Chemical Composition and Antimicrobial Properties of Piper ovatum Vahl

Natural products of plant origin: an emerging therapeutic for dermatomycosis

Dermatomycosis or superficial mycosis is considered one of the chronic fungal infections and a global challenge for the public health system. The severity of dermatomycosis is proportionately increasing with the emerging population of immunocompromised individuals, and it is becoming more prevalent, even life-threatening, in several tropical countries. In this context, improper long-term treatment with synthetic antifungal drugs and their related side effects imposes additional challenges in treating dermatomycosis. Thus, the present scenario highlights the need for a novel and accurate treatment with minimal or no side effects. The multifaceted therapeutic properties of various natural products have garnered the interest of scientific communities in recent years. Generally, plant-based products have low toxicity levels and offer diverse formulations and unique biomolecules for clinical applicability against dermatomycosis. Thus, this study presents an overview of the pathogenesis and different treatment strategies for dermatomycosis. In addition, we highlight the implementation of natural products of plant origin for treating dermatomycosis infections and reducing adverse events. Further, their mode of action and role in the development of pharmaceutical drugs are discussed.

Microbial communities of Schisandra sphenanthera Rehd. et Wils. and the correlations between microbial community and the active secondary metabolites

Background

Schisandra sphenanthera Rehd. et Wils. is a plant used in traditional Chinese medicine (TCM). However, great differences exist in the content of active secondary metabolites in various parts of S. sphenanthera. Do microorganisms critically influence the accumulation of active components in different parts of S. sphenanthera?

Methods

In this study, 16S/ITS amplicon sequencing analysis was applied to unravel microbial communities in rhizospheric soil and different parts of wild S. sphenanthera. At the same time, the active secondary metabolites in different parts were detected, and the correlation between the secondary metabolites and microorganisms was analyzed.

Results

The major components identified in the essential oils were sesquiterpene and oxygenated sesquiterpenes. The contents of essential oil components in fruit were much higher than that in stem and leaf, and the dominant essential oil components were different in these parts. The dominant components of the three parts were γ-muurolene, δ-cadinol, and trans farnesol (stem); α-cadinol and neoisolongifolene-8-ol (leaf); isosapathulenol, α-santalol, cedrenol, and longiverbenone (fruit). The microbial amplicon sequences were taxonomically grouped into eight (bacteria) and seven (fungi) different phyla. Community diversity and composition analyses showed that different parts of S. sphenanthera had similar and unique microbial communities, and functional prediction analysis showed that the main functions of microorganisms were related to metabolism. Moreover, the accumulation of secondary metabolites in S. sphenanthera was closely related to the microbial community composition, especially bacteria. In endophytic bacteria, Staphylococcus and Hypomicrobium had negative effects on five secondary metabolites, among which γ-muurolene and trans farnesol were the dominant components in the stem. That is, the dominant components in stems were greatly affected by microorganisms. Our results provided a new opportunity to further understand the effects of microorganisms on the active secondary metabolites and provided a basis for further research on the sustainable utilization of S. sphenanthera.

Chemical Constituents and Biological Activities of Piper as Anticancer Agents: A Review

Cancer has become the primary cause of death worldwide, and anticancer drugs are used to combat this disease. Synthesis of anticancer drugs has limited success due to adverse side effects has made compounds from natural products with minimal toxicity gain much popularity. Piper species are known to have a biological effect on human health. The biological activity is due to Piper species rich with active secondary metabolites that can combat most diseases, including cancer. This review will discuss the phytochemistry of Piper species and their anticancer activity. The identification and characterization of ten active metabolites isolated from Piper species were discussed in detail and their anticancer mechanism. These metabolites were mainly found could inhibit anticancer through caspase and P38/JNK pathways. The findings discussed in this review support the therapeutic potential of Piper species against cancer due to their rich source of active metabolites with demonstrated anticancer activity.

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.

