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Chemical signals have an important role in the survival of many animals and are essential for the exploration of the resources available in their habitat. All phytophagous insects, including dipterans, use diverse chemical compounds released by plants as olfactory signals to locate their hosts. Spotted wing drosophila, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), is a generalist fly that uses numerous plants as hosts. In this study, we evaluated the attractiveness of extracts from six plants commonly used as ornamental and medicinal plants in the southern region of Mexico. When the flies were exposed to Piper auritum Kunth (Piperaceae) extract, we observed a stimulating‐attracting effect, especially on females, whereas the other five extracts showed no significant differences from their respective controls. In addition, gas chromatography coupled with mass spectrometry analysis of the P. auritum extract revealed 11 compounds, where safrole and methyl eugenol (ME) showed the highest concentrations of all the compounds found. ME has been shown to attract flies, mainly males of the genus Bactrocera. In this case, we found a stronger effect on female D. suzukii, indicating a potential effect of ME as a kairomone that mainly stimulates the attraction behavior of females. [ABSTRACT FROM AUTHOR]

The 'sacred leaf' or "Hoja Santa" (Piper auritum Kunth) has a great value for Mexican culture and has gained popularity worldwide for its excellent properties from culinary to remedies. To contribute to its heritage, in this project we proposed the green synthesis of silver oxide nanoparticles (Ag2O NPs) using an extract of "Hoja Santa" (Piper auritum) as a reducing and stabilizing agent. The synthesized Ag2O NPs were characterized by UV–Visible spectroscopy (plasmon located at 405 nm), X-ray diffraction (XRD) (particle size diameter of 10 nm), scanning electron microscopy (SEM) (particle size diameter of 13.62 ± 4.61 nm), and Fourier-transform infrared spectroscopy (FTIR) (functional groups from "Hoja Santa" attached to nanoparticles). Antioxidant capacity was evaluated using DPPH, ABTS and FRAP methods. Furthermore, the antimicrobial activity of NPs against a panel of clinically relevant bacterial strains, including both Gram-positive (Staphylococcus aureus) and Gram-negative bacteria (Salmonella Enteritidis and Escherichia coli O157:H7), was over 90% at concentrations of 200 µg/mL. Additionally, we assessed the antibiofilm activity of the NPs against Pseudomonas aeruginosa (reaching 98% of biofilm destruction at 800 µg/mL), as biofilm formation plays a crucial role in bacterial resistance and chronic infections. Moreover, we investigated the impact of Ag2O NPs on immune cell viability, respiratory burst, and phagocytic activity to understand their effects on the immune system. [ABSTRACT FROM AUTHOR]

AbstractDiseases caused by mycotoxin-producing fungi, especially Aspergillus ochraceus and Fusarium moniliforme, are on the rise, leading to contamination of agricultural products and seeds during processing and storage, resulting in significant economic losses and posing serious health risks to humans and animals. Controlling these diseases primarily relies on synthetic fungicides, which can leave behind toxic residues harmful to human and animal health, as well as the environment. Various strategies have been proposed for controlling these fungal diseases, including biological control using essential oils (EOs) derived from plants. EOs extracted from plants of the Piper and Pimenta genera contain secondary metabolites with antimicrobial properties. This study aims to analyze the effect of EOs from Piper auritum and Pimenta dioica on the fungi A. ochraceus and F. moniliforme. The EOs were obtained through steam distillation, and their antifungal activity was assessed using minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC), and % sporulation. The phytochemical composition of the EOs was determined by GC-MS. The fungal species exhibited susceptibility to the EOs, with MIC and MFC values of 0.16 and 1.21 mg/mL, respectively, for P. dioica against A. ochraceus, and 0.43 mg/mL against F. moniliforme. Meanwhile, the MIC and MFC values for P. auritum were 0.16 and 15 mg/mL, respectively, against A. ochraceus. The EOs demonstrated effective antifungal activity, likely attributed to the presence of bioactive compounds.

