Antioxidant and antimicrobial activities of 7-hydroxy-calamenene-rich essential oils from Croton cajucara Benth

Red sacaca essential oil-loaded nanostructured lipid carriers optimized by factorial design: cytotoxicity and cellular reactive oxygen species levels

Amazonian flora includes several species with the potential to develop pharmaceutical and biotechnological products. The essential oils from Amazonian species possess some biological properties, such as antioxidant, antibacterial, and cytotoxic activities. The essential oil of red sacaca (RSO), Croton cajucara Benth., contains metabolites characterized by antioxidant and anti-inflammatory activities. Nanostructured lipid carriers (NLC) are an advantageous alternative for the effective delivery of drugs because they can solubilize lipophilic actives and reduce their cytotoxicity. This study aimed to optimize the synthesis of RSO-loaded nanostructured lipid carriers (NLC-RSO) using a 23 factorial design and investigate their antioxidant and cytotoxic effects. The red sacaca essential oil (RSO) metabolite profile was characterized using gas chromatography coupled with a mass spectrometer (GC-MS), identifying 33 metabolites, with linalool and 7-hydroxy-calamenene as the major ones, as reported in the literature. The optimized NLC-RSO formulation had a particle size less than 100 nm and a polydispersity index lower than 0.25. After characterizing NLC-RSO using Fourier-transform infrared spectroscopy, powder X-ray diffraction, zeta potential, moisture content, and wettability, in vitro cytotoxicity were performed in A549 and BEAS-2B cell lines using the resazurin metabolism assay. The data indicated a lower IC50 for RSO than for NLC-RSOs in both cell lines. Furthermore, low cytotoxicity of blank nanoparticles (blank NP) and medium chain triglycerides-loaded nanostructured lipid carriers (NLC-MCT) towards both pulmonary cell lines was noted. At a concentration of 50-100 μg/mL, free RSO exhibited higher cytotoxicity than NLC-RSO, demonstrating the protective effect of this lipid carrier in reducing cytotoxicity during metabolite delivery. Similarly, free RSO showed higher 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging than NLC-RSO, also indicating this protective effect. The 2',7'-dichlorofluorescein diacetate (DCFH-DA) intracellular reactive oxygen species (ROS) level assay did not show differences between the treatments at higher but non-cytotoxic dosages. Taken together, our results suggest that NLC-RSOs are potential RSO delivery systems for applications related to cancer treatment.

The Volatile Organic Compounds of Streptomyces spp.: An In-Depth Analysis of Their Antifungal Properties

The study of volatile organic compounds (VOCs) has expanded because of the growing need to search for new bioactive compounds that could be used as therapeutic alternatives. These small molecules serve as signals to establish interactions with other nearby organisms in the environment. In this work, we evaluated the antifungal effect of VOCs produced by different Streptomyces spp. This study was performed using VOC chamber devices that allow for the free exchange of VOCs without physical contact between microorganisms or the diffusible compounds they produce. Antifungal activity was tested against Escovopsis weberi, a fungal pathogen that affects ant nest stability, and the results showed that Streptomyces spp. CS014, CS057, CS131, CS147, CS159, CS207, and CS227 inhibit or reduce the fungal growth with their emitted VOCs. A GS-MS analysis of volatiles produced and captured by activated charcoal suggested that these Streptomyces strains synthesize several antifungal VOCs, many of them produced because of the presence of E. weberi, with the accumulation of various VOCs determining the growth inhibition effect.

Chemistry and Bioactivity of Croton Essential Oils: Literature Survey and Croton hirtus from Vietnam