Potential of Piper spp. as a source of new compounds for the leishmaniases treatment

Current treatment guidelines for leishmaniasis is based on chemotherapy with drugs that show a set of limitations such as high cost, toxicity, difficult route of administration, and lack of efficacy in endemic areas. In this context, phytopharmaceutical products and herbal medicines emerge as promising alternatives for developing new treatment against leishmaniasis. This review discusses the perspectives of leishmaniasis treatment based on natural products and phytotherapy highlighting the Piper genus, especially P. aduncun and P. mollicomum Kunth covering the period of 1998 to 2020. Leishmanicidal activity of pure compounds of Piper spp. [3-(3,4,5-trimethoxyphenyl) propanoic acid, 3-chlorosintenpyridone, 2'-hydroxy-3',4',6'-trimethoxy-chalcone, cardamonin, conocarpan, cubebin, eupomatenoid, flavokavain B, ( +)-(7R,8S)-epoxy-5,6-didehydrokavain, N-[7-(3',4'-methylenedioxypheny l-2(E),4(E)-heptadienoyl-pyrrolidine, N-[7-(3',4'-methylenedioxyphenyl)-2(Z),4(Z)-heptadienoyl-pyrrolidine, piperovatine, pellitorine, and piplartine (piperlongumine)] were proved against the promastigote and amastigote forms of parasite related with cutaneous (L. (L.) amazonensis, L. (V.) braziliensis, and L. (V.) guyanensis) and visceral (L. (L.) donovani, L. (L.) chagasi, and L. (L.) infantum). We also discussed the perspective of leishmaniasis treatment, considering the potential synergism between different promising species of Piper, presenting some interesting interaction possibilities for future studies between plants. Finally, the necessary steps for technological development of phytomedicines and herbal medicines with the desirable quality requirements for medicines are highlighted. The data presented here highlight the use of Piper spp. as source of pharmacological compounds that can lead to effective, safe, and inexpensive treatments for leishmaniasis.

Chemical Composition, Antipathogenic and Cytotoxic Activity of the Essential Oil Extracted from Amorpha fruticosa Fruits

The purpose of this paper was to characterize and investigate the antimicrobial potential of Amorpha fruticosa fruits essential oil (EO). The EO was extracted by hydrodistillation, analyzed by GC-MS, and then evaluated for its interaction with microbial and mammalian cells. The antimicrobial activity was assessed against bacterial and fungal strains, in a planktonic and adherent growth state, using qualitative and quantitative assays. The main components identified in A. fruticosa fruits EO were δ-cadinene, γ-muurolene, and α-muurolene. The Gram-positive strains proved to be more susceptible than Gram-negative bacteria and fungal strains. The EO exhibited good antibiofilm activity, inhibiting the microbial adherence to the inert (96-well plates and Foley catheter section) and cellular substrata. The flow cytometry analysis revealed as one of the possible mechanisms of antimicrobial action the alteration of cell membrane hydrophobicity. The cytotoxicity on the L929 cell line occurred at concentrations higher than 0.3 mg/mL. Taken together, our results demonstrate that A. fruticosa fruits EO contains active compounds with selective inhibitory effect on different microbial strains in planktonic and biofilm growth state, explained at least partially by the interference with microbial membranes due to their hydrophobic character.

Antimicrobial activity of Asteraceae species against bacterial pathogens isolated from postmenopausal women

Purpose

Investigation of the antibacterial action of aqueous extracts of Bidens sulphurea, Bidens pilosa, and Tanacetum vulgare, species of Asteraceae family that are popularly used for the treatment of genito-urinary infection.

Methods

The minimum inhibitory concentration (MIC) and minimal bacterial concentration (MBC) of the extracts against standard strains of Staphylococcus aureus (ATCC25923), Enterococcus faecalis (ATCC29212), Escherichia coli (ATCC25922), and Pseudomonas aeruginosa (ATCC27853) and against bacteria that were isolated from cultures of vaginal secretions and urine from menopausal women with a diagnosis of recurrent urinary tract infections (rUTI) were determined by broth microdilution.

