Toxicity,behavior impairment,and repellence of essential oils from pepper‐rosmarin and patchouli to termites

Plant essential oils are potential sources of insecticidal compounds, but have rarely been explored for their effect on termites. In the present study, we assessed the chemical composition of essential oils of Lippia sidoides Cham. (pepper‐rosmarin; Verbenaceae) and Pogostemon cablin (Blanco) Benth. (patchouli; Lamiacaeae) and evaluated their toxicity, behavioral impairment, and repellence to termite species of the genera Amitermes and Microcerotermes (Isoptera: Termitidae: Termitinae). The main components of essential oils of L. sidoides and P. cablin were thymol (44.6%) and patchouli alcohol (36.6%), respectively. The essential oil of P. cablin was most potent against Amitermes cf. amifer Silvestri and had the lowest LD₅₀ (0.63 μg mg^?1). There was no difference in toxicity for Microcerotermes indistinctus Mathews between the essential oils of L. sidoides (LD₅₀ = 1.49 μg mg^?1) and P. cablin (LD₅₀ = 1.67 μg mg^?1). Pogostemon cablin essential oil was the most toxic to M. indistinctus (LC₅₀ = 0.32 μl ml^?1) and A. cf. amifer (LC₅₀ = 0.29 μl ml^?1). The essential oils analyzed exhibited high toxicity and repellence to the termites, in addition to reducing behavioral interactions among individuals, thus constituting potential termiticides.     

The Genus Myrtus L. in Algeria: Composition and Biological Aspects of Essential Oils from M. communis and M. nivellei: A Review

The genus Myrtus L. (Myrtaceae family) comprises two species, Myrtus communis L. (known as common myrtle) growing wild all around the Mediterranean basin and Myrtus nivellei Batt . and Trab . (known as Saharan myrtle), found in central Sahara. Only one country, Algeria, hosts both species, M. communis in the North and M. nivellei in the South. The aim of this review was to collect, summarize, and compare the main results reported relative to the essential oils isolated from aerial parts of both species: botanical aspects, habitat, traditional use, chemical composition, new compounds, antimicrobial activity, antioxidant activity, anti‐inflammatory effect, and insecticidal activity. Both essential oils have potential applications in human health.     

Chemical Composition and Antimicrobial Activity of the Essential Oil from Aerial Parts and Roots of Eryngium barrelieri Boiss. and Eryngium glomeratum Lam. from Tunisia

The study of chemical composition and biological activity of unexplored essential oils may open new perspectives on their potential use in facing major health concerns such as drug‐resistant infections. The present study investigates the chemical composition and antimicrobial effects of previously unstudied essential oils obtained from genus Eryngium: Eryngium glomeratum Lam . and Eryngium barrelieri Boiss . The chemical compositions of the essential oils from aerial parts and roots of both species were studied using GC and GC/MS analytical technics. The analysis led to the identification of 102 compounds totalizing 85 – 94% of all detected compounds. Essential oils were characterized by the predominance of oxygenated sesquiterpenes. The oils obtained from aerial parts were tested against 36 microbial strains by agar dilution method and showed minimum inhibitory concentrations (MIC) in the range of 2 – 625 μg/ml. A strong antibacterial activity against multiresistant Pseudomonas aeruginosa was observed especially from E. glomeratum essential oil with MIC value up to 2 μg/ml. These findings give significant information about the pharmacological activity of these essential oils, which suggest their potential use to develop new remedies, or as sources of active compounds.     

