Acute aquatic toxicity of western juniper (Juniperus occidentalis) foliage and Port Orford cedar (Chamaecyparis lawsoniana) heartwood oils

In vitro larvicidal efficacy of Lantana camara essential oil and its nanoemulsion and enzyme inhibition kinetics against Anopheles culicifacies

Mosquitoes are important vectors for the transmission of several infectious diseases that lead to huge morbidity and mortality. The exhaustive use of synthetic insecticides has led to widespread resistance and environmental pollution. Using essential oils and nano-emulsions as novel insecticides is a promising alternative approach for controlling vector borne diseases. In the current study, Lantana camara EO and NE were evaluated for their larvicidal and pupicidal activities against Anopheles culicifacies. The inhibitory effect of EO and NE on AChE, NSE (α/β), and GST was also evaluated and compared. GC-MS analysis of oil displayed 61 major peaks. The stable nano-emulsion with an observed hydrodynamic diameter of 147.62 nm was formed using the o/w method. The nano-emulsion exhibited good larvicidal (LC50 50.35 ppm and LC90 222.84 ppm) and pupicidal (LC50 54.82 ppm and LC90 174.58 ppm) activities. Biochemical evaluations revealed that LCEO and LCNE inhibited AChE, NSE (α/β), and GST, displaying LCNE to be a potent binder to AChE and NSE enzyme, whereas LCEO showed higher binding potency towards GST. The nano-emulsion provides us with novel opportunities to target different mosquito enzymes with improved insecticidal efficacy. Due to its natural origin, it can be further developed as a safer and more potent larvicide/insecticide capable of combating emerging insecticide resistance.

Chamaecyparis lawsoniana and Its Active Compound Quercetin as Ca2+ Inhibitors in the Contraction of Airway Smooth Muscle

The Cupressaceae family includes species considered to be medicinal. Their essential oil is used for headaches, colds, cough, and bronchitis. Cedar trees like Chamaecyparis lawsoniana (C. lawsoniana) are commonly found in urban areas. We investigated whether C. lawsoniana exerts some of its effects by modifying airway smooth muscle (ASM) contractility. The leaves of C. lawsoniana (363 g) were pulverized mechanically, and extracts were obtained by successive maceration 1:10 (w:w) with methanol/CHCl3. Guinea pig tracheal rings were contracted with KCl, tetraethylammonium (TEA), histamine (HIS), or carbachol (Cch) in organ baths. In the Cch experiments, tissues were pre-incubated with D-600, an antagonist of L-type voltage-dependent Ca2+ channels (L-VDCC) before the addition of C. lawsoniana. Interestingly, at different concentrations, C. lawsoniana diminished the tracheal contractions induced by KCl, TEA, HIS, and Cch. In ASM cells, C. lawsoniana significantly diminished L-type Ca2+ currents. ASM cells stimulated with Cch produced a transient Ca2+ peak followed by a sustained plateau maintained by L-VDCC and store-operated Ca2+ channels (SOCC). C. lawsoniana almost abolished this last response. These results show that C. lawsoniana, and its active metabolite quercetin, relax the ASM by inhibiting the L-VDCC and SOCC; further studies must be performed to obtain the complete set of metabolites of the extract and study at length their pharmacological properties.

New weapons against the disease vector Aedes aegypti: From natural products to nanoparticles

Despite the global burden of viral diseases transmitted by Aedes aegypti, there is a lack of effective means of prevention and treatment. Strategies for vector control include chemical and biological approaches such as organophosphates and Bacillus thuringiensis var. israelensis (Bti), among others. However, important concerns are associated, such as resistance in mosquito larvae and deleterious effects on non-target organisms. In this scenario, novel approaches against A. aegypti have been investigated, including natural products (e.g. vegetable oil and extracts) and nanostructured systems. This review focuses on potential strategies for fighting A. aegypti, highlighting plant-based materials and nanomaterials able to induce toxic effects on egg, larva, pupa and adult mosquitoes. Issues including aspects of conventional vector control strategies are presented, and finally new insights on development of eco-friendly nanoformulations against A. aegypti are discussed.