Results

The MIC values of the three extracts against Gram-positive and Gram-negative standard bacterial strains ranged from 7.81 to 125.00 mg ml^-1, and the MBC values ranged from 7.81 to 500.00 mg ml^-1. However, B. sulphurea was more efficient. In the urine samples, the three extracts inhibited the growth of coagulase-negative Staphylococcus spp., and the B. pilosa was the most active extract against E. coli compared with the other ones. For the vaginal secretion samples, no significant differences in the inhibition of coagulase-positive Staphylococcus spp. and P. mirabilis were found among the extracts. T. vulgare and B. sulphurea were more effective in inhibiting coagulase-negative Staphylococcus spp. compared with B. pilosa. E. coli was more susceptible to the B. sulphurea extract compared with the B. pilosa and T. vulgare extracts.

Conclusion

The present results suggested the potential medicinal use of Asteraceae species, especially B. sulphurea, as therapeutic agents against rUTI-related bacteria.

Piper Species: A Comprehensive Review on Their Phytochemistry, Biological Activities and Applications

Piper species are aromatic plants used as spices in the kitchen, but their secondary metabolites have also shown biological effects on human health. These plants are rich in essential oils, which can be found in their fruits, seeds, leaves, branches, roots and stems. Some Piper species have simple chemical profiles, while others, such as Piper nigrum, Piper betle, and Piper auritum, contain very diverse suites of secondary metabolites. In traditional medicine, Piper species have been used worldwide to treat several diseases such as urological problems, skin, liver and stomach ailments, for wound healing, and as antipyretic and anti-inflammatory agents. In addition, Piper species could be used as natural antioxidants and antimicrobial agents in food preservation. The phytochemicals and essential oils of Piper species have shown strong antioxidant activity, in comparison with synthetic antioxidants, and demonstrated antibacterial and antifungal activities against human pathogens. Moreover, Piper species possess therapeutic and preventive potential against several chronic disorders. Among the functional properties of Piper plants/extracts/active components the antiproliferative, anti-inflammatory, and neuropharmacological activities of the extracts and extract-derived bioactive constituents are thought to be key effects for the protection against chronic conditions, based on preclinical in vitro and in vivo studies, besides clinical studies. Habitats and cultivation of Piper species are also covered in this review. In this current work, available literature of chemical constituents of the essential oils Piper plants, their use in traditional medicine, their applications as a food preservative, their antiparasitic activities and other important biological activities are reviewed.

Larvicidal potential of piperovatine in the control of cattle tick

Rhipicephalus (Boophilus) microplus is one of the most important ectoparasites in cattle breeding worldwide, causing direct and indirect losses to animals and producers. Chemical acaricides are utilized in the control of cattle tick and the increase in the development of resistance by ectoparasites makes new alternative necessary. Therefore, research studies have been carried out using bioactive molecules that are quickly degraded and that reduce poisoning to appliers and non-target organisms, environmental contamination and development of resistance. Thus, this study aimed to isolate piperovatine from the roots of Piper corcovadensis, a native species to Brazil, and to evaluate the larvicidal activity against Rhipicephalus (Boophilus) microplus by larval packet test and in ex situ in an open environment. Piperovatine was isolated by classical column chromatography, and identified by ¹H and ¹³C NMR. The lethal concentration (LC) of piperovatine that killed 50% (LC₅₀) and 99% (LC₉₉) of the larvae was determined by Probit analysis. The results indicated LC₅₀ 5.17 and LC₉₉ 25.41 μg/mL. LC₉₉ was tested in ex situ in an open environment, and an efficiency of 96.63% was found, indicating that piperovatine kept the larvicidal action determined in in vitro test and in open environment. Therefore, this study shows new perspectives to develop products that can be applied in natural conditions to control this ectoparasite.

