Antifungal Activity Of Crude Extracts Research Articles

Chemical Composition, and Antibacterial and Antifungal Activities of Crude Extracts from Pistacia lentiscus L. Fruit

Chemical Composition, and Antibacterial and Antifungal Activities of Crude Extracts from Pistacia lentiscus L. Fruit

Antifungal Activity of Plantago lanceolata and Sida ovata Leaf Extracts against Dermatomycotic Fungi.

Plantago lanceolata and Sida ovata have been used as medicinal plants for centuries to cure numerous diseases. This study aimed to evaluate antifungal activity of P. lanceolata and S. ovata leaf extracts against dermatomycotic fungi. Crude extracts from leaves of both plants were prepared using methanol and ethyl acetate. Phytochemical screening of both plants leaves was performed. Antifungal activity of crude extracts was evaluated against three dermatomycotic fungi (Candida albicans, Malassezia furfur, and Malassezia globosa). In addition, minimum inhibitory concentration (MIC) of the extracts was determined by microbroth dilution method. Maximum inhibition zone of 32.00 ± 11.64 mm was exhibited when combined ethyl acetate extract of both plants was applied against M. globosa. Best effect of MIC was demonstrated by ethyl acetate extract against most tested dermatomycotic fungi. Average MIC of ethyl acetate and methanol extracts ranged as follows: (0.19 ± 0.00 to 0.65 ± 0.00 mg/mL and 0.19 ± 0.00 to 0.52 ± 0.22 mg/mL) and (0.65 ± 0.22 to 1.56 ± 0.00 mg/mL and 0.19 ± 0.00 to 0.52 ± 0.00 mg/mL), respectively. Their synergistic effect was better than the effect of individual plant leaf extract. Minimum fungicidal concentration (MFC) values varied across the fungal pathogens when extracts from both plants and their combinations were used. The findings from the current study support the traditional use of P. lanceolata and S. ovata against dermatomycotic fungal infections, which could potentially be exploited for the treatment of superficial infection in humans.

Evaluation of the antimicrobial activity of the crude ethanol extract, essential oil, and fractions from Campomanesia pubescens leaves

Campomanesia pubescens (DC.) O. Berg (Myrtaceae), widely known as “gabiroba”, is a shrub or subshrub used in folk medicine (leaves and barks of the stem) in the form of decoction or infusion in combating urinary tract disorders, diarrhea, and as an astringent. The present work aimed to evaluate the antimicrobial activity of essential oil, crude ethanol extract and hexane fractions, dichloromethane, ethyl acetate, and aqueous from C. pubescens leaves against Gram-positive, Gram-negative bacteria, and fungi. The leaves were collected in Hidrolândia - Goiás and the essential oil was obtained by hydrodistillation in a Clevenger apparatus. The extract and fractions were tested against bacteria and fungi using the microdilution method. The aqueous fractions and ethyl acetate showed strong inhibiting activity (MIC= 8 to 16 μg/mL) against Candida glabrata, Cryptococcus neoformans, and Saccharomyces cerevisiae and moderate activity (MIC= 32 to 64 μg/mL) against Candida krusei, Candida parapsilosis, and Candida tropicalis. There is no report in the literature on the antifungal activity of ethanol extract and fractions of the leaves of C. pubecens. It is concluded through this study that the aqueous fractions and ethyl acetate from C. pubecens leaves presented strong antifungal activity which may justify its popular use in the treatment of urinary tract disorders. Therefore, this species has therapeutic potential that underlies more in-depth studies. This is the first study of the antifungal activity of crude extract and fractions from C. pubecens leaves.

Antifungal Activity of Crude Extracts of Tectona grandis L.f. against Wood Decay Fungi

Wood is mainly made up of cellulose, hemicelluloses, lignin polymers and other organic and inorganic substances, making it susceptible to deteriorate by various biological agents. Tectona grandis L.f. (Teak) is a timber species with high resistance to biological deterioration, valued for its durability, beauty, and mechanical resistance. The purpose of this work was to evaluate the antifungal activity of crude extracts from teak on various fungi that cause wood deterioration. For this, Teak heartwood was obtained, then fragmented and pulverized until obtaining a flour which was used for compounds extraction using the Soxhlet technique coupled to a rotary evaporator through solvents of increasing polarity (hexane, dichloromethane, tetrahydrofuran, and acetone). The extracts obtained were tested against fungal organisms collected in the field, and the LC50 was determined using teak crude extracts on Artemia salina as a biological model. The results obtained showed that a high flour yield was obtained with hexane (0.951 g), followed by tetrahydrofuran (0.446 g), dichloromethane (0.348 g), and acetone (0.152 g). By using nine fungal organisms that predominantly correspond to the genus Aspergillus, the extractable compounds were tested, inhibiting 25% of mycelial growth with tetrahydrofuran (T. versicolor), and 40.9% with dichloromethane (G. trabeum). Likewise, the biological model of A. salina showed an LC50 of 84.9 μg/mL with hexane, 43.3 μg/mL with dichloromethane, 59.6 μg/mL with tetrahydrofuran, and 54.7 μg/mL with acetone. For this reason, it is concluded that Teak wood contains many extractable compounds in relation to its weight, besides having antimicrobial activity when extracted through polar compounds such as dichloromethane and tetrahydrofuran.

