Prevalence of Diterpenes in Essential Oil of Euphorbia mauritanica L.: Detailed Chemical Profile,Antioxidant, Cytotoxic and Phytotoxic Activities

Plants belonging to Euphorbia L. genus are considered very interesting from a medicinal point of view due to their diverse metabolites and bioactivities. The essential oil (EO) of Euphorbia mauritanica L. is not studied up to date. Therefore, the present study aimed to explore the chemical profile of this EO and evaluate its antioxidant, cytotoxic, and allelopathic potentialities. The EO was extracted from the whole plant via hydrodistillation and then, analyzed by gas chromatography/mass spectrometry (GC/MS). The correlation of E. mauritanica with the other Euphorbia plants was established using chemometric analysis. The antioxidant activity was determined based on scavenging of the free radical, 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). The anti-proliferation of the EO on the Hep G2 and MCF-7 cells was evaluated. Finally the allelopathic activity of the EO was assessed against the two noxious weeds, Dactyloctenium aegyptium and Urospermum picroides. Forty-one compounds were identified using GC/MS analysis, with an abundance of terpenoids (91.54 %) that were categorized into mono- (30.75 %), sesqui- (15.23 %), and diterpenes (45.56 %). Interestingly, the results revealed the preponderance of diterpenoid constituents although they are rarely found in the EOs of the plant kingdom. The major compounds were (3E)-cembrene A (18.66 %), verticiol (17.05 %), limonene (7.91 %), eucalyptol (7.26 %), α-pinene (5.61 %), neo-cembrene A (3.52 %), kaur-16-ene (3.24 %), and cembrene (3.09 %). The EO showed moderate antioxidant activity where it attained IC₅₀ values of 83.34 and 64.21 μg mL⁻¹ for DPPH and ABTS compared to 23.01 and 19.23 μg mL⁻¹ for ascorbic acid as standard, respectively. The EO exhibited very weak cytotoxic effect on MCF-7 and Hep G2 cells. The EO showed significant allelopathic activities against the weeds D. aegyptium and U. picroides in a concentration-dependent manner. EO was found more effective against U. picroides than D. aegyptium with IC₅₀ values of 0.79, 0.45, and 0.67 mg mL⁻¹ and 1.17, 0.55, and 1.08 mg mL⁻¹ for germination, root, and shoot growth, respectively. Due to the high content of diterpenes in E. mauritanica, further study is recommended for more characterization of pure forms of the identified diterpenes as well as evaluating their bioactivity either solely or synergistically.     

Chemical,Antioxidant, and Antimicrobial Evaluation of Essential Oils and an Anatomical Study of the Aerial Parts from Baccharis Species (Asteraceae)

The aim of this study was to evaluate the chemical, antioxidant, and antimicrobial activity of the essential oils as well as the anatomy of the aerial parts from Baccharis aracatubaensis, Baccharis burchellii, and Baccharis organensis owing to the therapeutic potential of Baccharis. The volatile constituents were analyzed using GC/MS, the antioxidant activity was evaluated by oxygen radical absorbance capacity (ORAC_FL) and DPPH assays, and the antimicrobial activity by a microdilution technique. Of the 56 compounds identified, only seven (β‐caryophyllene, γ‐muurolene, bicyclogermacrene, β‐germacrene, spathulenol, τ‐muurolol, and α‐cadinol) were common in the three specimens studied. Of these, γ‐muurolene was found abundantly in B. aracatubaensis, while bicyclogermacrene was abundant in B. burchellii and B. organensis. The essential oils exhibited antioxidant activity in the ORAC_FL (>500.0 μmol TE g^?1) and DPPH assays. However, they did not exhibit any antimicrobial activity. Secretory ducts and flagelliform glandular trichomes were observed in the anatomical study of all the Baccharis species studied.     