Larvicidal Activity of Essential Oils of Five Apiaceae Taxa and Some of Their Main Constituents Against Culex quinquefasciatus

Apiaceae are aromatic herbs producing essential oils which are used on an industrial scale for various purposes. Notably, Apiaceae essential oils may replace synthetic insecticides keeping most of their efficacy and avoiding environmental pollution and human poisoning. In the present work, we explored the insecticidal potential of the essential oils from five Apiaceae taxa, namely Sison amomum, Echinophora spinosa, Heracleum sphondylium subsp. sphondylium, Heracleum sphondylium subsp. ternatum, and Trachyspemum ammi, as well as their major constituents (sabinene, p‐cymene, terpinolene, myristicin, and thymol), against the filariasis vector Culex quinquefasciatus. For the purpose, the essential oils were obtained by hydrodistillation and their composition was achieved by gas chromatography/mass spectrometry (GC/MS). Their acute toxicity on third instar larvae of C. quinquefasciatus was determined. The two most active essential oils were those from T. ammi fruits and E. spinosa roots, showing LC₅₀ below 20 μl/l and LD₉₀ below 50 μl/l. These oils were dominated by the monoterpene phenol thymol and the phenylpropanoid myristicin, respectively, which showed the strongest larvicidal activity (LC₅₀ of 15.1 and 16.3 μl/l, respectively) among the pure compounds tested. These results showed that Apiaceae may be useful as source of larvicidal compounds to be used for the development of cheap, effective and eco‐friendly insecticidal formulations.     

Composition and Biological Activity of Picea pungens and Picea orientalis Seed and Cone Essential Oils

The increasing consumption of natural products lead us to discover and study new plant materials, such as conifer seeds and cones, which could be easily available from the forest industry as a waste material, for their potential uses. The chemical composition of the essential oils of Picea pungens and Picea orientalis was fully characterized by GC and GC/MS methods. Seed and cone oils of both tree species were composed mainly of monoterpene hydrocarbons, among which limonene, α‐ and β‐pinene were the major, but in different proportions in the examined conifer essential oils. The levorotary form of chiral monoterpene molecules was predominant over the dextrorotary form. The composition of oils from P. pungens seeds and cones was similar, while the hydrodistilled oils of P. orientalis seeds and cones differed from each other, mainly by a higher amount of oxygenated derivatives of monoterpenes and by other higher molar mass terpenes in seed oil. The essential oils showed mild antimicrobial action, however P. orientalis cone oil exhibited stronger antimicrobial properties against tested bacterial species than those of P. pungens. Effects of the tested cone essential oils on human skin fibroblasts and microvascular endothelial cells (HMEC‐1) were similar: in a concentration of 0 – 0.075 μl/ml the oils were rather safe for human skin fibroblasts and 0 – 0.005 μl/ml for HMEC‐1 cells. IC₅₀ value of Picea pungens oils was 0.115 μl/ml, while that of Picea orientalis was 0.105 μl/ml. The value of IC₅₀ of both oils were 0.035 μl/ml for HMEC‐1 cells. The strongest effect on cell viability had the oil from Picea orientalis cones, while on DNA synthesis the oil from Picea pungens cones.     

Chemical Composition of Volatiles; Antimicrobial,Antioxidant and Cholinesterase Inhibitory Activity of Chaerophyllum aromaticum L. (Apiaceae) Essential Oils and Extracts

The present study reports the chemical composition of the headspace volatiles (HS) and essential oils obtained from fresh Chaerophyllum aromaticum root and aerial parts in full vegetative phase, as well as biological activities of their essential oils and MeOH extracts. In HS samples, the most dominant components were monoterpene hydrocarbons. On the other hand, the essential oils consisted mainly of sesquiterpenoids, representing 73.4% of the root and 63.4% of the aerial parts essential oil. The results of antibacterial assay showed that the aerial parts essential oil and MeOH extract have no antibacterial activity, while the root essential oil and extract showed some activity. Both of the tested essential oils exhibited anticholinesterase activity (47.65% and 50.88%, respectively); MeOH extract of the root showed only 8.40% inhibition, while aerial part extract acted as an activator of cholinesterase. Regarding the antioxidant activity, extracts were found to be more effective than the essential oils.     

