全 文 ：Ｒeceived:October 15，2015 Accepted:June 8，2016
Foundation Item:This work was financed by the grant from the Hi-Tech
Ｒ＆D Program of China (2011AA10A202)
* Corresponding author Tel:86-10-62731199;E-mail:lgzhou@ cau． edu．
cn
天然产物研究与开发 Nat Prod Ｒes Dev 2016，28:1266-1272
文章编号:1001-6880(2016)8-1266-07
柠檬草和肿柄菊叶精油的抗线虫活性
王伟轩，王 愧，徐建美，周立刚*
中国农业大学植物保护学院植物病理学系，北京 100193
摘 要:柠檬草(Cymbopogon citratus)和肿柄菊(Tithonia diversifolia)为引种到我国的热带和亚热带植物。采用
水蒸气蒸馏法提取柠檬草和肿柄菊叶精油，得率分别为 1． 02%和 1． 05%(w /w)。通过 GC 和 GC-MS 分析精油
的组成。从柠檬草叶精油中鉴定出 20 个化合物，单萜和倍半萜占 81． 25%，精油中含量较高的化合物有:柠檬
醛(49． 76%)、月桂烯(8． 54%)、橙花醇(5． 92%)。从肿柄菊叶精油中鉴定出 20 个化合物，单萜和倍半萜占
95. 85%，精油中含量较高的化合物有:α-松油醇(20． 31%)、1，8-桉树脑(14． 67%)、1，7，7-三甲基二环［2． 2． 1］
庚-2-醇(14． 32%)、2，6，6-三甲基二环［3． 3． 1］庚-2-烯(13． 51%)和 1，1，4，7-四甲基十氢-1H-环丙并［e］薁-4-醇
(7． 39%)。两种精油对松材线虫、南方根结线虫、全齿复合线虫和秀丽隐杆线虫均表现较强的抑制活性。两种
精油对南方根结线虫的抑制活性均最强，用柠檬草精油处理南方根结线虫 24 h和 48 h，半抑制浓度(IC50)分别
为 1． 068 μg /mL和 0． 747 μg /mL;用肿柄菊精油处理南方根结线虫 24 h和 48 h，IC50值分别为 1． 118 μg /mL 和
1． 039 μg /mL。研究结果为揭示柠檬草和肿柄菊精油中的抗线虫成分，以及这两种植物精油作为抗线虫剂的开
发提供了依据。
关键词:柠檬草;肿柄菊;精油;化学组成;抗线虫活性;松材线虫;南方根结线虫
中图分类号:Q946． 8 文献标识码:A DOI:10． 16333 / j． 1001-6880． 2016． 8． 017
Antinematodal Activity of the Leaf Essential Oils of
Cymbopogon citratus and Tithonia diversifolia
WANG Wei-xuan，WANG Kui，XU Jian-mei，ZHOU Li-gang*
Department of Plant Pathology，College of Plant Protection，China Agricultural University，Beijing 100193，China
Abstract:The leaf essential oils of lemongrass (Cymbopogon citratus)and Mexican sunflower (Tithonia diversifolia)
were obtained with a yield of 1． 02% (w /w)and 1． 05% (w /w) ，respectively by hydro-distillation． The chemical com-
ponents of the essential oils were investigated by GC-FID and GC-MS． Citral (49． 76%) ，myrcene (8． 54%)and nerol
(5． 92%)were the major compounds of the 20 identified components which accounted for 98． 00% of the total lemon-
grass oil where 81． 25% belonged to monoterpenoids and sesquiterpenoids． α-Terpineol (20． 31%) ，1，8-cineole
(14. 67%) ，1 7，7-trimethylbicyclo［2． 1． 1］heptan-2-ol (14． 32%) ，2，6，6-trimethylbicyclo［3． 1． 1］hept-2-ene
(13. 51%)and 1，1，4，7-tetramethyldecahydro-1H-cyclopropa［e］azulene-4-ol (7． 39%)were the major compounds of
the 20 identified components which accounted for 98． 49% of the total Mexican sunflower oil where 95． 85% belonged to
monoterpenoids and sesquiterpenoids． Both essential oils had similar antinematodal activity with a broad spectrum． A-
mong the four tested nematodes (Bursaphelenchus xylophilus;Meloidogyne incognita，Panagrellus redivivus and Cae-
norhabditis elegans) ，both oils showed the strongest inhibition on root knot nematode (M． incognita)with the IC50 values
of 1． 068 μg /mL and 0． 747 μg /mL respectively at 24 h and 48 h of treatment for the lemongrass oil，and 1． 118 μg /mL
and 1． 039 μg /mL respectively at 24 h and 48 h of treatment for the Mexican sunflower oil． The results provided support-
ing data for activity-guided fractionation of the antinematodal components from these two oils as well as future develop-
ment of the essential oils as the antinematodal agents．
Key words:Cymbopogon citratus;Tithonia diversifolia;essential oil;chemical composition;antinematodal activity;Bur-