Macro- and microscopic techniques have long been used to describe plant materials and establish plant structural profiles. These techniques are commonly used in botanical authentication to identify the genuine and closely allied species used in botanical research. Advanced microscopic techniques were used in this study to differentiate three different Piper species used as kava or kava-kava. The genuine species is Piper methysticum and the other two species commonly called false-kava or kava-kava, are Piper auritum and Piper excelsum. Macroscopic characteristics, including a black-spotted stem and fibrous root, are characteristic of P. methysticum, whereas the stem of P. auritum is greenish with no spots, and the P. excelsum stem is purple-pink. Microscopic attributes include the characteristic collenchyma of stems and the pattern of arrangement of peripheral and medullary vascular bundles. The starch grains are smaller in P. excelsum than in the other two species. Energy-dispersive X-ray spectroscopy analysis of the crystals indicates the expected calcium, magnesium, and silica, along with lesser amounts of sodium, and potassium. The crystals present in the Piper species vary in shape, size, and elemental composition. Combining macro- and microscopical techniques and resulting characteristics are instrumental in differentiating the three Piper species., Competing Interests: Conflict of Interest. The authors declare that they have no competing interests., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Microscopy Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

An ethanol extract of Piper auritum leaves (PAEE) inhibits the mutagenic effect of three food-borne aromatic amines (2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP); 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx); 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx) in the TA98 Salmonella typhimurium strain. Preincubation with MeIQx demonstrated in mutagenesis experiments that inhibition of Cytochrome P450 (CYP), as well as direct interaction between component(s) of the plant extract with mutagens, might account for the antimutagenic observed effect. Gas chromatography/mass spectrometry analysis revealed that safrole (50.7%), α-copaene (7.7%), caryophyllene (7.2%), β-pinene (4.2%), γ-terpinene (4.1%) and pentadecane (4.1%) as the main components of PAEE. Piper extract and safrole were able to inhibit the rat liver microsomal CYP1A1 activity that participates in the amines metabolism, leading to the formation of the ultimate mutagenic/ molecules. According to this, safrole and PAEE inhibited MeIQx mutagenicity but not that of the direct mutagen 2-nitrofluorene. No mutagenicity of plant extract or safrole was detected. This study show that PAEE and its main component safrole are associate with the inhibition of heterocyclic amines activation due in part to the inhibition of CYP1A subfamily activity., (© The Author(s) 2024. Published by Oxford University Press on behalf of the UK Environmental Mutagen Society.)

Diseases caused by Fusarium in Agave are increasing and causing economic losses. Then, it is necessary to seek alternatives in pathogenic prevention and control to reduce the use of chemical fungicides, thus promoting a type of disease control which is friendly to the environment. The oils and leaf extracts of some plants are efficient in controlling pests and diseases. Piper auritum ("hierba santa") contains essential oils, which fulfill ecological functions such as attracting pollinators and causing allelopathic effects. Baccharis glutinosa ("jarilla") is also used in the treatment of various infectious diseases. Different extracts from plants have biological activity against microorganisms that affect important crops. The objective of this research was to evaluate the antimicrobial activity of essential oil and extracts from two plants with traditional use in the state of Chiapas on the phytopathogenic (Fusarium spp.) fungi of Agave spp. Extracts from P. auritum and B. glutinosa were tested against phytopathogenic fungi, in a complete randomized experimental design. ANOVA was performed with six treatments and three replicates per treatment, used on three species of Fusarium. The essential oil from leaves of Piper auritum had the greatest (96 h) significant inhibition effect on Fusarium oxysporum f. sp. comiteca (75.32%), Fusarium oxysporum f. sp. tequilana (86.57%) and Fusarium solani f. sp. comiteca (63.36%). Thus, P. auritum showed a clear fungistatic effect. [ABSTRACT FROM AUTHOR]