Evaluation of Chemical Composition and Antileishmanial and Antituberculosis Activities of Essential Oils of Piper Species

Essential oils from fresh Piperaceae leaves were obtained by hydrodistillation and analyzed by gas chromatography mass spectrometry (GC-MS), and a total of 68 components were identified. Principal components analysis results showed a chemical variability between species, with sesquiterpene compounds predominating in the majority of species analyzed. The composition of the essential oil of Piper mosenii was described for the first time. The cytotoxicity of the essential oils was evaluated in peritoneal macrophages and the oils of P. rivinoides, P. arboretum, and P. aduncum exhibited the highest values, with cytotoxic concentration at 50% (CC50) > 200 µg/mL. Both P. diospyrifolium and P. aduncum displayed activity against Leishmania amazonensis, and were more selective for the parasite than for the macrophages, with a selectivity index (SI) of 2.35 and >5.52, respectively. These SI values were greater than the 1 for the standard drug pentamidine. The antileishmanial activity of the essential oils of P. diospyrifolium and P. aduncum was described for the first time. P. rivinoides, P. cernuum, and P. diospyrifolium displayed moderate activity against the Mycobacterium tuberculosis H37Rv bacillus, with a minimum inhibitory concentration (MIC) of 125 µg/mL. These results are relevant and suggests their potential for therapeutic purposes. Nevertheless, further studies are required to explain the exact mechanism of action of these essential oils.

A Survey of the Chemical Compounds of Piper spp. (Piperaceae) and Their Biological Activities

The genus Piper is one of the largest genera in the Piperaceae, with most species widely distributed globally, covering all continents. To date, many Piper species have been scientifically investigated for their chemical diversities and interesting broad spectrum of bioactivities, including central nervous system (CNS), pesticidal, antifungal and antibacterial effects. This review systematically summarizes the scaffolds of the alkaloids reported, the major chemicals isolated from Piper spp., and their biological activities. Besides the alkaloids, some neolignans with rearranged skeletons show structural diversities, while the chalcones, flavonoids and kava-pyrones have some potential activities. Herein, the sesquiterpenes and phenolic compounds from Piper species and their bioactivities are also surveyed.

Cytotoxic Effect and TLC Bioautography-Guided Approach to Detect Health Properties of Amazonian Hedyosmum sprucei Essential Oil

Bioautography has been used as rapid and easy strategy to detect and identify bioactive fractions/molecules in the never before investigated Hedyosmum sprucei Solms (Chloranthaceae) essential oil (EO). The antioxidant activity, performed through DPPH bioautographic assay and spectrophotometric evaluations (IC₅₀ = 230 ± 10 µg/mL), seemed to be mainly due to α-cadinol and α-muurolol. (HP)TLC bioautography, focused on antimicrobial capacities, pointed out α-cadinol, α-muurolol, τ-muurolol, caryophyllene oxide, and methyleugenol as the most effective compounds against Staphylococcus aureus, considered as testing strain. Moreover, the microdilution method, assessed among a wide panel of microorganisms, revealed Listeria grayi and Staphylococcus aureus as the most sensitive among human tested strains and Clavibacter michiganensis among phytopathogens. GC-MS chemical profile showed that bioactive molecules represented only a small quantity of the whole EO: germacrene D (23.16%), β-caryophyllene (15.53%), δ-cadinene (5.50%), α-copaene (5.08%), and α-phellandrene (3.48%) were the main compounds, highlighting an uncommon composition among the genus Hedyosmum. Finally, H. sprucei EO was checked for cytotoxic potential against A549 (lung cancer) and MCF-7 (breast cancer) cell lines showing promising cytotoxic effects against both cell lines after 48 h (IC₅₀ A549 = 44.05 ± 2.35 µg/mL; IC₅₀ MCF-7 = 32.76 ± 4.92 µg/mL) and 72 h (IC₅₀ A549 = 43.55 ± 2.80 µg/mL; IC₅₀ MCF-7 = 33.64 ± 0.43 µg/mL).

