used (85
out of 112), but it is not overused. The overuse of Solanaceae that
we observed in Apillapampa seems less widespread. Nonetheless,
the Solanaceae is a family well known to contain highly bioactive
species, which in many cases relates to the presence of alkaloids
(Moerman, 1996; Gurib-Fakim, 2006). The Poaceae figures among
the three most underutilized families in nearly all studies in the
literature, as well as in Apillapampa.
3.2. Life forms
More than half (51%) of all medicinal plants are herbs, while
about one fourth (26%) are shrubs. In accordance with their representation in the entire inventoried flora, a far lower number
of vines, trees and ferns are used as medicines: 18 (5.3%), 16
(4.7%) and 12 (3.5%) species, respectively. All inventoried ferns and
(hemi-)parasites (12 and 11 species, respectively) have a therapeutic value. This seems to confirm Bennett and Prance’s (2000)
argument that parasitic plants have the reputation to be utilized
more commonly as medicines as compared to other life forms.
The number of medicinal plants used per growth form correlates
with the total number of species inventoried for each growth form
in Apillapampa (Kendall’s b = 0.76; p = 0.002). However, medicinal
species are not evenly distributed among growth forms (p < 0.01;
exact Goodness of Fit Test on contingency table). Binomial analysis
shows that shrubs (p < 0.001) and ferns (p = 0.04) are overrepresented as medicinal species. Ninety (90) of 95 inventoried shrub
species and all 12 fern species are used medicinally, while the predicted species numbers are 72 and 9, respectively. If ␣ increases
from 0.05 to 0.1 (hemi-)parasites (p = 0.06) would contain more
medicinal species than expected from the null model, whereas trees
would contain less (p = 0.06).
The prevalence of herbaceous plants in the pharmacopoeia of
Apillapampa is not a surprise. Various authors have linked the popularity of herbs in traditional medicine to their higher likeliness to
contain bioactive phytochemicals as compared to woody growth
forms (e.g. Stepp and Moerman, 2001; Stepp, 2004; Voeks, 2004).
The fact that nearly all inventoried shrub species are used medicinally is therefore less expected and we hypothesize that the local
therapeutic importance of this growth form relates to its higher
visibility and availability to people throughout the year (cf. Turner,
63
1988; Voeks, 2004; Thomas, 2008). Indeed, during the dry season,
nearly all annual herbs disappear (except on irrigated land and in
humid places). Woody plants persist during the dry season and
therefore they are the only medicinal alternative during half of the
year. For that reason, they are more likely to be better known by people, also as sources of herbal medicines (cf. Voeks, 2004; Thomas
et al., 2008).
3.3. Culturally most relevant medicinal remedies and species
3.3.1. Medicinal plant remedies
A total of 1400 different plant remedies (i.e. medicinal plant
uses) have been documented in Apillapampa. A plant remedy or
a medicinal plant use is defined here as the use of one particular
plant species for one particular health condition (irrespective of
preparation or plant part used) and as mentioned by one or more
participants. Plotting the number of remedies against the number of participants who confirmed these remedies results in an
inverted “J” curve, characterized by an exponentially decreasing
number of medicinal remedies with increasing number of participants confirming remedies. On average, remedies were confirmed
by 1.6 (±1.4) participants. Only 29% of all reported remedies (i.e.
406 remedies) were confirmed by at least two participants. Such
low level of consensus may seem surprising, especially when taking into account that nearly half of our participants are traditional
healers. Nonetheless, this finding corresponds to a widespread
tendency (e.g. Friedman et al., 1986; Barrett, 1995; Alexiades,
1999; Casagrande, 2002) whereby the distribution of knowledge
about plant remedies follows a pattern in which few remedies are
known to almost everyone while most knowledge is idiosyncratic.
Casagrande (2002) hypothesized that this phenomenon reflects the
existence of an upper limit to the amount of medicinal plant knowledge that can be transferred and distributed throughout pre-literate
communities. On the other hand, the idiosyncratic nature of medicinal plant knowledge might be related to the fact that preparation
and use of medicinal plants is more difficult to learn as compared
to other use categories such as food. In this respect, Phillips and
Gentry (1993b) have argued that learning and experimenting with
medicinal plants, as opposed to food plants, can be a life-long
process. For the study population of the second study (cf. methodology), we demonstrated indeed a highly significant linear relation
between medicinal plant knowledge and participant age (R2 = 0.46
and p < 0.001; Thomas, 2008). An alternative explanation for the
idiosyncratic nature of medicinal knowledge could be that the population is progressively losing its medicinal plant knowledge due to
modernization (Phillips and Gentry, 1993b).
