Identification of insecticidal constituents of the essential oil of Curcuma wenyujin rhizomes active against Liposcelis bostrychophila Badonnel

CwJAZ4/9 negatively regulates jasmonate-mediated biosynthesis of terpenoids through interacting with CwMYC2 and confers salt tolerance in Curcuma wenyujin

Plant JASMONATE ZIM-DOMAIN (JAZ) genes play crucial roles in regulating the biosynthesis of specialized metabolites and stressful responses. However, understanding of JAZs controlling these biological processes lags due to numerous JAZ copies. Here, we found that two leaf-specific CwJAZ4/9 genes from Curcuma wenyujin are strongly induced by methyl-jasmonate (MeJA) and negatively correlated with terpenoid biosynthesis. Yeast two-hybrid, luciferase complementation imaging and in vitro pull-down assays confirmed that CwJAZ4/9 proteins interact with CwMYC2 to form the CwJAZ4/9-CwMYC2 regulatory cascade. Furthermore, transgenic hairy roots showed that CwJAZ4/9 acts as repressors of MeJA-induced terpenoid biosynthesis by inhibiting the terpenoid pathway and jasmonate response, thus reducing terpenoid accumulation. In addition, we revealed that CwJAZ4/9 decreases salt sensitivity and sustains the growth of hairy roots under salt stress by suppressing the salt-mediated jasmonate responses. Transcriptome analysis for MeJA-mediated transgenic hairy root lines further confirmed that CwJAZ4/9 negatively regulates the terpenoid pathway genes and massively alters the expression of genes related to salt stress signaling and responses, and crosstalks of multiple phytohormones. Altogether, our results establish a genetic framework to understand how CwJAZ4/9 inhibits terpenoid biosynthesis and confers salt tolerance, which provides a potential strategy for producing high-value pharmaceutical terpenoids and improving resistant C. wenyujin varieties by a genetic approach.

Exploring the chemical characterization and insecticidal activities of Curcuma angustifolia roxb. leaf essential oils against three major stored product insects

Botanical pesticides are safe and widely used in pest management. Curcuma angustifolia belongs to the family Zingiberaceae and is a rhizomatous medicinal herb. Following rhizome harvesting, leaves are discarded as waste. However, they can be effectively utilized by extracting essential oils, which are potential biopesticides. The aim of the study is to evaluate the efficacy of the leaf essential oil of Curcuma angustifolia as a potential biopesticide against three stored grain pests, Lasioderma serricorne, Tribolium castaneum, and Callasobruchus chinensis, by their contact, fumigant, and repellent activities. The leaves yield 0.39 ± 0.02 % of oil by hydrodistillation. GC-MS/MS characterization identified curzerenone (18.37 %), geranyl-p-cymene (17.32 %), α-elemenone (13.59 %), eucalyptol (7.58 %) as the main constituents. When exposed to different concentrations of C. angustifolia oil, the test insect displayed noticeably high repellency rates. It also showed better contact toxicity at 24 h, LC50 = 0.22 mg/cm2 for cigarette beetle, LC50 = 0.64 mg/cm2 for red flour beetle, LC50 = 0.07 mg/cm2 for pulse beetle) and fumigation toxicities (LC50 = 10.8 mg/L air at 24 h, for cigarette, LC50 = 29.5 mg/L air for red flour beetle, LC50 = 7.9 mg/L air for pulse beetle). Additionally, a phytotoxicity study was done on paddy seeds, and the results showed no effect on seed germination or seedling growth. It was evident from this study that C. angustifolia oil from waste leaves can be utilized as a botanical pesticide to manage the adults of these storage pests.

Phytochemical profiling of the essential oils from three Curcuma species and their in vitro and in silico dengue protease inhibition activity

The chemical compositions, in vitro and in silico anti-dengue activity of the essential oils of the rhizomes of Curcuma longa Linn., C. aeruginosa Roxb., and C. xanthorrhiza Roxb. had been investigated. The C. longa oil was mainly composed of ar-turmerone (54.0%) and curlone (17.7%), while the C. aeruginosa oil was rich in curzerenone (23.4%), 1,8-cineole (21.2%), and camphor (7.1%). Xanthorrhizol (21.6%), β-curcumene (19.5%), ar-curcumene (14.2%), and camphor (9.2%) were the major compounds in the C. xanthorrhiza oil. Among the oils, the C. longa oil was found to be the most active NSB-NS3 protease inhibitor (IC50 1.98 μg/mL). PLS biplot disclosed that the essential oils were classified into three separated clusters based on their characteristic chemical compositions, with C. longa positioned closest to the in vitro anti-dengue activity. Four compounds from the C. longa oil have both hydrogen and hydrophobic bonds that could be responsible for the DENV-2 NS2B-NS3 inhibitory effect.

Phytochemical Investigation, In Silico/In Vivo Analgesic, and Anti-inflammatory Assessment of the Egyptian Cassia occidentalis L

Cassia occidentalis L., from Fabaceae family phytochemical screening, revealed several biologically active principles mainly flavonoids and anthraquinones. GLC analysis of the lipoidal matter afforded 12 hydrocarbons: 9-dodecyl-tetradecahydro-anthracene (48.97 %), 9-dodecyl-tetradecahydro-phenanthrene (14.43 %), and 6 sterols/triterpenes: iso-jaspisterol (11.99%) and fatty acids were palmitic acid (50 %), and Linoleic acid (16.06%). Column chromatography led to the isolation of fifteen compounds (1-15), elucidated using spectroscopic evidence. First report of undecanoic acid (4) from the family Fabaceae, while p-dimethyl amino-benzaldehyde (15) was first time isolated from a natural origin. Eight compounds isolated for the first time from C. occidentalis L.; β-amyrin (1), β-sitosterol (2), stigmasterol (3), camphor (5), lupeol (6), chrysin (7), pectolinargenin (8), and 1, 2, 5-trihydroxy anthraquinone (14) besides five known compounds previously isolated; apigenin (9), kaempferol (10), chrysophanol (11), physcion (12), and aloe-emodin (13). In-vivo evaluation of anti-inflammatory and analgesic effects of C. occidentalis L. extracts where the n-butanol and total extracts showed the highest activities. The percentage of the inhibitory effect of the n-butanol extract was 29.7 at a dose of 400 mg/Kg. Furthermore, identified phytoconstituents were docked into the active sites of enzymes nAChRs, COX-1, and COX-2 to evaluate binding affinity. Phyto-compounds Physcion, aloe-emodin, and chrysophanol were found to have a good affinity for targeted receptors compared to co-crystalized inhibitors, validating the analgesic and anti-inflammatory effects of the phytochemicals.