Piperlongumine Blocks JAK2-STAT3 to Inhibit Collagen-Induced Platelet Reactivity Independent of Reactive Oxygen Species

BACKGROUND

Piperlongumine (PL) is a compound isolated from the piper longum plant. It possesses anti-cancer activities through blocking the transcription factor STAT3 and by inducing reactive oxygen species (ROS) in cancer, but not normal cells. It also inhibits platelet aggregation induced by collagen, but the underlying mechanism is not known.

OBJECTIVE

We conducted in vitro experiments to test the hypothesis that PL regulates a non-transcriptional activity of STAT3 to specifically reduce the reactivity of human platelets to collagen.

RESULTS

PL dose-dependently blocked collagen-induced platelet aggregation, calcium influx, CD62p expression and thrombus formation on collagen with a maximal inhibition at 100 μM. It reduced platelet microvesiculation induced by collagen. PL blocked the activation of JAK2 and STAT3 in collagen-stimulated platelets. This inhibitory effect was significantly reduced in platelets pretreated with a STAT3 inhibitor. Although PL induced ROS production in platelets; quenching ROS using excessive reducing agents: 20 μM GSH and 0.5 mM L-Cysteine, did not block the inhibitory effects. The NADPH oxidase inhibitor Apocynin also had no effect.

CONCLUSIONS

PL inhibited collagen-induced platelet reactivity by targeting the JAK2-STAT3 pathway. We also provide experimental evidence that PL and collagen induce different oxidants that have differential effects on platelets. Studying these differential effects may uncover new mechanisms of regulating platelet functions by oxidants in redox signals.

Chemical Compositions and Antimicrobial Activity of the Essential Oils of Piper abbreviatum, P. erecticaule and P. lanatum (Piperaceae)

The study was designed to examine the chemical composition and antimicrobial activities of essential oils extracted from the aerial parts of three Piper species: Piper abbreviatum, P. erecticaule and P. lanatum, all from Malaysia. GC and GC/MS analysis showed qualitative and quantitative differences between these oils. GC and GC-MS analysis of P. abbreviatum, P. erecticaule and P. lanatum oils resulted in the identification of 33, 35 and 39 components, representing 70.5%, 63.4% and 78.2% of the components, respectively. The major components of P. abbreviatum oil were spathulenol (11.2%), ( E)-nerolidol (8.5%) and β-caryophyllene (7.8%), whereas P. erecticaule oil mainly contained β-caryophyllene (5.7%) and spathulenol (5.1%). Borneol (7.5%), β-caryophyllene (6.6%) and α-amorphene (5.6%) were the most abundant components in P. lanatum oil. Antimicrobial activity was carried out using disc diffusion and broth micro-dilution method against nine microorganisms. All of the essential oils displayed weak activity towards Gram-positive bacteria with MIC values in the range 250–500 μg/mL. P. erecticaule oil showed the best activity on Aspergillus niger (MIC 31.3 μg/mL), followed by P. lanatum oil (MIC 62.5 μg/mL). This study demonstrated that the essential oils have potential as antimicrobial agents and may be useful in the pharmaceutical and cosmetics industries.

Early state research on antifungal natural products

Nosocomial infections caused by fungi have increased greatly in recent years, mainly due to the rising number of immunocompromised patients. However, the available antifungal therapeutic arsenal is limited, and the development of new drugs has been slow. Therefore, the search for alternative drugs with low resistance rates and fewer side effects remains a major challenge. Plants produce a variety of medicinal components that can inhibit pathogen growth. Studies of plant species have been conducted to evaluate the characteristics of natural drug products, including their sustainability, affordability, and antimicrobial activity. A considerable number of studies of medicinal plants and alternative compounds, such as secondary metabolites, phenolic compounds, essential oils and extracts, have been performed. Thus, this review discusses the history of the antifungal arsenal, surveys natural products with potential antifungal activity, discusses strategies to develop derivatives of natural products, and presents perspectives on the development of novel antifungal drug candidates.