Chemical Composition and Antimicrobial Activity of Essential Oils from the Aerial Parts of Asteriscus graveolens (Forssk.) Less. and Pulicaria incisa (Lam.) DC.: Two Asteraceae Herbs Growing Wild in the Hoggar

In recent years, antimicrobial activities of essential oils have been intensively explored, mainly in researching and developing new antimicrobial agents to overcome microbial resistance. The present study investigates the chemical composition and antimicrobial activities of essential oils obtained from two Asteraceae: Asteriscus graveolens (Forssk .) Less . and Pulicaria incisa (Lam .) DC. Chemical analysis was performed using a combination of capillary GC‐FID and GC/MS analytical techniques. The major component of Asteriscus graveolens were cis‐chrysanthenyl acetate (31.1%), myrtenyl acetate (15.1%), and kessane (11.5%), while for Pulicaria incisa the main components were chrysanthenone (45.3%) and 2,6‐dimethylphenol (12.6%). The oils obtained from the aerial parts were tested against sixteen microbial strains by agar well diffusion technique and dilution methods and showed minimum inhibitory concentrations (MIC) in the range of 19 – 1250 μg/ml. A good antibacterial activity against a common nosocomial pathogen, Acinetobacter baumanniiATCC 19606 was observed, especially from Pulicaria incisa essential oil, with a MIC value up to 19 μg/ml. These results give significant information about the pharmacological activity of these essential oils, which suggest their benefits to human health, having the potential to be used for medical purposes.     

Essential Oils as Biocides for the Control of Fungal Infections and Devastating Pest (Tuta absoluta) of Tomato (Lycopersicon esculentum Mill.)

Thymus capitatus and Tetraclinis articulata essential oils as well their major components (carvacrol and α‐pinene) were evaluated for their antifungal and insecticidal activities. Both oils showed good in vitro antifungal activity against Fusarium oxysporum, Aspergillus niger, Penicillium sp., Alternaria alternata, and Botrytis cinerea, the fungi causing tomato rot. In vivo results indicate the efficacies of both essential oils and carvacrol of reduce postharvest fungal pathogens, such as B. cinerea and Al. alternata that are responsible of black and gray rot of tomato fruit. Disease incidence of Al. alternata and B. cinerea decreased on average from 55% to 80% with essential oil of Th. capitatus and pure carcvacrol, while Te. articulata essential oil exhibited inhibition of fungal growth of 55% and 25% against Al. alternata and B. cinerea, respectively, with concentration of 0.4 μl/l air. The insecticidal activity of Th. capitatus and Te. articulata essential oils exhibited also a good insecticidal activity. At the concentration of 0.2 μl/ml air, the oils caused mortality over 80% for all larval stages of Tuta absoluta and 100% mortality for the first‐instar after 1.5 h only of exposure. α‐Pinene presented lower insecticidal and antifungal activities compared to essential oils of Th. capitatus, Te. articulata and pure carvacrol. Thus, these essential oils can be used as a potential source to develop control agents to manage some of the main pests and fungal diseases of tomato crops.     

Chemical composition,insecticidal and biochemical effects of Melaleuca alternifolia essential oil on the Helicoverpa armigera

Pesticide resistance has developed as a result of long‐term and extensive use of chemical pesticides. Essential oils from aromatic plants may provide a new and safe alternative to conventional insecticides. In this study, the insecticidal activities of the essential oil of Melaleuca alternifolia and their chemical constituents against Helicoverpa armigera Hubner were investigated, and the underlying mechanisms were studied. The essential oil showed distinct antifeedant (AFC₅₀ = 8.93 mg/ml) and good contact (LD₅₀ = 50.28 μg/larva) activities against H. armigera at 24 hr. Ten chemical components were identified using a gas chromatograph/mass spectrometer, and mainly included terpinen‐4‐ol (40.09%), γ‐terpinene (21.85%), α‐terpinene (11.34%), α‐terpineol (6.91%), α‐pinene (5.86%), terpinolene (3.24%) and 1,8‐cineole (1.83%). Among them, five components were determined and results showed that these constituents possessed obvious antifeedant activities. The activities of acetylcholinesterase and glutathione S‐transferase were notably inhibited by the essential oil, as compared with the control, with strong dose‐ and time‐dependent effects. The results provide a basis for their development and utilization in the control of insects in the future.     