Chemical Diversity and Anti-Insect Activity Evaluation of Essential Oils Extracted from Five Artemisia Species

As a source of aromatic plants, the genus Artemisia has long been considered to have the potential to develop plant pesticides. In this study, components of essential oils from A. dalai-lamae, A. tangutica, A. sieversiana, A. tanacetifolia and A. ordosica were identified by GC-MS. A total of 56 constituents were analysed, and each species consisted of 9 to 24 constituents. Principle component analysis (PCA) revealed that A. dalai-lamae, A. tangutica and A. tanacetifolia are characterised by monoterpene hydrocarbons and oxygenated monoterpenes. Hierarchical cluster analysis (HCA) showed the most remarkable similarity between A. sieversiana and A. ordosica, but the similarity was still lower than 50%. Contact toxicity and repellency of essential oils were evaluated by bioassays; A. ordosica oil exhibited the most substantial contact toxicity (LD50 = 52.11 μg/cm2) against Liposcelis bostrychophila, while A. tangutica oil showed the most potent contact toxicity (LD50 = 17.42 μg/adult) against Tribolium castaneum. Except for A. dalai-lamae, the other four species showed the same level (p > 0.05) of repellent activity as the positive control against both pests at high concentrations. The results indicated that these five Artemisia species had high chemical diversity and great potential to be developed into more effective and environmentally friendly anti-insect agents.

Transcriptome sequencing and functional characterization of new sesquiterpene synthases from Curcuma wenyujin

Tubers of Curcuma wenyujin are rich in essential oils, mainly various sesquiterpenes, showing antibacterial, anti-viral and anti-tumor effects. However, the molecular mechanism of C. wenyujin is deficient and related sesquiterpene synthases are still unclear. In this study, the transcriptome data of tubers and leaves from C. wenyujin were obtained and assembled into 78 092 unigenes. Of them, 244 unigenes were predicted to be involved in terpenoid biosynthesis while 131 unigenes were categorized as the "Terpenoid backbone biosynthesis" (TBB) term. Twenty-two unigenes possessed terpene synthase domain; five were predicted to be sesquiterpene synthases. Of the 208 unigenes annotated as cytochromes P450, 8 unigenes with full-length coding sequences were part of the CYP71 clade that primarily may perform hydroxylations of specialized metabolites. Furthermore, Ten DEGs related to the C5 precursor supply and sesquiterpene synthesis were validated by Real-time PCR; that showed a close correspondence with transcriptome sequence. A novel germacrene B synthase (CwGBS) and α-santalene synthase (CwSS) were identified in metabolically engineering E. coli. This study provided the first de novo transcriptome comparative analysis of leaf and tuber tissues from C. wenyujin, aiming to understand genetic mechanisms. Key genes involved in the biosynthesis of sesquiterpene will help for revealing the underlying mechanisms of C. wenyujin.

Bioactivity-guided discovery of quality control markers in rhizomes of Curcuma wenyujin based on spectrum-effect relationship against human lung cancer cells

BACKGROUND

Due to the diversity of the ingredients, the complexity of the mechanism of action, the uncertainty of the effective ingredients, coupled with the multiple species and multiple growing areas, the quality control (QC) of Traditional Chinese Medicines (TCMs) is challenging. Discovering and identifying effective compounds from the complex extracts of TCMs and then establishing a scientific QC method is the key to the holistic QC of TCMs.

PURPOSE

To develop an anti-lung-cancer-guided spectrum-effect relationship approach for the discovery of QC markers of the rhizome of Curcuma wenyujin (WEZ) and establish a bioactive compounds-based holistic QC method.

METHODS

The chemical profiling of the volatile oil (WVO) from 42 batches of WEZ collected from different growing areas was performed by GC-MS. The anti-lung cancer activity of different WVO samples was determined by CCK-8 assay against human lung cancer cells (A549). The apoptosis and cell cycle analysis under different concentrations of WVO were detected by flow cytometry. SIMCA-P software was used to perform multivariate statistical analysis on the chemical composition of different WVO samples and to find the different components. Active compounds were screened using a PLSR model of the spectrum-effect relationship. Bioactive compounds-based fingerprint and quantification of the leading bioactive compounds were developed by GC-MS and GC-FID, respectively.

RESULTS

Seventy-eight compounds were detected in WVO and 54 were successfully identified. The multivariate statistical analysis uncovered that WVO components and the anti-A549 activity of WVO at the concentration of 60 nl/ml differ greatly according to the origin of the plant. The WVO at the concentration of 60 nl/ml (IC₅₀) increased A549 cells apoptosis significantly with late and early apoptosis of 15.61% and 7.80%, and the number of cells in the G2/M phase were also increased significantly under this concentration. The spectrum-effect relationship analysis revealed that 44 compounds were positively correlated with their activities, and the result was verified by A549 cell viability assay. Sixteen positively correlated compounds were further selected as QC markers according to their relative amount > 0.5% and anticancer activity. Finally, the 16 QC markers-based GC-MS fingerprint was established to holistically control the quality of WEZ, and a GC-FID method was developed for the quantification of leading bioactive compounds, β-elemene and β-caryophyllene.

CONCLUSION

Based on an anti-lung-cancer-guided spectrum-effect relationship approach, the bioactive compounds-based holistic QC method was successfully developed for WEZ, which could provide a valuable reference for the QC of TCMs.

Transmission modes of COVID-19 disease pandemic in the light of ancient wisdom of Ayurveda medicine: a review

Human-to-human transmission of the Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) occurs most often when people are in the incubation stage of the disease or are carriers and have no symptoms. SARS-CoV-2 transmission on different levels showed that the cold and dry climate, hot wind and relative humid wind, maximum wind speed, turbulent wind, intensified recirculating flow were causing transmission higher than factors. The role of environmental factors described in Ayurveda like air, water, soil, season, frequent earthquakes, sunlight exposure, frequent thunderstorm with lightening, and factors from arthropods were revalidated in perspective of COVID-19 transmission. The authors searched the information regarding epidemic diseases in Ayurveda textbooks. Pubmed, Science Direct, Wikipedia, Elsevier, Lancet, and Springer were approached for the latest knowledge relating to SARS-CoV-2 and COVID-19. Google Scholar search engine was thoroughly checked upon for scientific evidence regarding the Ayurveda drugs. Various environmental factors like soil, air, water, frequent earthquake disasters, wildlife animals, aquatic birds, space, inevitable disastrous factors, weather or seasonal hazards, violent thunderstorm with lightning, intermediate hosts, sunlight exposure etc. were considered for their role in the genesis of the disease. The Ayurvedic concepts behind the etiology and development of epidemics are the same as modern epidemiological theories. The mysteries of many aspects of the current pandemic might be deciphered by traditional medicine knowledge and thus adding upon to the integrative medicine concept.

Germacrone: A Potent Secondary Metabolite with Therapeutic Potential in Metabolic Diseases, Cancer and Viral Infections

Natural products, an infinite reserve of bioactive molecules, will continue to serve humans as an important source of therapeutic agents. Germacrone is a bioactive natural compound found in the traditional medicinal plants of family Zingiberaceae. This multifaceted chemical entity has become a point of focus during recent years due to its numerous pharmacological applications, e.g., anticancer, anti-inflammatory, antiviral, antioxidant, anti-adipogenic, anti-androgenic, antimicrobial, insecticidal, and neuroprotective. Germacrone is an effective inducer of cell cycle arrest and apoptosis in various cancers (breast, brain, liver, skin, prostate, gastric, and esophageal) via modulation of different cell signaling molecules and pathways involved in cancer proliferation. This is the first report highlighting the wide spectrum of pharmacological activities exhibited by germacrone. The reported data collected from various shreds of evidences recommend that this multifaceted compound could serve as a potential drug candidate in the near future.

