Repellent Activity Research Articles

Encapsulation of carvacrol and thymol with yeast cell wall and its repellent activity against Amblyomma sculptum and Rhipicephalus sanguineus (Sensu Lato).

The main way to avoid contact with ticks and consequently tick-borne disease is the use of synthetic repellents. The search of new repellent compounds to increase the possibilities of use in strategies controls are necessary. The present study evaluated the repellent activity of two natural terpenes carvacrol and thymol in each one two different formulation (encapsulated and nonencapsulated with yeast cell wall) against the ticks Amblyomma sculptum and Rhipicephalus sanguineus sensu lato nymphs. Nymphs of A. sculptum and R. sanguineus s.l. of a single generation were used. The vertical filter paper repellency assay were performed with different concentration of both terpenes encapsulated and nonencapsulated in yeast cell wall. The repellent concentration 50% (RC50) were calculated to each compound formulation. Both carvacrol and thymol (encapsulated and nonencapsulated), had a repellent activity against A. sculptum and R. sanguineus s.l nymphs. Amblyomma sculptum was more sensitive to nonencapsulated carvacrol (RC50 values: 0.0032 to 0.0082mg/cm2 after 1 and 15min) (P < 0.05), while R. sanguineus s.l. was more sensitive to encapsulated carvacrol (RC50 values: 0.00008 to 0.0035mg/cm2 after 1 and 15min) (P < 0.05). Among tick species, R. sanguineus s.l. was more sensitive for most compounds than A. sculptum (P < 0.05). Although with distinct repellent activities, carvacrol and thymol encapsulated can be a promising alternative to synthetic repellents against A. sculptum and R. sanguineus s.l.

Chemical Composition, Toxicity, and Repellency of Essential Oils from Three Hedychium Species Against Stored-Product Insects.

Stored products are constantly infested by insects, so finding eco-friendly bioinsecticides for insect management is important. The work aimed to assess the insecticidal and repellent activity of essential oil (EO) from Hedychium glabrum S. Q. Tong, Hedychium coronarium Koen., and Hedychium yunnanense Gagnep. against Tribolium castaneum, Lasioderma serricorne, and Liposcelis bostrychophila. Results showed that 88 chemical components were identified in the extracted Hedychium EOs, indicating that they exhibited diversity in components. According to principal component analysis (PCA), the composition of the EO from the H. yunnanense stem and leaf (EOHYSL) was significantly different from other EOs due to the different organs and species. The biological activity also varied continuously with plant species and organs. Only the EO of H. yunnanense (EOHY) showed strong fumigant toxicity. While in the contact tests, EOHGR showed the strongest toxicity effect on L. bostrychophila, with a LC50 value of 71.76 μg/cm2, which was closest to the positive control (Pyrethrin). All EOs had remarkable repellent activities against the three target insects, and repellency increased with concentration. According to the results of the comprehensive score, EOHY had the highest potential, which ranged from 0.7999 to 0.8689. Thus, Hedychium EOs possess potential biorational traits to be biological insecticides.

Functional analysis of three odorant receptors in Plutella xylostella response to repellent activity of 2,3-dimethyl-6-(1-hydroxy)-pyrazine

Plutella xylostella is an important pest showing resistance to various chemical pesticides, development of botanical pesticides is an effective strategy to resolve above problem and decrease utilization of chemical pesticides. Previous study showed that 2,3-dimethyl-6-(1-hydroxy)-pyrazine has significant repellent activity to P. xylostella adult which mainly effect to the olfactory system, however the molecular targets and mechanism are still unclear. Based on the RNA-Seq and RT-qPCR data, eight ORs (Odorant receptor) in P. xylostella were selected as candidate targets response to repellent activity of 2,3-dimethyl-6-(1-hydroxy)-pyrazine. Here, most of the ORs in P. xylostella were clustered into three branches, which showed similar functions such as recognition, feeding, and oviposition. PxylOR29, PxylOR31, and PxylOR46 were identified as the potential molecular targets based on the results of repellent activity and EAG response tests to the adults which have been injected with dsRNA, respectively. Additionally, the three ORs were higher expressed in antenna of P. xylostella, followed by those in the head segment. Furthermore, it was found that the bindings between these three ORs and 2,3-dimethyl-6-(1-hydroxy)-pyrazine mainly depend on the hydrophobic effect of active cavities, and the binding to PxylOR31 was more stabler and easier with an energy of −16.34 kcal/mol, together with the π-π T-shaped interaction at PHE195 site. These findings pave the way for the complete understanding of pyrazine repellent mechanisms.