The effect of several plant in the control of weevil Zabrotes subfasciatus (Boh.) (Coleoptera; Bruchidae) was evaluated. The plant were caisimón of anisette, apasote, bitter broom, sage, sassafras, garlic leek and nim were used. In the experiment they were carried out 2 variants, one to see the effect on a female of the insect and another to observe the behavior in group of Z. subfasciatus. The effects of the same ones were evaluated in the ovoposición and in the time of permanency of the insect on each plant residual. the death to Z. subfasciatus. The residuals of the molinaje of bitter broom, I age leek, caisimón of anisette and sage those that bigger repelencia effect had were, as much in the permanency as in the number of eggs ovopositados for the female of Z. subfasciatus. Correlation didn’t exist among the time of permanency of the insect in the different treatments and the number of on eggs. The biggest quantity in eggs was ovopositados it has more than enough sassafras.

The leishmaniosis disease incidence is high in tropical regions, and its current treatment has shown severe secondary effects. Considering this problem, many studies have focused on plants, looking for chemical components that have anti-leishmanial activity, and are free of adverse effects for human beings. The purpose of this work was to find a chemical component with this kind of activity in Piper auritum. In a phytochemical screening of this plant, we found some cumarins, terpens, triterpens and reducing sugars; and later, we identified the components trans-Z-a-bisabolene epoxide and Safrol. The first component presented a CI50 of 50.0 µg/mL of anti-Leishmania activity. The Safrol, which is the major component of the essential oils of this plant, did not show antiparasitic activity. These results are discussed considering treatment of leishmaniasis. [ABSTRACT FROM AUTHOR]

Riparian vegetation has great functional importance in agroscapes because it establishes physical connections between natural ecosystems embedded in an agricultural matrix. Throughout the tropics, the historical demand for cropland and pastures in the lands adjacent to streams has led to the replacement of forests by exotic grasses. In order to find new methods for initiating the restoration of riparian forests, we evaluated the use of the pioneer shrubs Tithonia diversifolia and Piper auritum as nurse species for their effects on (1) competition with dominant grasses; (2) natural regeneration and the ecological facilitation of six native tree species of different successional stages; and (3) influence on microclimate. Over a period of 15 months, 4.4% coverage of P. auritum was insufficient to inhibit grasses. In contrast, 81% coverage of T. diversifolia limited the growth of dominant grasses such as Cenchrus purpureus, Paspalum paniculatum, and Cynodon plectostachyus likely by intercepting more than 90% of photosynthetically active radiation ( PAR), even though other factors cannot be ruled out. T. diversifolia showed simultaneous effects of facilitation and competition by promoting higher survival of the planted native trees while slowing the growth of pioneer species and inhibiting the regeneration of native woody plants probably as a result of high light interception. This study suggests that planting T. diversifolia as a nurse shrub may facilitate early stages of restoration by inhibiting the growth of pastures, but requires pruning, both to increase light availability and promote the growth of planted trees and the recruitment of woody plants. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the antioxidant activity of hexane extracts from leaves of Piper auritum (HS). Eight complementary in vitro test methods were used, including inhibition of DPPH· radicals, nitric oxide, superoxide anion, ion-chelating, ABTS, oxygen radical absorbance capacity, β-carotene bleaching and peroxy radical scavenging. The results indicated that HS possesses high antioxidant activity. To add to these finding we tested the effect against oxidative stress in liver, pancreas and kidney in diabetic rats. Low levels of SOD, CAT, GPx and GSH in diabetic rats were reverted to near normal values after treatment with HS. These results suggest that P. auritum prevents oxidative stress, acting as a suppressor of liver cell damage. Given the link between glycation and oxidation, we proposed that HS might possess significant in vitro antiglycation activity. Our data confirmed the inhibitory effect of HS on bovine serum albumin, serum glycosylated protein, glycation of LDL, and glycation hemoglobin. The effect of HS on diabetic renal damage was investigated using streptozotocin-induced diabetic rats. The oral administration of HS at a dose of 200 and 400 mg/kg body weight/day for 28 days significantly reduced advanced glycation endproduct (AGE) formation, elevated renal glucose and thiobarbituric acid-reactive substance levels in the kidneys of diabetic rats. This implies that HS would alleviate the oxidative stress under diabetes through the inhibition of lipid peroxidation. These findings indicate that oxidative stress is increased in the diabetic rat kidney and that HS can prevent renal damage associated with diabetes by attenuating the oxidative stress.