saphelenchus xylophilus;Meloidogyne incognita
Introduction
Plant parasitic nematodes (e． g．，root-knot nematodes
and pine wood nematode) ，which constitute one of the
most important pest species groups affecting a wide va-
riety of plants，cause significant damage to a broad
range of vegetables，agricultural crops and forest
trees［1］． Ｒoot-knot nematodes belong to the genus
Meloidogyne which mainly damage vegetable crops ［2］．
Pine wood nematode (Bursaphelenchus xylophilus)has
been the most serious forest pathogen which devastates
pine trees ［3］． For decades，the control of nematodes
has relied heavily on the synthetic nematicides which
have resulted in significant environmental pollution and
resistance． Hence it is necessary to continuously search
for environment-friendly and efficacious nemati-
cides［4］． Many plants have been reported to possess an-
tinematodal activity，and a series of antinematodal sub-
stances of plant origin such as terpenoids，alkaloids，fla-
vonoids and polythiophenes have been identified［5］．
Furthermore，the use of plant products is one of the
promising methods for nematode control． They are
cheap，easy to apply，produce no pollution hazards，and
have the capacity to structurally and nutritionally im-
prove soil health［6］． Plant essential oils and their com-
ponents possess multi-biological activities such as anti-
microbial，insecticidal，antiviral and antinematodal
properties． They have received much attention to pre-
vent plant and animal diseases ［7-9］．
Lemongrass (Cymbopogon citratus) (Gramineae) is
indigenous medicinal plant in tropical and subtropical
areas of Asia for the treatment of various diseases such
as stomachache and gastric ulcer，and is cultivated in
South and Central America，Africa，and other tropical
and subtropical areas［10］． The essential oil from lemon-
grass has been reported to have a variety of biological
activities such as antifungal ［11］，antibacterial ［12］，phy-
totoxic effects on the germination and seedling growth
of bamyardgrass (Echinochloa crus-galli)［13］，anti-
Leishmania activity ［14］．
Mexican sunflower (Tithonia diversifolia) (Composi-
tae)is a traditional medicinal plant of Central Ameri-
can countries for the treatment of malaria，fever and
wound［15］． It mainly contains sesquiterpene lactones，
monoterpenes，and flavonoids to have phytotoxic，leish-
manicidal，and anti-hyperglycemic activities［15-18］． The
essential oil of Mexican sunflower has been character-
ized for its composition［19］，and was screened to show
its allelopathic effect［20］．
Both lemongrass and Mexican sunflower were brought
to China at the end of the last century［20］． However，no
reports have documented on the chemical components
and antinematodal activity of the leaf essential oils of
these two plants from China． The aim of the present
study was to analyze the chemical composition of the
leaf essential oils of lemongrass and Mexican sunflower
from China by GC-MS as well as to evaluate their in
vitro antinematodal activity for future development of
the essential oils as antinematodal agents．
Materials and Methods
Plant materials