Analysis of amide compounds in different parts of Piper ovatum Vahl by high-performance liquid chromatographic

Background:

Piper ovatum (Piperaceae) has been used in traditional medicine for the treatment of inflammations and as an analgesic. Previous studies have showed important biological activities of the extracts and amides from P. ovatum leaves.

Objective:

In this study, a high-performance liquid chromatographic (HPLC) method was developed and validated for quantitative determination of the amides in different parts of Piper ovatum.

Materials and Methods:

The analysis was carried out on a Metasil ODS column (150 × 4.6 mm, 5μm) at room temperature. HPLC conditions were as follows: acetonitrile (A), and water (B), 1.0% acetic acid. The gradient elution used was 0–30 min, 0-60% A; 30–40 min, 60% A. Flow rate used was 1.0mL/min, and detection at 280nm.

Results:

The validation using piperlonguminine, as the standard, demonstrated that the method shows linearity (linear correlation coefficient = 0.998), precision (relative standard deviation <5%) and accuracy (mean recovery = 103.78%) in the concentration range 31.25 – 500μg/mL. The limit of detection and quantification were 1.21 and 4.03μg/mL, respectively. This method allowed the identification and quantification of piperlonguminine and piperovatine in the hydroethanolic extracts of P. ovatum obtained from the leaves, stems and roots. All the extracts showed the same chromatographic profile. The leaves and roots contained the highest concentrations of piperlonguminine and the stems and leaves showed the most concentrations of piperovatine.

Conclusion:

This HPLC method is suitable for routine quantitative analysis of amides in extracts of Piper ovatum and phytopharmaceuticals containing this herb.

Development of a Direct Headspace Collection Method from Arabidopsis Seedlings Using HS-SPME-GC-TOF-MS Analysis

Plants produce various volatile organic compounds (VOCs), which are thought to be a crucial factor in their interactions with harmful insects, plants and animals. Composition of VOCs may differ when plants are grown under different nutrient conditions, i.e., macronutrient-deficient conditions. However, in plants, relationships between macronutrient assimilation and VOC composition remain unclear. In order to identify the kinds of VOCs that can be emitted when plants are grown under various environmental conditions, we established a conventional method for VOC profiling in Arabidopsis thaliana (Arabidopsis) involving headspace-solid-phase microextraction-gas chromatography-time-of-flight-mass spectrometry (HS-SPME-GC-TOF-MS). We grew Arabidopsis seedlings in an HS vial to directly perform HS analysis. To maximize the analytical performance of VOCs, we optimized the extraction method and the analytical conditions of HP-SPME-GC-TOF-MS. Using the optimized method, we conducted VOC profiling of Arabidopsis seedlings, which were grown under two different nutrition conditions, nutrition-rich and nutrition-deficient conditions. The VOC profiles clearly showed a distinct pattern with respect to each condition. This study suggests that HS-SPME-GC-TOF-MS analysis has immense potential to detect changes in the levels of VOCs in not only Arabidopsis, but other plants grown under various environmental conditions.

The natural compounds piperovatine and piperlonguminine induce autophagic cell death on Trypanosoma cruzi

The currently available treatments for Chagas disease show limited therapeutic potential and are associated with serious side effects. Our group has been attempting to find alternative drugs isolated from natural products as a potential source of pharmacological agents against Trypanosoma cruzi. Here, we demonstrate the antitrypanosomal activity of the amides piperovatine and piperlonguminine isolated from Piper ovatum against epimastigotes and intracellular amastigotes. We also investigated the mechanisms of action of these compounds on extracellular amastigote and epimastigote forms of T. cruzi. These amides showed low toxicity to LLCMK(2) mammalian cells. By using transmission and scanning electron microscopy, we observed that the compounds caused severe alterations in T. cruzi. These alterations were mainly located in plasma membrane and mitochondria. Furthermore, the study of treated parasites labeled with Rh123, PI and MDC corroborate with our TEM data. These mitochondrial dysfunctions induced by the amides might trigger biochemical alterations that lead to cell death. Altogether, our data evidence a possible autophagic process.