Chemical Composition and Biological Investigations of Eryngium triquetrum Essential Oil from Algeria

The chemical composition, antibacterial and antioxidant activities of the essential oil obtained from Eryngium triquetrum from Algeria were studied. The chemical composition of sample oils from 25 locations was investigated using GC‐FID and GC/MS. Twenty‐four components representing always more than 87% were identified in essential oils from total aerial parts of plants, stems, flowers and roots. Falcarinol is highly dominant in the essential oil from the roots (95.5%). The relative abundance of falcarinol in the aerial parts correlates with the phenological stages of the plant. Aerial parts of E. triquetrum produce an essential oil dominated by falcarinol during the early flowering stage, and then there is a decrease in falcarinol and rebalancing of octanal during the flowering stage. To our knowledge, the present study is the first report of the chemical composition of E. triquetrum essential oil. Evaluation of the antibacterial activity by means of the paper disc diffusion method and minimum inhibitory concentration assays, showed a moderate efficiency of E. triquetrum essential oil. Using the DPPH method, the interesting antioxidant activity of E. triquetrum essential oil was established. These activities could be attributed to the dominance of falcarinol. The outcome of our literature search on the occurrence of falcarinol in essential oils suggests that E. triquetrum from Algeria could be considered as a possible source of natural falcarinol.     

Chemical Composition,Antimicrobial and Insecticidal Activities of Flowers Essential Oils of Alpinia zerumbet (Pers.) B.L.Burtt & R.M.Sm. from Martinique Island

Alpinia species, used as ornamental plants and flavoring agents, are renowned for their therapeutic properties and their subsequent use in traditional medicines throughout the world. Alpinia zerumbet (Pers .) B.L.Burtt & R.M.Sm . is the most common Alpinia species encountered in Martinique. Several essential oils (EOs) obtained by hydrodistillation of A. zerumbet flowers collected in various locations on the island at different seasons were analysed to evaluate the influence of the collection period and area on the EOs’ chemical compositions and to assess their bioactivity. A combination of GC‐FID and GC/MS techniques was used to examine the volatile constituents, leading to the identification of a total of 71 components accounting for 97.8 – 99.3% of the respective total GC‐FID areas: among them, nineteen compounds were characterized for the first time in A. zerumbet EOs. The antimicrobial activity of these EOs was assessed against eight bacterial, yeast and fungal strains and two multi‐resistant strains: some significant bacteriostatic and fungistatic activities of A. zerumbet flower oils were evidenced. Finally, an interesting insecticidal activity of the flower EO was highlighted for the first time against Aedes aegypti.     

Hydrosols evaluation in pest control: insecticidal and settling inhibition potential against Myzus persicae (Sulzer)

The hydrosols are by‐products derived during the extraction of essential oils. Although essential oils have been widely evaluated for their insecticidal activities, the possible use of hydrosols in pest control has been almost unknown. The effects of the hydrosols of Origanum majorana (marjoram), Mentha pulegium (pennyroyal), and Melissa officinalis (lemon balm) on the survival and settling behaviour of the aphid pest Myzus persicae were investigated. The hydrosols were isolated using Clevenger hydrodistillation (i) with conventional heating (HD) and (ii) assisted by microwaves (MWHD). GC‐MS analysis showed that the volatiles occurring in the hydrosols were similar between the two techniques. Hydrosols were assayed for possible settling inhibitory effects on M. persicae in Petri dishes (15 cm diameter). In each dish, a sprayed together with an unsprayed eggplant leaf piece was placed. An adult aphid <24 h old was released on the treated leaf and its path length was recorded during the initial 10 min. Then, its position (on the treated or untreated leaf) was recorded 10, 20, 30, 60 min and 24 h after spraying. M. officinalis HD hydrosol resulted in fourfold increase of the path length compared with the control (deionized water). The last observation (24 h) revealed that M. officinalis and M. pulegium HD hydrosols had the strongest inhibitory effect. Additionally, O. majorana hydrosols caused 10–15% aphid mortality after 24 h. In this study, the wider use of the MWHD technique is further supported as in addition to its well‐known advantages (i.e. shorter distillation time, less energy consumption), the effects of the hydrosols produced are comparable to those obtained by HD. Most importantly, the results clearly showed that the potential of hydrosols in pest control ought not to be ignored and should attract the interest of future studies.     