香茅精油的抑菌和抗氧化活性研究

选用产自福建厦门的香茅(Cymbopogon nardus),测定香茅精油对白色粘性沙雷氏菌、红色粘性沙雷氏菌、大肠杆菌、金黄葡萄球菌、铜绿假单胞菌和紫色杆菌等6种菌的抑菌活性,并利用ABTS^.+自由基清除法以及超氧阴离子清除法研究香茅精油的抗氧化活性。结果表明,新鲜香茅精油的平均提取率为0.29,对6种供试菌种都有较高的抑制作用,其中对紫色杆菌的抑制活性最强,且香茅精油有极高的清除ABTS^.+自由基以及超氧阴离子自由基的能力,证明香茅精油具有广谱抑菌活性及强抗氧化活性。     

Chemical Characterization,Antioxidant Capacity and Antimicrobial Potential of Essential Oil from the Leaves of Baccharis oreophila Malme

This is the first time that composition, antimicrobial potential and antioxidant ability of essential oil from the leaves of Baccharis oreophila are reported. Essential oil was obtained by hydrodistillation and analyzed by GC/MS. Antimicrobial potential was evaluated by diffusion disk and broth microdilution methods. ABTS^.+, DPPH^. and FRAP methods were employed for antioxidant activity evaluation. Essential oil yield was 0.47 %. Sixty‐five compounds were identified, representing 88.53 % of the total essential oil, which showed to be rich in oxygenated (37.88 %) and hydrocarbons sesquiterpenes (34.84 %). The main constituents were khusimone (16.37 %) and spathulenol (16.12 %). Antimicrobial activity was verified against S. aureus (10.33±0.5 mm, MIC: 1250 μg mL^?1) and C. albicans (8.66±0.5 mm, MIC: >2500 μg mL^.1). Antioxidant ability was evidenced by FRAP (4.09 μmol FeSO₄ E mL^?1), ABTS^.+ (1.45 μmol TE mL^?1) and DPPH^. (1.04 μmol TE mL^?1) scavenging capacity. Results showed that this essential oil has interesting biological potential, encouraging further investigations especially in relation to action mechanisms of antimicrobial and antioxidant activity.     

Achillea filipendulina Lam.: Chemical Constituents and Antimicrobial Activities of Essential Oil of Stem,Leaf, and Flower

In this study, we extracted the essential oils of the stem, leaf, and flower of Achillea filipendulina, analyzed them, and studied their antibacterial properties. Of 16, 53, and 35 compounds identified in the stem, leaf, and flowers, respectively, only five are present in all three segments of the plant. The essential oil of the stem was mainly composed of neryl acetate, spathulenol, carvacrol, santolina alcohol, and trans‐caryophyllene oxide. However, the main identified components of leaf were 1,8‐cineole, camphor, ascaridole, trans‐isoascaridole, and piperitone oxide and the main components of the flower oil were ascaridole, trans‐isoascaridole, 1,8‐cineole, p‐cymene, and camphor. The extracted oil from different segments demonstrated varying antibacterial properties against both Gram‐positive and Gram‐negative bacteria, demonstrated by disk, minimum inhibitory concentration, and minimum bactericidal concentration methods. These suggest that the application of all segments of aerial parts of A. filipendulina may have a better therapeutic effect in fighting pathogenic systems.     

Myrtus communis Essential Oil: Chemical Composition and Antimicrobial Activities against Food Spoilage Pathogens

Myrtus communis is a typical plant of the Mediterranean area, which is mainly used as animal and human food and, in folk medicine, for treating some disorders. In the present study, we evaluated in vitro antibacterial and antifungal properties of the essential oils of Myrtus communis (McEO), as well as its phytochemical composition. The GC/MS analysis of the essential oil revealed 17 compounds. Myrtenyl acetate (20.75%), 1,8‐cineol (16.55%), α‐pinene (15.59%), linalool (13.30%), limonene (8.94%), linalyl acetate (3.67%), geranyl acetate (2.99%), and α‐terpineol (2.88%) were the major components. The antimicrobial activity of the essential oil was also investigated on several microorganisms. The inhibition zones and minimal inhibitory concentration (MIC) values of bacterial strains were in the range of 16–28 mm and 0.078–2.5 mg/ml, respectively. The inhibitory activity of the McEO against Gram‐positive bacteria was significantly higher than against Gram‐negative. It also exhibited remarkable activity against several fungal strains. The investigation of the mode of action of the McEO by the time‐kill curve against Listeria monocytogenes (food isolate) showed a drastic bactericidal effect after 5 min using a concentration of 312 μg/ml. These results evidence that the McEO possesses antimicrobial properties, and it is, therefore, a potential source for active ingredients for food and pharmaceutical industries.     