Highest consensus was recorded for the remedies listed in
Table 1. The majority of participants agreed on these uses and therefore the chance that these plants are bioactive may be higher than
for other species. It is interesting to note that all these remedies
consist of native plant species.
3.3.2. Quality of medicine
The fact that a plant species is used to treat a particular health
condition does not necessarily mean that it is perceived as effective
in alleviating symptoms or eliminating causal factors. When asked
to systematically assess the quality of each remedy on an ordinal
scale, people in Apillapampa assigned a score of “good to excellent”
to 64% of medicinal plant uses (on a total of 1119 responses), followed by “fair” (35%). Only 1% (10 responses) referred to the rather
bad quality of herbal remedies. Of those remedies classified as “fair”,
participants often declared that they are sometimes effective in
alleviating particular symptoms, but on other occasions or in some
patients do not help at all.
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E. Thomas et al. / Journal of Ethnopharmacology 122 (2009) 60–67
Table 1
Medicinal plant remedies with highest participant consensus.
Scientific name
Family
Health
condition
Number of
confirming
participants
Trixis aggregata Rusby
Krameria lappacea
(Dombey) Burdet &
B.B. Simpson
Schinus molle L.
Echeveria sp. (ET468)
Achyrocline ramosissima
(Sch.Bip.) Britton ex
Rusby
Gnaphalium
gaudichaudianum DC.
Passiflora umbilicata
(Griseb.) Harms
Tessaria fastigiata
(Griseb.) Cabrera
Calceolaria engleriana
Kraenzl.
Mutisia ledifolia Decne.
ex Wedd.
Asteraceae
Krameriaceae
Bruises
Madrea
12
11
Anacardiaceae
Crassulaceae
Asteraceae
Rheumatism
Otitis
Cough
10
10
10
Asteraceae
Cough
10
Passifloraceae
Bruises
10
Asteraceae
Malnutrition
9
Scrophulariaceae
Fracture/sprains
9
Asteraceae
Cough
9
a
Culture-bound syndrome associated with heavy labour on agricultural fields;
several of its symptoms correspond with the biomedical definition of a hernia, but
according to Vandebroek et al. (2008) it could be related to Chagas’ disease.
3.3.3. Medicinal plant species
On average, 4.3 (±1.4) participants provided ethnomedicinal
information on a medicinal plant species. The medicinal use of
86 (25% of the total number of medicinal plants) and 147 species
(43%) was confirmed by only one and two participants, respectively.
Species with the most diverse ethnomedical applications are listed
in Table 2. The majority of species in this list are also native ones.
The species presented in Table 2 also obtained high scores for
medicinal use values (UVs ) and quality use values (QUVs ) (Table 3),
partly because medicinal UVs and QUVs values are correlated
with the number of medicinal applications per species (Kendall’s
b = 0.75 and 0.62, respectively; p < 0.001 for both). As shown in
Table 2
Medicinal plant species with highest number of different medicinal applications.
Scientific name
Family
#part
#med uses
Schinus molle L.
Medicago sativa L.a
Trixis aggregata Rusby
Schkuhria pinnata (Lam.) Kuntze
ex Thell.
Baccharis sagittalis (Less.) DC.
Otholobium pubescens (Poir.) J.W.
Grimes
Cestrum parqui L’Hér.
Tripodanthus acutifolius (Ruiz &
Pav.) Tiegh.
Agalinis lanceolata (Ruiz & Pav.)
D’Arcy
Solanum nitidum Ruiz & Pav.
Ephedra americana Humb. et
Bonpl. ex Willd.
Sonchus asper (L.) Hilla
Caiophora canarinoides (Lenné &
K. Koch) Urb. & Gilg
Satureja boliviana (Benth.) Briq.
Lepechinia meyenii (Walp.) Epling
Rosa × noisettiana Thory cf.a
Valeriana decussata Ruiz & Pav.