El objetivo del presente trabajo fue evaluar el comportamiento productivo y el rendimiento de la canal en pollos de engorda, con el uso de harina de hojas de plantas aromáticas como aditivo fitoterapéutico al 0,07% en la dieta. Fueron utilizados 280 pollitos machos de la estirpe Ross 308, de 1 a 42 días de edad, distribuidos de forma aleatoria en un diseño completamente al azar, en cuatro tratamientos y siete repeticiones con 10 pollos cada una. Las combinaciones fueron en proporción 50:50 de harina de Origanum vulgare y Piper auritum (OHS), O. vulgare y Ocimum basilicum (OA), O. basilicum y P. auritum (HSA), y un testigo con flavomicina al 4%. El grupo testigo obtuvo el mayor peso corporal (2.385 g), consumo de alimento (204 g por ave por día) y mortalidad acumulada (21,87%), al final de la prueba. No hubo diferencias con la combinación de OA (2.198 g) y HSA (2.023 g) en peso corporal y consumo de alimento. La combinación OA registró la menor (1,96) y OHS la mayor (2,44) conversión de alimento. No se encontraron diferencias en el rendimiento de la canal. La combinación al 50% de O. vulgare y O. basilicum, incluida al 0,07% en la dieta para pollos de engorda, es una alternativa como promotora del crecimiento y no altera el rendimiento de la canal.The objective of this study was to determine the growth performance and carcass yield in broilers using leaf meals as an additive phytotherapy of herbs at 0.07% in the diet. Two hundred eighty male chicks of Ross 308 strain, with 1 to 42 days of age, were randomly assigned in a completely randomized design with four treatments and seven replicates of 10 chickens each. The blends were in the proportion of 50:50 of Origanum vulgare and Piper auritum (OHL), O. vulgare and Ocimum basilicum (OA), O. basilicum and P. auritum (AHL), and one control group with flavomicim at 4%. The control group showed the highest body weight (2,385 g), feed consumption (204 g per broiler per day) and accumulative mortality (21.87%), at the end of the assay. There was no difference with OA (2,198 g) and AHL (2,023 g) blends in body weight and feed consumption. The blend OA had the lowest (1.96) and OHL had the highest (2.44) feed conversion. There was no difference in the carcass yield. The blend at 50% of O. vulgare and O. basilicum, included at 0.07% in the diet for broilers, is an alternative for promoting growth and does not alter the yield carcass.

Leishmaniasis is one of the most important parasitic infections, but current treatments are unsatisfactory due to their toxicity, cost and resistance. Therefore, the development of new antileishmanial compounds is imperative. Many people who live in endemic areas use plants as an alternative to treat the disease. In this paper, we characterised the essential oil from Piper auritum, evaluated its cytotoxicity and determined its antileishmanial activity. The chromatogram obtained by gas chromatography revealed 60 peaks and we found that safrole was the most abundant compound, composing 87% of the oil. The oil was active against the promastigotes of Leishmania major, Leishmania mexicana, Leishmania braziliensis and Leishmania donovani with a favourable selectivity index against peritoneal macrophages from BALB/c mice. The Piper-oil inhibited the growing of intracellular amastigotes of L. donovani with an IC50 value of 22.3 ± 1.8 μg/mL. This study demonstrates the usefulness of the essential oils as a promising alternative to treat leishmaniasis.

