Inhibitory effect of various aqueous medicinal plant extracts on citrinin production and fungal biomass by Penicillium notatum and Aspergillus niger.

Citrinin is a nephrotoxic mycotoxin produced by several species of the genus Aspergillus, Penicillium and Monascus. Citrinin is generally formed after harvest and occurs mainly in stored grains The efficacy of different concentrations of aqueous leaf extracts of Aervalanata, Nerium oleander Rhazya stricta Decne and Cleome amblyocarpa (5 to 10 mg/mL) on growth and citrinin production in two fungal strains Penicillium notatum and Aspergillus niger was investigated. Mycotoxin production and fungal biomass by the isolates was suppressed, depending on the concentration of the plant extract added to culture media at the time of spore inoculation. Citrinin production in fungal mycelia grown for 15 days in culture media containing 5-10 mg/mL of the aqueous extracts of A. lanata, N. oleander, R. stricta Decne and C. amblyocarpa showed inhibition of approximately 14.2 to 91.8 % in Penicillium notatum and 13.4 to 90.3% in Aspergillus niger. Among the all four extracts Rhazya stricta Decne was more efficient than other tested plant extracts in inhibiting the citrinin production ranging from 22.4 to 91.8% in P. notatum and 32.6 to 93.2% in A. niger.

Evaluation of Antimicrobial Activity of Glucose Oxidase from Aspergillus niger EBL-A and Penicillium notatum

This work aimed to study the production and purification of glucose oxidase by Aspergillus niger and Penicillium notatum using corn steep liquor as the substrate and evaluate its antimicrobial activity for use in pharmaceutical and food industries. The enzyme was purified by ammonium sulfate precipitation (60-85%), DEAE-cellulose ion exchange and Sephadex G-200 size exclusion chromatography. The crude enzyme extracts of A. niger and P. notatum showed 2.32 and 5.53 U mg-1 specific activities, respectively, which after desalting was 15.52 and 12.05 U mg-1, and after ion exchange and gel filtration chromatography was 29.09 - 62 and 25.72 - 59.37 U mg-1 for A. niger and P. notatum, respectively. The antimicrobial activity was determined by disc diffusion method against selected microbial strains where glucose oxidase from A. niger showed anti-bacterial activity, while no fungicidal effects were shown by both A. niger and P. notatum glucose oxidases.

Aislamiento y caracterización de la fracción hexánica de las hojas de Vernonanthura patens (Kunth) H. Rob. con actividad antifúngica / Isolation and characterization of hexane fraction from Vernonanthura patens (Kunth) H. Rob leaves with antifungal action

Introducción: la medicina folclórica ecuatoriana, utiliza las cocciones de las hojas de Vernonanthura pathens (Kunth H. Rob), para combatir entre otras, paludismo, dolores pre y posparto, estomacales, erupciones de piel, diarreas y parásitos. Objetivos: examinar la presencia de actividad antifúngica en fracciones obtenidas de un extracto metanólico de las hojas de V. patens. Métodos: el extracto metanólico de hojas se fraccionó por columna cromatográfica empleando los siguientes sistemas de disolventes: hexano, hexano/acetato de etilo, acetato de etilo y acetato de etilo/metanol. La actividad antifúngica se midió mediante la técnica de difusión en agar con medio (potato dextrosa agar) PDA, en pocillos de 5 mm de diámetro, adicionando 20 µL de las fracciones en concentraciones de 100 y 200 µg/mL disueltas en dimetilsulfóxido. La fracción activa fue analizada para su identificación estructural por cromatografía gaseosa-espectrometría de masas. Resultados: de las fracciones obtenidas solo presentó actividad antifúngica la fracción de hexano al 100 por ciento, con porcentajes de inhibición del 57,6 y 80,2 por ciento frente a Penicillium notatum, y 64,8 y 81,5 porciento frente a Fusaryum oxysporum, a los quince días de incubación. Se propusieron las estructuras de 29 compuestos como constituyentes de la fracción hexánica, los que en su mayoría, son hidrocarburos. Conclusiones: se comprobó la presencia de actividad antifúngica en la fracción de hexano al 100 por ciento, lo que puede incrementar el arsenal de usos medicinales de la planta estudiada y enriquecer la medicina folclórica ecuatoriana

Introduction: the Ecuadorian folk medicine uses the coction from Vernonanthura pathens (Rob H. Kunth) leaves to treat, malaria, pain before and after childbirth, stomachache, skin rashes, diarrheas and parasitism. Objectives: to examine the presence of antifungal activity in fractions obtained from a methanol extract from V. patens leaves. Methods: the methanol extract from the leaves was fractionated by column chromatography using the following solvent systems: hexane, hexane/ethyl acetate, ethyl acetate and ethyl acetate/methanol. Antifungal activity was measured by the agar diffusion technique with PDA medium in 5 mm wells, by adding 20 µL fractions at concentrations of 100 and 200 µg/mL dissolved in dimethylsulfoxide. The active fraction was analyzed for structural identification by gas chromatography-mass spectrometry. Results: of the fractions obtained, only the 100 percent hexane fraction showed antifungal activity, since its inhibitory percentages were 57.6 and 80.2 percent against Penicillium notatum and 64.8 and 81.5 percent vs. Fusaryum oxysporum on the fifteenth day of incubation. The structures of 29 compounds were suggested to be the constituents of the hexane fraction, most of them hydrocarbons. Conclusions: the presence of antifungal activity in the 100 percent hexane fraction was proved, which can extend the medicinal uses of the studied plant and to enrich the Ecuadorian folk medicine

Study on Thermodynamics and Adsorption kinetics of Purified endoglucanase (CMCase) from Penicillium notatum NCIM NO-923 produced under mixed solid-state fermentation of waste cabbage and Bagasse

In the current study, one thermostable endoglucanase was purified from Penicillium notatum NCIM NO-923 through mixed solid state fermentation of waste cabbage and bagasse. The molecular weight of the purified enzyme was 55kDa as determined by SDS polyacrylamide gel electrophoresis (SDS-PAGE). The enzyme had low activation energy (Ea) of 36.39KJ mol-1 for carboxymethyl cellulose hydrolysis and the enthalpy and entropy for irreversible inactivation was 87 kJ mol −1 and 59.3 J mol −1 K−1 respectively. The enzyme was quite thermostable with a Tm value of 62.2˚C. The pKa1 and pKa2 of ionizable groups of the active sites were 2.5 and 5.3 respectively. Apparent Km, Vmax and Kcat of the enzyme were found to be 5.2 mg mL-1, 80 U/gds and 322.4 sec-1 respectively. The enzyme showed about 1.4 fold increased activity in presence of 10mM MgSO4. Adsorption of endoglucanase on Avicel at wide pH range was studied at different temperatures. Langmuir type adsorption isotherm at 10˚C showed maximum adsorption strength of enzyme at pH 3.0, which was in a range of optimum pH of the enzyme.