Using essential oils to control vectors, intermediate hosts, and disease-causing microorganisms is a promising approach. The genus Croton in the family Euphorbiaceae is a large genus, with many species containing large amounts of essential oils, however, essential oil studies are limited in terms of the number of Croton species investigated. In this work, the aerial parts of C. hirtus growing wild in Vietnam were collected and analyzed by gas chromatography/mass spectrometry (GC/MS). A total of 141 compounds were identified in C. hirtus essential oil, in which sesquiterpenoids dominated, comprising 95.4%, including the main components β-caryophyllene (32.8%), germacrene D (11.6%), β-elemene (9.1%), α-humulene (8.5%), and caryophyllene oxide (5.0%). The essential oil of C. hirtus showed very strong biological activities against the larvae of four mosquito species with 24 h LC50 values in the range of 15.38-78.27 μg/mL, against Physella acuta adults with a 48 h LC50 value of 10.09 μg/mL, and against ATCC microorganisms with MIC values in the range of 8-16 μg/mL. In order to provide a comparison with previous works, a literature survey on the chemical composition, mosquito larvicidal, molluscicidal, antiparasitic, and antimicrobial activities of essential oils of Croton species was conducted. Seventy-two references (seventy articles and one book) out of a total of two hundred and forty-four references related to the chemical composition and bioactivity of essential oils of Croton species were used for this paper. The essential oils of some Croton species were characterized by their phenylpropanoid compounds. The experimental results of this research and the survey of the literature showed that Croton essential oils have the potential to be used to control mosquito-borne and mollusk-borne diseases, as well as microbial infections. Research on unstudied Croton species is needed to search for species with high essential oil contents and excellent biological activities.

Synergistic and Antibiofilm Effects of the Essential Oil from Croton conduplicatus (Euphorbiaceae) against Methicillin-Resistant Staphylococcus aureus

Bacterial resistance refers to the ability of bacteria to resist the action of some antibiotics due to the development of adaptation and resistance mechanisms. It is a serious public health problem, especially for diseases caused by opportunistic bacteria. In this context, the search for new drugs, used alone or in combination, appears as an alternative for the treatment of microbial infections, and natural products, such as essential oils, are important in this process due to their structural diversity, which increases the probability for antimicrobial action. The objective of this study was to extract and identify the chemical components of the essential oil from Croton conduplicatus (EOCC), to evaluate the antimicrobial activity, to investigate the effect of the interaction between the EOCC and different antibiotics and to evaluate its antibiofilm potential. The EOCC was obtained by hydrodistillation. Based on chemical characterisation, 70 compounds were identified, with 1.8 cineole (13.15%), p-cymene (10.68%), caryophyllene (9.73%) and spathulenol (6.36%) being the major constituents. The minimum inhibitory concentration (MIC) values of EOCC were 256 and 512 µg mL^-1 for methicillin-sensitive and -resistant Staphylococcus aureus strains (MSSA and MRSA), respectively. The combinations of EOCC with the antibiotics oxacillin and ampicillin were synergistic (OXA/EOCC and AMP/EOCC combined decreased the OXA MIC and AMP MIC to 0.5 and 0.25 for MSSA, respectively, and OXA/EOCC and AMP/EOCC combined decreased the OXA MIC and the AMP MIC to 1 and 0.5 for MRSA, respectively) and could modify the resistance profile of MSSA and MRSA strains. The results indicated that EOCC was also able to partially inhibit biofilm formation. Our study presents important information about the chemical composition of EOCC and its antimicrobial potential and provides a reference to determine the mechanisms of action of EOCC and its use in pharmaceutical formulations.

First Report on the Chemical Composition, Antioxidant Capacity, and Preliminary Toxicity to Artemia salina L. of Croton campinarensis Secco, A. Rosário & PE Berry (Euphorbiaceae) Essential Oil, and In Silico Study

Croton campinarensis Secco, A. Rosário & PE Berry is an aromatic species recently discovered in the Amazon region. This study first reports the chemical profile, antioxidant capacity, and preliminary toxicity to A. salina Leach of the essential oil (EO) of this species. The phytochemical profile of the essential oil was analyzed by gas chromatography (GC/MS) and (GC-FID). The antioxidant capacity of the EO was measured by its inhibition of ABTS^•+ and DPPH^• radicals. Molecular modeling was used to evaluate the mode of interaction of the major compounds with acetylcholinesterase (AChE). The results indicate that the EO yield was 0.24%, and germacrene D (26.95%), bicyclogermacrene (17.08%), (E)-caryophyllene (17.06%), and δ-elemene (7.59%) were the major compounds of the EO sample. The EO showed a TEAC of 0.55 ± 0.04 mM·L^-1 for the reduction of the ABTS^•+ radical and 1.88 ± 0.08 mM·L^-1 for the reduction of the DPPH^• radical. Regarding preliminary toxicity, the EO was classified as toxic in the bioassay with A. salina (LC₅₀ = 20.84 ± 4.84 µg·mL^-1). Through molecular docking, it was found that the majority of the EO components were able to interact with the binding pocket of AChE, a molecular target related to toxicity evaluated in A. salina models; the main interactions were van der Waals and π-alkyl interactions.