The leaves of lemongrass (Cymbopogon citratus)and
Mexican sunflower (Tithonia diversifolia)were collect-
ed in Kunming of China in June 2011． They were dried
in the shade at room temperature． The plant taxonom-
ical identifications were done by Dr． Zhilong Liu of
China Agricultural University，where the voucher speci-
mens were deposited．
Preparation of the essential oils
The dry leaves (1． 0 kg for each species)of lemon-
grass and Mexican sunflower were separately submitted
to hydro-distillation in a Clevenger-type apparatus at
100 ℃ for 4 h． The distilled oil was extracted with di-
ethyl ether and dried over anhydrous sodium sulfate．
After filtration，the yields of the essential oils were
10. 2 g (1． 02%，w /w) for lemongrass and 10． 5 g
(1. 05%，w /w)for Mexican sunflower． The oils were
then preserved in a sealed dark glass vial at 4 ℃ until
required．
Oil analysis
The composition of each leaf essential oil was deter-
mined using GC-FID and GC /MS． The same column
and analysis conditions were used for both GC-FID and
GC /MS． An Agilent 6890N Network GC system was e-
quipped with an HP-5MS column［30 m × 0． 25 mm
(5% -phenyl)-methylpolysiloxane capillary column，
film thickness 0． 25 μm］，a split-splitless injector heat-
ed at 250 ℃ and a flame ionization detector (FID)at
7621Vol. 28 WANG Wei-xuan，et al:Antinematodal Activity of the Leaf Essential Oils of Cymbopogon citratus and Tithonia diversifolia
240 ℃ ． The oven temperature was programmed as fol-
lows:initial temperature 50 ℃ for 1． 50 min，increased
by 10 ℃ /min up to 180 ℃，2 min at 180 ℃，and then
increased by 6 ℃ /min up to 280 ℃，10 min at 280
℃ ． Helium (99． 999%)was used as carrier gas at a
flow rate of 1． 0 mL /min． The injection volume was 1． 0
μL (split ratio 1∶ 20)． GC-MS analyses were performed
using an Agilent 6890N Network GC system with an
Agilent 5973 Network mass selective detector，mass
spectrometer in EI mode at 70 eV in m /z range 10-550
amu．
The components were identified by comparison of their
mass spectra with NIST 2002 library data of the GC-MS
system，as well as by comparison of their retention indi-
ces (ＲI)with the relevant literature data ［12，13，19-22］．
The relative amount (ＲA)of each individual compo-
nent of the essential oil was expressed as the percent-
age of the peak area relative to the total peak area． ＲI
value of each component was determined relative to the
retention times (ＲT)of a series of C8-C40 n-alkanes
with linear interpolation on the HP-5MS column［23］．
Culture of the nematodes
The pinewood nematode (B． xylophilus)was kindly
supplied by Dr． Bingyan Xie from the Institute of Vege-
tables and Flowers，Chinese Academy of Agricultural
Sciences． The fungus Botrytis cinerea was cultured on
potato dextrose agar (PDA)plate at 25 ℃ in dark-
ness． When the fungus was fully grown，the plate was
inoculated with the pinewood nematodes，and then cul-
tured until the fungal mycelia had been completely con-
sumed．
The root-knot nematode M． incognita，which was kindly
supplied by Dr． Heng Jian from the College of Plant
Protection，China Agricultural University，was cultured
on Ipomoea aquatica under greenhouse conditions to