Bioactivity-guided fractionation of methanol extracts from leaves of Piper auritum produced four triterpenoid saponin compounds 1-4. Structures were established based on interpretation of mass spectrometry (MS), nuclear magnetic resonance (NMR) data. 21-( p-methoxycinnamoyl)-olean-12-ene-28oic cid-3- O-α- L-arabinopyranosyl-(1→2)-β- D-glucopyranoside ( 1) and olean-12-ene-28 methyl ester-3- O-α- L-arabinofuranosyl-(1→2)-β- D-glucopyranoside ( 2) were orally administered to diabetic mice at dosage of 10 mg/kg of body weight per day for 30 days and resultant biochemical parameters were studied. Both compounds significantly ( p<0.05) decreased serum glucose, total cholesterol, and triglyceride levels, compared with controls. Low density lipoprotein and high density lipoprotein cholesterol levels were ameliorated. The effects of lipid peroxidation and oxidative stress in the liver, pancreas, and kidney were reversed, with reductions insulin resistance and stimulation of insulin production. β-Glucosidase activities were studied in vitro. Compounds 1 and 2 can be used to improve glucose and lipid metabolism and to reduce the imbalance between generation of reactive oxygen species and scavenging enzyme activities for prevention of diabetic complications. [ABSTRACT FROM AUTHOR]

Highlights: [•] Great amount of phenolics was observed in Piper auritum and Porophyllum ruderale. [•] Little antioxidant activity was observed in the two types of dried plants. [•] The ethanol–water blend, used for extracting phenolics, was important. [•] Safrole was the main compound found in P. auritum. [•] No relationship was observed between antioxidant activity and total phenolics. [ABSTRACT FROM AUTHOR]

In this work, the antifungal activity of four natural extract essential oils was determined in vitro on three isolates of Fusarium spp (F2 and F5 of Fusarium solani (Martius) Appel & Wollenweber emend. Snyder & Hansen and F3 of Fusarium redolens Wollenweber), pathogens in the tomato (Solanum lycopersicum L.) crop in Cuba. The bioassay was performed as a completely randomized design using the method of filter paper disks inoculated with the oils placed in direct contact with the discs of the Fusarium isolates. The fungal radial growth was evaluated for up to 96 hours. The Casimon of anise (Piper auritum Kunth) oil produced complete growth inhibition of the isolates; meanwhile, the oil from the platanillo of Cuba (Piper aduncum subsp. ossanum (C. DC) Saralegui) showed to have a high fungistatic power. Melaleuca oil (Melaleuca quinquinervia (Cav) ST Blake showed little growth inhibition in the three isolates, whereas any of the isolates was inhibited by Citrus (Citrus sinensis L. Osbeck) at any of the concentration tested, which limits the possible use of these in the practice. The Casimon of anise oil was the most prominent, and it is recomended to be further nvestigated for its properties for the control of plan pathogens. [ABSTRACT FROM AUTHOR]

The aim of this study was to identify the component (s) of the essential oil of Piper auritum associated with the antibacterial effect against Xanthomonas albilineans and Xanthomonas campestris pv. campestris. The essential oil of P. auritum was obtained by hydrodistillation in a Clevenger type apparatus. The Minimum Inhibitory Concentration (MIC) and the Minimum Bactericidal Concentration (MBC) against both bacteria were determined by the method of serial dilutions. The components responsible for the biological activity were identified by fractionating the essential oil by dry chromatography, and the fractions were investigated by GC / MS and tested against the above mentioned bacteria. This oil has a strong antibacterial activity with MIC and MBC of 0,12 and 0,25 mg.ml-1 against X. albilineans and X. campestris pv. campestris, respectively. The principal component responsible for the observed biological activity was safrole; however, the whole essential oil met all the requirements for being used as a promissory antibacterial agent. [ABSTRACT FROM AUTHOR]

