Antifungal Properties of Essential Oils Derived from the Genus Cymbopogon: A Systematic Review.

Essential oils (EOs) are products of secondary metabolism with recognized organoleptic characteristics and biological properties. Recently, there has been a growing demand for EOs in the national and international market, mainly due to the recognition of their use as complementary medicine practices, and the increased use in the industries of pharmaceutics, cosmetics, well-being, veterinary and agroecology, boosting the productive sector. In this context, EOs from grasses of the Cymbopogon (Poaceae) are promising sources of bioactive compounds, due to their recognized biological properties, such as anti-inflammatory, antibacterial, antifungal, antidiabetic, repellent, and larvicide. Thus, the present study aims to carry out a review of the scientific literature of the main works related to the evaluation of the antifungal action of essential oils extracted from plants of the Cymbopogon genus, compiling the species that showed the best results and relating them to their main chemical constituents. This review covers the following species: C. citratus, C. flexuosus, C. winterianus, C. martinii, C. nardus, C. giganteus, C. schoenanthus, C. khasans, and C. proximus. Among them, C. citratus was the most assessed, being associated with the vast majority of studies (61.9 %), and it was also the species that showed the best results in terms of MIC.

Where should I start? A scoping review about the publications on clove cigarettes.

INTRODUCTION: The general lack of knowledge about the composition of clove cigarettes and the large number of terms that can be used to define different types of cigarettes that contain cloves makes it difficult to find scientific articles focused on the subject. We reviewed the publications that cited clove cigarettes to assess their relevance. METHODS: We searched publications on Scopus, ScienceDirect, PubMed, and Portal CAPES during the first semester of 2021, without date restrictions. Through a quality assessment, the studies found were assorted in ten different categories. RESULTS: Indonesian clove cigarettes-also known as kretek-are a mixture of tobacco and cloves rolled in a cigarette and sprayed with oils, plant extract, and food flavorings, in an unknown quantity and composition, different from each brand, which is usually kept in secret. Due to the relatively low prevalence of use in the general population, most publications on tobacco products tend to ignore clove cigarettes or place them in an existing category. Clove cigarettes can be hand-rolled, machine-made, filtered, unfiltered, and each form can be named differently. The interchangeable use of each term, sometimes grouping conventional cigarettes in the mix, can lead the researcher to consider a publication that should be excluded. CONCLUSION: The existing regulations on flavored cigarettes, although well-intentioned, are still somewhat vague and broad, leaving possible loopholes that can be exploited by the tobacco industries. Fully understanding the precise effects caused by clove cigarettes can be an important tool in future discussions about tobacco control.

Antimicrobial Activity of Volatile Oils from Brazilian Stingless Bees Melipona quadrifasciata quadrifasciata and Tetragonisca angustula Propolis.

Few studies were performed on the volatile components' properties of propolis from native Brazilian stingless bees. This work sought to extract, chemically characterize, and evaluate of the antimicrobial properties of volatile oils from propolis of the stingless bees Melipona quadrifasciata quadrifasciata (MQ) and Tetragonisca angustula (TA). The volatile oils from the pulverized propolis samples were obtained in a Clevenger apparatus and characterized by gas chromatography coupled to mass spectrometry (GC/MS) and to flame ionization detector (GC-FID). All samples showed promising activity against Mycoplasma pneumoniae, with MICs from 103 to 224 µg mL-1 , nonetheless, they were less active against cell walled bacteria. Activity against Candida species was moderate, but one MQ sample showed a MIC value of 103 µg mL-1 against C. tropicallis. Oils' fractionation showed no improvement in antibacterial activity. The promising antibacterial effect against this microorganism is likely related to the synergism between the components of the volatile oils.

Curcumin and n-acetylcysteine cocrystal produced with supercritical solvent: characterization, solubility, and preclinical evaluation of antinociceptive and anti-inflammatory activities.