THE EFFECTIVENESS OF VARIOUS CITRONELLA OIL NANOGEL FORMULATIONS AS A REPELLENT OF AEDES AEGYPTI MOSQUITO

Objective: The aim of this research is to determine the effectiveness of the repellency of various citronella oil nanogel formulations against Aedes aegypti mosquito bites applied to guinea pigs. Methods: The Citronella oil nanogel was prepared by emulsification technique combined with gelling formation. The nanoemulsion formula consists of 6% Citronella oil, 10% propylene glycol, 6% combination of Tween 80 and Span 80 in variation to 4 formula, and deionized water until 100%. Nanoemulsions were then added to the gel base which is composed of Carbopol 940 and TEA. The nanogel formed was characterized physically and its effectiveness against Aedes aegypti mosquito using guinea pigs as an animal model. The repellent activity was determined by the amount of mosquito bites on the guinea pigs’s skin. Results: The organoleptic test displayed that all formulas comply with the requirements, except formula 1. The formula 2, 3, and 4 have particle size below 100 nm and the polydispersity index (PDI) less than 0.5. According to the repellent assay showed that all formulas have the effectiveness much higher than without the intervention. Formula 3 has the highest effectiveness of repellent activity against Aedes aedgypti in guinea pigs’ skin. The repellent activity of Formula 3 showed a significant difference (p-value of 0.005) as compared to nanogel without Citronella oil. Conclusion: The protective power of Citronella oil nanogel Formula 3 is the most effective as compared to the other formula.

Efficacy and underlying mechanisms of the essential oil derived from Rosmarinus officinalis against Aleuroglyphus ovatus (Acari: Acaridae)

ABSTRACT Rosemary (Rosmarinus officinalis L) essential oil (REO) has an inhibitory effect against pests and is regarded as a safe alternative to synthetic acaricides. This study investigated the acaricidal and repellent activity of REO and underlying mechanisms against Aleuroglyphus ovatus, an important mite pest of stored products. Gas Chromatography-Mass Spectrometry analysis of REO indicated that the compounds of 1,8-cineole (25.20%) was the highest. REO at 13% concentration provided the highest repellent effect (92.67%) on A. ovatus, and the lowest repellent activity (48.67%) was at 0.8% concentration. Microscopic observations revealed that the mite epidermis started to shrink after treatment with REO at 6 h post-treatment. The enzyme level of catalase (CAT), acetylcholinesterase (AChE) and superoxide dismutase (SOD) decreased significantly (P < 0.05), whereas there was a significant increase (P < 0.05) in nitric oxide synthase (NOS) and glutathione-s-transferases (GST) activities in A. ovatus treated with REO. In the molecular docking study, camphor and 1,8-cineole, the main monoterpenes of REO, bind more closely with CAT and AChE, and PI-conjugated interaction, hydrogen bonding, and hydrophobic were found by molecular docking 3D model. Overall, our results indicate the potential of REO as an effective botanical acaricide to manage A. ovatus.