侧柏叶精油的抗细菌和抗氧化活性(英文)

采用水蒸气蒸馏法提取侧柏叶精油,通过GC和GC-MS分析精油的组成。从侧柏叶精油中鉴定出29种成分,主要为单萜和倍半萜,含量较高的化合物有:8-丙氧基-柏木烷(15.41%)、松油烯-4-醇(12.98%)、α-蒎烯(9.85%)、桧烯(9.92%)和3-蒈烯(6.77%)。侧柏叶精油具有广谱的抗细菌活性,对供试细菌的最低杀菌浓度(MBC)在0.1 mg/mL和1.0 mg/mL之间,最低抑菌浓度(MIC)在0.063 mg/mL和0.90 mg/mL之间,半抑制浓度(IC50)在0.044 mg/mL和0.763 mg/mL之间。侧柏叶精油能有效抑制菲啰嗪与Fe2+的螯合(IC50值为0.409mg/mL)和β-胡萝卜素-亚油酸的氧化(IC50值为0.526 mg/mL)。     

Analysis of Chemical Composition and Assessment of Antioxidant,Cytotoxic and Synergistic Antibacterial Activities of Essential Oils from Different Plant Parts of Piper boehmeriifolium

The essential oils (EOs) from leaves, stems, and whole plant of Piper boehmeriifolium were analyzed using GC/FID and GC/MS. The main constituents of P. boehmeriifolium EOs were β‐caryophyllene, caryophyllene oxide, β‐elemene, spathulenol, germacrene D, β‐selinene, and neointermedeol. The antioxidant potential of the EOs were determined using DPPH^?, ABTS^?+ and FRAP assays. In ABTS^?+ assay, the leaf oil exhibited a remarkable activity with an IC₅₀ value of 7.36 μg/mL almost similar to BHT (4.06 μg/mL). Furthermore, the antibacterial activity of the oils as well as their synergistic potential with conventional antibiotics were evaluated using microdilution and Checkerboard assays. The results revealed that the oils from different parts of P. boehmeriifolium inhibited the growth of all tested bacteria and the minimum inhibitory concentrations were determined to be 0.078 – 1.250 mg/mL. In combination with chloramphenicol or streptomycin, the oils showed significant synergistic antibacterial effects in most cases. Besides, the results of MTT assay indicated that the oil of the whole plant exhibited significant cytotoxic activities on human hepatocellular carcinoma cells (HepG2) and human breast cancer cells (MCF‐7). In summary, the P. boehmeriifolium oils could be regarded as a prospective source for pharmacologically active compounds.     

密花香薷挥发油化学成分及其抗菌、抗病毒活性的研究

采用水蒸气蒸馏法提取密花香薷挥发油,测得密花香薷挥发油的得率为0.12％.利用气相色谱-质谱(GC-MS)联用技术对密花香薷挥发油的化学成分进行了分析研究,鉴定了26种化合物,占挥发油总量的76.04％.体外抗菌试验和抗病毒试验的结果表明:密花香薷挥发油具有抗菌和抗病毒作用.     

Chemical Composition and Allelopathic,Phytotoxic and Pesticidal Activities of Atriplex cana Ledeb. (Amaranthaceae) Essential Oil

The chemical composition and allelopathic, phytotoxic and pesticidal activities of Atriplex cana Ledeb . (Amaranthaceae) essential oil were investigated. Nineteen compounds were identified via GC/MS, representing 82.3 % of the total oil, and the most abundant constituents were dibutyl phthalate (21.79 %), eucalyptol (20.14 %) and myrtenyl acetate (15.56 %). The results showed that volatile organic compounds (VOCs) released by A. cana significantly inhibited seedling growth of Amaranthus retroflexus L. and Poa annua L., and 80 g of fresh stems and leaves of A. cana in a 1.5 L airtight container almost completely suppressed the seed germination of both plants. Meanwhile, 5 μg/mL essential oil completely inhibited the seed germination of A. retroflexus, Medicago sativa L., P. annua and Echinochloa crusgalli L. Pesticidal testing revealed that the essential oil had strong behavioral avoidance and lethal effects on Aphis pomi DeGeer . Five microliters of essential oil/Petri dish treatment resulted in an 84.5 % mortality rate after 12 h, and the mortality rate reached nearly 100 % after 48 h. This report is the first one on the chemical composition as well as the biological activity of the essential oil of A. cana, and our results indicate that the oil is valuable in terms of being further exploited as a bioherbicide/insecticide.     