Transcriptome analysis of Curcuma wenyujin from Haikou and Wenzhou, and a comparison of the main constituents and related genes of Rhizoma Curcumae

For more than a thousand years, Rhizoma Curcumae (known as E zhu), a Chinese herbal medicine, has been used to eradicate blood stasis and relieve aches. The plant Curcuma wenyujin, which is grown primarily in Wenzhou, China, is considered the best source of Rhizoma Curcumae. In this study, we sought to ascertain differences in transcript profiles of C. wenyujin grown in traditional (Wenzhou) and recently established (Haikou) production areas based on Illumina and RNA (RNA-seq) sequencing. We also examined differences in the main components of the volatile oil terpene; curcumin, polysaccharide, and starch constituents and related genes in the corresponding pathways, in C. wenyujin cultivated in the two production areas. We accordingly found that the essential oil (2.05%), curcumin (1.46%), and polysaccharide (8.90%) content in Wenzhou rhizomes was higher than that in the rhizomes of plants from Haikou (1.60%, 0.91%, and 6.15%, respectively). In contrast, the starch content of Wenzhou rhizomes (17.0%) was lower than that of Haikou rhizomes (23.8%). Furthermore, we detected significant differences in the oil components of Haikou and Wenzhou rhizomes, with curzerene (32.34%), curdione (21.35%), and germacrene B (9.39%) being the primary components of the essential oil derived from Wenzhou rhizomes, and curzerene (20.13%), curdione (14.73%), and cineole (9.76%) being the main constituents in Haikou rhizomes. Transcriptome and qPCR analyses revealed considerable differences in gene expression between Wenzhou and Haikou rhizomes. The expression of terpene, curcumin, and polysaccharide pathway-related genes in Wenzhou rhizomes was significantly up-regulated, whereas the expression of starch-associated genes was significantly down-regulated, compared with those in Haikou rhizomes. Difference in the content of terpene, curcumin, polysaccharides, and starch in rhizomes from the two production areas could be explained in terms of differences in expression of the related genes.

Psocoptera (Psocodea) in Spice and Medicinal Dehydrated Plants Sold in Bulk in a Big Metropolis in Brazil

In Brazil, the production of dried herbs and condiments is on a smaller scale than that of its other agricultural sectors; however, it has been growing and attracting new producers, driven by the stimulus to provide healthy and gourmet foods. Insects in the order Psocoptera may cause loss of quality in such dried foods, and because of their small size, these insects can be easily transported by commerce. No information is available on how these insects may be entering Brazil via the importation of dehydrated products or how they may be exported with the increase of Brazilian dried food production. To examine these issues, 10 sites offering foods sold in bulk within the city of São Paulo, Brazil, were chosen. At each food site, the same 20 species of aromatic spice and medicinal dehydrated plants were purchased. In the laboratory, they were analyzed for the presence of insects immediately after acquisition. After removal of nymphal and adult psocopterans, the plants were kept in vials under environmental conditions to be investigated 40 days later. Psocopterans were found in 12 of the 20 dehydrated plant species. Eleven psocopteran species were recorded, including six species of unidentified Liposcelis. Liposcelis bostrychophila (Badonnel) was found in all samples with the presence of insects. The other frequent species were Liposcelis entomophila (Enderlein) and Lepinotus reticulatus (Enderlein). Lepinotus reticulatus constitutes the first record in Brazil. In total, 1,021 insects were recorded in the evaluation right after purchase, and this number grew to 3,734 individuals recovered 40 days later under laboratory conditions. The data show that in a relatively short period of storage, a population increase occurs that may cause loss of product quality and a decrease in organoleptic properties. Thus, it is necessary to have greater surveillance of the products so that consumers have access to quality dehydrated foods.

Chemical Composition and Biological Activities of Essential Oils of Curcuma Species

Members of the genus Curcuma L. have been used in traditional medicine for centuries for treating gastrointestinal disorders, pain, inflammatory conditions, wounds, and for cancer prevention and antiaging, among others. Many of the biological activities of Curcuma species can be attributed to nonvolatile curcuminoids, but these plants also produce volatile chemicals. Essential oils, in general, have shown numerous beneficial effects for health maintenance and treatment of diseases. Essential oils from Curcuma spp., particularly C. longa, have demonstrated various health-related biological activities and several essential oil companies have recently marketed Curcuma oils. This review summarizes the volatile components of various Curcuma species, the biological activities of Curcuma essential oils, and potential safety concerns of Curcuma essential oils and their components.

Supercritical carbon dioxide extract of Cinnamomum cassia bark: toxicity and repellency against two stored-product beetle species

The extract from Cinnamomum cassia Presl bark was obtained with supercritical CO₂ fluid extraction (SFE). Chemical components of the SFE extract were characterized by GC-MS spectrometry. The repellency and contact toxicity of the SFE extract were evaluated against the adults of Tribolium castaneum and Lasioderma serricorne along with those of its two main compounds. The results of GC-MS analysis indicated that 33 volatile constituents were identified from the extract. The main components included trans-cinnamaldehyde (32.1%), 3,3-dimethylhexane (10.6%) and 2,4-di-tert-butylphenol (7.9%). Testing results showed that the SFE extract had potent contact toxicity against T. castaneum and L. serricorne with LD₅₀ values of 3.96 and 23.89 μg/adult, respectively. LD₅₀ values of trans-cinnamaldehyde against T. castaneum and L. serricorne were 5.78 and 3.24 μg/adult, respectively. Additionally, percentage repellency values of the SFE extract and trans-cinnamaldehyde against T. castaneum and L. serricorne were rather high (PR = 100% and PR > 90%, respectively) at 78.63 and 15.73 nL/cm² at 2 h post-exposure. 2,4-Di-tert-butylphenol showed some repellency against both beetle species. Considering its insecticidal and repellent effects, the SFE extract from C. cassia bark might be used in integrated pest management programs for T. castaneum and L. serricorne.

Contact Toxicity and Repellency of the Essential Oils of Evodia lenticellata Huang and Evodia rutaecarpa (Juss.) Benth. Leaves against Three Stored Product Insects

The essential oils (EOs) extracted from Evodia lenticellata Huang and Evodia rutaecarpa (Juss.) Benth. leaves are screened to evaluate their contact toxicity and repellency towards Tribolium castaneum (Coleoptera: Tenebrionidae), Lasioderma serricorne (Coleoptera: Anobiidae) and Liposcelis bostrychophila (Psocoptera: Liposcelididae) adults. The EOs are obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS). The principal components in the E. lenticellata EO are identified to be caryophyllene oxide (28.5%), β-caryophyllene (23.1%), β-elemene (14.5%), and β-cubebene (4.7%), while the main components of the E. rutaecarpa EO are α-pinene (39.4%), β-elemene (13.5%), α-ocimene (7.6%), and α-selinene (4.0%). These two kinds of EOs and their individual compounds all showed different levels of contact toxicity and repellent activity against three stored-product insects.