Prospecting of essential oils in combination with florfenicol against motile Aeromonas isolated from tambaqui (Colossoma macropomum)

Natural products with antimicrobial activity and their association with synthetic antimicrobials are a sustainable option in fish farming. The objective of this study was to determine antimicrobial activity, antibiofilm potential and synergism of five essential oils (EOs) with florfenicol against motile Aeromonas isolated from Amazonian Colossoma macropomum. As their major constituent, the EOs of the species of Aloysia triphylla, Croton cajucara (red and white morphotype), Cymbopongo citratus and Lippia gracilis present β-pinene (22.1%), germacrene D (11.5%), linalool (23%), geranial (45.7%) and carvacrol (42.2%), respectively. The EOs of L. gracilis and C. citratus showed the best antimicrobial activities against the Aeromonas strains (5 mg mL^-1). All EOs interfered with biofilm formation and consolidated biofilm. The EOs of A. triphylla, C. citratus and L. gracilis showed a synergistic effect with florfenicol, reducing the amount of the chemical into the water systems while treatment.

Two new clerodane diterpenoids and a new pyran-2-one derivative with anti-neuroinflammatory activities from Croton crassifolius

Two new clerodane diterpenoids (1 and 2), a new pyran-2-one derivative (3), along with five known compounds (4‒8), were isolated from Croton crassifolius. Notably, crassifolin X (1) is a novel clerodane diterpenoid, characterized with a peculiar δ-lactone core being formed between C-1 and C-4. Their structures, including absolute configurations, were established on the basis of spectroscopic methods (UV, IR, HRESIMS and NMR), and circular dichroism experiments. In addition, all compounds were evaluated for their anti-neuroinflammatory activities based on the expression of TNF-α and IL-6 levels on LPS-induced BV2 cells, and compounds 1‒3 and 5 showed potential anti-neuroinflammatory activity.

Evaluating the Efficacy of 30 Different Essential Oils against Varroa destructor and Honey Bee Workers (Apis mellifera)

Simple Summary

Worldwide, mass losses of honey bee colonies are being observed more frequently due to Varroa mite infestation. Therefore, varroosis is considered a major problem in beekeeping participating to a large extent in colony collapse disorder. Except for direct damage of bees and suppressing their immune system caused by parasitism, Varroa mites transfer viral particles straight to bee hemolymph which can have a fatal impact. To control the mite population, several acaricidal treatments are used. Commonly used treatments are synthetic acaricides with a high risk of developing Varroa resistance population and contamination of bee products by acaricidal residues. Other commonly used treatments are organic acids, which are increasingly associated with damage of brood, adult bees, and premature deaths of queens. Therefore, in this study, we evaluated the varroacidal effect of 30 individual essential oils. The toxicity of the most effective oils selected by screening was subsequently tested on Varroa mites and adult honey bee workers simultaneously. In addition, the main components of these essential oils were specified. Several essential oils were proven to be effective against the adult female of Varroa mites and at the same dose safe for adult honey bee workers under laboratory conditions, especially manuka, peppermint, oregano, litsea, and cinnamon.

Abstract

Essential oils and their components are generally known for their acaricidal effects and are used as an alternative to control the population of the Varroa destructor instead of synthetic acaricides. However, for many essential oils, the exact acaricidal effect against Varroa mites, as well as the effect against honey bees, is not known. In this study, 30 different essential oils were screened by using a glass-vial residual bioassay. Essential oils showing varroacidal efficacy > 70% were tested by the complete exposure assay. A total of five bees and five mites were placed in the Petri dishes in five replications for each concentration of essential oil. Mite and bee mortality rates were assessed after 4, 24, 48, and 72 h. The LC₅₀ values and selectivity ratio (SR) were calculated. For essential oils with the best selectivity ratio, their main components were detected and quantified by GC-MS/MS. The results suggest that the most suitable oils are peppermint and manuka (SR > 9), followed by oregano, litsea (SR > 5), carrot, and cinnamon (SR > 4). Additionally, these oils showed a trend of the increased value of selective ratio over time. All these oils seem to be better than thymol (SR < 3.2), which is commonly used in beekeeping practice. However, the possible use of these essential oils has yet to be verified in beekeeping practice.