In-vitro Antifungal efficacy of Some Medicinal Plants

The aims of the present study are to examine in-vitro antifungal activity of crude extracts of Sudanese medicinal plants against two fungal species in order to verify their possible inhibitory activity and to identify the bioactive compounds responsible for the observed activity. Minimum inhibitory concentration (MIC) and phytochemical screening were investigated for the most active extracts to detect the active group of secondary metabolites. Agar diffusion method was used to test their sensitivity. Chloroform, methanol and aqueous extracts of a total number of 23 plants belonging to 19 genera and 17 families were investigated against Saccharomyces cerevisiae and Candida albicans. Among them, seven plant extracts showed efficacy against at least one of the two fungal cultures, and the methanol extracts of the different plants species exhibited a well marked antifungal activity. The bark methanolic extract of Terminalia arjuna (Combretaceae), gave the lowest minimum inhibitory concentration (MIC) value (4.25 μg/ml) against C. albicans, whereas the stem methanolic extracts of Anogeissus schimperi (Combretaceae), gave the lowest MIC value (0.18 μg/ml) against S. cerevisiae.

Antifungal activity of crude extracts of Ageratum conyzoides and Chromolaena odorata for management of Lasiodiplodia theobromae and Lasiodiplodia pseudotheobromae through in vitro evaluation

Lasiodiplodia is an important genus of fungi causing destructive diseases on perennial crops, including cocoa. Two crucial species of Lasiodiplodia that cause diseases in cocoa are Lasiodiplodia theobromae and Lasiodiplodia pseutheobromae. A variety of weeds is the potential to be applied as botanical fungicides to control the pathogens. The main objective of this study was to evaluate Ageratum conyzoides and Chromolaena odorata leaf extract to inhibit the growth of L. theobromae and L. pseudotheobromae on a synthetic medium. Solvent organic was methanol for weed extraction with a ratio of 1:5. The experiment was conducted through the poison food technique method, both in the solid and liquid medium in three different concentrations, 1, 3, and 5%. The result showed that A. conyzoides and C. odorata were significantly inhibited the colony growth of both Lasiodiplodia in all concentrations in a solid medium. A. conyzoides performed better than C. odorata in all concentrations of both Lasiodiplodia in inhibition. A. conyzoides 5% performed well to suppress the colony growth of L. pseudotheobromae (100%), followed by A. conyzoides 3% and A. conyzoides 1%. A. conyzoides 5% able to inhibit the colony growth of L. theobromae until 100%, followed by A. conyzoides 3% and 1%. Meanwhile, A. conyzoides and C. odorata extract tested on PDB medium at 1, 3, and 5% reduced the fungal biomass significantly at all concentrations. C. odorata was found most effective in inhibiting fungal biomass of both pathogens either on wet weight or on dry weight at 1, 3, and 5% %. A. conyzoides and C. odorata can manage the growth of L. theobromae and L. pseudotheobromae through in vitro conditions.

Effect of water deficits on the growth and secondary metabolites of Salvia dolomitica Codd. and Salvia namaensis Schinz

