73RESEARCH
CHILEAN JOURNAL OF AGRICULTURAL RESEARCH 71(1):73-82 (JANUARY-MARCH 2011)
CHEMICAL COMPOSITION, INSECTICIDAL, AND ANTIFUNGAL
ACTIVITIES OF FRUIT ESSENTIAL OILS OF THREE COLOMBIAN
Zanthoxylum SPECIES
Juliet A. Prieto1*, Oscar J. Patiño1, Wilman A. Delgado1, Jenny P. Moreno1, and Luis E. Cuca1
ABSTRACT
This study determined the chemical composition of essential oils isolated from Zanthoxylum monophyllum (Lam.)
P. Wilson, Z. rhoifolium Lam., and Z. fagara (L.) Sarg. fruits by steam distillation, as well as testing antifungal
and insecticidal activities of essential oils as potential pesticides. Gas chromatography-mass spectrometry (GC/MS)
analysis identified 57 compounds. The main constituents in Z. rhoifolium oil were β-Myrcene (59.03%), β-phellandrene
(21.47%), and germacrene D (9.28%), the major constituents of Z. monophyllum oil were sabinene (25.71%),
1,8-cineole (9.19%), and cis-4-thujanol (9.19%), whereas fruit oil of Z. fagara mainly contained germacrene D-4-ol
(21.1%), elemol (8.35%), and α-cadinol (8.22%). Zanthoxylum fagara showed the highest activity on Colletotrichum
acutatum Simmonds (EC50 153.9 μL L-1 air), and Z. monophyllum was the most active against Fusarium oxysporum
Schlechtend: Fr. f. sp. lycopersici (EC50 140.1 μL L-1 air). Zanthoxylum monophyllum essential oil showed significant
fumigant activity against Sitophilus oryzae (L.). This study demonstrated that Zanthoxylum essential oils exhibit
important fungicidal activity on F. oxysporum and C. acutatum, which could become an alternative to synthetic
fungicides to control plant fungal diseases, and Z. monophyllum oil is a potential fumigant against S. oryzae.
Key words: Zanthoxylum monophyllum; Z. rhoifolium; Z. fagara; Sitophilus oryzae; Fusarium oxysporum f. sp.
lycopersici; Colletotrichum acutatum; fumigant, antifungal, insecticidal.
1Universidad Nacional de Colombia, Facultad de Ciencias, Bogotá,
KR 30 45 03, Colombia. AA 14490. *Corresponding author
(japrietor@unal.edu.co, japrietor86@gmail.com).
Received: 7 June 2010.
Accepted: 24 September 2010.
INTRODUCTION
Crop losses due to insects and plant diseases caused by
fungi, bacteria, and viruses cause significant economic
losses (Kotan et al., 2008; Kordali et al., 2008). Insect
pests often cause extensive loss of products stored in
tropical and semitropical environments (Isman, 2000).
For example, Sitophilus species are serious cosmopolitan
pests of stored grain (Liu and Ho, 1999). Sitophilus
zeamais Motschulsky (maize weevil), S. oryzae L. (rice
weevil), and S. granaries L. are the main representatives
of this genus, which principally attack rice (Oryza sativa
L.), maize (Zea mays L.), wheat (Triticum sativum
Lam.), and sorghum (Sorghum bicolor (L.) Moench)
among others, through direct feeding on grain kernels
causing unfavorable effects on food quality, safety, and
preservation (Huang et al., 1997; Tapondjou et al., 2002;
Kim et al., 2003; Park et al., 2003; Arannilewa, 2007).
Harvest losses due to fungal disease in world crop
production may amount to 12% or more in developing
countries (Horbach et al., 2010). Many pathogens
including Fusarium oxysporum (vascular wilt), F. solani
(fruit rot) and Colletotrichum gloeosporoides (fruit rot)
cause severe pre- and post-harvest damage to agriculture
(Bajpai et al., 2008). Fusarium is a plant pathogen that
causes wilt diseases of several economically important
plants and is also known to produce toxins thought
to contribute to wilting by affecting cell membrane
permeability and disrupting cell metabolism (Garcés
de Granada et al., 2001; Pawar and Thaker, 2007).
Colletotrichum are pathogens that cause anthracnose in
a wide range of woody and herbaceous crops. Symptoms
are broad-ranging and include stem rot, dieback, and
seedling blight. Fruits are affected during the pre- and
post-harvest period (Roca et al., 2003; Muñoz et al.,
2009).