obtain fresh egg masses． Fresh eggs were then kept in
water for egg hatching． The second stage juveniles
(J2s)that emerged from the eggs after 48 h were incu-
bated at 30 ℃ and were used for nematicidal assay．
The nematode Panagrellus redivivus，which was kindly
supplied by Prof． Keqin Zhang at the Laboratory for
Conservation and Utilization of Bio-Ｒesources，Yunnan
University，was cultured on oatmeal agar plate at 25 ℃
in darkness for 3-5 days．
The nematode Caenorhabditis elegans was kindly sup-
plied by Dr． Chongling Yang at the Institute of Genetics
and Developmental Biology，Chinese Academy of Sci-
ences． The nematode was inoculated on Luria-Bertani
(LB)agar plate where the bacterium Escherichia coli
was cultured previously for 2-3 days． After another 3-5
days cultivation，the propagated nematodes were ready
for the assay．
Antinematodal activity
Each essential oil (5． 0 mg)was dissolved in 1． 0 mL
of the mixture of ethanol-Tween-20 (9∶ 1，v /v)to ob-
tain the initial stock solution at 5 mg /mL，which was
further diluted to 6． 25，12． 5，25，50，100，125 and 250
μg /mL． The test nematode solution (90 μL containing
40 to 50 nematodes)was added into each well of the
sterile 96-well microplate，and then 10 μL of sample
stock solution was added into each well and mixed
thoroughly． 10 μL of the mixture of ethanol-Tween-20
(9∶ 1，v /v)was used as the negative control． Five rep-
licates were carried out for each treatment，and the ex-
periments were repeated thrice． Dead /paralysis and ac-
tive nematodes were counted after 12，24 and 48 h，re-
spectively． The nematodes were considered to be dead
when they did not move to physical stimuli with a fine
needle［24，25］． The mean percentage of mortality was
then calculated． Avermectin，which was kindly provided
by Dr． Shankui Yuan at the Institute for the Control of
Agrochemicals，Chinese Ministry of Agriculture，was
used as the positive control with the purity of 97． 2% ．
Data analysis
The mortality (%) was adjusted according to the
method of Ntalli by eliminating the natural death /paral-
ysis in negative control ［26］． To describe the antinema-
todal effects of the essential samples against the nema-
todes，the median antinematodal concentration (IC50)
values were calculated using the linear relation between
the inhibitory probability and concentration logarithm
according to the method of Sakuma ［27］．
Ｒesults and Discussion
Essential oil analysis
After extraction，the yields (w /w)of the leaf essential
8621 Nat Prod Ｒes Dev Vol. 28
oils of lemongrass (C． citratus)and Mexican sunflower
(T． diversifolia) were calculated as 1． 02% and
1. 05%，respectively． The oils were analyzed for their
chemical composition by GC and GC-MS． Twenty com-
pounds were identified which accounted for 98． 00% of
the total lemongrass oil (Table 1)． The lemongrass oil
was dominated by monoterpenoids and sesquiterpenoids
which accounted for 81． 25% of the total oil and char-
acterized by a high percentage of citral (49． 76%) ，
myrcene (8． 54%)and nerol (5． 92%)． The chemical
profile of the lemongrass oil in this study was similar to
those of the previous reports only a few components