Curcumin presents a promising anti-inflammatory potential, but its low water-solubility and bioavailability hinder its application. In this sense, cocrystallization represents a tool for improving physicochemical properties, solubility, permeability, and bioavailability of new drug candidates. Thus, the aim of this work was to produce curcumin cocrystals (with n-acetylcysteine as coformer, which possesses anti-inflammatory and antioxidant activities), by the anti-solvent gas technique using supercritical carbon dioxide, and to test its antinociceptive and anti-inflammatory potential. The cocrystal was characterized by differential scanning calorimetry, powder X-ray diffraction and scanning electron microscopy. The cocrystal solubility and antichemotaxic activity were also assessed in vitro. Antinociceptive and anti-inflammatory activities were carried out in vivo using the acetic acid-induced abdominal writhing and carrageenan-induced paw oedema assays in mice. The results demonstrated the formation of a new crystalline structure, thereby confirming the successful formation of the cocrystal. The higher solubility of the cocrystal compared to pure curcumin was verified in acidic and neutral pH, and the cocrystal inhibited the chemotaxis of neutrophils in vitro. In vivo assays showed that cocrystal presents increased antinociceptive and anti-inflammatory potency when compared to pure curcumin, which could be related to an improvement in its bioavailability.

Polyphenolic Composition and in Vitro Antihypertensive and Anti-Inflammatory Effects of Cuphea lindmaniana and Cuphea urbaniana.

The present study investigates the chemical composition, anti-inflammatory, and antihypertensive activities, in vitro, from extracts of Cuphea lindmaniana and Cuphea urbaniana leaves. The extraction was performed ultrasound-assisted, and UHPLC/MS analysis was in positive mode ionization. The anti-inflammatory activity of the extracts and miquelianin were assayed at concentrations 0.001-10 µg/mL by chemotaxis on rat polymorphonuclear neutrophils. The antihypertensive activity was performed by angiotensin-converting enzyme (ACE) inhibition. From the nineteen proposed compounds, six of them are described for the first time in this genus. The extracts displayed antichemotactic effect with a reduction of 100 % of the neutrophil migration, in vitro, in most concentrations. The ACE-inhibition presented results ranging from 19.58 to 22.82 %. In conclusion, C. lindmaniana and C. urbaniana extracts contain a rich diversity of flavonoids and display in vitro anti-inflammatory and antihypertensive potential. Thus, this study could serve as a scientific baseline for further investigation, on developmental novel products with therapeutic actions.

Antineoplastic potential and chemical evaluation of essential oils from leaves and flowers of Tagetes ostenii Hicken.

Breast and cervical cancer represent a major problem of women's global public health. Here, we investigated the chemical composition of essential oils from leaves and flowers of T. ostenii and the antineoplastic potential in a cervical cancer and breast cancer cell line, SiHa and MCF-7; and non-tumoral cells, HaCat. The chemical analysis revealed a predominance of oxygenated monoterpenes in both essential oils. The IC50 after 24 h of treatment was 72 ng/mL for EO 1 and 83 ng/mL for EO 2 in SiHa cells. For MCF-7 the IC50 was 174.3 ng/mL for EO 1. For HaCat cells it was 54.45 ng/mL for EO 1 and 20.83 ng/mL for EO 2. A synergistic effect with both essential oils and cisplatin was also verified. SiHa cells had their wound healing capacity reduced after 48 h of treatment with EO 2 and both essential oils were able to significantly inhibit the adhesion process and clonogenic ability after 24 h of treatment. Our results suggest a long-lasting inhibitory activity in SiHa cells because of the low recovery capacity of cells after treatment withdrawal. Flow cytometer with annexin V/propidium iodide demonstrated a majority cell death through late apoptosis after 24, 48 and 72 hours of treatment.

Development of analytical method for the quality control of the fruit bark of Punica granatum L. (pomegranate) and antichemotatic activity of extract and rich fraction in punicalagins.

Pomegranate is of current interest owing to the existing potential for industrial uses of fruit peels. This includes its availability as a raw vegetable material, a byproduct that constitutes residue in the use of the species and is recognized as a functional product, and beneficial health properties, as will be demonstrated in the studies cited. Therefore, it is necessary to ensure its effectiveness and safety. Toward this end, the aim of this study was to develop and validate an analytical method for the separation and quantification of total punicalagin present in the bark of the fruit of Punica granatum by HPLC. Purity tests such as water determination and total ashes were also performed. The ability of the extract and enriched fraction of punicalagin to inhibit leukocyte migration in vitro was determined by the Boyden's chamber method. The developed HPLC method demonstrated good separation and quantification of the punicalagin α and ß anomers. The method is efficient and reliable, and can ultimately be used for the analysis of the extract of pomegranate. The crude extract and the fraction of punicalagins significantly inhibited leukocyte migration at concentrations of 1 and 10 µg/mL in relation to the negative control, indicating potential antichemotactic action.