Citrus Essential Oils as Potential Insecticides Against Thrips flavus

Background: Essential oils (EOs) are recognized for their potent insecticidal activity and are widely considered promising agents for pest control. Methods: The insecticidal activity of seven commercial citrus EOs against the global phytophagous pest Thrips flavus was evaluated using bioassays conducted under laboratory conditions. Moreover, the chemical composition of these EOs was analyzed using gas chromatography-mass spectrometry (GC-MS). Results: Among the 45 identified compounds, the major constituents were d-limonene (23.77%– 95.10%), methyl jasmonate (38.76%), and linalyl acetate (34.55%). Orange flower oil, sweet orange oil, tangerine peel oil, bergamot oil, lime oil, lemon oil, and grapefruit oil exhibited good insecticidal activity against T. flavus without demonstrating significant repellent activity. Orange flower oil and sweet orange oil showed higher insecticidal toxicity, with LC50 values of 0.20 g/L and 0.37 g/L, respectively. In pot experiments, the higher control efficacy against T. flavus was found after 7 days of treatment for orange flower oil (91.14±1.27% at 720.00 g a.i.·hm−2 and 100% at 900.00 g a.i.·hm−2), sweet orange oil (91.14±5.52% at 900.00 g a.i.·hm−2), tangerine peel oil (96.20±2.19% at 720 g a.i.·hm−2 and 100% at 900.00 g a.i.·hm−2), lemon oil (96.20±2.19% at 900 g a.i.·hm−2), and lime oil (97.47±2.53% at 900.00 g a.i.·hm−2). Conclusion: Taken together, orange flower oil and tangerine peel oil, which were found to contain d-limonene and methyl jasmonate, demonstrated rapid and more effective insecticidal activity compared to the other EOs tested, which makes these two EOs promising alternatives to chemical insecticides.

Repellent activity of Salix alba bark extract and guava oil-based formulation against the oriental fruit fly, Bactrocera dorsalis (Diptera: Tephritidae)

Repellent activity of Salix alba bark extract and guava oil-based formulation against the oriental fruit fly, Bactrocera dorsalis (Diptera: Tephritidae)

Cationic polymer coating that rapidly inactivates bacteria and resists bacterial adhesion

AbstractAmphiphilic cationic polymers mimicking the membrane‐disrupting mechanism of natural antimicrobial peptides displays high‐efficacy bactericidal activity and meanwhile good biocompatibility, while electrostatic adsorption enables bacteria to adhere to substrate surfaces, effectively lowering the antimicrobial effect, so it is worthwhile to tackle the problem of bacterial adhesion to prolong its antibacterial activity. Herein, a kind of polyquaternium latex (PQL) was synthesized to coat polypropylene nonwoven fabrics (PPNFs) with bacterial repellency and rapid biocidal activity toward both Staphylococcus aureus and Escherichia coli. Compared with polyquaternium solution coatings, latex coatings provided PPNFs with unique microscopic morphology and surface chemistry rich in polyoxyethylene moieties, achieving better resistance to bacterial adhesion, and meanwhile PQL coated PPNFs also delivered 99% killing rates against both bacteria within 2 min. After exposure to ultrasonic cleaning for 4 h, PQL modified PPNFs still demonstrated good bactericidal activity. Moreover, they also displayed low cytotoxicity. This work provides guidance for the design of antibacterial and antiadhesion coatings to combat bacterial infection.

Repellent activity of the non-host semiochemical (E)-2-octenal against Amblyomma sculptum and Amblyomma dubitatum ticks under field conditions.

Amblyomma ticks pose a significant public health threat due to their potential to transmit pathogens associated with rickettsial diseases. (E)-2-octenal, a compound found in donkeys (Equus asinus), exhibits strong repellent properties against Amblyomma sculptum nymphs under laboratory conditions. This study assessed the effectiveness of the (E)-2-octenal in wearable slow-release devices for personal human protection against Amblyomma ticks under natural conditions. Slow-release devices treated with (E)-2-octenal and untreated controls were prepared and tested on two volunteers walking through a tick-infested area in Goiania, Brazil. The experiment was conducted twice daily for three series of 10 days, with each volunteer wearing two devices attached to each leg, one on the ankle and one just above the thigh. Volunteers with control and treated devices exchanged them between rounds. Also, the daily release rate of (E)-2-octenal from the slow-release devices was determined in the laboratory, increasing significantly from 0.77± 0.14µg/day on the first day to 9.93 ± 1.92µg/day on the 4th day and remaining constant until the 16th day. A total of 5409 ticks were collected from both volunteers. Treated devices resulted in recovering fewer ticks (n = 1,666; 31%) compared to untreated devices (control: n = 3,743; 69%). (E)-2-octenal effectively repelled Amblyomma spp. larvae, A. sculptum adults, and exhibited pronounced repellency against A. dubitatum nymphs and adults. These findings suggest the potential of (E)-2-octenal delivered by wearable slow-release devices as a green-based repellent. Further improvements, however, are necessary to provide better protection for humans against A. sculptum and A. dubitatum in field conditions.