Repellent,Insecticidal and Antimicrobial Activities of Leaf Essential Oils from Three Eucalyptus Species

Developing effective and eco‐friendly antimicrobials and pesticides has become a highly important issue. The repellent, insecticidal and antimicrobial activity of essential oils (EOs) isolated by hydrodistillation from dried leaves of the three Eucalyptus species (E. cloeziana, E. umbellata and E. benthamii) were investigated. During GC/MS analysis, α‐pinene (47.36 %), 1,8‐cineol (38.53 %) and α‐pinene (35.31 %) were identified as major components of E. cloeziana, E. umbellata and E. benthamii, respectively. The EOs from E. cloeziana exhibited the longest effective protection time (465 min, at 50.0 % w/w) for humans among the EOs studied. The effective protection time was 30 min and 300 min at concentrations of 12.5 % (w/w) and 25.0 % (w/w), respectively. Fumigating insecticidal activity of EOs from three Eucalyptus species was tested by airtight fumigation in conical flask, which indicated that essential oils had a highly and rapidly insecticidal activity on Culex pipiens quinquefasciatus. The antimicrobial activity of EOs was evaluated by using disc diffusion and agar dilution methods. There was no significant difference in the antibacterial activity of EOs from E. cloeziana and E. umbellate and they had the same MICs (20 mL/L) on Staphylococcus aureus, Salmonella typhi, Bacillus subtilis and Escherichia coli. E. benthamii had the worst microbial inhibitory effect among the three Eucalyptus essential oils and the MIC value for the test species is 40 mL/L except for Rhodotorula Harrison (10 mL/L).     

薄荷精油抗菌活性研究

采用气相色谱—质谱联用仪分析了薄荷精油的成分,在鉴定出的21种成分中,异佛尔酮(41.22%)、β-石竹烯(10.01%)、斯巴醇(2.89%)、β-蒎烯(1.45%)和桉树脑(1.13%)为主要成分。采用琼脂扩散法和微量肉汤稀释法对薄荷精油的抗菌活性进行了研究。结果表明,枯草芽孢杆菌及变形杆菌出现最大的抑菌环。MIC实验中,薄荷精油的浓度范围为5.00%~0.039%。在所选的8种菌种中,变形杆菌的MIC及MBC值最低,分别为0.625%及1.25%。结果充分证明,薄荷精油对于所选的8种病原菌都有很好的抗菌活性,在食品及制药工业中有广阔的应用前景。     

Comparative Study of Chemical Composition,Cholinesterase Inhibition and Antioxidant Potential of Mentha pulegium L. Essential Oil

Perennial plant Mentha pulegium L. (pennyroyal, Lamiaceae) can be found in Europe and Mediterranean. In areas where it thrives, M. pulegium is used in nutrition and as medicinal plant. Essential oil of M. pulegium is also a frequent constituent of foods and fragrances, because of mint-like odor. Regarding the use of M. pulegium in traditional medicine and nutrition, as well as fact that essential oils are potential sources of bioactive components, this study was conducted to examine the chemical composition of essential oil of M. pulegium wild growing in Bosnia and Herzegovina and its biological activity. The chemical profile testing was made using GC/MS and GC/FID technique. Potential of cholinesterase inhibition was tested by Ellman's assay. The antioxidant activity was tested by DPPH and FRAP assay. The dominant components in analyzed oil were pulegone 54.4 %, p-menthone 14.0 % and piperitenone 12.8 %. Good antioxidant activity and moderate cholinesterase inhibition potential of tested essential oil indicates to possibility of its use in treatment of diseases related to free radicals, Alzheimer disease and as lipid protecting antioxidant.     