Synthetic insecticides and fumigants are widely used
to control grain pests and plant diseases. However, the
indiscriminate application of synthetic products has led
to various problems including toxic residues in treated
products, environmental pollution, and resistance against
74 CHIL. J. AGR. RES. - VOL. 71 - Nº 1 - 2011
pesticides by microorganisms and grain insect pests
(Huang et al., 1997; Isman 2006; Bakouri et al., 2008;
Kotan et al., 2008; Ye et al., 2010). Therefore, because of
increasing drawbacks of the continued use of conventional
fumigants, an effort is needed to develop new alternative
pesticides to replace those being currently used.
Essential oils are potential botanical sources of
alternative compounds to fumigants being currently used
because of their low toxicity for warm-blooded animals,
high volatility and toxicity for stored grain pests and plant
microorganisms (Lee et al., 2001; Abad et al., 2007).
Zanthoxylum genus (Rutaceae) is made up of about 250
species of trees and shrubs in the world’s tropical and
temperate regions (Pirani, 1993). It is economically very
important as a source of edible fruits, raw material for
the cosmetics and perfume industries, as well as culinary
applications. In Asia, Z. bungeanum Maxim. fruits are
the most popular huajiao commercial product called “da
hong pao’’ (big red robe). “Green huajiao”, fruit of Z.
schinifolium Siebold & Zucc. (Yang, 2008), is the other
widely used spice in Sichuan. Zanthoxylum species have
shown significant insecticidal and antifungal activity.
The bark methanol extract of Z. xanthoxyloides caused
significant mortality rates in S. oryzae and Callosobruchus
maculatus, two stored-product insect pests (Owusu et
al., 2007). Zanthoxylum monophyllum bark methanol
extract showed significant activity against seven
human pathogen fungi (Gómez et al., 2007). Ethanolic
extracts of Z. americanum leaves, fruits, stem bark,
and root demonstrated a broad spectrum of antifungal
and antibacterial activity against Candida albicans,
Aspergillus fumigatus, Cryptococcus neoformans, and
Fusarium oxysporum (Bafi-Yeboa et al., 2005).
In addition to culinary applications, many species of
Zanthoxylum are used in traditional medicine especially in
America, Africa, and Asia. Zanthoxylum rhoifolium Lam
is popular in South America for inflammatory, microbial,
cancerous, and malaria processes (Da Silva et al., 2007a;
2007b). Zanthoxylum fagara is used in Cuba for the
treatment of diarrhea, chest diseases, intermittent fever,
earaches, and tooth diseases (Dieguez-Hurtado et al.,
2003). Zanthoxylum monophyllum is used as an analgesic
to treat nasal inflammation, jaundice, and eye infections
in Venezuela and as colorant (Cuca et al., 1998; Díaz and
Ortega, 2006; Da Silva et al., 2007a).
Zanthoxylum species accumulate volatile oils in
leaves, fruits, and inflorescences (Adesina, 2005). There
are numerous reports on the chemical composition and
the various biological activities of Zanthoxylum species
essential oils (Choochote et al., 2007; Boehme et al.,
2008; Yang, 2008). The chemical composition of essential
oils of Z. rhoifolium flowers, fruits, and leaves (Gonzaga
et al., 2003; Moura et al., 2006; Da Silva et al., 2007a;
2007b; Boehme et al., 2008), and biological properties
of fruit and leaf essential oils, such as antibacterial and
cytotoxic resultshave been previously reported (Moura et
al., 2006; Da Silva et al., 2007b; Boehme et al., 2008).
The volatile chemical composition of Z. monophyllum
and Z. fagara leaves from Costa Rica have also been
reported (Setzer et al., 2005). However, there are no
studies about their biological properties. The composition
and biological properties of fruit essential oils of Z.
monophyllum and Z. fagara have not yet been investigated.
We report the chemical composition, insecticidal
activity against S. oryzae, and antifungal activity against
F. oxysporum f. sp. lycopersici and C. acutatum of
fruit essential oils of three Colombian plant species: Z.
monophyllum, Z. fagara, and Z. rhoifolium.
MATERIALS AND METHODS
Plant material
The fruits of Z. monophyllum (4º11’24.3’’ N, 74º30’48.9’’
W) and Z. fagara (4º11’22.0’’ N, 74º30’58.4’’ W) were
collected in January 2008 in the town of Icononzo, Tolima,
Colombia, whereas Z. rhoifolium fruits (4º19’30.4’’ N,
74º26’17.1’’ W) were collected in February 2008 in the
town of Fusagasugá, Cundinamarca, Colombia. Plant
samples were identified by the Colombian National
Herbarium of the Universidad Nacional de Colombia.