Cheilanthes scariosa (Sw.) C. Presl.
Ephedra rupestris Benth.
Calceolaria parvifolia Wedd. ssp.
parvifolia
Anacardiaceae
Fabaceae
Asteraceae
Asteraceae
12
9
13
12
17
17
13
13
Asteraceae
Fabaceae
10
12
13
12
Solanaceae
Loranthaceae
11
10
12
12
Scrophulariaceae
11
12
Solanaceae
Ephedraceae
12
12
12
12
Asteraceae
Loasaceae
10
12
12
11
Lamiaceae
Lamiaceae
Rosaceae
Valerianaceae
Pteridaceae
Ephedraceae
Scrophulariaceae
5
9
10
10
10
10
8
11
11
11
11
11
11
10
#part = participants interviewed; #med uses = medicinal uses.
a
Introduced species.
Table 3, medicinal quality use values are consistently lower than use
values since not all reported ethnomedical applications of species
are of “good” quality. To demonstrate the relevance of calculating quality use values over use values, we regressed the medicinal
quality use values of species on their medicinal use value. This
regression results in a R2 value of 81.6, which indicates that assigning a quality to medicinal uses explains nearly one fifth (18.4%) of
the variance in QUVs values.
A weakness of UVs is that it does not satisfactorily incorporate
consensus among participants. For example, if three participants
each name two different medicinal uses for species A, then its
medicinal use value equals two ((2 + 2 + 2)/3) and the number of
reported health conditions six. If these participants unanimously
agree that species B is used for treating two different health conditions, the result is also a medicinal use value of two, while consensus
for species A is zero and for species B it is 100%.
QUVs values seem to express participant consensus better than
UVs . It is noticeable how ranking based on QUVs values (Table 3)
includes species that have the highest consensus for particular
remedies (Table 1) together with species that have the most diverse
ethnomedical applications (Table 2). Ranking based on UVs values
seems to favour the latter species more. This property of QUVs to
partially incorporate participant consensus might be related to the
fact that a higher consensus about remedies parallels a higher frequency of responses related to remedies that are considered to be
of “good quality”. A technique that takes into account participant
consensus and thus can be used to evaluate the latter assumption
is the informant agreement ratio (IAR) for medicinal species. We
interpreted the formula originally proposed by Trotter and Logan
(1986) as follows:
0 < IARs =
nr − na
<1
nr − 1
whereby nr is the total number of medicinal responses registered
for species s and na is the number of ailments or health conditions
that are treated with this species. The IARs of a medicinal species
varies between 0 (when the number of health conditions treated
equals the number of medicinal responses) and 1 (whereby all participants agree upon the exclusive use of the species for a particular
health condition).
When applied to our data set, species’ IARs values correlate positively with the number and proportion of “good quality” responses
per species (Kendall’s b = 0.30 (p < 0.001) and 0.14 (p = 0.004),
respectively), confirming our hypothesis that species for which
participant consensus is higher also yield more “good quality”
responses. Hence, since a species’ QUVs is also positively correlated
with the number of “good quality” medicinal responses per species
(Kendall’s b = 0.64; p < 0.001), this may explain in part why QUVs
expresses consensus better than UVs . These observations corroborate Casagrande’s (2002) argument that emic perception of efficacy
is the variable that most accounts for the distribution of knowledge about medicinal plants. Other authors have also argued that, in
many cases, consensus correlates with (pharmacological) efficacy
(Trotter and Logan, 1986; Moerman, 2007).
Table 4 lists medicinal species with the highest IARs values. Although both medicinal UVs and QUVs correlate with IARs
(Kendall’s b = 0.41 and 0.30, respectively; p < 0.001 for both cases),
ranking of species based on IARs values give different results as
compared to ranking based on medicinal UVs and QUVs values
(Table 3). The only species that occur in both tables are Achyrocline
ramosissima, Tessaria fastigiata, Passiflora umbilicata, Gnaphalium
gaudichaudianum and Minthostachys andina. This outcome is, at
least in part, due to the fact that rankings based on UVs and QUVs
values favour plant species with multiple medicinal applications,
whereas IARs mainly selects species with high participant consensus. For example, a plant with only one medicinal application that
E. Thomas et al. / Journal of Ethnopharmacology 122 (2009) 60–67
65
Table 3
Medicinal plant species with the highest medicinal use value (UV) and quality use value (QUV). The top ten species according to UV, QUV and IARs values are underlined in
the corresponding columns.