Chemical compositions, antioxidant and antimicrobial activities of essential oils of Piper caninum Blume

Chemical composition, antioxidant and antimicrobial activities of the fresh leaves and stems oils of Piper caninum were investigated. A total of forty eight constituents were identified in the leaves (77.9%) and stems (87.0%) oil which were characterized by high proportions of phenylpropanoid, safrole with 17.1% for leaves and 25.5% for stems oil. Antioxidant activities were evaluated by using β-carotene/linoleic acid bleaching, DPPH radical scavenging and total phenolic content. Stems oil showed the highest inhibitory activity towards lipid peroxidation (114.9 ± 0.9%), compared to BHT (95.5 ± 0.5%), while leaves oil showed significant total phenolic content (27.4 ± 0.5 mg GA/g) equivalent to gallic acid. However, the essential oils showed weak activity towards DPPH free-radical scavenging. Evaluation of antimicrobial activity revealed that both oils exhibited strong activity against all bacteria strains with MIC values in the range 62.5 to 250 μg/mL, but weak activity against fungal strains. These findings suggest that the essential oils can be used as antioxidant and antimicrobial agents for therapeutic, nutraceutical industries and food manufactures.

Antifungal activity of Piper diospyrifolium Kunth (Piperaceae) essential oil

In vitro activity of the essential oil from Piper diospyrifolium leaves was tested using disk diffusion techniques. The antifungal assay showed significant potencial antifungal activity: the oil was effective against several clinical fungal strains. The majority compounds in the essential oil were identified as sesquiterpenoids by GC-MS and GC-FID techniques.

Seasonal variation, chemical composition, and analgesic and antimicrobial activities of the essential oil from leaves of Tetradenia riparia (Hochst.) Codd in southern Brazil

The seasonal variation of the chemical composition of the essential oil from fresh leaves of Tetradenia riparia (Hochst.) Codd grown in southern Brazil was analyzed by GC-MS, and the analgesic and antimicrobial activities of this oil were assayed. The yield of essential oil ranged from 0.17% to 0.26%, with the maximum amount in winter and the minimum in spring. The results obtained from principal components analysis (PCA) revealed the existence of high chemical variability in the different seasons. The samples were clearly discriminated into three groups: winter, autumn, and spring-summer. Samples collected during winter contained the highest percentages of calyculone (24.70%), abietadiene (13.54%), and viridiflorol (4.20%). In autumn, the major constituents were ledol (8.74%) and cis-muurolol-5-en-4-alpha-ol (13.78%). Samples collected in spring-summer contained the highest percentages of fenchone (12.67%), 14-hydroxy-9-epi-caryophyllene (24.36%), and alpha-cadinol (8.33%). Oxygenated sesquiterpenes were predominant in all the samples analyzed. The observed chemovariation might be environmentally determined by a seasonal influence. The essential oil, when given orally at a dose of 200 mg/kg, exhibited good analgesic activity on acetic acid-induced writhing in mice, inhibiting the constrictions by 38.94% to 46.13%, and this effect was not affected by seasonal variation. The antimicrobial activity of the essential oil against the bacterial strains: Staphylococcus aureus, Bacillus subtilis, Enterococcus faecalis, Escherichia coli, Salmonella enterica, Pseudomonas aeruginosa, Klebsiella pneumonia, Proteus mirabilis, Morganella morganii, and Enterobacter cloacae, and the pathogenic fungus Candida albicans was assessed by the disc diffusion method and determination of the minimum inhibitory concentration. The results obtained, followed by measurement of the minimum inhibitory concentration (MIC), indicated that S. aureus, B. subtilis, and Candida albicans were the most sensitive microorganisms, showing largest inhibition, and the lowest MIC values varied from 15.6 to 31.2 microg/mL, 7.8 to 15.6 microg/mL, and 31.2 to 62.5 microg/mL, respectively.