Identification of Insecticidal Constituents from the Essential Oil from the Aerial Parts Stachys riederi var. japonica

The essential oil of Stachys riederi var. japonica (Family: Lamiaceae) was extracted by hydrodistillation and determined by GC and GC-MS. A total of 40 components were identified, representing 96.01% of the total oil composition. The major compounds in the essential oil were acetanisole (15.43%), anisole (9.43%), 1,8-cineole (8.07%), geraniol (7.89%), eugenol (4.54%), caryophyllene oxide (4.47%), caryophyllene (4.21%) and linalool (4.07%). Five active constituents (acetanisole, anisole, 1,8-cineole, eugenol and geraniol) were identified by bioactivity-directed fractionation. The essential oil possessed fumigant toxicity against maize weevils (Sitophilus zeamais) and booklice (Liposcelis bostrychophila), with LC₅₀ values of 15.0 mg/L and 0.7 mg/L, respectively. Eugenol and anisole exhibited stronger fumigant toxicity than the oil against booklice. 1,8-Cineole showed stronger toxicity, and anisole as well as eugenol exhibited the same level of fumigant toxicity as the essential oil against maize weevils. The essential oil also exhibited contact toxicity against S. zeamais adults and L. bostrychophila, with LC₅₀ values of 21.8 µg/adult and 287.0 µg/cm², respectively. The results indicated that the essential oil of S. riederi var. japonica and its isolates show potential as fumigants, and for their contact toxicity against grain storage insects.

α-Terpineol, a natural monoterpene: A review of its biological properties

Terpineols are monocyclic monoterpene tertiary alcohols which are naturally present in plant species. There are five common isomers of terpineols, alpha-, beta-, gamma-, delta- and terpinen-4-ol, of which α-terpineol and its isomer terpinen-4-ol are the most common terpineols found in nature. α-Terpineol plays an important role in the industrial field. It has a pleasant odor similar to lilacs and it is a common ingredient in perfumes, cosmetics, and aromatic scents.

In addition, α-terpineol attracts a great interest as it has a wide range of biological applications as an antioxidant, anticancer, anticonvulsant, antiulcer, antihypertensive, anti-nociceptive compound. It is also used to enhance skin penetration, and also has insecticidal properties. This study reviews the relevance of α-terpineol based on scientific findings on Google Scholar, Pubmed, Web of Science, Scopus and Chemical Abstracts.

Collectively, the use of α-terpineol in medicine and in the pharmaceutical industry plays an important role in therapeutic applications. This review will, therefore, support future research in the utilization of α-terpineol.

High toxicity of camphene and γ-elemene from Wedelia prostrata essential oil against larvae of Spodoptera litura (Lepidoptera: Noctuidae)

The development of eco-friendly biopesticides in the fight against agricultural pests is an important challenge nowadays. The essential oil of Wedelia prostrata Hemsl. is known for its multipurpose biological activities in Chinese folk medicine. However, limited efforts attempted to understand the potential insecticidal activity of its main individual constituents and related mechanism of action. In this research, we investigated the insecticidal activity of W. prostrata against the crop pest Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae). Toxicity on 4th instar larvae was assessed after 24 h of exposure. The LC₅₀ and LC₉₀ of the W. prostrata essential oil were 167.46 and 322.12 μg/ml, respectively. GC-MS analyses were carried out to shed light on the oil chemical composition. Main constituents were the monoterpene camphene (9.6%) and the sesquiterpenes γ-elemene (7.6%), α-humulene (6.9%), and (E,E)-α-farnesene (7.3%). The pure constituents were evaluated for their insecticidal activity on S. litura 4th instar larvae. The most toxic molecule was camphene (LC₅₀ = 6.28 μg/ml), followed by γ-elemene, (LC₅₀ = 10.64 μg/ml), α-humulene (LC₅₀ = 12.89 μg/ml), and (E,E)-α-farnesene (LC₅₀ = 16.77 μg/ml). Overall, our experiments highlighted the promising potential of camphene and γ-elemene from W. prostrata essential oil against larvae of S. litura, allowing us to propose these two compounds for the development of newer pesticides in the fight against crop pests. Further studies aimed at evaluating the potential synergy between these two molecules, as well as their stability in field conditions are ongoing.

Efficacy of Compounds Isolated from the Essential Oil of Artemisia lavandulaefolia in Control of the Cigarette Beetle, Lasioderma serricorne

To develop natural product resources to control cigarette beetles (Lasioderma serricorne), the essential oil from Artemisia lavandulaefolia (Compositae) was investigated. Oil was extracted by hydrodistillation of the above-ground portion of A. lavandulaefolia and analyzed using gas chromatography-mass spectrometer (GC-MS). Extracted essential oil and three compounds isolated from the oil were then evaluated in laboratory assays to determine the fumigant, contact, and repellent efficacy against the stored-products’ pest, L. serricorne. The bioactive constituents from the oil extracts were identified as chamazulene (40.4%), 1,8-cineole (16.0%), and β-caryophyllene (11.5%). In the insecticidal activity assay, the adults of L. serricorne were susceptible to fumigant action of the essential oil and 1,8-cineole, with LC₅₀ values of 31.81 and 5.18 mg/L air. The essential oil, 1,8-cineole, chamazulene, and β-caryophyllene exhibited contact toxicity with LD₅₀ values of 13.51, 15.58, 15.18 and 35.52 μg/adult, respectively. During the repellency test, the essential oil and chamazulene had repellency approximating the positive control. The results indicated that chamazulene was abundant in A. lavandulaefolia essential oil and was toxic to cigarette beetles.

Molecular Targets for Components of Essential Oils in the Insect Nervous System-A Review

Essential oils (EOs) are lipophilic secondary metabolites obtained from plants; terpenoids represent the main components of them. A lot of studies showed neurotoxic actions of EOs. In insects, they cause paralysis followed by death. This feature let us consider components of EOs as potential bioinsecticides. The inhibition of acetylcholinesterase (AChE) is the one of the most investigated mechanisms of action in EOs. However, EOs are rather weak inhibitors of AChE. Another proposed mechanism of EO action is a positive allosteric modulation of GABA receptors (GABArs). There are several papers that prove the potentiation of GABA effect on mammalian receptors induced by EOs. In contrast, there is lack of any data concerning the binding of EO components in insects GABArs. In insects, EOs act also via the octopaminergic system. Available data show that EOs can increase the level of both cAMP and calcium in nervous cells. Moreover, some EO components compete with octopamine in binding to its receptor. Electrophysiological experiments performed on Periplaneta americana have shown similarity in the action of EO components and octopamine. This suggests that EOs can modify neuron activity by octopamine receptors. A multitude of potential targets in the insect nervous system makes EO components interesting candidates for bio-insecticides.

Repellency of zerumbone identified in Cyperus rotundus rhizome and other constituents to Blattella germanica

The compounds 1,8-cineole and zerumbone (ZER) from the Cyperus rotundus rhizome along with another 11 previously identified rhizome essential oil constituents and α-humulene, which lacks the only carbonyl group present in ZER, as well as binary mixtures of ZER and seven active compounds were tested for repellency to male B. germanica. The results were compared to N,N-diethyl-3-methylbenzamide (deet). In filter-paper choice tests, ZER was the most repellent compound, and α-humulene was ineffective, which indicates that the α,β-unsaturated carbonyl group of ZER is a prerequisite component for repellency. At 81.5 μg cm⁻², enhanced repellency was produced by binary mixtures of ZER and 1,8-cineole, (+)-dihydrocarvone or (R)-(+)-limonene (70:30, 50:50 and 30:70 ratios by weight). These mixtures were very effective against male B. germanica within 24 h and were more repellent than a single compound or deet alone. The optimum ZER content was determined to be more than 50%. In Ebeling choice box tests at 652.4 μg cm⁻², these compounds and deet resulted in complete repellency to intact male B. germanica, while they exhibited 35–47% repellency to antennectomized male one. Mixtures formulated from the active constituents of the C. rotundus rhizome could be useful as potential repellents for controlling B. germanica.