Chemical Profile of the Volatile Constituents and Antimicrobial Activity of the Essential Oils from Croton adipatus, Croton thurifer, and Croton collinus

The aim of this study was to determine the volatile phytochemical constituents and evaluate the antimicrobial activity of the essential oils of the leaves from Croton adipatus, Croton thurifer, and Croton collinus. Essential oils were extracted by hydro-distillation using the Clevenger extractor and the phytochemical analysis was determined by Gas chromatography-Mass Spectrometry (GC-MS). The antimicrobial activity was assessed using the agar diffusion and colorimetric broth microdilution methods against Staphylococcus aureus ATCC 25923, Bacillus subtilis ATCC 6633, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 9027, and Candida albicans ATCC The essential oils from C. adipatus, C. thurifer, and C collinus had 46, 38, and 35 volatile constituents respectively. The main compounds determined in C. adipatus were β-myrcene (18.34%), while in C. collinus was β-caryophyllene (44.7%), and in C. thurifer was an unknown component (C₁₀H₁₆: 22.38%). Essential oil of C. adipatus showed a MIC against B. subtilis (286.4 µg/mL) and C. albicans (572.8 ± 0 µg/mL); C. thurifer against S. aureus (296.1 ± 0 µg/mL) and B. subtilis (148 ± 0 µg/mL); and C. collinus against B. subtilis (72 ± 0 µg/mL) and C. albicans (576.2 ± 0 µg/mL). The three essential oils of Croton species demonstrated in vitro antimicrobial activity against a strain of bacteria or fungi.

Croton cajucara Essential Oil Nanoemulsion and Its Antifungal Activities

The purpose of this study was to develop a stable nanoemulsion (NE) containing Croton cajucara 7-hydroxycalamenene-rich essential oil (NECC) with antifungal activity. The NECCs were prepared using an ultrasonic processor with Pluronic® F-127 as the aqueous phase. In order to evaluate the NECCs, the droplet size, polydispersity index (PdI), percentage of emulsification, and pH were determined along with a stability study. The NECC selected for the study had 15% surfactant, showed 100% emulsification, Pdl of 0.249, neutral pH, droplet diameters of about 40 nm, and remained stable over 150 days at room temperature. In addition, the NECC activity against some species of Zygomycetes and Candida, as well as the potential to inhibit fungal extracellular proteases, were assessed, and, finally, the hemolytic activity was evaluated. The best NECC antifungal activities were against Mucorramosissimus (Minimal inhibitory concentration (MIC) = 12.2 μg/mL) and Candida albicans (MIC = 25.6 μg/mL). The highest extracellular protease activities of M. ramosissimus and C. albicans were detected at pH 3 and 4, respectively, which were totally inhibited after NECC treatment. The NECC showed no hemolytic effect at the highest concentration tested (2 mg/mL).

Crassifolins Q-W: Clerodane Diterpenoids From Croton crassifolius With Anti-Inflammatory and Anti-Angiogenesis Activities

Seven new clerodane diterpenoids, crassifolins Q-W (1-7), along with five known analogues (8-12), were isolated from the roots of Croton crassifolius. Their structures were identified by comprehensive spectroscopic analysis (UV, IR, NMR, and HR-ESI-MS), and their absolute configurations were determined by ECD spectra and X-ray crystallography. The activities of compounds 1-5 against inflammatory cytokines IL-6 and TNF-α levels on LPS-induced RAW 264.7 macrophages were assessed, and compound 5 showed the most significant activity with the secretion levels of IL-6 and TNF-α at 32.78 and 12.53%, respectively. Moreover, compounds 1-5 were screened for their anti-angiogenesis using a human umbilical vein endothelial cells in vitro mode; the results showed all of them exhibited obvious anti-angiogenesis activities, in particular, compound 5 showed the strongest anti-angiogenesis effect in the range of 6.25-50 μM.