Background: Salvia dolomitica Codd. and Salvia namaensis Schinz. are indigenous to southern Africa and are used as medicinal plants in folk medicine.Aim: This study aimed to assess the effects of different levels of water deficit treatments on the growth, concentration of secondary metabolites, and anti-Fusarium oxysporum activity of S. dolomitica and S. namaensis.Setting: Experiments were carried out on the Bellville campus of the Cape Peninsula University of Technology, Cape Town.Methods: Four weeks old seedlings of the two species were subjected to 3-, 6-, 9- and 12-day water deficit regimes. Secondary metabolites such as polyphenols, alkaloids, and flavanols were assessed using spectroscopic methods. The anti-fungal activities of crude extracts obtained from plants were evaluated in a micro-dilution bioassay.Results: In all treatments, the plant height, crown width, number of stems and leaves, and fresh and dry weights reduced with increased water deficits. Acetone extracts from all treatments showed anti-fungal activity. However, extracts from the treatment with moderate water deficit (6-day watering interval) recorded significantly (P 0.01) better inhibition of F. oxysporum at the 18 h post incubation than the commercial fungicide, Mancozeb.Conclusion: This research has revealed that mild to moderate water deficit level favours the accumulation of alkaloids in S. dolomitica. Meanwhile, mild to severe water deficit significantly lowered flavanol content in S. namaensis. There was a correlation between the increase in total alkaloid contents and the enhanced anti-fungal activity of extracts of S. dolomitica. The present findings pave the way for optimised cultivation of medicinal plants and development of bioactive natural products.

Entomogenous fungiisolated from Cryptotympana atrata with antibacterial and antifungal activity.

Although many entomogenous fungi have been discovered over the years, few studies on the crude extracts of fungi isolated from Cryptotympana atrata with antibacterial and antifungal activity were reported. In this study, total twenty entomogenous fungi were isolated for the first time. And among of them, two pure cultures were identified as Purpureocillium lilacinum and Aspergillus fumigatus with apparent morphology, microscopic identification and 18S rRNA gene sequence. The active strains were fermented to optimize in six different culture media at three different pH values. The antibacterial and antifungal activities of the metabolites were more potent and efficient in Fungal medium 3# at a pH of 6.2 than in the other tested media or at the other tested pH values. Total seven human pathogens and one insect pathogen were used to evaluate the antibacterial and antifungalactivity of crude extracts, among which 25% of the extracts exhibited antifungal activity against Verticillium lecanii, while 33.3% and 47.2% of the extracts exhibited antibacterial activity against the important human pathogens Staphylococcusaureus and Bacillus cereus, respectively. The range of the MICs was from 15.6 to 250μg mL-1, and 35% of the fungal metabolites exhibited antibacterial activity against Pseudomonas aeruginosa, Bacillus thuringiensis and Enterobacter aerogenes at 1000μgmL-1 except the previously described antibacterial activities. Furthermore, the phylogeneticrelationships of the two identified fungi were also constructed. In brief, it is the first reporting about enthompathogenic fungi from Cryptotympana atrata and provides candidate strains with potential use as biological agents and against multidrug-resistant organisms.

In vitro antifungal activity and phytochemical characterization of Eugenia uniflora, Libidibia ferrea and Psidium guajava

The aim of this study was evaluate the in vitro antifungal activity of crude extracts from Eugenia uniflora, Libidibia ferrea and Psidium guajava. The extracts were obtained by turbo-extraction using water (AQ) or acetone-water (AC-W) (7:3, v/v) as solvents and lyophilized to obtain the crude extracts (CE). The CE were characterized by UV-Vis, TLC and HPLC. The activity of CEs was investigated against clinical isolates of Candida spp. and the Minimum Inhibitory Concentration (MIC), MIC50 and MIC90 were determinated. The analysis by TLC showed that all CEs presented polyphenols (flavonoids and tannins). The CEs from E. uniflora showed higher amount of polyphenols (30.35 ± 2.15%, AC-W) and the HPLC analysis revealed the tannins in all extracts. The CEs of E. uniflora showed MIC range from 1.9 to 500.0 µg/mL, and lower values of MIC50 and MIC90 against non-albicans Candida isolates. Regarding L. ferrea and P. guajava, the results showing MIC from 3.9 to 1000.0 µg/mL (CE-AQ) against C. albicans. The results demonstrate antifungal performance from CE against various species of Candida spp., suggesting that the herbal species may be use as new potential antifungal agents. Additionally, the polyphenol content can play a pivotal role in the antifungal properties of CE.

In vitro Antimicrobial Activities of Crude Extracts of Vernonia amygdalina and Croton macrostachyus against Some Bacterial and Fungal Test Pathogens