Proteomic Identification of eEF1A1 as a Molecular Target of Curcumol for Suppressing Metastasis of MDA-MB-231 Cells

Curcumol, a major volatile component in Rhizoma Curcumae, exhibits a potent antimetastatic effect on breast cancer cells. However, its molecular mechanism remains poorly understood. In this study, we employed two-dimensional gel electrophoresis-based proteomics to investigate the cellular targets of curcumol in MDA-MB-231 cells and identified 10 differentially expressed proteins. Moreover, Gene Ontology analysis revealed that these proteins are mainly involved in nine types of cellular components, seven different biological processes, and nine kinds of molecular functions, and 35 pathways (p < 0.05) were enriched by KEGG pathway analysis. Specially, eEF1A1, a well-characterized actin binding protein, draws our attention. Curcumol decreased eEF1A1 expression at both mRNA and protein levels. EEF1A1 expression was shown to be correlated with the invasiveness of cancer cells. Importantly, overexpression of eEF1A1 significantly reversed the inhibition of curcumol regarding the invasion and adhesion of MDA-MB-231 cells (p < 0.05). Together, our data suggest that eEF1A1 may be a potential molecular target underlying the antimetastatic effect of curcumol.

Chemical constituents and biological research on plants in the genus Curcuma

Curcuma, a valuable genus in the family Zingiberaceae, includes approximately 110 species. These plants are native to Southeast Asia and are extensively cultivated in India, China, Sri Lanka, Indonesia, Peru, Australia, and the West Indies. The plants have long been used in folk medicine to treat stomach ailments, stimulate digestion, and protect the digestive organs, including the intestines, stomach, and liver. In recent years, substantial progress has been achieved in investigations regarding the chemical and pharmacological properties, as well as in clinical trials of certain Curcuma species. This review comprehensively summarizes the current knowledge on the chemistry and briefly discusses the biological activities of Curcuma species. A total of 720 compounds, including 102 diphenylalkanoids, 19 phenylpropene derivatives, 529 terpenoids, 15 flavonoids, 7 steroids, 3 alkaloids, and 44 compounds of other types isolated or identified from 32 species, have been phytochemically investigated. The biological activities of plant extracts and pure compounds are classified into 15 groups in detail, with emphasis on anti-inflammatory and antitumor activities.

GC×GC-TOFMS Analysis of Essential Oils Composition from Leaves, Twigs and Seeds of Cinnamomum camphora L. Presl and Their Insecticidal and Repellent Activities

Interest in essential oils with pesticidal activity against insects and pests is growing. In this study, essential oils from different parts (leaves, twigs and seeds) of Cinnamomum camphora L. Presl were investigated for their chemical composition, and insecticidal and repellent activities against the cotton aphid. The essential oils, obtained by hydrodistillation, were analyzed by GC×GC-TOFMS. A total of 96 components were identified in the essential oils and the main constituents found in the leaves and twigs were camphor, eucalyptol, linalool and 3,7-dimethyl-1,3,7-octatriene. The major components found in the seeds were eucalyptol (20.90%), methyleugenol (19.98%), linalool (14.66%) and camphor (5.5%). In the contact toxicity assay, the three essential oils of leaves, twigs and seeds exhibited a strong insecticidal activity against cotton aphids with LC50 values of 245.79, 274.99 and 146.78 mg/L (after 48 h of treatment), respectively. In the repellent assay, the highest repellent rate (89.86%) was found in the seed essential oil at the concentration of 20 μL/mL after 24 h of treatment. Linalool was found to be a significant contributor to the insecticidal and repellent activities. The results indicate that the essential oils of C. camphora might have the potential to be developed into a natural insecticide or repellent for controlling cotton aphids.

Effects of Ethacrynic Acid Addition to Diet on Fitness and Development in the Psocid Liposcelis bostrychophila Badonnel

Fertility life table provides a comprehensive description of arthropod population dynamics by the estimation of parameters about arthropod population growth potential. It can also clarify the sublethal effects of chemicals on insects. Ethacrynic acid (EA), an inhibitor of glutathione S-transferases, is a diuretic compound that has been confirmed to modulate drug resistance in organisms. In this study, the effects of EA on growth and development of Liposcelis bostrychophila Badonnel were investigated in the laboratory to explore the potential possibilities of EA as an active agent to manage insecticide-resistant psocids. The treatment of psocids was obtained by feeding on the routine diet containing 3% EA for three successive generations, and psocids on routine diet served as control. The results indicated that EA possessed some negative effects on the life-table parameters of the psocid in F1 and F2 generations. The addition of EA to diet stunted psocids growth by lengthening development time and increasing mortality with a greater effect in the F2 generation. In the third generation of psocids on EA diet, it seemed there was a return to normal. Psocid fitness was influenced by addition of EA to standard diet. Using rm values, the fitness for EA diet in F1, F2, and F3 compared with the counterpart of routine diet was calculated as 0.80, 0.74, and 0.87, respectively.

Acaricidal activity of compounds from Cinnamomum camphora (L.) Presl against the carmine spider mite, Tetranychus cinnabarinus

BACKGROUND

Tetranychus cinnabarinus (Boisduval) is one of the most important, highly polyphagous pests of a wide range of field and greenhouse crops throughout the world. The control of this mite is still based primarily on the use of synthetic chemical pesticides. In this study, we screened eight plant extracts from China and evaluated the natural compounds showing acaricidal properties from the plant extract, considering their potential use as an alternative to synthetic pesticides.

RESULTS

In bioassay screening assays, the Cinnamomum camphora (L.) Presl extract showed significantly greater acaricidal activity against T. cinnabarinus than the other seven plant extracts tested. Five compounds were identified from the C. camphora extract via repeated column chromatography and gas chromatography-mass spectrometry analysis. All the compounds presented acaricidal activity, with 2,4-di-tert-butylphenol and ethyl oleate exhibiting the greatest activity. At 7 days after treatment in a potted seedling experiment, the LC50 values of 2,4-di-tert-butylphenol and ethyl oleate were found to be 1850.94 and 2481.65 mg kg(-1) respectively. Microscopic observations showed that the mites displayed the symptomology of poisoning.

CONCLUSION

These results demonstrated that the C. camphora extract and its two active components show the potential to be developed as new natural acaricides for controlling carmine spider mites.