Voucher specimens of Z. monophyllum (Lam.) P. Wilson
(COL-517520), Z. rhoifolium Lam. (COL-522896), and
Z. fagara (L.) Sarg. (COL-522891) were deposited in
the Colombian National Herbarium of the Universidad
Nacional de Colombia, Bogotá, Colombia.
Isolation of essential oils
Samples of fresh fruits (approximately 2 kg) of each
Zanthoxylum species were submitted to steam distillation
(ca. 4 h). Oils were dried over anhydrous sodium sulfate
and stored at 0-5 ºC for further analysis.
Gas chromatography-flame ionization detector analysis
(GC/FID)
Volatile compound analysis was performed with a gas
chromatography system (Hewlett Packard 5890 GC) with
a fused capillary column (50 m × 0.25 mm × 0.25 μm, HP-
5MS, Crossbond 5% phenyl-95% dimethylpolysiloxane,
Sigma-Aldrich, St. Louis, Missouri, USA) directly
coupled to a flame ionization detector (FID). Injection
conditions were the following: injector temperature at 250
ºC; oven temperature program at 45 ºC (2 min), 150 ºC (5
min) at a rate of 2 ºC min-1, then at 150 ºC (2 min), 280
ºC (5 min) at a rate of 8 ºC min-1; split 30:1 during 1.50
min, carrier gas He: 1 mL min-1, constant flow; sample
volume 1 μL.
75J. PRIETO et al. - CHEMICAL COMPOSITION, INSECTICIDAL, AND……..
Gas chromatography-mass spectrometry analysis (GC/
MS)
The GC/MS analyses were performed in electronic impact
(EI) mode with a Hewlett Packard-5890 GC system with a
fused capillary column (50 m × 0.25 mm × 0.25 μm, HP-
5MS, Crossbond 5% phenyl-95% dimethylpolysiloxane)
directly coupled to a Hewlett Packard 5973 selective mass
detector. Injection conditions were the same as described
above. The mass spectrometer was operated at 70 eV.
Oil component identification
Oils were analyzed by GC-MS and GC with capillary
columns (HP-5MS). Chemical constituents were
identified based on the comparison of their mass spectral
pattern and retention indices with those obtained from the
Wiley 138.L, NBS 75K.L, and SDBS libraries, as well as
those published by Adams (1995). Retention indices (RI)
were calculated according to the literature (Van Den Dool
and Kratz, 1963).
Insect rearing
Rice weevils were obtained from a colony maintained in
the Laboratory of Entomology, Universidad Nacional de
Colombia, Bogotá. Weevils were reared on maize grains.
Cultures were maintained in the dark at 25 ± 1 °C and 70
± 5% relative humidity.
Fungal cultures
Fusarium oxysporum f. sp. lycopersici was obtained from
the culture collection of the Universidad de Cundinamarca
(Laboratory of Phytopathology). Colletotrichum
acutatum was obtained from the culture collection of the
Universidad Nacional de Colombia, Bogotá (Laboratory
of Vegetal Natural Products, Faculty of Science). Cultures
were maintained and grown on potato dextrose agar
(PDA) medium and incubated at 28 ± 1 °C.
Insecticidal activity assay
To determine the fumigant toxicity of Zanthoxylum oils,
paper filter disks (Whatman Nº 1, 2-cm diameter pieces)
were adhered to the inside of the Petri dish covers (90 x
15 mm) and then impregnated with oil at doses calculated
to give equivalent fumigant concentrations of 242-967
μL L-1 air (20, 40, 60, and 80 μL oil). Twenty adult
insects (1 to 10-d-old) were placed on each Petri dish.
Phostoxin®-Fugran (phosphine - 300 μg L-1 air) and
Nuvan® 50 E.C. (clorvox - 100 μL L-1 air) were used as
positive controls. Petri dishes were sealed with Parafilm
and incubated at 25 ± 1 °C and 70 ± 5% RH. Each
concentration and control was replicated three times.
Mortality was determined after 12, 24, and 48 h from the
start of exposure (Negahban et al., 2007; Kotan et al.,
2008). Insect mortality percentage (%M) was calculated
by Abbott’s correction formula (Pitasawat et al., 2007).
LC50 and LC95 values, as well as the corresponding 95%
confidence intervals, were estimated by probit analysis
(Finney, 1971).