Antichemotactic and Antifungal Action of the Essential Oils from Cryptocarya aschersoniana, Schinus terebinthifolia, and Cinnamomum amoenum.

The purpose of this work was to determine the chemical composition and evaluate the antichemotactic, antioxidant, and antifungal activities of the essential oil obtained from the species Cryptocarya aschersoniana Mez, Cinnamomum amoenum (Ness & Mart.) Kosterm., and Schinus terebinthifolia Raddi, as well as the combination of C. aschersoniana essential oil and terbinafine against isolates of dermatophytes. Allo-aromadendrene, bicyclogermacrene, and germacrene B were identified as major compounds in essential oils. The essential oil of C. aschersoniana shown 100 % inhibitory effect on leukocyte migration at the concentration of 10 µg/mL while S. terebinthifolia oil presented 80.1 % inhibitory effect at the same concentration. Only S. terebinthifolia oil possessed free-radical-scavenging activity which indicates its antioxidant capacity. The essential oils were also tested against fungal isolates of dermatophyte species (Trichophyton rubrum, Trichophyton mentagrophytes, Microsporum canis and Microsporum gypseum), resulting in MIC ranging from 125 µg/mL to over 500 µg/mL. C. aschersoniana oil combined with terbinafine resulted in an additive interaction effect. In this case, the essential oil may act as a complement to conventional therapy for the topical treatment of superficial fungal infections, mainly because it is associated with an anti-inflammatory effect.

Effect of Free and Nanoencapsulated Copaiba Oil on Monocrotaline-induced Pulmonary Arterial Hypertension.

Copaiba oil comes from an Amazonian tree and has been used as an alternative medicine in Brazil. However, it has not been investigated yet in the treatment of cardiovascular diseases. This study was designed to test whether copaiba oil or nanocapsules containing this oil could modulate monocrotaline (MCT)-induced pulmonary arterial hypertension (PAH). Male Wistar rats (170 ± 20 g) received oil or nanocapsules containing this oil (400 mg/kg) by gavage daily for 1 week. At the end of this period, a single injection of MCT (60 mg/kg i.p.) was administered and measurements were performed after 3 weeks. The animals were divided into 6 groups: control, copaiba oil, nanocapsules with copaiba oil, MCT, oil + MCT, and nanocapsules + MCT. Afterward, echocardiographic assessments were performed, and rats were killed to collect hearts for morphometry and oxidative stress. MCT promoted a significant increase in pulmonary vascular resistance, right ventricle (RV) hypertrophy, and RV oxidative stress. Both oil and copaiba nanocapsules significantly reduced RV hypertrophy and oxidative stress. Pulmonary vascular resistance was reduced by copaiba oil in natura but not by nanocapsules. In conclusion, copaiba oil seems to offer protection against MCT-induced PAH. Our preliminary results suggest that copaiba oil may be an important adjuvant treatment for PAH.

A Chemometrics Approach to the Investigation of the Intraspecific Variability of the Volatile Oil of Eupatorium tremulum from Southern Brazil.

Eupatorium tremulum is a South American shrub reported to cause cattle digestive intoxication, of which the volatile oil, mainly composed by bisabolane- and amorphane-type sesquiterpenoids, exhibits high quantitative variability. This report describes the application of chemometric tools for the identification of volatile compounds that characterize phenophasical changes in the plant. Preblooming, blooming, and postblooming specimens were paired-sampled and submitted to hydrodistillation and GC-MS analysis. Differential results were analyzed by orthogonal projection to latent structures-discriminant analysis (OPLS-DA), and the substances with different distribution in each phase were highlighted. Mean results between phases were submitted to factor analysis (FA), and correlations between the variables were demonstrated. Preblooming to blooming phase change was characterized by decreased levels of amorpha-4-en-7-ol (13) and epi-α-bisabolol (19) and increased amounts of amorpha-4,7(11)-diene (1). Blooming to postblooming change was characterized by decreases in 1, germacrene D (2), and ß-bisabolene (4) and increases in 13 and 19. Finally, enhanced levels of 1, 4, and 2 reflected the change from the postblooming to the preblooming phase. FA revealed a strong correlation in the variability between the bisabolane hydrocarbons, possibly related to its common enzymatic origin. Another strong source of negative correlation showed bisabolane- and amorphane-type alcohols, on one side, and amorphane-type furans, on the other side, to occur in two alternative oxidation routes. Finally, 1 was strongly negatively correlated to its oxidized furan and ketofuran derivatives [verboccidentafuran (16) and 3-oxo-verboccidentafuran (23)] and additionally to a third compound, putatively identified as a biosynthetic intermediate between this hydrocarbon and the furans, amorpha-4,7(11)-dien-8-one (20).