In Vitro Evaluation of Essential Oils and Saturated Fatty Acids for Repellency against the Old-World Sand Fly, Phlebotomus papatasi (Scopoli) (Diptera: Psychodidae).

The sand fly, Phlebotomus papatasi (Scopoli, 1786), is a major vector for Leishmania major in the Middle East, which has impacted human health and US military operations in the area, demonstrating the need to develop effective sand fly control and repellent options. Here, we report the results of spatial repellency and avoidance experiments in a static air olfactometer using the female P. papatasi testing essential oils of Lippia graveolens (Mexican oregano), Pimenta dioica (allspice), Amyris balsamifera (amyris), Nepeta cataria (catnip), Mentha piperita (peppermint), and Melaleuca alternifolia (tea tree); the 9-12 carbon saturated fatty acids (nonanoic acid, decanoic acid, undecanoic acid, and dodecanoic acid); and the synthetic repellents DEET and IR3535. The materials applied at 1% exhibited varying activity levels but were not significantly different in mean repellency and avoidance from DEET and IR3535, except in regards to nonanoic acid. Some materials, particularly nonanoic and undecanoic acids, produced sand fly mortality. The observed trends in mean repellency over exposure time included the following: (1) P. dioica oil, M. alternifolia oil, decanoic acid, undecanoic acid, DEET, and IR3535 exhibited increasing mean repellency over time; (2) oils of N. cataria, A. balsamifera, M. piperita, and dodecanoic acid exhibited relatively constant mean repellency over time; and (3) L. graveolens oil and nonanoic acid exhibited a general decrease in mean repellent activity over time. These studies identified the essential oils of N. cataria and A. balsamifera as effective spatial repellents at reduced concentrations compared to those of DEET. Additional research is required to elucidate the modes of action and potential synergism of repellents and essential oil components for enhanced repellency activity.

Design and Evaluation of Poly Herbal Mosquito Repellent Incense Sticks

The current study's goal was to create multi-herb mosquito-repellent incense sticks. Two formulations were made F1 and F2. The F1 formulation contains less quantity of poly herbal ingredients than the F2 formulation. The developed formulation's effectiveness as a mosquito repellent was assessed. The Incense mosquito sticks were prepared by hand rolling method in research laboratory. The herbal ingredients used are the Holy basil, Neem, Rosemary, Camphor, Cinnamon bark, lemongrass oil. The Acacia used as a binder to roll the sticks and lemon grass oil used as flavoring agent. The prepared formulation F1 and F2 was evaluated its efficacy. The F2 formulation containing increased quantity of poly herbs so it shows better repellent activity than F1 formulation. So the uses of natural herbs in the formulation of mosquito repellent sticks are free from carcinogenic chemicals, cheaper, and easy to formulate.

Leaf micromorphology in Rosaceae tribe Spiraeeae (subfamily Amygdaloideae) and its systematic and ecological implications

Abstract We conducted a comparative micromorphological study on the leaves of all nine genera of the Rosaceae tribe Spiraeeae, including the monotypic Korean genus Pentactina. Spiraeeae possess amphistomatic and hypostomatic leaves. Leaf epidermal characteristics varied with the morphology of stomatal complexes, epidermal cells, trichomes, and epicuticular waxes. Specific leaf epidermal features may be systematically relevant for identifying lower taxonomic levels, genera, and/or species. For example, papillate epidermal cell types were consistently observed in Spiraea sect. Calospira. Hirtellous trichomes are diagnostic characteristics of the genera Holodiscus and Kelseya among this tribe. Short-stalked capitate glandular and crispate villous trichomes were only observed in Holodiscus microphyllus and Spiraea douglasii, respectively. We also confirmed that leaf epidermal characteristics strongly support the independent taxonomic position of the Korean endemic Pentactina and the transfer from Physocarpus to Spiraea of Physocarpus insularis. Moreover, we identified xeromorphic features in the studied taxa and inferred their ecological functions, such as water repellence and anti-transpirant activities. This study presents new perspectives for future research on character evolution and xeromorphic adaptation on the basis of leaf epidermal characteristics.