Cytotoxic Essential Oils from Eryngium campestre and Eryngium amethystinum (Apiaceae) Growing in Central Italy

Eryngium campestre and E. amethystinum are thorny herbs belonging to the Apiaceae family and spontaneously growing in stony pastures and dry meadows, preferentially on calcareous substrates. In the Mediterranean countries, these plants have been used as a food or traditional remedies to treat various ailments. In the present work, we have analyzed the chemical composition of the essential oils distilled from the aerial parts by GC‐FID and GC/MS, and evaluated their cytotoxic effects on a panel of human cancer cells, namely A375 (human malignant melanoma), MDA‐MB 231 cells (human breast adenocarcinoma), and HCT116 cells (human colon carcinoma), by the MTT assay. Furthermore, the Eryngium essential oils were evaluated for antioxidant and acetylcholinesterase (AChE) activities. The two essential oils were rich in sesquiterpene hydrocarbons, with germacrene D as the major compound, accompanied by allo‐aromadendrene, β‐elemene, spathulenol, and ledol. They turned out to be highly cytotoxic on the tumor cells, with IC₅₀ values (1.65 – 5.32 and 1.57 – 2.99 μg/ml for E. amethystinum and E. campestre, respectively) comparable or close to those of the anticancer drug cisplatin. The E. amethystinum essential oil exhibited a moderate antioxidant activity, whereas that of E. campestre a weak AChE inhibition.     

Let them eat termites—prey‐baiting provides effective control of Argentine ants,Linepithema humile,in a biodiversity hotspot

Invasive ants threaten biodiversity, ecosystem services and agricultural systems. This study evaluated a prey‐baiting approach for managing Argentine ants in natural habitat invaded by Argentine ants. Blackmound termites (Amitermes hastatus) were topically exposed to fipronil and presented to Argentine ants (Linepithema humile). In laboratory assays, L. humile colonies were offered fipronil‐treated termites within experimental arenas. The termites were readily consumed, and results demonstrate that a single termite topically treated with 590 ng fipronil is capable of killing at least 500 L. humile workers in 4 days. Field studies were conducted in natural areas invaded by L. humile. Fipronil‐treated termites scattered within experimental plots provided rapid control of L. humile and ant densities throughout the treated plots declined by 98 ± 5% within 21 days. Results demonstrate that the prey‐baiting approach is highly effective against L. humile and may offer an effective alternative to traditional bait treatments. Furthermore, prey‐baiting offers environmental benefits by delivering substantially less toxicant to the environment relative to current control methods which rely on commercial bait formulations and may offer greater target specificity.     

Chemical Composition and Antioxidant Activity of Essential Oils and Methanol Extracts of Different Parts from Juniperus rigida Siebold & Zucc.

The chemical composition and antioxidant activity of essential oils and MeOH extracts of stems, needles, and berries from Juniperus rigida were studied. The results indicated that the yield of essential oil from stems (2.5%) was higher than from needles (0.8%) and berries (1.0%). The gas chromatography/mass spectrometer (GC/MS) analysis indicated that 21, 17, and 14 compounds were identified from stems, needles, and berries essential oils, respectively. Caryophyllene, α‐caryophyllene, and caryophyllene oxide were primary compounds in both stems and needles essential oils. However, α‐pinene and β‐myrcene mainly existed in berries essential oils and α‐ionone only in needles essential oils. The high‐performance liquid chromatography (HPLC) analysis indicated that the phenolic profiles of three parts exhibited significant differences. Needles extracts had the highest content of chlorogenic acid, catechin, podophyllotoxin, and amentoflavone, and for berries extracts, the content of those compounds was the lowest. Meanwhile, three in vitro methods (DPPH, ABTS, and FRAP) were used to evaluate antioxidant activity. Stems essential oil and needles extracts exhibited the powerful antioxidant activity than other parts. This is the first comprehensive study on the different parts of J. rigida. The results suggested that stems and needles of J. rigida are useful supplements for healthy products as new resources.     