Anticholinesterase activity and identification of huperzine A in three Mexican lycopods: Huperzia cuernavacensis, Huperzia dichotoma and Huperzia linifolia (Lycopodiaceae).

Huperzine A (Hup A), the alkaloid produced by the Chinese medicinal plant Huperzia serrata, has been documented to be a promising agent for the treatment of Alzheimer's disease due to its potent acetylcholinesterase inhibitory (AChEI) activity. The search for anticholinesterase natural products, as well as for alternative sources of Hup A in Mexican lycopods, prompted us to investigate these plants. The action of methanolic and alkaloidal extracts of three Huperzia species (H. cuernavacensis, H. dichotoma, and H. linifolia) was evaluated using an in vitro anticholinesterase activity assay. Also, chromatographic and spectroscopic analyses were employed to detect the presence of Hup A. Methanolic and alkaloidal extracts of H. cuernavacensis showed IC50 =5.32±0.8µg/mL and 0.74±0.05µg/mL; H. dichotoma displayed AChEI with IC50 values =14.11±2.1µg/mL and 0.64±0.09µg/mL; and H. linifolia presented IC50 =158.37±8.7µg/mL and 4.2±1.24µg/mL, respectively, compared to the control Hup A (IC50= 0.16±0.03µg/mL). Hup A was identified in the extracts of H. dichotoma, but it was not detected in the extracts of H. cuernavacensis and H. linifolia by 1H NMR techniques. This study reveals H. dichotoma as a new source of Hup A, and presents H. linifolia and H. cuernavacensis as potential candidates to obtain other anticholinesterase compounds useful in the Alzheimer's disease treatment.

Chemical analysis and in vitro antiviral and antifungal activities of essential oils from Glechon spathulata and Glechon marifolia.

CONTEXT: Glechon spathulata Benth. and Glechon marifolia Benth. (Lamiaceae, Mentheae) are aromatic plants used in traditional medicine for the treatment of viral infections. OBJECTIVE: The chemical composition and antiviral and antifungal activities of Glechon spathulata and Glechon marifolia essential oils were investigated. MATERIALS AND METHODS: The oils were obtained by hydrodistillation and analyzed by GC-FID and GC-MS. Anti-herpes virus (HSV-1) activity was examined in Vero cells by yield reduction assay, in doses of 0.0095% v/v and 0.039% v/v, for G. spathulata and G. marifolia oil, respectively. Antifungal activity was carried by the broth microdilution method, in oil concentrations that ranged from 5.2 to 500 µg/mL. RESULTS: ß-Caryophyllene (14.2% and 32.2% for G. spathulata and G. marifolia, respectively) and bicyclogermacrene (17.1% and 16.5%, respectively) were the major components of both oils. At noncytotoxic concentrations of the essential oils, the viral titer was reduced by up to 2 log10 for KOS and VR-733 strains. The antifungal activity was observed against Trichophyton rubrum (MIC 10-83 µg/mL) and Epidermophyton floccosum (MIC 83-500 µg/mL). The oil of G. spathulata exhibited activity against the three strains tested (KOS, VR733, and 29-R), whereas G. marifolia oil was active against two strains, KOS and VR733. DISCUSSION AND CONCLUSION: The chemical composition for G. spathulata and G. marifolia essential oils is very similar. The oil of G. spathulata can be promising as a new antifungal agent against dermatophytes. The findings add important information to the biological activity of Glechon species essential oils, specifically its antiviral and antidermatophytic properties.

Xanthan-carrageenan film containing sesame seed oil: A nanocomposite pharmaceutical platform for trichomoniasis treatment.