Effectiveness of Citronella and Basil Essential Oil Spray as Repellents against Aedes aegypti Mosquitoes

Background: In 2023, Dengue Fever cases in Indonesia reached 35,694 cases from January to May. Dengue Fever is caused by the bite of Aedes aegypti mosquitoes. Mosquito control efforts have been widely conducted, including the use of chemical insecticides. The use of chemical insecticides can lead to environmental contamination and cause skin irritation. An alternative approach that can be taken is to use natural insecticides. One of the natural insecticides that can be used as a repellent is citronella and basil essential oils. Citronella and basil essential oils contain geraniol and citronellal, which can cause mortality in mosquitoes. This study intends to evaluate the effectiveness of a spray mixture of basil leaves and citronella essential oil as a mosquito repellent. Materials and Methods: Aedes aegypti mosquitoes, basil leaf essential oil, citronella essential oil, propylene glycol, glycerin, butylated hydroxytoluena and etanol 96% v/v. Subsequently, an evaluation of physical properties was conducted, including organoleptic testing, pH, and viscosity evaluation, as well as irritation and repellent activity test. Results: The spray formulations in the control and F1 are clear in color, while F2 and F3 are clear with a slightly yellowish hue. The scent produced has the characteristic smell of citronella. The pH and viscosity tests resulted in pH values consistent with the skin's pH range of 4.5-7 and viscosity within the range of 1-1000 Cp. The spray formulation did not irritate after 48 hours of observation. The results of the effectiveness test indicate that F2 can protect against mosquito bites for 1 hour, while F3 can protect for 3 hours. Conclusion: Citronella essential oil and basil leaves are effective as a repellent for the Aedes aegypti mosquito for 3 hours of use in concentration 15%.

Discovery and properties of novel analogues of the aphid pheromones nepetalactone and nepetalactol.

Pheromones have unique advantages for pest control. Current aphid pheromone research focuses on alarm and sex pheromones. However, practical applications are limited so far, as (E)-β-farnesene has only been investigated to a small extent as an alarm pheromone and only male aphids are targeted by sex pheromones. Previous literature reports electrophysiological responses and repellent behavior of asexual aphids to nepetalactone (1B), therefore our objective was to modify nepetalactone's structure to identify key fragments responsible for repellent effects, as guidance for subsequent modifications and further investigation. In this study, seven derivatives were designed and synthesized based on nepetalactol (1A) and nepetalactone (1B) as lead compounds. Free-choice tests, conducted using cowpea aphids (Aphis craccivora), revealed that the lactone moiety was crucial for the repellent activity, and the removal of the carbonyl group eliminated the repelling effect. Compound (±)1I, an analogue of nepetalactone (1B), demonstrated a significantly higher repellent value than nepetalactone (1B) at three different concentrations, and even at 0.1 mg/mL it maintained a considerable repellent effect (26.5%). Electrostatic potential and density functional theory calculations supported the importance of the carbonyl group for the repellent effects. The newly discovered para-pheromone (±)1I shows improved repellent effects and potential for development as a novel biological control agent. Based on our innovative findings, analogues with improved efficacy and properties can be designed and prepared. Our research contributes to understanding the effects of structural modifications on pheromone activity and properties, which is crucial for exploring novel pheromone-based products for crop protection. © 2024 Society of Chemical Industry.

Development of terpenoid repellents against Aedes albopictus: a combined study of biological activity evaluation and computational modelling

ABSTRACT To explore novel terpenoid repellents, 22 candidate terpenoid derivatives were synthesized and tested for their electroantennogram (EAG) responses and repellent activities against Aedes albopictus. The results from the EAG experiments revealed that 5-(2-hydroxypropan-2-yl)-2-methylcyclohex-2-en-1-yl formate (compound 1) induced distinct EAG responses in female Aedes albopictus. At concentrations of 0.1, 1, 10, 100, and 1000 mg/L, the EAG response values for compound 1 were 179.59, 183.99, 190.38, 193.80, and 196.66 mV, demonstrating comparable or superior effectiveness to DEET. Repellent activity analysis indicated significant repellent activity for compound 1, closest to the positive control DEET. The in silico assessment of the ADMET profile of compound 1 indicates that it successfully passed the ADMET evaluation. Molecular docking studies exhibited favourable binding of compound 1 to the active site of the odorant binding protein (OBP) of Aedes albopictus, involving hydrophobic forces and hydrogen bond interactions with residues in the OBP pocket. The QSAR model highlighted the influential role of hydrogen-bonding receptors, positively charged surface area of weighted atoms, polarity parameters of molecules, and maximum nuclear-nuclear repulsion force of carbon-carbon bonds on the relative EAG response values of the tested compounds. This study holds substantial significance for the advancement of new terpenoid repellents.