Chemical Variability,Antioxidant and Antifungal Activities of Essential Oils and Hydrosol Extract of Calendula arvensis L. from Western Algeria

The chemical composition of the essential oils and hydrosol extract from aerial parts of Calendula arvensis L. was investigated using GC‐FID and GC/MS. Intra‐species variations of the chemical compositions of essential oils from 18 Algerian sample locations were investigated using statistical analysis. Chemical analysis allowed the identification of 53 compounds amounting to 92.3 – 98.5% with yields varied of 0.09 – 0.36% and the main compounds were zingiberenol 1 (8.7 – 29.8%), eremoligenol (4.2 – 12.5%), β‐curcumene (2.1 – 12.5%), zingiberenol 2 (4.6 – 19.8%) and (E,Z)‐farnesol (3.5 – 23.4%). The study of the chemical variability of essential oils allowed the discrimination of two main clusters confirming that there is a relation between the essential oil compositions and the harvest locations. Different concentrations of essential oil and hydrosol extract were prepared and their antioxidant activity were assessed using three methods (2,2‐diphenyl‐1‐picrylhydrazyl, Ferric‐Reducing Antioxidant Power Assay and β‐carotene). The results showed that hydrosol extract presented an interesting antioxidant activity. The in vitro antifungal activity of hydrosol extract produced the best antifungal inhibition against Penicillium expansum and Aspergillus niger, while, essential oil was inhibitory at relatively higher concentrations. Results showed that the treatments of pear fruits with essential oil and hydrosol extract presented a very interesting protective activity on disease severity of pears caused by P. expansum.     

Differential Cytotoxic Activity of Essential Oil of Lippia citriodora from Different Regions in Morocco

The aim of this work was to investigate the cytotoxic effect of the essential oil of dried leaves of Lippia citriodora (H.B. & K.) harvested in different regions of Morocco. This effect was evaluated against the P815 murine mastocytoma cell line using the MTT assay. Interestingly, this work demonstrated for the first time that these essential oils exhibited a strong cytotoxic activity against the P815 cell line, with IC₅₀ values ranging from 7.75 to 13.25 μg/ml. This cytotoxicity began early and increased in a dose‐ and time‐dependent manner. The chemical profile of these essential oils was analyzed by gas chromatography coupled to mass spectrometry. Importantly, the difference in terms of major components’ contents was not significant suggesting probably that the differential cytotoxicity between these essential oils could be attributed to the difference in the content of these essential oils in minor compounds, which could interact with each other or with the main molecules. Finally, this study demonstrated for the first time that essential oils of L. citriodora from different regions in Morocco induced apoptosis against P815 tumor cell line.     

Chemical Composition and Spectrum of Insecticidal Activity of the Essential Oils of Ocimum gratissimum L. and Cymbopogon citratus Stapf on the Main Insects of the Cotton Entomofauna in Côte d'Ivoire