Essential Oils of Polyalthia suberosa Leaf and Twig and Their Cytotoxic and Antimicrobial Activities

Essential oils from the leaf and twig of Polyalthia suberosa (Roxb.) Thwaites were analyzed using GC/MS/FID. A total of sixty-three constituents were namely identified accounting for 96.03 and 94.12 % in the hydrodistilled oils of the leaf and twig, respectively. Monoterpenes, monoterpenoids, sesquiterpenes, and sesquiterpenoids were characteristic derivatives of P. suberosa essential oils. Sesquiterpenes bicyclogermacrene (26.26 %) and (E)-caryophyllene (7.79 %), and monoterpene β-pinene (12.71 %) were the major constituents of the leaf oil. Sesquiterpenes (E)-caryophyllene (17.17 %) and α-humulene (9.55 %), sesquiterpenoid caryophyllene oxide (9.41 %), and monoterpenes camphene (8.16 %) and tricyclene (6.35 %) were to be main components in the twig oil. The leaf oil indicated cytotoxic activity against three cancer cell lines HepG2, MCF7 and A549 with the IC₅₀ values of 60.96–69.93 μg/mL, while the twig oil inhibited MCF7 with the IC₅₀ value of 66.70 μg/mL. Additionally, the twig oil successfully suppressed the growth of the negative Gram bacterium Pseudomonas aeruginosa, fungus Aspergillus niger, and yeast Candida albicans with the same MIC value of 50 μg/mL, whereas the leaf oil had the same result on the negative Gram bacterium Escherichia coli.     

Chemical Composition,Toxicity and Repellency of Inula graveolens Essential Oils from Roots and Aerial Parts against Stored-Product Beetle Tribolium castaneum (Herbst)

In this work, essential oils extracted from roots and aerial parts of Inula graveolens by hydrodistillation and their fractions obtained by chromatographic simplification were first investigated for their chemical composition by GC/MS and then evaluated for the first time for their repellency and contact toxicity properties against Tribolium castaneumadults. Twenty-eight compounds were identified in roots essential oil (REO), which accounted for 97.9 % of the total oil composition, with modhephen-8-β-ol (24.7 %), cis-arteannuic alcohol (14.8 %), neryl isovalerate (10.6 %) and thymol isobutyrate (8.5 %) as major constituents. Twenty-two compounds were found in the essential oil from aerial parts (APEO), which accounted for 93.9 % of the total oil, with borneol (28.8 %), caryophylla-4(14),8(15)-dien-6-ol (11.5 %), caryophyllene oxide (10.9 %), τ-cadinol (10.5 %) and bornyl acetate (9.4 %) as main compounds.REO and APEO displayed stronger repellency after 2 h of exposure (80.0 and 90.0 %, respectively) against T. castaneum at the concentration of 0.12 μL/cm². After fractionation, fractions R₄ and R₅ exhibited greater effects (83.3 % and 93.3 %, respectively) than the roots essential oil. Furthermore, the fractions AP₂ and AP₃ showed higher repellency (93.3 and 96.6 %, respectively) than the aerial parts oil. The LD₅₀ values of oils from roots and aerial parts topically applied were 7.44 % and 4.88 %, respectively. Results from contact toxicity assay showed that fraction R₄ was more effective than the roots oil with LD₅₀ value of 6.65 %. These results suggests that essential oils of roots and aerial parts from I. graveolens may be explored as potential natural repellent and contact insecticides against T. castaneum in stored products.     

Antiprotozoal,Schistosomicidal, and Antimicrobial Activities of the Essential Oil from the Leaves of Baccharis dracunculifolia

Baccharis dracunculifolia DC. (Asteraceae), popularly known as ‘alecrim do campo’, is a native plant from Brazil used in folk medicine as febrifuge, anti‐inflammatory, antiseptic, and to treat skin sores. Also, B. dracunculifolia is the most important plant source of the Brazilian green propolis, which is recognized for its antiseptic and antiprotozoal activities. This study aimed at investigating the in vitro antiprotozoal, schistosomicidal, and antimicrobial activities of the essential oil from the leaves of B. dracunculifolia. The essential oil was obtained by hydrodistillation and analyzed by GC and GC/MS, which allowed the identification of 14 compounds, mainly oxygenated sesquiterpenes, such as (E)‐nerolidol (33.51%) and spathulenol (16.24%). The essential oil showed activity against promastigote forms of Leishmania donovani, with IC₅₀ values of 42 μg/ml. The essential oil displayed high activity in the schistosomicidal assay, since all pairs of Schistosoma mansoni adult worms were dead after incubation with the essential oil (10, 50, and 100 μg/ml). B. dracunculifolia essential oil was neither cytotoxic against Vero cells, nor active in the antimicrobial and antiplasmodial assays.     