Evaluation of Antioxidant and Enzyme Inhibition Properties of Croton hirtus L'Hér. Extracts Obtained with Different Solvents

Croton hirtus L'Hér methanol extract was studied by NMR and two different LC-DAD-MSn using electrospray (ESI) and atmospheric pressure chemical ionization (APCI) sources to obtain a quali-quantitative fingerprint. Forty different phytochemicals were identified, and twenty of them were quantified, whereas the main constituents were dihydro α ionol-O-[arabinosil(1-6) glucoside] (133 mg/g), dihydro β ionol-O-[arabinosil(1-6) glucoside] (80 mg/g), β-sitosterol (49 mg/g), and isorhamnetin-3-O-rutinoside (26 mg/g). C. hirtus was extracted with different solvents-namely, water, methanol, dichloromethane, and ethyl acetate-and the extracts were assayed using different in vitro tests. The methanolic extracts presented the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS), and ferric reducing antioxidant power (FRAP) values. All the tested extracts exhibited inhibitory effects on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), with a higher activity observed for dichloromethane (AChE: 5.03 and BChE: 16.41 mgGALAE/g), while the methanolic extract showed highest impact against tyrosinase (49.83 mgKAE/g). Taken together, these findings suggest C. hirtus as a novel source of bioactive phytochemicals with potential for commercial development.

Inhibition of pathogenic Vibrio harveyi using calamenene, derived from the Indian gorgonian Subergorgia reticulata, and its synthetic analog

We report the synthesis and antimicrobial properties of a partially reduced dihydronathphthoquinone analogue of 2-methoxy, 5-acetoxy calamenene, extracted from Subergorgia reticulata. The growth of a pathogenic Vibrio harveyi strain was effectively controlled by the calamenene derivative 1 (Cala1) and its synthetic analog 2 (Cala2). Complete mortality of V. harveyi was observed with 2.5 and 0.5 µg mL-1 concentrations of Cala1 and Cala2, respectively. The metabolic assays demonstrated that Cala1 is a bacteriostatic agent while Cala2 showed bactericidal properties. It was confirmed that translocation of Cala2 into the cytoplasm does not induce any change to the integrity of the bacterial cell wall. The Cala2 induced damage to the genetic material of 70% of cells while genetic material of 91% of cells treated with Cala1 remained intact. The Cala2 is, therefore, proposed as a potential bactericidal compound against the aquaculture pathogen V. harveyi. The fact that the Cala2 exhibited minimal cytotoxicity to Artemia nauplii indicates its potential use as an antimicrobial agent for aquaculture operations.

Sesquiterpenes in grapes and wines: Occurrence, biosynthesis, functionality, and influence of winemaking processes

Grapes are an important global horticultural product, and are mainly used for winemaking. Typically, grapes and wines are rich in various phytochemicals, including phenolics, terpenes, pyrazines, and benzenoids, with different compounds responsible for different nutritional and sensory properties. Among these compounds, sesquiterpenes, a subcategory of the terpenes, are attracting increasing interest as they affect aroma and have potential health benefits. The characteristics of sesquiterpenes in grapes and wines in terms of classification, biosynthesis pathway, and active functions have not been extensively reviewed. This paper summarizes 97 different sesquiterpenes reported in grapes and wines and reviews their biosynthesis pathways and relevant bio-regulation mechanisms. This review further discusses the functionalities of these sesquiterpenes including their aroma contribution to grapes and wines and potential health benefits, as well as how winemaking processes affect sesquiterpene concentrations.

Protective Effect of the Hexanic Extract of Eryngium carlinae Inflorescences In Vitro, in Yeast, and in Streptozotocin-Induced Diabetic Male Rats

In the present study, we investigated the composition and antioxidant activity of the hexanic extract of Eryngium carlinae inflorescences by employing in vitro assays to measure antioxidant capacity and 2,2-diphenyl-1-picrylhydrazyl scavenging activity. We also applied the hexanic extract to Saccharomyces cerevisiae, under hydrogen peroxide-induced stress. Finally, we tested the extract in male Wistar rats with and without streptozotocin-induced diabetes. The compounds in the hexanic extract were analyzed by gas-chromatography-mass spectrometry, which revealed mainly terpenes and sesquiterpenes, including (Z)β-farnesene (38.79%), β-pinene (17.53%), calamene (13.3%), and α-farnesene (10.38%). In vitro and in S. cerevisiae, the extract possessed antioxidant activity at different concentrations, compared to ascorbic acid (positive control). In normoglycemic and hyperglycemic rats, oral administration of 30 mg/kg of the extract reduced blood glucose levels; lipid peroxidation in liver, kidney and brain; protein carbonylation; and reactive oxygen species (ROS) production. It also increased catalase activity in the brain, kidneys and liver. These findings show that this hexanic extract of E. carlinae inflorescences possessed antioxidant properties.