Among the alternatives to environmentally toxic and socio-economically unacceptable chemical pesticides, essential oils from Ocimum gratissimum and Cymbopogon citratus were tested on the main pests and beneficial insects of the cotton plant in Côte d′Ivoire. After extraction and chemical analysis of the essential oils, field trials were carried out using a Fisher block system with three treatment repetitions where their effects compared with those of a registered synthetic insecticide (IBIS A 52 EC). Foliar applications of the products were carried out in accordance with the cotton plant protection extension programme in Côte d′Ivoire from the 45th to the 115th day after plant emergence, with one application every fortnight. Twenty-three and forty compounds representing about 96 and 99 % of the oil composition of O. gratissimum and C. citratus respectively were elucidated. The most abundant compounds were p-cymene and thymol (O. gratissimum) and myrcene, neral and geranial (C. citratus). The essential oil of O. gratissimum at concentrations of 2 and 5 % showed insecticidal activity on all pests (biting-sucking and carpophagous), except the phyllophagous Syllepte derogata. C. citratus, at a low concentration (1 %), was particularly toxic to whiteflies (Bemisia tabaci), however, it favoured the action of beneficial insects, specifically black ants and ladybirds in the cotton plots, unlike the chemical product. EO of O. gratissimum (1.60 and 4.62 mg GALAE/g, respectively) and C. citratus (2.26 and 2.78 mg GALAE, respectively) exhibited also significant acetyl and butyryl cholinesterase inhibitors. Insecticide formulations based on the essential oils of O. gratissimum and C. citratus offer favourable prospects for their use in cotton cultivation as an alternative to chemical pesticides.     

Influence of Morphological Variability and Habitat on the Chemical Composition of Essential Oils of an Algerian Endemic Origanum Species (Origanum floribundum Munby)

The genus Origanum L. (Lamiaceae) enjoys a socioeconomic interest and constitutes one of the most popular spices. In the literature, the study of this taxon is limited mainly to the chemical composition, antimicrobial, antifungal, and antioxidant activities of the essential oils. In Algeria, few works have been done in this area, including the endemic and rare species: Origanum floribundum Munby . In this study, our contribution highlights the influence of the ecological parameters and of the variation of morphological traits on the chemical composition and the antioxidant activity of the essential oils of six populations. The major oils constituents are carvacrol, γ‐terpinene, and p‐cymene with carvacrol predominance (31.8 – 60.8%) in over five populations (MS1 – MS4 and MS6). However, the population of Ain Terraeur (MS5) of which individuals present a foliar polymorphism, distinguishes itself by p‐cymene predominance (42.6%). This would denote a new chemotype and/or variety which seem well differentiated on the dendrogram of the Ascending Hierarchical Classification (A.H.C) and its foliar morphology. The antioxidant activity of the six samples evaluated by the scavenging activity of free radicals DPPH^? and ABTS^?+ showed a potent efficiency for the sample with foliar polymorphism population (IC₅₀ = 51.6 ± 0.31 and 12.71 ± 0.37 μg/ml, respectively).     

Essential Oil Variability in Natural Populations of Artemisia campestris (L.) and Artemisia herba‐alba (Asso) and Incidence on Antiacetylcholinesterase and Antioxidant Activities

The intraspecific variability of Artemisia herba‐alba and A. campestris essential oils and the evaluation of their antioxidant and antiacetylcholinesterase activities were determined. Artemisia herba‐alba essential oil was found rich in camphor (19.61%), α‐thujone (19.40%), β‐thujone (9.44%), chrysanthenone (9.26%), and trans‐sabinyl acetate (8.43%). The major compounds of A. campestris essential oil were germacrene D (16.38%), β‐pinene (16.33%), and limonene (9.17%). Significant variation in the essential oil composition was observed among populations of each species. The divergence between populations was attributed to the variation of some climatic factors such as altitude, annual rainfall, winter cold stress, summer precipitation, summer drought stress, evapotranspiration, and humidity. Artemisia herba‐alba and A. campestris essential oils exhibited promising antioxidant and antiacetylcholinesterase activities. The level of activity varied significantly according to the species and the essential oil. The highest scavenging activity (IC₅₀ = 0.14 mg/ml) and the uppermost capacity to prevent β‐carotene bleaching (IC₅₀ = 0.10 mg/ml) characterized A. campestris from population 6. A. campestris population 3 possessed the uppermost ability to reduce ferric ions (450.7 μmol Fe²⁺/g EO). The population 2 of A. campestris showed the strongest antiacetylcholinesterase activity (IC₅₀ = 0.02 mg/ml). The variation of these activities between the essential oils was explained by their composition differences.