Trichomoniasis is a common sexually transmitted infection that poses significant complications for women. Challenges in treatment include adverse effects and resistance to standard antimicrobial agents. Given this context, a sesame seed oil nanoemulsion (SONE) was developed and showed anti-Trichomonas vaginalis activity. To facilitate the local application of SONE, a polysaccharide film was developed using xanthan gum (XG) and κ-carrageenan gum (CG). A blend of XG and CG (at 2 %, ratio 1:3) plasticized with glycerol produced a more promising film (XCF) than using the gums individually. The film containing SONE (SONE-XCF) was successfully obtained by replacing the aqueous solvent with SONE via solvent evaporation technique. The hydrophilic SONE-XCF exhibited homogeneity and suitable mechanical properties for vaginal application. Furthermore, SONE-XCF demonstrated mucoadhesive properties and high absorption capacity for excessive vaginal fluids produced in vaginitis. It also had a disintegration time of over 8 h, indicating long retention at the intended site of action. Hemolysis and chorioallantoic membrane tests confirmed the safety of the film. Therefore, SONE-XCF is a biocompatible film with a natural composition and inherent activity against T. vaginalis, possessing exceptional characteristics that make it appropriate for vaginal application, offering an interesting alternative for trichomoniasis treatment.

Development by design of experiment and validation of a HPLC-UV method for simultaneous quantification of 1-nitro-2-phenylethane and methyleugenol: Application to nail permeation/retention studies.

Aniba canelilla (Kunth) Mez is an aromatic tree from Amazon region whose essential oil presents 1-nitro-2-phenylethane (NP) and methyleugenol (ME) as major compounds. Several properties are attributed to Aniba canelilla essential oil (ACEO), such as antifungal. Onychomycoses are fungal nail infections that require novel therapeutic alternatives, especially topical ones. However, to ensure the success of topical therapy, the active compound should be able to penetrate/permeate the nail plate, which is challenging due to the highly keratinized composition of this structure. Thus, the aims of this article were to develop, validate and apply a high-performance liquid chromatography method (HPLC-UV) to quantify NP and ME in porcine hoof extract (PHE) and receptor fluid (RF) during in vitro permeation/retention studies in nail model, for which porcine hoof membranes were used. For method development, two Designs of Experiment (DoE) were adopted: 23 Full Factorial and Box-Behnken. Retention times of 5.65 and 7.49 min were achieved for NP and ME, respectively. The method was full validated for NP and ME quantification in receptor fluid, in accordance with the recommended parameters by ICH Q2(R1) Guideline. In addition, the method was full validated for NP and ME quantification in porcine hoof extract, considering the parameters and criteria of ICH M10 Guideline. In vitro permeation/retention studies were carried out in nail model, and promising results were obtained. NP reached the receptor fluid in the order of 441.1 ± 92.1 µg/cm2 at 72 h. The amount of NP and ME retained into porcine hoof membrane was 1272.6 ± 225.7 µg/cm2 and 84.7 ± 20.4 µg/cm2, respectively, at 72 h. Our findings open perspective to develop topical formulations containing ACEO as active compound aiming the management of onychomycosis.

Monoamine oxidase inhibition by monoterpene indole alkaloids and fractions obtained from Psychotria suterella and Psychotria laciniata.

Alkaloid fractions of Psychotria suterella (SAE) and Psychotria laciniata (LAE) as well as two monoterpene indole alkaloids (MIAs) isolated from these fractions were evaluated against monoamine oxidases (MAO-A and -B) obtained from rat brain mitochondria. SAE and LAE were analysed by HPLC-PDA and UHPLC/HR-TOF-MS leading to the identification of the compounds 1, 2, 3 and 4, whose identity was confirmed by NMR analyses. Furthermore, SAE and LAE were submitted to the enzymatic assays, showing a strong activity against MAO-A, characterized by IC(50) values of 1.37 ± 1.05 and 2.02 ± 1.08 µg/mL, respectively. Both extracts were also able to inhibit MAO-B, but in higher concentrations. In a next step, SAE and LAE were fractionated by RP-MPLC affording three and four major fractions, respectively. The RP-MPLC fractions were subsequently tested against MAO-A and -B. The RP-MPLC fractions SAE-F3 and LAE-F4 displayed a strong inhibition against MAO-A with IC(50) values of 0.57 ± 1.12 and 1.05 ± 1.15 µg/mL, respectively. The MIAs 1 and 2 also inhibited MAO-A (IC(50) of 50.04 ± 1.09 and 132.5 ± 1.33 µg/mL, respectively) and -B (IC(50) of 306.6 ± 1.40 and 162.8 ± 1.26 µg/mL, respectively), but in higher concentrations when compared with the fractions. This is the first work describing the effects of MIAs found in neotropical species of Psychotria on MAO activity. The results suggest that species belonging to this genus could consist of an interesting source in the search for new MAO inhibitors.