Piper Essential Oils Inhibit Rhizopus oryzae Growth, Biofilm Formation, and Rhizopuspepsin Activity

Piper is the largest genus of the Piperaceae family. The species of this genus have diverse biological activities and are used in pharmacopeia throughout the world. They are also used in folk medicine for treatment of many diseases in several countries including Brazil, China, India, Jamaica, and Mexico. In Brazil, Piper species are distributed throughout the national territory, making this genus a good candidate for biological activity screening. During our studies with Piper essential oils, we evaluated its activity against Rhizopus oryzae, the main agent of mucormycosis. The main compounds of seven Piper essential oils analyzed were Piper callosum—safrole (53.8%), P. aduncum—dillapiole (76.0%), P. hispidinervum—safrole (91.4%), P. marginatum—propiopiperone (13.2%), P. hispidum—γ-terpinene (30.9%), P. tuberculatum—(E)-caryophyllene (30.1%), and Piper sp.—linalool (14.6%). The minimum inhibitory concentration of Piper essential oils against R. oryzae ranged from 78.12 to >1250 μg/mL. The best result of total inhibition of biofilm formation was obtained with Piper sp. starting from 4.88 μg/mL. Considering the bioactive potential of EOs against planktonic cells and biofilm formation of R. oryzae could be of great interest for development of antimicrobials for therapeutic use in treatment of fungal infection.

Chemical Characterization, Analgesic, Antioxidant, and Anticholinesterase Potentials of Essential Oils From Isodon rugosus Wall. ex. Benth

Isodon rugosus Wall. ex. Benth is an important species and is used in folk medicine for different types of pains such as abdominal pain, earache, toothache, gastric, and generalized body pain. Recently, we also have reported the antinociceptive potential of chloroform fraction of I. rugosus. In this research, we have investigated the antinociceptive, antioxidant and anti-cholinesterase potentials of essential oils from I. rugosus (Ir.EO), and have determined a possible mechanism of anti-nociception. The Ir.EO was subjected to gas chromatography-mass spectroscopy analysis to find out its chemical constituents. The Ir.EO was assayed for analgesic potential following acetic acid induced writhing, formalin test and hot plate method in animal models. The antioxidant activity was conducted against DPPH and ABTS free radicals following spectroscopic analysis. The cholinesterase inhibitory assays were performed using Ellman's assay. The GC-MS analysis of Ir.EO revealed the identification of 141 compounds. Ir.EO demonstrated strong antinociceptive potential in all three in-vivo models. With the use of nalaxone, it was confirmed that the essential oil was acting on the central pathway of nociception. The Ir.EO also exhibited strong free radicals scavenging potential, exhibiting IC₅₀ values of 338 and 118 μg/ml for DPPH and ABTS free radicals respectively. In AChE and BChE inhibitory assays, the observed IC₅₀ values were 93.56 and 284.19 μg/ml respectively. The encouraging antinociceptive, antioxidant and anticholinesterase results revealed that Ir.EO is a rich source of bioactive compounds as obvious from the GC-MS results.

Chemical Composition of Four Essential Oils of Eugenia from the Brazilian Amazon and Their Cytotoxic and Antioxidant Activity

Background:Eugenia species are appreciated for their edible fruits and are known as having anticonvulsant, antimicrobial and insecticidal actions. Methods: The plant material was collected in the southeastern Pará state of Brazil and submitted to hydrodistillation. GC-MS analyzed the oils, and their antioxidant and cytotoxic activities were evaluated by the DPPH and MTT assays. Results: The main components identified in the Eugenia oils were 5-hydroxy-cis-calemene, (2E,6E)-farnesol, (2E,6Z)-farnesol, caryophylla-4(12),8(13)-dien-5α-ol-5β-ol, E-γ-bisabolene, β-bisabolene, germacrene D, and ishwarane. The oil of E. egensis showed the most significant antioxidant activity (216.5 ± 11.6 mg TE/mL), followed by the oils of E. flavescens (122.6 ± 6.8 mg TE/mL) and E. patrisii (111.2 ± 12.4 mg TE/mL). Eugenia oils were cytotoxic to HCT-116 (colon cancer) cells by the MTT assay, where the most active was the oil of E. polystachya (10.3 µg/mL), followed by the oils of E. flavescens (13.9 µg/mL) and E. patrisii (16.4 µg/mL). The oils of E. flavescens and E. patrisii showed the highest toxicity for MRC5 (human fibroblast) cells, with values of 14.0 µg/mL and 18.1 µg/mL, respectively. Conclusions: These results suggest that Eugenia oils could be tested in future studies for the treatment of colon cancer and oxidative stress management.