were different［12，13，21］． Similarly，α-terpineol (20． 31%)，
1，8-cineole (14． 67%)，1 7，7-trimethylbicyclo［2． 1． 1］
heptan-2-ol (14． 32%) ，2 6，6-trimethylbicyclo［3． 1．
1］hept-2-ene (13． 51%)and 1，1，4，7-tetramethyl-
decahydro-1H-cyclopropa［e］azulene-4-ol (7． 39%)
were the major compounds of the 20 identified compo-
nents which accounted for 98． 49% of the total Mexi-
can sunflower oil where 95． 85% belonged to monoter-
penoids and sesquiterpenoids (Table 2)． The chemical
profile of the leaf essential oil of Mexican sunflower in
Table 1 Chemical composition of the leaf essential oil from lemongrass
Compounda
Molecular
formula ＲI
b ＲA(%)c
6-Methyl-5-hepten-2-one C8H14O 974 1． 64
Myrcene = 7-Methyl-3-methyleneocta-1，6-diene C10H16 977 8． 54
Melonal = 2，6-Dimethyl-5-hepten-1-al C9H16O 1066 0． 85
Seudenone = 3-Methyl-2-cyclohexen-1-one C7H10O 1072 1． 24
Linalool = 3，7-Dimethylocta-1，6-dien-3-ol C10H18O 1120 3． 97
(E)-3，3-Dimethylhepta-1，5-diene C9H16 1170 1． 77
2，6，6-Trimethylcyclohexa-1，3-dienecarbaldehyde C10H14O 1180 1． 23
(E)-2-(2-Methylpropylidene)cyclohexanone C10H16O 1206 5． 42
Nerol = (E)-3，7-Dimethylocta-2，6-dien-1-ol C10H18O 1283 5． 92
Citral = (E)-3，7-Dimethylocta-2，6-dienal C10H16O 1303 49． 76
Undecan-2-one C11H22O 1318 1． 75
3，7-Dimethylocta-1，6-dien-3-yl formate C11H18O2 1327 0． 79
7-Isopropyl-1，4a-dimethyl-1，2，3，4，4a，5，6，8a-octahydronaphthalen-1-ol C15H26O 1659 5． 39
4-Isopropyl-1-methyl-6-methylene-1，2，3，5，6，7，8，8a-octahydronaphthalene C15H22 1678 1． 33
10-Epicadinol = 4-Isopropyl-1，6-dimethyl-1，2，3，4，4a，7，8，8a-octahydronaphthalen-1-ol C15H26O 1692 2． 41
1，1，3a，7-Tetramethyl-1a，2，3，3a，4，5，6，7b-octahydro-1H-cyclopropa［a］naphthalene C15H25 1700 1． 95
(3E，6Z)-6-(3，3-Dimethyloxiran-2-ylidene)-5，5-dimethylhex-3-en-2-one C12H18O 1761 1． 94
1-(4-Hydroxy-7-isopropyl-4-methyl-octahyydro-1H-inden-1-yl)ethanone C15H26O2 1777 0． 75
3，5，5-Trimethylcyclopent-2-enone C8 H12O 1942 0． 62
3，4，4-Trimethylcyclopent-2-enone C8 H12O 1946 0． 73
Total 98． 00
Monoterpene hydrocarbons 8． 54
Oxygenated monoterpenes 60． 88
Sesquiterpene hydrocarbons 3． 28
Oxygenated sesquiterpenes 8． 55
Others 16． 75
a:The identified constituents were listed in their order of elution． b:ＲI indicated the retention indices calculated against C8 -C40 n-alkanes on the HP-5MS
column． c:ＲA indicated relative amount (peak area relative to the total peak area)．
9621Vol. 28 WANG Wei-xuan，et al:Antinematodal Activity of the Leaf Essential Oils of Cymbopogon citratus and Tithonia diversifolia
Table 2 Chemical composition of the leaf essential oil from T． diversifolia
Compounda
Molecular
formula ＲI
b ＲA(%)c
2，6，6-Trimethylbicyclo［3． 1． 1］hept-2-ene C10H16 917 13． 51
o-Cymene C10H14 1022 2． 29
1，8-Cineole = 1，3，3-Trimethyl-2-oxa-bicyclo［2． 2． 2］octane C10H18O 1034 14． 67
1-Isopropyl-4-methylcyclohexa-1，4-diene C10H16 1072 0． 57
2-(5-Methyl-5-vinyl-tetrahydrofuran-2-yl)propan-2-ol C10H18O2 1093 1． 36
6-Methyl-2-(oxiran-2-yl)hept-5-en-2-ol C10H18O2 1111 1． 54
Linalool = 3，7-Dimethylocta-1，6-dien-3-ol C10H18O 1121 0． 77
1，3，3-Trimethylbicyclo［2． 1． 1］heptan-2-ol C10H18O 1141 4． 64
2(2，2，3-Trimethylcyclopent-3-enyl)acetaldehyde C10H16O 1153 2． 64