Alkaloid profiling and anticholinesterase activity of South American Lycopodiaceae species.

The alkaloid extracts of four Huperzia and one Lycopodiella species, from Brazilian habitats, were tested for their in vitro anticholinesterase activities. IC(50) values showed a potent acetylcholinesterase inhibition for H. reflexa (0.11 ± 0.05 µg/mL), followed by H. quadrifariata (2.0 ± 0.3 µg/mL), H. acerosa (5.5 ± 0.9 µg/mL), H. heterocarpon (25.6 ± 2.7 µg/mL) and L. cernua (42.6 ± 1.5 µg/mL). A lower inhibition of butyrylcholinesterase was observed for all species with the exception of H. heterocarpon (8.3 ± 0.9 µg/mL), whose alkaloid extract presented a selectivity for pseudocholinesterase. Moreover, the chemical study of the bioactive extracts performed by GC-MS, revealed the presence of a number of Lycopodium alkaloids belonging to the lycopodane, flabellidane and cernuane groups. Surprisingly, the potent acetylcholinesterase inhibitors huperzines A and B were not detected in the extracts, suggesting that other alkaloids may be responsible for such an effect.

Acetylcholinesterase Inhibition Activity of Hippeastrum papilio (Ravenna) Van Scheepen (Amaryllidaceae) Using Zebrafish Brain Homogenates.

The Amaryllidaceae family constitutes an interesting source of exclusive alkaloids with a broad spectrum of biological activity. Galanthamine, the most relevant one, has been commercialized for the palliative treatment of Alzheimer's disease symptoms since 2001 due to its potential as an acetylcholinesterase (AChE) inhibitor. In vitro screenings against AChE by applying different Amaryllidaceae species and alkaloids have been reported in the literature; however, they are usually carried out using purified market enzymes. The main goal of this work is to evaluate the AChE inhibitory potential of Hippeastrum papilio (Amaryllidaceae) extracts using zebrafish brain homogenates. The biological assays show that the H. papilio bulb extracts present an interesting AChE inhibitory activity in comparison with the positive reference control galanthamine (IC50 values of 1.20 ± 0.10 and 0.79 ± 0.15 µg/mL, respectively). The chemical profile of H. papilio shows that this species has a high amount of galanthamine, which may contribute to the inhibitory effect on AChE activity of zebrafish brains. Computational experiments were used to build the model for zebrafish AChE and to evaluate the interactions between galanthamine and the enzymic active site. This work suggests that zebrafish could represent an important model in the search for bioactive molecules from the Amaryllidaceae family for the treatment of Alzheimer's disease.

Neuroinflammation and hypersensitivity evidenced by the acute and 28-day repeated dose toxicity tests of ostrich oil in mice.

The ostrich oil (OO) has been topically used for decades to treat skin diseases. Its oral use has been encouraged through e-commerce advertising several health benefits to OO without scientific evidence on its safety or effectiveness. This study presents the chromatographic profile of a commercially available OO and its acute and 28-day repeated dose in vivo toxicological profiles. OO anti-inflammatory and antinociceptive effects were also investigated. Omega-9 (ω-9; oleic acid; 34.6%) and -6 (linoleic acid; 14.9%) were detected as OO main constituents. A high single dose of the OO (2 g/kg of ω-9) demonstrated no or low acute toxicity. However, when orally treated with OO (30-300 mg/kg of ω-9) for 28 consecutive days, mice exhibited altered locomotor and exploratory activities, hepatic damage, and increased hindpaw sensitivity accompanied by increased levels of cytokine and brain-derived neurotrophic factor in their spinal cords and brains. Lack of anti-inflammatory or antinociceptive activities was also evidenced in 15-day-OO treated mice. These results indicate that chronic consumption of OO induces hepatic injury, in addition to neuroinflammation and subsequent hypersensitivity and behavioural changes. Thus, there is no evidence to support OO use to treating illness in humans.

Chemical composition and amoebicidal activity of Croton pallidulus, Croton ericoides, and Croton isabelli (Euphorbiaceae) essential oils.