The effect of several plant in the control of weevil Zabrotes subfasciatus (Boh.) (Coleoptera; Bruchidae) was evaluated. The plant were caisimón of anisette, apasote, bitter broom, sage, sassafras, garlic leek and nim were used. In the experiment they were carried out 2 variants, one to see the effect on a female of the insect and another to observe the behavior in group of Z. subfasciatus. The effects of the same ones were evaluated in the ovoposición and in the time of permanency of the insect on each plant residual. the death to Z. subfasciatus. The residuals of the molinaje of bitter broom, I age leek, caisimón of anisette and sage those that bigger repelencia effect had were, as much in the permanency as in the number of eggs ovopositados for the female of Z. subfasciatus. Correlation didn't exist among the time of permanency of the insect in the different treatments and the number of on eggs. The biggest quantity in eggs was ovopositados it has more than enough sassafras. [ABSTRACT FROM AUTHOR]

The aim of this work was to determine the in vitro antifungal activity of ten essential oils on Alternaria solani SORAUER. The effect by direct contact and exposure to vapors was evaluated. The bioassays were performed using a completely randomized design and the method of paper discs inoculated with the oils facing phytopathogen discs; the fungal radial growth was evaluated. All the oils, except those from Citrus sinensis (L.) Osbeck (sweet orange), inhibited the mycelial growth until the seventh day. At day 14, a total inhibition was observed in the treatments with the oils from Pimpinella anisum L. (anise), Ocimum basilicum L. (white basil), Ocinum basilicum L. var. genovese (Genovese basil), and Piper auritum Kunth (anise caisimon). No fungicidal effect was shown by the volatile metabolites of the oils; however, the inhibition of A. solani mycelial growth was observed in the treatments with the extracts of Ruta chalepensis L. (ruda) and P. auritum. These results open new perspectives for the control of this pathogen. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the antioxidant activity of hexane extracts from leaves of Piper auritum (HS). Eight complementary in vitro test methods were used, including inhibition of DPPH. radicals, nitric oxide, superoxide anion, ionchelating, ABTS, oxygen radical absorbance capacity, β-carotene bleaching and peroxy radical scavenging. The results indicated that HS possesses high antioxidant activity. To add to these finding we tested the effect against oxidative stress in liver, pancreas and kidney in diabetic rats. Low levels of SOD, CAT, GPx and GSH in diabetic rats were reverted to near normal values after treatment with HS. These results suggest that P. auritum prevents oxidative stress, acting as a suppressor of liver cell damage. Given the link between glycation and oxidation, we proposed that HS might possess significant in vitro antiglycation activity. Our data confirmed the inhibitory effect of HS on bovine serum albumin, serum glycosylated protein, glycation of LDL, and glycation hemoglobin. The effect of HS on diabetic renal damage was investigated using streptozotocin-induced diabetic rats. The oral administration of HS at a dose of 200 and 400 mg/kg body weight/day for 28 days significantly reduced advanced glycation endproduct (AGE) formation, elevated renal glucose and thiobarbituric acid-reactive substance levels in the kidneys of diabetic rats. This implies that HS would alleviate the oxidative stress under diabetes through the inhibition of lipid peroxidation. These findings indicate that oxidative stress is increased in the diabetic rat kidney and that HS can prevent renal damage associated with diabetes by attenuating the oxidative stress. [ABSTRACT FROM AUTHOR]