6，6-Diethyl-2-methylenebicyclo［3． 1． 1］heptan-3-ol C10H16O 1168 5． 11
1，7，7-Trimethylbicyclo［2． 1． 1］heptan-2-ol C10H18O 1194 14． 32
1-Isopropyl-4-methylcyclohex-3-enol C10H18O 1203 1． 82
α-Terpineol = 2-(4-Methyl-1-cyclohex-3-enyl)propan-2-ol C10H18O 1220 20． 31
(6，6-Dimethylbicyclo［3． 1． 1］hept-2-en-2-yl)methanol C10H16O 1225 0． 36
2-Methyl-5-(prop-1-en-2-yl)cyclohex-2-enol C10H16O 1245 1． 48
Carvacrol = 5-Isopropyl-2-methylphenol C10H14O 1306 0． 44
Isoledene = 1，1，4，7-Tetramethyl-1a，2，3，4，6，7，7b-octahydro-1-H-cyclopropa［e］azulene C15H24 1605 0． 66
1，1，7-Trimethyl-4-methylene-decahydro-1H-cyclopropa［e］azulen-7-ol C15H24O 1615 3． 38
1，1，4，7-Tetramethyldecahydro-1H-cyclopropa［e］azulene-4-ol C15H26O 1622 7． 39
2-(4a，8-Dimethyl-1，2，3，4，4a，5，6，8a-octahydronaphtalen-2-yl)propan-2-ol C15H26O 1689 1． 23
Total 98． 49
Monoterpene hydrocarbons 16． 37
Oxygenated monoterpenes 66． 82
Sesquiterpene hydrocarbons 0． 66
Oxygenated sesquiterpenes 12． 00
Others 2． 64
a:The identified constituents were listed in their order of elution． b:ＲI indicated the retention indices calculated against C8 -C40 n-alkanes on the HP-5MS
column． c:ＲA indicated relative amount (peak area relative to the total peak area)．
this study was similar to those of the previous reports
though a few components were different from each other
［19-22］． The reasons for this phenomenon may be differ-
ent geographical environments，growth seasons and age
of the plant，in addition to the method of oil prepara-
tion［28］．
Antinematodal activity
The antinematodal activity of the leaf essential oils of
lemongrass and Mexican sunflower was evaluated a-
gainst 4 representative nematodes (i． e．，Bursaphelen-
chus xylophilus;Meloidogyne incognita，Panagrellus
redivivus and Caenorhabditis elegans)． Its potency was
assessed quantitatively by IC50 values which were
shown in Table 3． Both essential oils had the similar
antinematodal activity with a broad spectrum． Among
the test nematodes，M． incognita was the most sensitive
nematode to the oils with the IC50 values of 1． 068 μg /
mL and 0． 747 μg /mL respectively at 24 h and 48 h of
treatment for the lemongrass oil，and 1． 118 μg /mL and
1． 039 μg /mL respectively at 24 h and 48 h of treat-
ment for the Mexican sunflower oil．
0721 Nat Prod Ｒes Dev Vol. 28
Table 3 Antinematodal activity of the leaf essential oils of lemongrass and Mexican sunflower
Tested
nematode
Period of
treatment(h)
IC50(μg /mL)
Leaf essential oil
of lemongrass
Leaf essential oil
of T． diversifolia
CK +
(Avermectin)
B． xylophilus 12 1． 420 3． 884 2． 103
24 1． 347 3． 350 1． 568
48 1． 280 1． 526 0． 871
M． incognita 12 1． 220 1． 646 1． 877
24 1． 068 1． 118 1． 547
48 0． 747 1． 039 1． 102
P． redivivus 12 1． 885 1． 776 1． 814
24 1． 521 1． 410 0． 976
48 1． 261 1． 053 0． 781
C． elegans 12 2． 383 1． 836 1． 733
24 1． 507 1． 493 1． 542
48 1． 174 1． 230 1． 448
Conclusion
We reported the chemical composition of the leaf essen-
tial oils of lemongrass (C． citratus)and Mexican sun-
flower (T． diversifolia)from China along with their an-
tinematodal activity in this study． Both essential oils
were dominated by monoterpenoids and sesquiterpe-