Scientific name
Family
#med uses
#part
UVs
QUVs
IARs
Trixis aggregata Rusby
Schinus molle L.
Otholobium pubescens (Poir.) J.W. Grimes
Cestrum parqui L’Hér.
Agalinis lanceolata (Ruiz & Pav.) D’Arcy
Tessaria fastigiata (Griseb.) Cabrera
Minthostachys andina (Britton) Epling
Medicago sativa L.a
Tripodanthus acutifolius (Ruiz & Pav.) Tiegh.
Solanum tripartitum Dunal
Solanum nitidum Ruiz & Pav.
Baccharis sagittalis (Less.) DC.
Krameria lappacea (Dombey) Burdet & B.B. Simpson
Solanum palitans C.V. Morton
Passiflora umbilicata (Griseb.) Harms
Gnaphalium gaudichaudianum DC.
Achyrocline ramosissima (Sch.Bip.) Britton ex Rusby
Calceolaria engleriana Kraenzl.
Geranium soratae R. Knuth
Mentzelia fendleriana Urb. & Gilg
Asteraceae
Anacardiaceae
Fabaceae
Solanaceae
Scrophulariaceae
Asteraceae
Lamiaceae
Fabaceae
Loranthaceae
Solanaceae
Solanaceae
Asteraceae
Krameriaceae
Solanaceae
Passifloraceae
Asteraceae
Asteraceae
Scrophulariaceae
Geraniaceae
Loasaceae
13
17
12
12
12
5
8
17
12
6
12
13
9
7
7
5
2
7
5
5
13
14
14
14
14
12
14
15
14
9
13
12
14
9
12
12
10
14
8
5
2.46
2.14
2.00
1.86
1.79
1.75
1.71
1.60
1.57
1.55
1.54
1.50
1.43
1.44
1.33
1.25
1.30
1.29
1.13
1.20
2.00
1.42
1.17
1.15
1.04
1.00
1.10
0.65
0.55
0.83
1.10
1.29
1.14
1.33
1.22
1.21
1.17
1.17
1.13
1.10
0.61
0.45
0.59
0.56
0.54
0.80
0.70
0.30
0.48
0.62
0.42
0.29
0.58
0.62
0.80
0.71
0.92
0.65
0.50
0.20
#part = participants interviewed; #med uses = medicinal uses.
a
Introduced species.
is known to all interviewed participants will receive UVs and QUVs
values of maximally 1, and therefore has little chance of being listed
among the most important medicinal species. On the other hand,
its IARs value would also be 1, acknowledging the maximum level
of consensus. In line with this observation, the number of different medicinal uses per species is significantly higher (p < 0.001;
Mann–Whitney) for species with high medicinal UVs and QUVs values (listed in Table 3) than for species with high IARs values (listed
in Table 4).
Use values imply that the local importance of a plant is primarily
determined by its number of medicinal uses. This proposition has
rarely been tested, but Byg and Balslev (2001) were able to show
a positive correlation between the perceived importance of palm
species by local participants in Madagascar and their use values
and number of uses. Although this relation might be valid when all
different plant uses are pooled together, it is not necessarily so for
medicinal plant use. We believe that assessing the local importance
of a medicinal plant should not be based solely on the number of
uses or use values of the respective species, but on a combination
of the former and the level of consensus between participants. The
QUVs and IARs indexes we proposed here seem highly suitable for
this purpose. Medicinal QUVs values appear to be more sensitive
to the number of ethnomedical applications per plant species and
incorporate the emic perception of therapeutic qualities, whereas
IARs values address informant consensus. Therefore, our proposal is
to combine both parameters into the ‘Quality Use Agreement Value’
(QUAVs ), which is defined as:
QUAVs = QUVs × IARs
In Table 5, ranking of the twenty highest scoring medicinal
species according to QUAVs values shows that species from the
top twenty ranking according to IARs and QUVs , respectively are
represented in relatively even proportions (10 and 13 species,
respectively). Hence, this index seems to provide a valid and easily
Table 4
IARs values for medicinal plant species in Apillapampa. Only those species are listed for which the number of responses is higher than 3.