Background: The large-leafed perennial plant Piper auritum known as Hoja Santa, is used for its leaves that because of their spicy aromatic scent and flavor have an important presence in Mexican cuisine, and in many regions, this plant is known for its therapeutic properties. Materials and Methods: In the present study, we investigated the effect of hexane, chloroform and methanol extracts from Piper auritum on cell culture system and the effect in streptozotocin-induced type 1 diabetic rats treated by 28 days on the physiological, metabolic parameters and oxidative stress. Results: The hexane extract of P. auritum (HS) treatment significantly reduced the intake of both food, water and body weight loss as well as levels of blood glucose, serum cholesterol, triglycerides and increase HDL-cholesterol. After 4-week administration of HS antioxidant enzyme as SOD, CAT, GSH, GPx in pancreas were determined. These enzyme increased significantly compared with those of the diabetic rats control and normal animals. For all estimated, the results of HS treated groups leading to a restoration of the defense mechanism. The treatment also improves pancreatic TBARS-reactive substance level and serum NO and iNOS. To determine the insulin releasing activity, after extract treatment the serum and pancreatic sections were processed for examination of insulin-releasing activity using an immunocytochemistry kit. The results showed that administration of the hexane extract (200 and 400 mg/kg) exhibited a significant increase in serum and pancreas tissue insulin. Administration of streptozotocin decreased the insulin secretory activity in comparison with intact rats, but treatment with the HS extract increased significantly the activity of the beta cells in comparison with the diabetic control rats. The extract decreased serum glucose in streptozotocininduced diabetic rats and increased insulin release from the beta cells of the pancreas. In cultured RIN-5F cells, we examined whether hexane extract of P. auritum would protect the pancreasderived β-cells from oxidative stress. Moreover, HS could protect pancreatic β-cells from advanced glycation end products-induced oxidative stress. Conclusion: From these results, HS is suggested to show anti-diabetic effect by stimulating insulin-dependent and by protecting pancreatic β-cells from advanced glycation end products-induced oxidative stress. [ABSTRACT FROM AUTHOR]

The Piper genus, belonging to the Piperaceae family, has been the objective of phytochemical and biological studies because of its several etnobotanical applications. The essential oils of Piper species have been used with many purposes. One of them is that they inhibit the growth of a large number of human, animal and plant pathogens. The aim of this work was to carry out the chemical and microbiological study of the essential oil of Piper auritum (Caisimón de anís). The composition of the essential oil of leaves and stems of this plant, obtained by hydrodistillation in a Clevenger-type apparatus, was researched by GC/MS. The essential oil was tested against Xanthomonas albilineans and Acidovorax avenae subsp. avenae for antibacterial properties by using the agar diffusion method. The main constituent of the oil was safrole (74,29%). The bioassay showed that the essential oil had a strong bactericidal activity. [ABSTRACT FROM AUTHOR]

The antioxidant and antimicrobial effects of Hierba Santa (Piper auritum Kunth) ethanolic extracts (HSEE) from plant powder of particle sizes 425 μm (EPA) and 850 μm (EPB) were evaluated in raw and raw-cooked beef burgers stored for 9 days at 4 °C, as well as raw-frozen and raw-frozen-cooked beef burgers stored for 90 days at −20 °C. Four treatments were prepared, including control (without extract), solution of sodium ascorbate (NaASC at 500 mg/kg), MEPA (meat with HSEE from EPA at 750 mg/kg) and MEPB (meat with HSEE from EPB at 750 mg/kg). The in vitro antioxidant and antimicrobial activities as well as total phenolic, chlorophyll and carotenoid content of HSEE were studied. The chemical composition was evaluated in beef used for the burgers. Beef burgers were evaluated for thiobarbituric acid reactive substances (TBARS), pH, color, metmyoglobin content and microbial load. Results indicated that HSEE showed in vitro antioxidant activity and their incorporation in beef burgers inhibited lipid oxidation compared with NaASC, while pH was lower than the maximum allowed limit. However, neither EPB nor EPA were effective in reducing the total bacteria count (TBC) in raw beef burgers. Therefore, HSEE could be recommended as a natural antioxidant in beef burgers. • Antioxidant and antimicrobial effects of Hierba Santa ethanolic extracts (HSEE) were evaluated. • Two particle sizes of 425 μm (EPA) and 850 μm (EPB) were used for the preparation of HSEE. • Antioxidant activity in vitro was highest for HSEE from plant powder of particle size 850 μm (EPB). • EPB improved oxidative stability but did not inhibit bacterial growth in burgers. • HSSE have potential as a natural antioxidant in beef burgers. [ABSTRACT FROM AUTHOR]