noids which accounted for 81． 25% of the total lemon-
grass oil and 95． 85% of the total Mexican sunflower
oil． Citral (49． 76%) ，myrcene (8． 54%)and nerol
(5． 92%)were the major compounds of the 20 identi-
fied components in the lemongrass oil． α-Terpineol
(20． 31%) ，1 8-cineole (14． 67%) ，1 7，7-trimethyl-
bicyclo［2． 1． 1］heptan-2-ol (14． 32%) ，2 6，6-trime-
thylbicyclo［3． 1． 1］hept-2-ene (13． 51%)and 1，1，
4，7-tetramethyldecahydro-1H-cyclopropa［e］azulene-4-
ol (7． 39%)were the major compounds of the 20 iden-
tified components in the Mexican sunflower oil． Both
essential oils had similar antinematodal activity with a
broad spectrum． They showed the strongest inhibition
on root-knot nematode (M． incognita)with the IC50
values of 1． 068 μg /mL and 0． 747 μg /mL respectively
at 24 h and 48 h of treatment for the lemongrass oil，
and 1． 118 μg /mL and 1． 039 μg /mL respectively at
24 h and 48 h of treatment for the Mexican sunflower
oil． Antinematodal activity of the leaf essential oils may
be due to the fact that the oil had abundant monoterpe-
noids and sesquiterpenoids that should be further stud-
ied． Biological properties of the essential oils are of
great interest in agriculture，food，cosmetic and pharma-
ceutical industries［7-9］． The present study provided ad-
ditional data supporting the future utilization and devel-
opment of lemongrass and Mexican sunflower essential
oils as the antinematodal agents． The underlying antine-
matodal mechanism of these two oil as well as their ac-
tive components need to be further studied and clari-
fied．
Ｒeferences
1 Li J，Zou C，Xu J，et al． Molecular mechanisms of nematode-
nematophagous microbe interactions:basis for biological con-
trol of plant-parasitic nematodes． Annu Ｒev Phytopathol，
2015，53:67-95．
2 Castagnone-Sereno P，Danchin EGJ，Perfus-Barbeoch L，et
al． Diversity and evolution of root-knot nematodes，genus
Meloidogyne:new insights from the genomic era． Annu Ｒev
Phytopathol，2013，51:203-220．
3 Futai K． Pine wood nematode，Bursaphelenchus xylophilus．
Annu Ｒev Phytopathol，2013，51:61-83．
4 Oka Y，Koltai H，Bar-Eyal M，et al． New strategies for the
control of plant-parasitic nematodes． Pest Mang Sci，2000，
56:983-988．
5 Zhou L，Wang J，Wang K，et al． Secondary metabolites with
1721Vol. 28 WANG Wei-xuan，et al:Antinematodal Activity of the Leaf Essential Oils of Cymbopogon citratus and Tithonia diversifolia
antinematodal activity from higher plants． Stud Nat Prod
Chem，2012，37:67-114．
6 Ntalli NG，Caboni P． Botanical nematicides:a review． J Agric
Food Chem，2012，60:9929-9940．
7 Burt S． Essential oils:their antibacterial properties and po-
tential applications in foods． Int J Food Microbiol，2004，94:
223-253．
8 Dudareva N，Negre F，Nagegowda DA，et al． Plant volatiles:
recent advances and future perspectives． Crit Ｒev Plant Sci，
2006，25:417-440．
9 Bakkali F，Averbeck S，Averbeck D，et al． Biological effects
of essential oils． Food Chem Toxicol，2008，46:446-475．
10 Ｒavinder K，Pawan K，Gaurav S，et al． Pharmacognostical in-
vestigation of Cymbopogon citratus (DC)Stapf． Pharm Lett，
2010，2:181-189．
11 Mahanta JJ，Chutia M，Bordoloi M，et al． Cymbopogon citratus