Chemical Composition and Insecticidal Activities of the Essential Oil of Clinopodium chinense (Benth.) Kuntze Aerial Parts against Liposcelis bostrychophila Badonnel

Water-distilled essential oil from Clinopodium chinense (Labiatae) aerial parts at the flowering stage was analyzed by gas chromatography-mass spectrometry. Thirty-five compounds, accounting for 99.18% of the total oil, were identified, and the main components of the essential oil of C. chinense were spathulenol (18.54%), piperitone (18.9%), caryophyllene (12.04%), and bornyl acetate (8.14%). Based on bioactivity-directed fractionation, bornyl acetate, caryophyllene, and piperitone were identified from the essential oil. The essential oil possessed fumigant toxicity against booklice (Liposcelis bostrychophila) with a 50% lethal concentration (LC50) value of 423.39 μg/liter, while the isolated constituents, bornyl acetate and piperitone, had LC50 values of 351.69 and 311.12 μg/liter against booklice, respectively. The essential oil also exhibited contact toxicity against L. bostrychophila with an LC50 value of 215.25 μg/cm(2). Bornyl acetate, caryophyllene, and piperitone exhibited acute toxicity against booklice with LC50 values of 321.42, 275.00, and 139.74 μg/cm(2), respectively. The results indicated that the essential oil and its isolated constituents have potential for development into natural insecticides or fumigants for control of insects in stored grains.

Chemical Composition and Bioactivities of the Essential Oil from Etlingera yunnanensis against Two Stored Product Insects

The chemical composition of the essential oil of Etlingera yunnanensis rhizomes and its contact and repellent activities against Tribolium castaneum (Herbst) and Liposcelis bostrychophila (Badonnel) were investigated. The essential oil obtained from E. yunnanensis rhizomes with hydrodistillation was performed by gas chromatography-flame ionization detection and gas chromatography-mass spectrometry. The main components of the essential oil were identified to be estragole (65.2%), β-caryophyllene (6.4%), 1,8-cineole (6.4%), limonene (5.2%), and α-pinene (2.4%). It was found that the essential oil of E. yunnanensis rhizomes possessed contact toxicity against T. castaneum and L. bostrychophila (LD₅₀ = 23.33 μg/adult and LD₅₀ = 47.38 μg/cm², respectively). Estragole, 1,8-cineole, and limonene exhibited stronger contact toxicity (LD₅₀ values of 20.41, 18.86, and 13.40 μg/adult, respectively) than β-caryophyllene (LD₅₀ = 41.72 μg/adult) against T. castaneum adults. Estragole possessed stronger contact toxicity (LD₅₀ = 30.22 µg/cm²) than β-caryophyllene, 1,8-cineole, and limonene (LD₅₀ values of 74.11, 321.20, and 239.62 μg/adult, respectively) against L. bostrychophila adults. Repellency of the crude oil was also evaluated. The essential oil and constituents possessed strong repellent activity against T. castaneum adults. The four individual constituents showed weaker repellent activity than the essential oil against L. bostrychophila adults. The results indicated that the essential oil of E. yunnanensis rhizomes and the individual constituents had the potential to be developed as a natural insecticide and repellent for the control of T. castaneum and L. bostrychophila.

Analysis of the essential oil of Illicium henryi Diels root bark and its insecticidal activity against Liposcelis bostrychophila Badonnel

Water-distilled essential oil from Illicium henryi (Illiciaceae) root bark was analyzed by gas chromatography-mass spectrometry. Thirty-four compounds, accounting for 97.86% of the total oil, were identified. The main components of the essential oil of I. henryi root bark were safrole (46.12%), myristicin (20.39%), and 1,8-cineole (6.17%), followed by α-cadinol (3.784%) and linalool (3.22%). The essential oil had higher levels of phenylpropanoids (66.89%) than of monoterpenoids (14.83%) and sesquiternoids (16.14%). Three constituents were isolated from the oil based on bioactivity fractionation. The essential oil possessed fumigant toxicity against booklice (Liposcelis bostrychophila), with a 50% lethal concentration (LC50) of 380.39 μg/liter of air, while the two isolated constituents myristicin and safrole had LC50s of 121.95 and 322.54 μg/liter, respectively. Another constituent, 1,8-cineole, showed weaker toxicity, with an LC50 of 1,120.43 μg/liter. The essential oil also exhibited contact toxicity against L. bostrychophila, with an LC50 of 96.83 μg/cm(2). Myristicin (LC50, 18.74 μg/cm(2)) and safrole (LC50, 69.28 μg/cm(2)) exhibited stronger acute toxicity than 1,8-cineole (LC50, 1,049.41 μg/cm(2)) against the booklice. The results indicated that the essential oil and its constituent compounds have potential for development into natural insecticides for control of psocids in stored grains.

Bioactivity of essential oil from Artemisia stolonifera (Maxim.) Komar. and its main compounds against two stored-product insects

Artemisia stolonifera, a perennial herb, is widely distrbuted in China. The aim of this study was to analyze the essential oil from the aerial parts of Artemisia stolonifera, as well as to evaluate the bioactivity of the oil and its main constituents. The essential oil was analyzed by gas chromatography-flame ionization detector and gas chromatography-mass spectrometry that allowed characterizing 22 compounds. The main components were eucalyptol (32.93%), β-pinene (8.18%), camphor (6.12%) and terpinen-4-ol (6.11%), and obtained from the essential oil after a further isolation. During the contact toxicity tests, the essential oil (LD50 = 8.60 μg/adult) exhibited stronger toxicity against Tribolium castaneum adults than those isolated constituents, however, camphor and terpinen-4-ol showed 1 and 2 times toxicity against Lasioderma serricorne adults than the essential oil (LD50 = 12.68 μg/adult) with LD50 values of 11.30 and 5.42 μg/adult, respectively. In the fumigant toxicity tests, especially on Tribolium castaneum, the essential oil (LC50 = 1.86 mg/L air) showed almost the same level toxicity as positive control, methyl bromide (LC50 = 1.75 mg/L air). Moreover, the essential oil and its four isolated constituents also exhibited strong repellency against two stored-product insects.

Contact toxicity and repellency of the essential oil of Liriope muscari (DECN.) bailey against three insect tobacco storage pests

In order to find and develop new botanical pesticides against tobacco storage pests, bioactivity screening was performed. The essential oil obtained from the aerial parts of Liriope muscari was investigated by GC/MS and GC/FID. A total of 14 components representing 96.12% of the oil were identified and the main compounds in the oil were found to be methyl eugenol (42.15%) and safrole (17.15%), followed by myristicin (14.18%) and 3,5-dimethoxytoluene (10.60%). After screening, the essential oil exhibit potential insecticidal activity. In the progress of assay, it showed that the essential oil exhibited potent contact toxicity against Tribolium castaneum, Lasioderma serricorne and Liposcelis bostrychophila adults, with LD50 values of 13.36, 11.28 µg/adult and 21.37 µg/cm2, respectively. The essential oil also exhibited strong repellency against the three stored product insects. At the same concentrations, the essential oil was more repellent to T. castaneum than to L. serricorne adults. The results indicate that the essential oil of Liriope muscari has potential to be developed into a natural insecticide or repellent for controlling insects in stored tobacco and traditional Chinese medicinal materials.