Water relations dynamics during simulated sunflecks at high (36°C) and medium (27°C) temperatures and high and low vapour pressure deficits beween leaf and air (VPD) were studied on shade-grown Piper auritum H.B. & K. plants, a pioneer tree, common in gaps and clearings of tropical rain forests. The leaves of P. auritum wilt rapidly when exposed to high light. Exposure to high VPD and high light caused substantial and rapid dehydration of leaves. Dehydration could be prevented under high humidity irrespective of temperature. Water stored in leaf cells served as initial source for transpiration upon high light exposure. This effect increased with increasing VPD and temperature. The pronounced decrease in leaf water content over time in high light caused a rapid decrease in leaf water potential (Ψl) and a concomitant increase in water potential gradient (ΔΨ/Δ x) between trunk and leaf, yet the high leaf elasticity (small bulk elastic modulus, ε) allowed turgor maintenance under most conditions. Under high VPD and high temperature, stomata remained open and ΔΨ/Δ x frequently exceeded 0.95 MPa · m−1, the cavitation-inducing threshold (ΔΨ/Δ xcav) causing high rates of acoustic emissions from stems and leaf petioles and leading to concomitant losses in hydraulic conductance per leaf area ( kl). At medium temperature (high VPD), stomatal closure contained xylem embolism by keeping ΔΨ/Δ x at or below this threshold. We argue that wilting substantially contributes to creating a sufficient driving force for water uptake from the soil, and reducing the VPD (through a decrease in radiation load and thus leaf temperature) to avoid excessive dehydration. [ABSTRACT FROM AUTHOR]

Piper auritum (H.B. & K.), a pioneer tree restricted to open sites and Piper hispidum (Swartz), a shrub common in sites ranging from recent clearings to shaded understory, both adjust photosynthetic characteristics in response to light availability during growth. The sensitivity of photosynthetic capacity to light availability during growth was indistinguishable for the two species growing in their natural habitat. Photosynthetic capacity was strongly correlated with leaf nitrogen in both species, and the relationship was similar between species. Dark respiration and leaf specific mass were more sensitive to light during growth in P. hispidum, the species with the broad habitat ange, than in P. auritum. In general, similarities between the species were more striking than differences between them. The differences in dark respiration could have important implications for carbon balance. The difference in the responsiveness of leaf specific mass to light indicates that the broad-ranging species maintains access to modes of response little utilized by the open-site specialist. We did not and, in the gas exchange characteristics, any evidence that the open site specialist is better suited than the generalist to high-light sites. [ABSTRACT FROM AUTHOR]

An efficient whole plant regeneration method from callus cultures of Piper auritum was achieved through organogenesis derived from leaf tissue. Proliferating callus and shoot cultures derived from leaf tissue explants placed on Murashige and Skoog (MS) medium supplemented with 2.0 mg⋅L-1 2, 4-dichlorophenoxyacetic acid (2,4-D) plus 1.5 mg⋅L-1 kinetin. Optimum combination of hormones (mg⋅L-1) for shoot induction was 0.5 2,4-D : 1.5 mg⋅L-1 kinetin (by volume), that resulted in a high rooting rate (49.6 shoots per explant). All of the plants elongated when using a medium consisting of 0.1 mg⋅L-1 2.4-D plus 1 mg⋅L-1 kinetin. Elongated shoots were successfully rooted (100%) on half-strength MS medium supplemented with 2.0 mg⋅L-1 indole-3-acetic acid. All plantlets survived to the growing conditions of a greenhouse. This study demonstrates that leaf tissue of P. auritum is competent for adventitious shoot regeneration and establishes an efficient and useful protocol for the multiplication and conservation of P. autirum for further investigation of its medicinally active constituents. [ABSTRACT FROM AUTHOR]