Scientific name
Family
#part
#resp
#med uses
IARs
Tessaria dodonaeifolia (Hook. et Arn.) Cabrera
Achyrocline ramosissima (Sch.Bip.) Britton ex Rusby
Passiflora umbilicata (Griseb.) Harms
Dunalia brachyacantha Miers
Tessaria fastigiata (Griseb.) Cabrera
Bidens mandonii (Sherff) Cabrera
Dodonaea viscosa Jacq.
Echeveria sp. (ET468)
Gamochaeta americana (Mill.) Wedd.
Trichocereus tunariensis Cardenas
Plantago orbignyana Steinh.
Hypseocharis pimpinellifolia Remy
Vassobia fasciculata (Miers) Hunz.
Gnaphalium melanosphaeroides Sch.Bip. ex Wedd.
Margyricarpus pinnatus (Lam.) Kuntze
Spathantheum orbignyanum Schott
Gnaphalium gaudichaudianum DC.
Rumex conglomeratus Murraya
Cosmos peucedanifolius Wedd.
Minthostachys andina (Britton) Epling
Asteraceae
Asteraceae
Passifloraceae
Solanaceae
Asteraceae
Asteraceae
Sapindaceae
Crassulaceae
Asteraceae
Cactaceae
Plantaginaceae
Oxalidaceae
Solanaceae
Asteraceae
Rosaceae
Araceae
Asteraceae
Polygonaceae
Asteraceae
Lamiaceae
8
10
12
8
12
8
14
13
10
8
11
13
15
9
10
13
12
8
12
14
3
13
16
7
21
5
17
13
9
9
9
13
19
8
8
15
15
11
11
24
1
2
3
2
5
2
5
4
3
3
3
4
6
3
3
5
5
4
4
8
1.00
0.92
0.87
0.83
0.80
0.75
0.75
0.75
0.75
0.75
0.75
0.75
0.72
0.71
0.71
0.71
0.71
0.70
0.70
0.70
#part = participants interviewed; #resp = responses; #med uses = medicinal uses.
a
Introduced species.
66
E. Thomas et al. / Journal of Ethnopharmacology 122 (2009) 60–67
Table 5
Ranking of medicinal species according to decreasing Quality Use Agreement Values (QUAVs ). Species from the top twenty ranking of QUVs and IARs , respectively, are marked
in bold in the corresponding columns. Ethnomedical uses, botanical family and voucher numbers of these species are given in Appendix A.
Scientific name
#med uses
#part
UVmed
QUVmed
IARs
QUAVs
Trixis aggregata Rusby
Achyrocline ramosissima (Sch.Bip.) Britton ex Rusby
Passiflora umbilicata (Griseb.) Harms
Gnaphalium gaudichaudianum DC.
Tessaria fastigiata (Griseb.) Cabrera
Minthostachys andina (Britton) Epling
Calceolaria engleriana Kraenzl.
Otholobium pubescens (Poir.) J.W. Grimes
Krameria lappacea (Dombey) Burdet & B.B. Simpson
Cestrum parqui L’Hér.
Vassobia fasciculata (Miers) Hunz.
Schinus molle L.
Dodonaea viscosa Jacq.
Tetraglochin cristatum (Britton) Rothm.
Gnaphalium cheiranthifolium Lam.
Agalinis lanceolata (Ruiz & Pav.) D’Arcy
Geranium soratae R. Knuth
Gamochaeta americana (Mill.) Wedd.
Gnaphalium melanosphaeroides Sch.Bip. ex Wedd.