In Vitro Trypanocidal and Antibacterial Activities of Essential Oils from Four Species of the Family Annonaceae

The objective of this study was to evaluate the chemical composition, and the trypanocidal and antibacterial activities of the essential oils from four species of Annonaceae: Bocageopsis multiflora (Mart .) R.E.Fr ., Duguetia quitarensis Benth ., Fusaea longifolia (Aubl. ) Saff ., and Guatteria punctata (Aubl .) R.A.Howard . The chemical composition of the essential oils from the aerial parts yielded 23, 20, 21 and 23 constituents, respectively, which were identified by GC/MS. The trypanocidal activity was evaluated against the amastigote and trypomastigote forms of T. cruzi. The antibacterial activity was evaluated by the microdilution method against enterohemorrhagic Escherichia coli, Pseudomonas aeruginosa, Streptococcus mutans, Streptococcus pyogenes, and methicillin‐resistant Staphylococcus aureus. The results of trypanocidal activity showed that the essential oils of the four species were active at the tested concentrations, with G. punctata essential oil being the most active, with IC₅₀=0.029 μg/mL, and selectivity index (SI)=32, being 34 times more active than the reference drug benznidazole. All EOs showed strong antibacterial activity (minimum inhibitory concentrations of 4.68–37.5 μg/mL) against strains of S. mutans.     

Chemical Composition and Antioxidant,Antiparasitic, Cytotoxicity and Antimicrobial Potential of the Algerian Limonium Oleifolium Mill. Essential Oil and Organic Extracts

This work aimed to investigate, for the first time, the chemical composition, antioxidant, antiparasitic, cytotoxicity, and antimicrobial activities of the aromatic plant Limonium oleifolium Mill. essential oil (EO) and organic extracts. L. oleifolium aerial parts essential oil was analyzed by GC-FID and GC-MS, and 46 constituents representing 98.25±1.12 % of the oil were identified. γ-Muurolene (10.81±0.07 %), cis-caryophyllene (7.71±0.06 %), o-cymene (7.07±0.01 %) and α-copaene (5.02±0.05 %) were the essential oil main compounds. The antioxidant activity of L. oleifolium EO and organic extracts (MeOH, CHCl₃, AcOEt, BuOH) was explored using 2,2-diphenyl-1-picrylhydrazyl (DPPH), ABTS, β-carotene/linoleic acid, cupric reducing antioxidant capacity (CUPRAC), and ferric reducing power assays. The results showed that L. oleifolium EO exhibit antioxidant capacity (IC₅₀=17.40±1.32 μg/mL for DPPH assay, IC₅₀=29.82±1.08 μg/mL for β-carotene assay, IC₅₀=25.23±1.01 μg/mL for ABTS assay, IC₅₀=9.11±0.08 μg/mL for CUPRAC assay and IC₅₀=19.41±2.06 mg/mL for reducing power assay). Additionally, the EO showed significant activity against trophozoite form of Acanthamoeba castellanii (IC₅₀=7.48±0.41 μg/mL) and promastigote form of Leishmania amazonensis (IC₅₀=19.36±1.06 μg/mL) and low cytotoxicity on murine macrophages (LC₅₀ 90.23±1.09 μg/mL), as well as good antimicrobial activity against Staphylococcus aureus, Escherichia coli, Klebsiella oxytoca, and Pseudomonas aeruginosa. These results suggest that L. oleifolium essential oil is a valuable source of bioactive compounds presenting antioxidant, antiparasitic, and antimicrobial activities. Furthermore, it is considered nontoxic.     

Chemical Profile and Phytotoxic Action of Hibiscus trionum Essential Oil

The chemical profile and phytotoxic action of Hibiscus trionum essential oil (EO) was studied. In total 17 compounds were identified via GC/MS, representing 94.18 % of the entire oil, with phytol (40.37 %) being the dominant constituent. Bioassay revealed that the EO inhibited root elongation of Medicago sativa and Amaranthus retroflexus by 32.66 % and 61.86 % at 5 mg/mL, respectively; meanwhile, the major component phytol also exhibited significant phytotoxic activity, suppressing radical elongation of Pennisetum alopecuroides, M. sativa and A. retroflexus by 26.08 %, 27.55 % and 43.96 % at 1 mg/mL, respectively. The fact that the EO showed weaker activity than phytol implied that some constituents might trigger antagonistic action to decrease the oil's activity. Our study is the first on the chemical profile and phytotoxic effect of H. trionum EO.