Ecotoxicity of plant extracts and essential oils: A review

Plant-based products such as essential oils and other extracts have been used for centuries due to their beneficial properties. Currently, their use is widely disseminated through a variety of industries and new applications are continuously emerging. For these reasons, they are produced industrially in large quantities and consequently they have the potential to reach the environment. However, the potential effects that these products have on the ecosystems' health are mostly unknown. In recent years, the scientific community started to focus on the possible toxic effects of essential oils and plant extracts towards non-target organisms. As a result, an increasing body of knowledge has emerged. This review describes the current state of the art on the toxic effects that essential oils and plant extracts have towards organisms from different trophic levels, including producers, primary consumers, and secondary consumers. The majority of the studies (76.5%) focuses on the aquatic environment, particularly in aquatic invertebrates (45.1%) with only 23.5% of the studies focusing on the potential toxicity of plant-derived products on terrestrial ecosystems. While some essential oils and extracts have been described to have no toxic effects to the selected organisms or the toxic effects were only observable at high concentrations, others were reported to be toxic at concentrations below the limit set by international regulations, some of them at very low concentrations. In fact, L(E)C₅₀ values as low as 0.0336 mg.L^-1, 0.0005 mg.L^-1 and 0.0053 mg.L^-1 were described for microalgae, crustaceans and fish, respectively. Generally, essential oils exhibit higher toxicity than extracts. However, when the extracts are obtained from plants that are known to produce toxic metabolites, the extracts can be more toxic than essential oils. Overall, and despite being generally considered "eco-friendly" products and safer than they synthetic counterparts, some essential oils and plant extracts are toxic towards non-target organisms. Given the increasing interest from industry on these plant-based products further research using international standardized protocols is mandatory.

Antibacterial and fungicidal effect of ethanol extracts from Juniperus sabina, Chamaecyparis lawsoniana, Pseudotsuga menziesii and Cephalotaxus harringtonia

We determined a high antibacterial effect of ethanol extracts of four species of gymnosperms (Juniperus sabina, Chamaecyparis lawsoniana, Pseudotsuga menziesii and Cephalotaxus harringtonia) against 23 strains of bacteria of families Enterobacteriaceae (Escherichia coli, Enterococcus faecalis, Salmonella typhimurium, S. adobraco, Proteus vulgaris, P. mirabilis, Serratia marcescens, Klebsiella pneumoniae), Staphylococcaceae (Staphylococcus aureus, S. epidermidis), Yersiniaceae (Yersinia enterocolitica), Bacillaceae (Bacillus subtilis, B. cereus), Listeriaceae (Listeria ivanovi, L. іnnocua, L. monocytogenes), Corynebacteriaceae (Corynebacterium xerosis), Campylobacteraceae (Campylobacter jejuni), Nocardiaceae (Rhodococcus equi), Pseudomonadaceae (Pseudomonas аeruginosa) and one strain of fungi of the Saccharomycetaceae family (Candida albicans). The experiment in vitro revealed zone of inhibition of growth of colonies, measuring over 8 mm, produced by ethanol extracts from J. sabina against seven species of bacteria (S. aureus, B. subtilis, B. cereus, L. іnnocua, C. xerosis, Rh. equi and P. аeruginosa), Ch. lawsoniana – against five species (E. coli, B. subtilis, L. іnnocua and Rh. equi), P. menziesii –two species (Rh. equi and P. mirabilis), C. harringtonia – ten species of microorganisms (E. coli, S. aureus, S. epidermidis, L. ivanovi, L. monocytogenes, C. xerosis, C. jejuni, P. vulgaris, S. marcescens and C. albicans). As a result of the research, the most promising plants for further in vivo study of antibacterial activity were C. harringtonia and J. sabina.

Antifungal and Antibacterial Activity of the Essential Oil of from Spain

The essential oils extracted from the young stems and leaves of Chamaecyparis lawsoniana(A.Murray) Parl. have been analysed by Gas Chromatography and Gas Chromatography coupled to Mass Spectrometry. A total of 66 compounds were identified representing around the 99% of the total oil. The oil was richer in monoterpenes than in sesquiterpenes. The only main component was limonene with a percentage composition of 77.7%. The rest of compounds that contribute to the fragrance had percentage composition lower that the 3.0%: p-cymen-7-ol (3.0%), myrcene (2.4%), camphor (2.1%), δ-elemene (1.6%), oplopanonyl acetate (1.6%), methyl perillate (1.3%), terpinen-4-ol (1.0%) and β-oplopenone 1.0%. The antibacterial and antifungal activity of this oil was also tested against different microorganisms. The only fungus tested, Candida albicans,was very sensitive to the treatment with an inhibition halos of 20mm. The oil was more effective with the Gram (+) than with Gram (-) bacteria. The inhibition halos were 12mm, 12-13mm and 12-13mm for Bacillus subtilis, Staphylococcus aureus and Micrococcus luteus respectively. We report new data of the antibacterial and antifungal activity of the essential oil of this species. The essential oil of C. lawsoniana could be considered as a good natural antibacterial and antifungal agent.