In vitro antifungal activity
PDA plates were prepared with glass Petri dishes (90
x 15 mm) for the in vitro antifungal activity test. Agar
plugs of actively growing cultures in PDA were placed
on one half of the Petri dish (covered with PDA) and a
sterilized paper disk was placed 2 cm from them. A 10
μL aliquot of each essential oil was added to the paper
disks in each of the PDA plates (maximum 5 μL per
disk). Plates were immediately sealed with Parafilm after
adding each essential oil and incubated for 3 d at 28 °C.
The diameter of concentric fungal mycelia was measured
and compared with the untreated control. Medium
effective concentration (EC50) values were determined
for essential oils that caused fungal growth inhibition.
Aliquots of 2, 5, 7, 10, and 15 μL (23.5 - 176.5 μL L-1
air) of each essential oil were added to paper disks in each
of the PDA plates (maximum 5 μL per disk). Plates were
replicated three times in each treatment. (Lee et al., 2007;
Kotan et al., 2008). In addition, Benlate 50WP (methyl-
[1-[(butylamino) carbonyl]-1H-benzimidazol-2-yl]
carbamate - 2 mg mL-1) and Derosal®-Bayer (methyl-1H-
benzimidazol-2-ylcarbamate - 1 mg mL-1) were employed
as chemical controls in the F. oxysporum f. sp. Lycopersici
and C. acutatum assays, respectively.
Statistical analysis
Data are presented as mean ± standard error. Statistical
significance was determined by the Duncan and Tukey
tests; ANOVA determined whether results obtained
for antifungal and insecticidal activity assays were
statistically different. Statistical significance was set at P
< 0.05.
RESULTS AND DISCUSSION
Oil chemical composition
Fifty-seven compounds were identified by gas
chromatography and mass spectrometry data in the fruit
essential oils of three Zanthoxylum species (Table 1).
Oils mainly contain monoterpenes and sesquiterpenes.
Identified volatile components accounted for 89 to
99% of oil composition. Monoterpenes represent more
than 70% of Z. rhoifolium oil composition (80.5%),
Z. monophyllum (71.6%), and only 6.16% of Z. fagara
oil composition. Sesquiterpenes represent 88.8% of Z.
fagara oil composition. Chemical profiles obtained for
these oils showed differences in composition among the
studied species (Figure 1) although volatile constituents
76 CHIL. J. AGR. RES. - VOL. 71 - Nº 1 - 2011
%
1 α-Thujene 929 1.6
2 α-Pinene 937 3.1 2.9
3 Camphene 950 0.1
4 Sabinene 978 25.7
5 β-Pinene 983 2.8
6 β-Myrcene 990 59.0 0.8 0.2
7 α-Phellandrene 1002 1.0
8 α-Terpinene 1016 1.4
9 β-Phellandrene 1034 21.5 0.2
10 1,8-Cineole 1037 9.2
11 Z-β-Ocimene 1044 0.5 0.1
12 E-β-Ocimene 1053 0.7
13 γ-Terpinene 1065 2.5
14 Trans-4-thujanol 1072 6.3
15 α-Terpinolene 1091 0.5
16 Cis-4-thujan 1100 9.2
17 2-Cyclohenen-1-ol 1125 0.6
18 Terpinen-4-ol 1176 3.5
19 α-Tepineol 1191 3.5
20 Dihydroneoisocarveol 1229 1.2
21 Sabinene hydrate acetate (trans) 1254 0.4
22 Geraniol 1256 0.6
23 2-Undecanone 1294 1.7
24 δ-Elemene 1337 0.4
25 α-Cubebene 1359 0.3 0.1
26 α-Copaene 1375 0.5 0.4
27 Geranyl acetate 1387 0.4
28 β-Elemene 1398 1.6 0.9
29 E-Caryophyllene 1423 1.6 1.0 2.7
30 γ-Elemene 1433 0.2
31 α-Caryophyllene 1453 0.4 1.5
32 Alloaromadendrene 1459 0.5
33 γ-Muurolene 1472 0.4
34 Germacrene D 1479 9.3 2.3 6.0
35 Bicyclogermacrene 1488 3.1 1.5 5.8
36 Germacrene A 1495 1.4 0.4
37 γ-Cadinene 1510 1.8
38 δ-Cadinene 1520 0.9 4.1
39 Cadina-1.4-diene 1529 0.4
40 α-Cadinene 1533 0.4
41 Elemol 1547 1.9 8.4
42 Germacrene B 1552 0.3 0.8
43 Trans-1-nerolidol 1560 0.5
44 Germacrene D-4-ol 1573 1.2 21.1
45 Guaiol 1601 0.9
46 10-α-Eudesm-4-en-11-ol 1623 0.8
47 γ-Eudesmol 1631 1.3
48 Hinesol 1637 3.2
49 Tau-muurolol 1640 1.6 5.2
Table 1. Chemical composition of Zanthoxylum species oils.