Larvicidal and repellent effects of essential oils on the brown dog tick (Rhipicephalus sanguineus Sensu lato) with description of new larval repellent activity test method

The aim of this research was to investigate the larvicidal and repellent effects of essential oils (EOs) obtained from two Lamiaceae plant species, Origanum minutiflorum O. Schwarz & P.H. Davis and Dorystoechas hastata Boiss. & Heldr. ex Bentham, both endemic to Turkey, on Rhipicephalus sanguineus s.l. Latreille (Acari: Ixodidae). The study also introduces a new test method that can be used to assess the repellent effects against ticks. Both plant EOs exhibited the highest larvicidal activity against brown dog tick larvae after 24 h and LC50 and LC90 values were determined as 0.101% and 0.125% for O. minutiflorum essential oil and 0.937% and 2.1% for D. hastata essential oil, respectively. In this study, we have described a detailed protocol for a novel larval repellent activity test (LRAT) for essential oils and extracts, using simple equipment. The advantages and limitations of LRAT, when compared to other tests commonly used to determine repellent effect against ticks, are also included in this study. The LRAT was developed with modifications of the larval immersion test (LIT) and proves to be a highly efficient and easily observable method. It can be used to test any active substance that may be toxic to humans and animals. According to the LRAT, at the end of 3 h, O. minutiflorum essential oil showed a high repellent effect, varying between 84.14% and 100% at 1% concentration. This result was not statistically different from the DEET, the positive control. When comparing the larvicidal and repellent activities, O. minutiflorum essential oil was found to be more effective than D. hastata essential oil.

Laboratory assessment of the acaricidal, repellent and anti-cholinesterase effects of Melaleuca alternifolia and Chamaemelum nobile essential oils against Hyalomma scupense ticks.

In cattle, Hyalomma scupense serves as an important vector of several pathogens resulting in diseases, subsequently affecting the agricultural field as well as the economy. Resistance to chemical acaricides has become widespread affirming the need for new drugs to tick control. The goal of this study was to investigate the acaricidal, repellent activities as well as the putative mode of action of two essential oils (EOs) from Melaleuca alternifolia (Tea tree) and Chamaemelum nobile (Roman chamomile) on Hyalomma scupense. The chemical composition of EOs was also evaluated. Different concentrations of EOs were tested in vitro for their acaricidal property on adults and larvae of H. scupense using adult immersion test (AIT) and larval packet test (LPT). Additionally, using Ellman's spectrophotometric method, the anticholinesterase (AChE) inhibition activity of M. alternifolia and C. nobile EOs was assessed in order to understand their putative mode of action. The main compounds of C. nobile were α-Bisabolene (22.20%) and (E)-β-Famesene (20.41%). The major components in the analyzed M. alternifolia were Terpinen-4-ol (36.32%) and γ-Terpinene (13.69%). Adulticidal and larvicidal assays demonstrated a promising efficacy of the essential oils against tick H. scupense. The lethal concentration (LC50) values obtained for M. alternifolia and C. nobile oils were 0.84 and 0.96 mg/mL in the AIT and 0.37 and 0.48 mg/mL in the LPT, respectively. Regarding repellent activity, M. alternifolia achieved 100% repellency at the concentration of 1 mg/mL while C. nobile showed 95.98% repellency activity at concentration of 4 mg/mL. Also, M. alternifolia and C. nobile EOs displayed potent AChE inhibition with IC50 value of 91.27 and 100.12 μg/mL, respectively. In the present study, M. alternifolia and, to a lesser degree, C. nobile EOs were found to be effective in vitro acaricides, repellents and acetylcholinesteraseinhibitor against H. scupense ticks. These plants may represent an economical and sustainable alternative to toxic synthetic acaricides in the management of ectoparasites of veterinary importance.

A Review of the Ethnobotanical Use, Chemistry and Pharmacological Activities of Constituents Derived from the Plant Genus Geijera (Rutaceae).