Antioxidant Activities and Reduced Amyloid-β Toxicity of 7-Hydroxycalamenene Isolated from the Essential Oil of Zelkova serrata Heartwood

The in vitro and in vivo antioxidant activities and its potential to protect against amyloid-β toxicity of essential oils from Zelkova serrata (Thunb.) Makino were investigated in the model organism Caenorhabditis elegans. The results revealed that the essential oil of Z. serrata heartwood exhibited great radical scavenging activities and high total phenolic content. In vivo assays showed significant inhibition of oxidative damage in wild-type C. elegans under juglone-induced oxidative stress and heat shock. Based on results from both in vitro and in vivo assays, the major compound in essential oil of heartwood, (-)-(1 S, 4 S)-7-hydroxycalamenene (1 S, 4 S-7HC), may contribute significantly to the observed antioxidant activity. Further evidence showed that 1 S, 4 S-7HC significantly delayed the paralysis phenotype in amyloid beta-expressing transgenic C. elegans. These findings suggest that 1 S, 4 S-7HC from the essential oil of Z. serrata heartwood has potential as a source for antioxidant or Alzheimer's disease treatment.

7-hydroxycalamenene Effects on Secreted Aspartic Proteases Activity and Biofilm Formation of Candida spp

Background:

The 7-hydroxycalamenenene-rich essential oil (EO) obtained from the leaves of Croton cajucara (red morphotype) have been described as active against bacteria, protozoa, and fungi species. In this work, we aimed to evaluate the effectiveness of 7-hydroxycalamenenene against Candida albicans and nonalbicans species.

Materials and Methods:

C. cajucara EO was obtained by hydrodistillation and its major compound, 7-hydroxycalamenene, was purified using preparative column chromatography. The anti-candidal activity was investigated by minimum inhibitory concentration (MIC) and secreted aspartic proteases (SAP) and biofilm inhibition assays.

Results:

7-hydroxycalamenene (98% purity) displayed anti-candidal activity against all Candida species tested. Higher activity was observed against Candida dubliniensis, Candida parapsilosis and Candida albicans, showing MIC values ranging from 39.06 μg/ml to 78.12 μg/ml. The purified 7-hydroxycalamenene was able to inhibit 58% of C. albicans ATCC 36801 SAP activity at MIC concentration (pH 7.0). However, 7-hydroxycalamenene demonstrated poor inhibitory activity on C. albicans ATCC 10231 biofilm formation even at the highest concentration tested (2500 μg/ml).

Conclusion:

The bioactive potential of 7-hydroxycalamenene against planktonic Candida spp. further supports its use for the development of antimicrobials with anti-candidal activity.

SUMMARY

Croton cajucara Benth. essential oil provides high amounts of 7-hydroxycalamenene

7-Hydroxycalameneneisolated from C. cajucarais active against Candida spp

7-Hydroxycalameneneinhibits C. albicans aspartic protease activity

7-Hydroxycalamenene was not active against C. albicans biofilm formation.

Composition and biological activities of slaughterhouse blood from red deer, sheep, pig and cattle

BACKGROUND

Animal blood is a large-volume by-product of the meat industry. Besides blood meal fertiliser, blood is marketed for human consumption as a supplement. Minimal comparative work on slaughterhouse animal blood fractions has been carried out. In this study, slaughterhouse deer, sheep, pig and cattle blood parameters were compared. Some blood constituents were determined. Fractionated blood was assessed for antioxidant activity (2,2-diphenyl-1-picrylhydrazyl radical scavenging, oxygen radical scavenging capacity and ferric reducing antioxidant power). Angiotensin converting enzyme (ACE) inhibitory activity and antimicrobial activity were also assessed.