Solanum palitans C.V. Morton
Hypseocharis pimpinellifolia Remy
13
2
3
5
5
8
7
12
9
12
6
17
5
7
5
12
5
3
3
8
4
13
10
12
12
12
14
14
14
14
14
15
14
14
14
11
14
8
10
9
9
13
2.46
1.29
1.33
1.25
1.75
1.71
1.29
2.00
1.43
1.86
1.27
2.14
1.21
1.29
1.09
1.79
1.13
0.9
0.89
1.44
1.00
2.00
1.17
1.22
1.21
1.00
1.10
1.17
1.17
1.14
1.15
0.88
1.42
0.83
0.96
0.91
1.04
1.13
0.75
0.78
1.33
0.73
0.61
0.92
0.87
0.71
0.80
0.70
0.65
0.59
0.58
0.56
0.72
0.45
0.75
0.65
0.64
0.54
0.50
0.75
0.71
0.42
0.75
1.23
1.08
1.06
0.86
0.80
0.77
0.75
0.69
0.66
0.64
0.64
0.64
0.63
0.62
0.58
0.56
0.56
0.56
0.56
0.56
0.55
#part = participants interviewed; #med uses = medicinal uses.
derived estimation of a medicinal plant’s cultural significance, at
least for the case of Apillapampa.
4. Conclusions
Our findings add value to the observation in literature that
indigenous pharmacopoeias around the world are far from random
assemblages. Some families clearly hold more medicinal species
than predicted by chance. The same reasoning also seems to apply
to different life forms in Apillapampa, where plants with a shrubby
habit are significantly overused. It is hypothesized that this is
related to the year-round availability of shrubs, as compared to
most annual and herbaceous plants that disappear during the dry
season.
Emic perception of medicinal plant efficacy varies from one
species to another in Apillapampa. All local Quechua participants (both healers and laypeople) recognise that some species
are more effective for treating particular symptoms or health
conditions than others. Therefore, we believe that the quality
of remedies should be taken into account when ranking plants
according to their cultural importance. The applicability of the
technique to incorporate the quality of plant use (i.e. quality use
values; QUVs ), proposed by us in this paper provides a ‘novel’ way
to approach and interpret plant use data, in the medicinal use
category and beyond. In addition, we have shown that a combination of QUVs with a re-interpreted consensus index regarding
the medicinal use of species (IARs ) in the QUAVs , might represent the cultural significance of medicinal plants better than
existing indexes. This is particularly because such an approach
takes into account (1) the average number of medicinal uses; (2)
the perceived quality of those medicinal uses; and (3) participant consensus about those medicinal uses. In the top ranking
of medicinal plants according to the present study using QUAVs ,
species from the top rankings according to IARs and QUVs , respectively, are represented in relatively even proportions. Therefore
the QUAVs index seems to provide an easily derived and valid
assessment of a plant’s significance within a culture. Future
pharmacological studies are needed to determine if these culturally most significant species also show the highest levels of
bioactivity.
Acknowledgements
The first study was funded by the Institute for the Promotion of Innovation through Science and Technology in Flanders
(IWT), Belgium, by means of a post-doctoral grant to Ina Vandebroek. The second study was financed by a doctoral research
grant of the Bijzonder Onderzoeksfonds (BOF) of Ghent University to Evert Thomas (Grant Number: B/03801/01 FONDS IV 1).
We are grateful to Jan-Bart Calewaert, Ben Michiels, Lisa De
Munk, Trees Cousy, Frieke Heens and David Douterlungne for
collaboration during data collection. Logistic support in Bolivia
was provided by the Centre of Biodiversity and Genetics and
the Herbarium Martin Cardenas of the Universidad Mayor de
San Simon in Cochabamba. Special thanks are due to the inhabitants and Subcentral of the community of Apillapampa for
their kind assistance in making this project successful. We are
also indebted to the professional botanists who identified several collections. They are S. Beck (flora of Bolivia), S. Clemants
(Chenopodiaceae), E. Emshwiller (Oxalidaceae), H.-J. Esser (Euphorbiaceae), R. Faden (Commelinaceae), A. Freire (Polygalaceae), D.
Goyder (Asclepiadaceae), I. Jiménez (Bolivian Pteridophyta), A.
Krapovickas (Malvaceae), J. Müller (Baccharis and Hieracium, Asteraceae), G. Navarro (Cactaceae), M. Nee (Solanaceae), A. Planchuelo
(Lupinus, Fabaceae), J. Pruski (Asteraceae), L. Rico (Fabaceae),
C. Ulloa (Berberidaceae), R. Vasquez (Bromeliaceae and Orchidaceae), D. Wasshausen (Asclepiadaceae), J. Wood (Asclepiadaceae
and Salvia, Lamiaceae) and C. Xifreda (Dioscorea, Dioscoreaceae).
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