Geijera Schott is a plant genus of the Rutaceae Juss. (rue and citrus) family, comprising six species which are all native to Oceania. Of the plants belonging to this genus, the most significant species that has a customary use is Geijera parviflora, which was used by Indigenous Australians, primarily as a pain reliever. Herein, a comprehensive review of the literature published on the genus Geijera from 1930 to 2023 was conducted. This is the first review for this plant genus, and it highlights the chemical constituents reported to date, together with the range of pharmacological properties described from the various species and different parts of the plant. These properties include anti-inflammatory, anti-microbial, anti-parasitic, insect repellent, analgesic, neuroactive, and anti-cancer activities. Finally, a reflection on some of the important areas for future focused studies of this plant genus is provided.

Sustainable Dyeing of Wool and Silk with Conocarpus erectus L. Leaf Extract for the Development of Functional Textiles

Natural dyes derived from plants offer a sustainable alternative to synthetic dyes for textile coloration. This study examined the extraction of natural dyes from Conocarpus erectus L. leaves and their application on wool and silk fabrics. Aqueous extraction in an alkaline medium was used to obtain dyes from raw leaves, which were then applied to pre-mordanted silk and wool fabrics by applying the ultrasonic-assisted exhaust dyeing method. The dyed fabrics were evaluated for color strength (K/S) and CIELAB color coordinates. The color fastness (washing, rubbing, and light), ultraviolet protection factor, mosquito repellency, and antibacterial activity were established using standard testing protocols. The surface morphologies of silk and wool were examined using scanning electron microscopy. Interestingly, the dyed fabrics displayed good color strength and color fastness properties. Moreover, the dyed wool samples revealed satisfactory antibacterial activity against Gram-negative (E. coli) and Gram-positive (S. aureus) in both qualitative and quantitative assessment methods, good ultraviolet protection in terms of UPF, and good mosquito repellency against Aedes aegypti. This study for the first time presented the application of a medicinal plant (Conocarpus erectus L.) in the field of textile dyeing and finishing. Hence, the use of Conocarpus erectus L. leaf dyes offers significant results on wool and silk fabrics and contributes to sustainable functional textile production.

Phytochemical characterization by HS-SPME-GC-MS and exploration of the antifungal, insecticidal and repellent activity of Ptychotis verticillata essential oil

The objective of this investigation was to assess the chemical makeup of essential oil derived from Ptychotis verticillata (PVEO), and to examine its antifungal, insecticidal, and repellent properties. PVEO was extracted through hydrodistillation, and its volatile constituents were analyzed using Headspace Solid-Phase Microextraction Gas Chromatography-Mass Spectrometry. Qualitative and quantitative evaluation of antifungal activity was carried out using the agar diffusion method and the minimum inhibitory concentration (MIC) test against Candida glabrata, Saccharomyces cerevisiae, Aspergillus niger and Penicillium digitatum. We evaluated the repellent potential, as well as the contact and inhalation toxicity of PVEO against Callosobruchus maculatus. The results of the study indicated that the essential oil of P. verticillata was composed mainly of γ-Terpinen (25.86%), β-Cymene (18.70%) O-Cymen-5-ol (16.78) and α-Pinene (12.13%). PVEO showed potent antifungal activity against all strains tested. The results of insecticidal activity of this essential oil were promising in adult C. maculatus. At a dose of 20 ml · dm–3 of air, EO caused maximum mortality with an LC50 value of 5.64 ml · dm–3 for the inhalation test and 3.4 ml · dm–3 for the contact test. In addition, a significant decrease in the number of eggs laid and adult emergence was observed as EO doses increased, reaching a reduction of around 95% at a dose of 20 ml · dm–3 of air. In terms of repellent activity, PVEO also showed encouraging results. It demonstrated an average repellent activity of around 92 ± 10.95%. Furthermore, molecular docking simulations corroborated the in vitro results and demonstrated that specific p-Menthen-3-one compounds formed more robust hydrogen bonding interactions with the target receptors. These experiments underscore PVEO’s effectiveness as a fungicide against the tested fungal strains, demonstrating its role as a bio-insecticide against C. maculatus adults, and its potential as an appealing repellent. This suggests that PVEO could serve as a valuable alternative within integrated pest management strategies.