Acanthamoeba is a free-living amoebae genus that causes amoebic keratitis which is a painful sight-threatening disease of the eyes. Its treatment is difficult, and the search for new drugs is very important. Here, essential oils obtained from the aerial parts of Croton pallidulus, Croton isabelli, and Croton ericoides (Euphorbiaceae), native plants of Southern Brazil, were tested against Acanthamoeba polyphaga and analyzed by gas chromatography and gas chromatography-mass spectrometry. The essential oils of C. pallidulus and C. isabelli were characterized by the presence of sesquiterpenes: germacrene D (15.5 %), terpinen-4-ol (13.2 %), and ß-caryophyllene (13.1 %) in C. pallidulus and bicyclogermacrene (48.9 %) in C. isabelli. The essential oil of C. ericoides presented mainly monoterpenes, ß-pinene (39.0 %) being the main component. Laboratory tests were carried out to determine the effect of the essential oils against A. polyphaga trophozoites. The essential oil of C. ericoides was the most active, killing 87 % of trophozoites at the concentration of 0.5 mg/mL. The essential oil of C. pallidulus killed only 29 % of the trophozoites at the same concentration. The essential oil of C. isabelli presented the lowest activity, killing only 4 % of the trophozoites at the concentration of 10 mg/mL. The essential oils of the three species showed cytotoxic effect by the methyl thiazolyl tetrazolium (MTT) method in Vero cells. The oil of C. ericoides, which showed the highest amoebicidal activity, was the most cytotoxic on these mammalian cells.

Chemical composition and anti-inflammatory activity of the essential oils of Piper gaudichaudianum and Piper mikanianum.

ETHNOPHARMACOLOGICAL RELEVANCE: Inflammation is the body's normal protective response to injury and is stimulated by pathogens, toxic compounds, damaged cells or radiation, promoting healing and restoring homeostasis to the injured tissue. Leaves of Piper gaudichaudianum Kunth, known as "pariparoba" are widely used in folk medicine for the relief of toothache, while the fresh roots are used as anti-inflammatory and to treat liver disorders. For P. mikanianum (Kunth) Steud is known as "aguaxima", is widely used in the treatment of inflammation, rheumatism and ulcer, with its roots being used for stomach disorders and as a diaphoretic in intermittent fevers. AIM OF THE STUDY: Therefore, this work aims to chemically characterize the essential oil of Piper gaudichaudianum and Piper mikanianum, as well as the evaluation of neutrophil antichemotactic activity of both essential oils in order to complement the information of its traditional use, taking the leaves as plant material and, with that, corroborating its use in folk medicine for the treatment of inflammatory diseases. MATERIALS AND METHODS: The essential oil from leaves of both Piper species were obtained from crushed fresh samples, by hydrodistillation using a Clevenger type-apparatus for 4 h. The yield determination was performed as vol/wt (v/w) and in triplicate. The amount of essential oil obtained was quantified in mL. The identification and quantification of the compounds was performed using gas chromatography-mass spectrometry (GC-MS) and gas chromatography-flame ionization detection (GC-FID). The in vitro anti-inflammatory activity was evaluated using the model of modified Boyden chamber. In this test the essential oils were tested for their ability to inhibit leukocyte chemotaxis stimulated by Escherichia coli lipopolysaccharide. RESULTS: The chemical composition of the essential oils revealed the identification of 26 constituents for P. gaudichaudianum being the sesquiterpenes ß-selinene (14.0%) and viridiflorene (10.5%) the main compounds, followed by caryophyllene oxide (9.3%) and (E)-nerolidol (9.0%). For P. mikanianum essential oil, ß-myrcene (17.2%) and bicyclogermacrene (26.3%) were the major components in the monoterpenes and sesquiterpene fractions, respectively. The essential oils were also tested for their ability to inhibit neutrophil chemotaxis in vitro when stimulated by Escherichia coli lipopolysaccharide. Both essential oils showed antichemotactic effect with reduction in migration of 0-72.2% for P. gaudichaudianum and 8.6-100% for P. mikanianum to same concentrations, suggesting a response to acute inflammatory processes. CONCLUSIONS: Since up to date there is no report of this biological activities by this mechanism (antichemotactic assay) for essential oils this species. These results showed that the essential oils of P. gaudichaudianum and P. mikanianum have a great capacity to inhibit neutrophil chemotaxis in an inflammatory process, in a dose-dependent way, suggesting anti-inflammatory potential, by preventing its accumulation at the injury site with the possibility of tissue damage. Findings of these studies support the traditional use of these species in the treatment of inflammatory processes.