Active monoterpene ketones isolated from Rosmarinus officinalis with fumigant and contact action against Tyrophagus putrescentiae (Schrank)

The acaricidal activities of an active material derived from Rosmarinus officinalis oil and its relative monoterpene ketones were determined using fumigant and contact toxicity bioassays against Tyrophagus putrescentiae and were compared with that of a commercial acaricide (benzyl benzoate). The active component of R. officinalis oil, isolated by silica gel column chromatography and high-performance liquid chromatography, was identified as camphor, based on various spectroscopic analyses. In the fumigant toxicity bioassay, camphor (2.25 μg/cm(3)) was 5.58 times more active than benzyl benzoate (12.56 μg/cm(3)) against T. putrescentiae, followed by (+)-camphor (3.89 μg/cm(3)) and (-)-camphor (5.61 μg/cm(3)). In the contact toxicity bioassay, camphor (1.34 μg/cm(2)) was 6.74 times more toxic than benzyl benzoate (9.03 μg/cm(2)) against T. putrescentiae, followed by (+)-camphor (2.23 μg/cm(2)) and (-)-camphor (2.94 μg/cm(2)). These results indicate that camphor and its derivatives are very useful as potential control agents against stored food mites regardless of the application method.

Acaricidal activities of bicyclic monoterpene ketones from Artemisia iwayomogi against Dermatophagoides spp

The acaricidal properties of 1,7,7-trimethylbicyclo[2.2.1]heptan-2-one isolated from Artemisia iwayomogi and its structural analogues were evaluated against Dermatophagoides farinae and D. pteronyssinus, and their effects were compared with that of the commercial acaricide benzyl benzoate. Based on the 50 % lethal dose (LD50) values against D. farinae, 1,7,7-trimethylbicyclo[2.2.1]heptan-2-one (0.82 μg/cm(2)) was 9.71 times more effective than benzyl benzoate (7.96 μg/cm(2)), followed by (1R)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-one (1.03 μg/cm(2)), (1S)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-one (1.58 μg/cm(2)), and (1R)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-one oxime (3.05 μg/cm(2)) in a filter paper bioassay. The acaricidal activities of 1,7,7-trimethylbicyclo[2.2.1]heptan-2-one and its structural analogues against D. pteronyssinus were similar to those against D. farinae. These results demonstrate that naturally occurring A. iwayomogi-isolated 1,7,7-trimethylbicyclo[2.2.1]heptan-2-one and its structural analogues are suitable for the production of natural acaricides against house dust mites.

Chemical Constituents and Insecticidal Activities of the Essential Oil ofCinnamomum camphoraLeaves againstLasioderma serricorne

During our screening program for agrochemicals from Chinese medicinal herbs and wild plants, the essential oil ofCinnamomum camphoraleaves was found to possess strong fumigant and contact toxicity againstLasioderma serricorneadults with LC50/LD50values of 2.5 mg/L air and 21.25 μg/adult, respectively. The essential oil obtained by hydrodistillation was investigated by GC and GC-MS. The main components of the essential oil were identified to beD-camphor (40.54%), linalool (22.92%), cineole (11.26%), and 3,7,11-trimethyl-3-hydroxy-6,10-dodecadien-1-yl acetate (4.50%). Bioactivity-directed chromatographic separation on repeated silica gel columns led to the isolation ofD-camphor and linalool.D-camphor and linalool showed strong fumigant toxicity (LC50= 2.36 and 18.04 mg/L air, resp.) and contact toxicity (LD50= 13.44 and 12.74 μg/adult, resp.) againstL. serricorne. The results indicate that the essential oil ofC. camphoraand its active compounds had the potential to be developed as natural fumigants and insecticides for control ofL. serricorne.

Isolation of Insecticidal Constituents from the Essential Oil ofAgeratum houstonianumMill. againstLiposcelis bostrychophilaBadonnel

The aim of this research was to determine chemical composition and insecticidal activities of the essential oil ofAgeratum houstonianumMill. aerial parts against booklice,Liposcelis bostrychophilaBadonnel, and to isolate any insecticidal constituents from the oil. Essential oil ofA. houstonianumwas obtained by hydrodistillation and analyzed by GC-MS. A total of 35 components in the essential oil were identified. The major compounds were precocene II (62.68%), precocene I (13.21%), andβ-caryophyllene (7.92%). Based on bioactivity-guided fractionation, precocene II and precocene I were isolated and identified as the active constituents. The essential oil exhibited contact toxicity againstL. bostrychophilawith an LC50value of 50.8 μg/cm2. Precocene II (LC50= 30.4 μg/cm2) exhibited stronger acute toxicity than precocene I (LC50= 64.0 μg/cm2) against the booklice. The essential oil and the two isolated constituents also possessed strong repellent activity againstL. bostrychophila. The results indicated that the essential oil and its constituent compounds have potential for development into natural insecticides or repellents for control of insects in stored grains.

Mining genes involved in insecticide resistance of Liposcelis bostrychophila Badonnel by transcriptome and expression profile analysis

BACKGROUND

Recent studies indicate that infestations of psocids pose a new risk for global food security. Among the psocids species, Liposcelis bostrychophila Badonnel has gained recognition in importance because of its parthenogenic reproduction, rapid adaptation, and increased worldwide distribution. To date, the molecular data available for L. bostrychophila is largely limited to genes identified through homology. Also, no transcriptome data relevant to psocids infection is available.

METHODOLOGY AND PRINCIPAL FINDINGS

In this study, we generated de novo assembly of L. bostrychophila transcriptome performed through the short read sequencing technology (Illumina). In a single run, we obtained more than 51 million sequencing reads that were assembled into 60,012 unigenes (mean size = 711 bp) by Trinity. The transcriptome sequences from different developmental stages of L. bostrychophila including egg, nymph and adult were annotated with non-redundant (Nr) protein database, gene ontology (GO), cluster of orthologous groups of proteins (COG), and KEGG orthology (KO). The analysis revealed three major enzyme families involved in insecticide metabolism as differentially expressed in the L. bostrychophila transcriptome. A total of 49 P450-, 31 GST- and 21 CES-specific genes representing the three enzyme families were identified. Besides, 16 transcripts were identified to contain target site sequences of resistance genes. Furthermore, we profiled gene expression patterns upon insecticide (malathion and deltamethrin) exposure using the tag-based digital gene expression (DGE) method.

CONCLUSION

The L. bostrychophila transcriptome and DGE data provide gene expression data that would further our understanding of molecular mechanisms in psocids. In particular, the findings of this investigation will facilitate identification of genes involved in insecticide resistance and designing of new compounds for control of psocids.

Growth-Inhibiting and morphostructural effects of constituents identified in Asarum heterotropoides root on human intestinal bacteria

BACKGROUND

The growth-inhibiting and morphostructural effects of seven constituents identified in Asarum heterotropoides root on 14 intestinal bacteria were compared with those of the fluoroquinolone antibiotic ciprofloxacin.

METHOD

A microtiter plate-based bioassay in sterile 96-well plates was used to evaluate the minimal inhibitory concentrations (MICs) of the test materials against the organisms.