Z.
monophyllum
Z.
fagara
Area
Peak Constituents RI1
Z.
rhoifolium
77
have been previously reported in other species of the
Zanthoxylum genus (Moura et al., 2006).
The main constituents found in Z. rhoifolium fruit
oil were β-myrcene (59.03%), β-phellandrene (21.47%),
germacrene D (9.28%), and bicyclogermacrene (3.13%).
Approximately 99.2% of Z. rhoifolium oil composition
was characterized. The remaining unidentified
components were mainly sesquiterpenes. The abundance
of monoterpenoid and sesquiterpenoid compounds in
fruit essential oil is in accordance with one previous
report (Gonzaga et al., 2003); however, oil composition
described in this study was qualitatively and quantitatively
different, particularly regarding the major constituents.
This suggests a considerable variability in the studied oil
samples because of the influence of the ecological and
chemical environment of each species, which affects the
presence and abundance of secondary metabolites (Spitaler
et al., 2006). The major constituents of oil derived from
fruits collected in Brazil were reported as menth-2-en-1-
ol (46.2%), β-myrcene (30.2%), (-)-linalool (15%), and
terpineol (8.45%).
The major constituents identified in Z. monophyllum
fruit oil were sabinene (25.71%), 1,8-cineole (9.19%),
trans-sabinene hydrate (9.19%), and cis-sabinene hydrate
(6.25%). Zanthoxylum fagara fruit oil mainly contained
germacrene D-4-ol (21.1%), elemol (8.35%), α-cadinol
(8.22%), germacrene D (5.96%), bicyclogermacrene
(5.75%), epi-α-muurolol (5.15%), and 5-neo-cedranol
(5.12%). Approximately 89.94% of Z. monophyllum
and 94.2% of Z. fagara oil compositions were
characterized. The remaining unidentified components
were monoterpenes and sesquiterpenes. The detailed
composition of fruit essential oils of Z. fagara and Z.
monophyllum are reported for the first time in this study.
Continuation Table 1.
%
50 Torreyol 1644 0.4 1.0
51 β-Eudesmol 1649 0.9 3.6
52 α-Cadinol 1654 4.1 8.2
53 5-Neo-cedranol 1680 5.1
54 Caryophyllene acetate 1701 0.6
55 E.E-Farnesol 1725 1.3
56 α-bisabolol acetate 1794 0.2
57 E.E-farnesyl acetate 1850 0.3
Monoterpenes --- 80.5 71.6 6.2
Sesquiterpenes --- 18.7 18.2 88.8
TOTAL --- 99.21 89.84 94.96
1Calculated retention index.
Z.
monophyllum
Z.
fagara
Area
Peak Constituents RI1
Z.
rhoifolium
Figure 1. Chemical profile of essential oils from
Zanthoxylum species fruits. For the key to identify
peaks, see Table 1.
J. PRIETO et al. - CHEMICAL COMPOSITION, INSECTICIDAL, AND……..
78 CHIL. J. AGR. RES. - VOL. 71 - Nº 1 - 2011
Insecticidal activity of the oils
Results show that the essential oils of Z. fagara, Z.
rhoifolium, and Z. monophyllum have different insecticidal
activity against S. oryzae adults. Insecticidal activity rises
by increasing the dose and exposure times (Figure 2).
Zanthoxylum monophyllum essential oil showed the best
fumigant activity against rice weevil, Z. rhoifolium oil had
weak fumigant toxicity while Z. fagara essential oil was
inactive (Figure 2).
Zanthoxylum monophyllum essential oil caused
significant mortality (about 90 to 99%) at 976 μL L-1 air
dose after 24 h exposure. After 48 h of treatment, a 484
μL L-1 air dose is enough to cause 90% insect mortality.
Fumigant activity of Z. monophyllum can be attributed
to 1,8-cineole, terpinen-4-ol, and α-terpinene present
in the essential oil; these compounds have shown 100%
mortality on insects of the Sitophilus genus after 12 h
exposure (Lee et al., 2004; Kordali et al., 2006).
The commercial fumigants Phosphamin (100 μg L-1
air) and Nuvan 50 (50 μL L-1 air) showed 100% mortality