RESULTS

Serum iron ranged from 35.3 ± 0.6 µmol L(-1) in cattle to 16.3 ± 3.1 µmol L(-1) in deer. Cattle had the highest total plasma proteins (81.7 ± 1.5 g L(-1)). While the plasma fractions contained considerable antioxidant activity, the red blood cell fractions of all four animal species contained higher antioxidant activity (P < 0.05). Negligible levels of ACE inhibitory activity were found for all animal blood fractions. Antimicrobial activity was detected towards Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa with sheep white blood cells from which a crude neutrophil extract was obtained which demonstrated concentration-dependent inhibitory effects on the growth rates of these bacterial strains.

CONCLUSION

Fractionated animal blood obtained from local slaughterhouses contains native proteins that possess antioxidant activity and antimicrobial activity.

Phytochemistry of Daphne oleoides

Genus Daphne belongs to the Thymelaeaceae family and consists of 70 species. Its various species exist in Europe, Philippine Islands, temperate and subtropical Asia, North Africa, Australia and Pacific. In Pakistan, Daphne is represented by three species. Our focused Daphne oleoides is widely found in diverse climatic conditions from northern cold to central hot regions which creates a rich diversity and novelty in biosynthetic levels of its chemical constituents and hence is a great opportunity. Daphne oeloides is a proven rich source of a variety of unique and interesting nature-made skeletons with a wide range of therapeutic properties. D. oleoides possesses effective therapeutic properties, therefore, has been used in herbal medicines and is still being used to treat various diseases. The modern research by various groups, including ourselves, has resulted in the isolation of a number of natural molecules including some novel tris- and bis- coumarins, daphnane diterpenoids and lignoids. Therefore, due to novelty and richness of the nature-made molecules, and their therapeutic potential combined with our significant work on D. oleoides, this report covers chemical constituents isolated from D. oleoides. The pharmacological activities of the isolated compounds and use of this species in folk medicine have also been reviewed.

Chemical Composition of the Essential Oil from Croton Oblongifolius and its Antibacterial Activity Against Propionibacterium Acnes

The essential oil of C. oblongifolius Roxb. stem bark was obtained by hydrodistillation. Chemical analysis by GC-MS identified 29 compounds. Terpinen-4-ol (17.8%) was a major component, together with α-guaiene (7.9%), E-caryophyllene (7.0%), myrcene (6.7%), (+)-cyclosativene (5.1%), sabinene (4.8%), aciphyllene (4.7%), pogostol (4.6%), γ-terpinene (3.4%), α-muurolol (3.2%) and germecrene D (3.2%). The essential oil exhibited antibacterial activity against Propionibacterium acnes ATCC 6919 with an MIC of 0.125%, v/v.

In vitro cytocidal effects of the essential oil from Croton cajucara (red sacaca) and its major constituent 7- hydroxycalamenene against Leishmania chagasi

BACKGROUND

Visceral leishmaniasis is the most serious form of leishmaniasis and can be lethal if left untreated. Currently available treatments for these parasitic diseases are frequently associated to severe side effects. The leaves of Croton cajucara are used as an infusion in popular medicine to combat several diseases. Previous studies have demonstrated that the linalool-rich essential oil from C. cajucara (white sacaca) is extremely efficient against the tegumentary specie Leishmania amazonensis. In this study, we investigated the effects of the 7-hydroxycalamenene-rich essential oil from the leaves of C. cajucara (red sacaca) against Leishmania chagasi, as well as on the interaction of these parasites with host cells.

METHODS

Promastigotes were treated with different concentrations of the essential oil for determination of its minimum inhibitory concentration (MIC). In addition, the effects of the essential oil on parasite ultrastructure were analyzed by transmission electron microscopy. To evaluate its efficacy against infected cells, mouse peritoneal macrophages infected with L. chagasi promastigotes were treated with the inhibitory and sub-inhibitory concentrations of the essential oil.

RESULTS

The minimum inhibitory concentrations of the essential oil and its purified component 7-hydroxycalamenene against L. chagasi were 250 and 15.6 μg/mL, respectively. Transmission electron microscopy analysis revealed important nuclear and kinetoplastic alterations in L. chagasi promastigotes. Pre-treatment of macrophages and parasites with the essential oil reduced parasite/macrophage interaction by 52.8%, while it increased the production of nitric oxide by L. chagasi-infected macrophages by 80%.

CONCLUSION

These results indicate that the 7-hydroxycalamenene-rich essential oil from C. cajucara is a promising source of leishmanicidal compounds.