L． essential oil as a potential antifungal agent against key
weed moulds of Pleurotus spp． spawans． Flavour Frag J，
2007，22:525-530．
12 Vazirian M，Kashani ST，Ardekani MＲS，et al． Antimicrobial
activity of lemongrass (Cymbopogon citratus (DC)Stapf．)
essential oil against food-borne pathogens added to cream-
filled cakes and pastries． J Essent Oil Ｒes，2012，24:579-
582．
13 Poonpaiboonpipat T，Pangnakorn U，Suvunnamek U，et al．
Phytotoxic effects of essential oil from Cymbopogon citratus
and its physiological mechanisms on bamyardgrass (Echino-
chloa crus-galli)． Ind Crop Prod，2013，41:403-407．
14 Machado M，Pires P，Dinis AM，et al． Monoterpenic alde-
hydes as potential anti-Leishmania agents:activity of Cymbo-
pogon citratus and citral on L． infantum，L． tropica and L． ma-
jor． Exp Parasitol，2012，130:223-231．
15 Chagas-Paula DA，Oliveira ＲB，Ｒocha BA，et al． Ethnobota-
ny，chemistry，and biological activities of the genus Tithonia
(Asteraceae)． Chem Biodiversity，2012，9:210-235．
16 Miranda MAFM，Varela ＲM，Torres A，et al． Phytotoxins from
Tithonia diversifolia． J Nat Prod，2015，78:1083-1092．
17 De Toledo JS，Ambrosio SＲ，Borges CHG，et al． In vitro leish-
manicidal activities of sesquiterpene lactones from Tithonia
diversifolia against Leishmania braziliensis promastigotes and
amastigotes． Molecles，2014，19:6070-6079．
18 Li X，Huang G，Zhao G，et al． Two new monoterpenes from
Tithonia diversifolia and their anti-hyperglycemic activity． Ｒec
Nat Prod，2013，7:351-354．
19 Moronkola DO，Ogunwande IA，Walker TM，et al． Identifica-
tion of the main volatile compounds in the leaf and flower of
Tithonia diversifolia (Hemsl)Gray． J Nat Med，2007，61:63-
66．
20 Li XX，Shen YD，Fan ZW，et al． Chemical constituents and
allelopathy of Tithonia diversifolia volatile oil． Guihaia，2013，
33:878-882．
21 Adams ＲP． Identification of Essential Oil Components by Gas
Chromatography /Quadrupole Mass Spectroscopy． Allured:
Carol Stream，IL，USA，2001．
22 Abdurahman HN，Ｒanitha M，Azhari HN． Extraction and
characterization of essential oil from the ginger (Zingiber of-
ficinale Ｒoscoe)and lemongrass (Cymbopogon citratus)by
microwave-assisted hydrodistillation． Int J Chem Environ
Eng，2013，4:221-226．
23 Magina MDA，Dalmarco EM，Wisniewski A，et al． Chemical
composition and antibacterial activity of essential oils of Eu-
genia species． J Nat Med，2009，63:345-350．
24 Hong L，Li G，Zhou W，et al． Screening and isolation of a ne-
maticidal sesquiterpene from Magnolia grandiflora． Pest
Manag Sci，2007，63:301-305．
25 Wang K，Luo C，Liu H，et al． Nematicidal activity of the alka-
loids from Macleaya cordata against certain nematodes． Afr J
Agric Ｒes，2012，7:5925-2929．
26 Ntalli NG，Ferrari F，Giannakou I，et al． Synergistic and an-
tagonistic interactions of terpenes against Meloidogyne incog-
nita and the nematicidal activity of essential oils from seven
plants indigenous to Greece． Pest Manag Sci，2011，67:341-
351．
27 Sakuma M． Probit analysis of preference data． Appl Entomol
Zool，1998，33:339-347．
28 Gudzic B，Djokovic D，Vajs V，et al． Composition and antimi-
crobial activity of the essential oil of Hypericum maculatum
Crantz． Flav Fragr J，2002，17:392-394．
2721 Nat Prod Ｒes Dev Vol. 28