RESULTS

δ-3-Carene (5) exhibited the most potent growth inhibition of Gram-positive bacteria (Clostridium difficile ATCC 9689, Clostridium paraputrificum ATCC 25780, Clostridium perfringens ATCC 13124, and Staphylococcus aureus ATCC 12600) and Gram-negative bacteria (Escherichia coli ATCC 11775 and Bacteroides fragilis ATCC 25285) (minimal inhibitory concentrations (MIC), 0.18-0.70 mg/mL) except for Salmonella enterica serovar Typhimurium ATCC 13311 (MIC, 2.94 mg/mL). The MIC of methyleugenol (2), 1,8-cineole (3), α-asarone (4), (-)-asarinin (6), and pellitorine (7) was between 1.47 and 2.94 mg/mL against all test bacteria (except for compound 2 against C. difficile (0.70 mg/mL); compounds 1 (23.50 mg/mL) and 4 (5.80 mg/mL) against C. paraputricum; compounds 2 (5.80 mg/mL), 4 (12.0 mg/mL), and 7 (0.70 mg/mL) against C. perfringens); compound 1 against E. coli (7.20 mg/mL) and S. enterica serovar Typhimurium (12.0 mg/mL). Overall, all of the constituents were less potent at inhibiting microbial growth than ciprofloxacin (MIC, 0.063-0.25 mg/ mL). The lactic acid-producing bacteria (four bifidobacteria and two lactobacilli) and one acidulating bacterium Clostridium butyricum ATCC 25779 were less sensitive and more susceptible than the five harmful bacteria and two nonpathogenic bacteria (B. fragilis and E. coli) to the constituents and to ciprofloxacin, respectively. Beneficial Gram-positive bacteria and harmful and nonpathogenic Gram-negative bacteria were observed to have different degrees of antimicrobial susceptibility to the constituents, although the antimicrobial susceptibility of the harmful Gram-positive bacteria and the harmful and nonpathogenic Gram-negative bacteria was not observed. Scanning electron microscopy observations showed different degrees of physical damage and morphological alteration to both Gram-positive and Gram-negative bacteria treated with α-asarone, δ-3-carene, pellitorine, or ciprofloxacin, indicating that they do not share a common mode of action.

CONCLUSION

A. heterotropoides root-derived materials described merit further study as potential antibacterial products or lead molecules for the prevention or eradication from humans from diseases caused by harmful intestinal bacteria.

Identification of repellent and insecticidal constituents of the essential oil of Artemisia rupestris L. aerial parts against Liposcelis bostrychophila Badonnel

The aim of this research was to determine the chemical composition and insecticidal and repellent activity of the essential oil of Artemisia rupestris L. aerial parts against the booklice Liposcelis bostrychophila Badonnel and isolation of insecticidal and repellent constituents from the essential oil. The essential oil of A. rupestris was obtained by hydrodistillation and analyzed by GC-MS. A total of 30 components of the essential oil of A. rupestris was identified and the principal compounds in the essential oil were α-terpinyl acetate (37.18%), spathulenol (10.65%), α-terpineol (10.09%), and linalool (7.56%), followed by 4-terpineol (3.92%) and patchoulol (3.05%). Based on bioactivity-guided fractionation, the four active constituents were isolated from the essential oil and identified as α-terpineol, α-terpinyl acetate, 4-terpineol and linalool. The essential oil of A. rupestris exhibited contact toxicity against L. bostrychophila with LD₅₀ value of 414.48 µg/cm². α-Terpinyl acetate (LD₅₀ = 92.59 µg/cm²) exhibited stronger contact toxicity against booklice than α-terpineol (LD₅₀ = 140.30 µg/cm²), 4-terpineol (LD₅₀ = 211.35 µg/cm²), and linalool (LD₅₀ = 393.16 µg/cm²). The essential oil of A. rupestris (LC₅₀ = 6.67 mg/L air) also possessed fumigant toxicity against L. bostrychophila while the four constituents, 4-terpineol, α-terpineol, α-terpinyl acetate and linalool had LC₅₀ values of 0.34, 1.12, 1.26 and 1.96 mg/L air, respectively. α-Terpinol and α-terpinyl acetate showed strong repellency against L. bostrychophila, while linalool and 4-terpinol exhibited weak repellency. The results indicate that the essential oil of A. rupestris aerial parts and its constituent compounds have potential for development into natural insecticides or fumigants as well as repellents for control of insects in stored grains.

Identification of insecticidal constituents of the essential oil of Acorus calamus rhizomes against Liposcelis bostrychophila Badonnel

The aim of this research was to determine the chemical composition of the essential oil of Acorus calamus rhizomes, its insecticidal activity against the booklouse, (Liposcelis bostrychophila) and to isolate any insecticidal constituents from the essential oil. The essential oil of A. calamus rhizomes was obtained by hydrodistillation and analyzed by GC-FID and GC-MS. A total of 32 components of the essential oil of A. calamus rhizomes was identified and the principal compounds in the essential oil were determined to be α-asarone (50.09%), (E)-methylisoeugenol (14.01%), and methyleugenol (8.59%), followed by β-asarone (3.51%), α-cedrene (3.09%) and camphor (2.42%). Based on bioactivity-guided fractionation, the three active constituents were isolated from the essential oil and identified as methyleugenol, (E)-methylisoeugenol and α-asarone. The essential oil exhibited contact toxicity against L. bostrychophila with an LD₅₀ value of 100.21 µg/cm² while three constituent compounds, α-asarone, methyleugenol, and (E)-methylisoeugenol had LD₅₀ values of 125.73 µg/cm², 103.22 µg/cm² and 55.32 µg/cm², respectively. Methyleugenol and (E)-methylisoeugenol possessed fumigant toxicity against L. bostrychophila adults with LC₅₀ values of 92.21 μg/L air and 143.43 μg/L air, respectively, while the crude essential oil showed an LC₅₀ value of 392.13 μg/L air. The results indicate that the essential oil of A. calamus rhizomes and its constituent compounds have potential for development into natural fumigants/insecticides for control of the booklice.

Identification of Insecticidal Constituents from the Essential Oil ofValeriana jatamansiJones againstLiposcelis bostrychophilaBadonnel

The aim of this research was to determine chemical composition and insecticidal activities of the essential oil ofValeriana jatamansiJones roots against booklice,Liposcelis bostrychophilaBadonnel, and to isolate insecticidal constituents from the oil. Essential oil ofV. jatamansiwas obtained by hydrodistillation and analyzed by GC-MS. A total of 27 components in the essential oil were identified. The major compounds were patchoulol (24.3%),α-bulnesene (13.8%), isovaleric acid (12.9%),α-guaiene (8.7%), and 3-methylvaleric acid (8.4%). Based on bioactivity-guided fractionation, isovaleric acid, 3-methylvaleric acid, and patchoulol were isolated and identified as the active constituents. The essential oil exhibited contact toxicity againstL. bostrychophilawith an LC50value of 236.4 μg/cm2. Patchoulol (LC50= 61.35 μg/cm2) exhibited stronger acute toxicity than 3-methylvaleric acid (LC50= 210.69 μg/cm2) against the booklice. The essential oil also possessed fumigant toxicity againstL. bostrychophilawith an LC50value of 6.0 mg/L, while 3-methylvaleric acid and isovaleric acid had LC50values of 5.53 mg/L and 5.67 mg/L against the booklice, respectively. The results indicated that the essential oil and its constituent compounds have potential to develop into natural insecticides or fumigants for control of insects in stored grains.