The aim of the present study was to investigate the antibacterial and antifungal activities of crude extracts of Vernonia amygdalina and Croton macrostachyus against four bacterial pathogenic species (i.e. Staphylococcus aureus, Streptococcus agalactiae, Salmonella typhi, Escherichia coli) and two fungal pathogenic species (i.e. Aspergillus flavus and Aspergillus niger). Antimicrobial activities of the resulting extracts were determined by measuring zone of inhibitions on cultures of six selected pathogens using the disc diffusion method. The minimum inhibitory concentration (MIC) of the two plant extracts against the same pathogens was determined using the broth dilution method. Chloroamphenicol was used as positive control for for bacterial pathogen and Tilt was also used as positive controls fungal pathogens. Meanwhile Dimethyl Sulfoxide was taken as a negative control for both. Highest percentage yield was recorded for methanol extract of V. amygdalina (14.89±0.25%) and the lowest yield was observed for the water extract of V. amygdalina (4.58±0.27). All the methanolic and ethanolic crude extracts had the highest growth inhibitory effects as compared with the water crude extracts on all bacterial pathogens. The methanol crude extract of C. macrostachyus had highest zone of inhibition (21±0.29 mm) against S. aureus, with a minimum inhibitory concentration of 25mg/ml. Similarly, the ethanol crude extract of C. macrostachyus had shown highest antifungal activity against A. niger with inhibition zone of 15.5±0.29. The results indicate the potential of these medicinal plants in treating some bacterial and fungal infection. Thus, further detailed studies are recommended to be carried out to characterize their bioactive compounds for development of new effective antimicrobial drugs.

Antifungal Activity of Some Ethnomedicinally Important Tuberous Plants of Family Liliaceae

Fungal spores are often present in air and soil which may cause internal as well as external infections. Phytochemicals are extracted from plants of family Liliaceae and identified having antifungal and antibiotic properties. The present study deals antifungal activity of crude extract of leaf of five species Asparagus L. and four species Chlorophytum Ker. Gawl. of family Liliaceae using a different polar and non-polar solvent like methanol, petroleum ether and acetone. Effects of different plant extract were tested on yeast (Candida albicans) and mold (Aspergillus niger) using potato dextrose agar medium by agar well diffusion method. Zone of inhibition produced by different plant extracts was calculated. Among these plants, Chlorophytum borivilianum Santapau and Fernandes., Chlorophytum tuberosum Baker. and Asparagus racemosus Willd. show maximum antifungal activities against two clinical fungi Candida albicans and Aspergillus niger. In case of three solvent, acetone plant extract showed a significant reduction, while methanol showed its minimum reduction in the growth of these two opportunist fungi. Streptomycin was used as control drug for antifungal studies.

In vitro screening of, antibacterial antifungal and cytotoxicity activities in crude extract of freshwater cyanobacterium Oscillatoria sp.

Cyanobacteria, highly diverse group of prokaryotes are recognized as a potent source of biologically active compounds with antiviral, antibacterial, antifungal, and anticancer properties.The aim of the present study was to screen antibacterial, antifungal and cytotoxic activities of intracellular secondary metabolites of freshwater cyanobacterium Oscillataria sp. Cyanobacterium Oscillatoria sp. was isolated from Senanayaka Samudraya reservoir (7 0 11’ 37.37 0 N 810 31’ 47.13 0 E), Sri Lanka.In vitro antibacterial and antifungal activity of Oscillatoria sp. was screened against Gram-positive Methicillin-resistant Staphylococcus aureus (MRSA) ATCC 25923, Bacillus anthracis and Gram-negative Pseudomonas aeruginosa (ATCC 25853), Salmonella typhi and Escherichia coli (ATCC 25922) and fungi, unicellular Candida albicans (ATCC 60192) and Candida tropicalis using agar disc diffusion method.The Minimum Inhibitory Concentrations (MIC), Minimum Bacteriocidal Concentration (MBC), Minimum Fungicidal Concentrations (MFC) and cytotoxic effects (brine shrimp bioassay) of Oscillatoria crude extract were determined. 10% and 60% of biomass was extracted with hexane and methanol respectively.Gas Chromatography-Mass Spectrometry (GC-MS) was used to identify compounds in the crude extract. The highest antibacterial and antifungal activity of crude extract were detectedin methanol extract against S.aureus (19 ± 2 mm)and C.albicans (10 ± 1 mm) within 24 hours wherein the hexane extract, antibacterial activity was detected only for S. aureus and mean diameter of inhibition zone was 11 ± 1mm within 24 hours.The lowest MIC of methanol extract against S. aureus wasfound as 156.25 µg/ml. The lowest MBC and MFC of methanol extract against S. aureus and C.albicans were 0.63 mg/ml and 1.25mg/ml respectively. Lethal concentration, 50% of the crude extract against brine shrimp was recorded at 2.50 g/l, 1.25 g/l and 0.625 g/l for 6, 12, 24 hrs intervals respectively. GC-MS analysis revealed that the methanol crude extract of Oscillatoria sp. contains important fatty acid namely hexadecanoic acid methyl ester, methyl tetradecane and 13-tetradecanoic acid and n-hexane extract contains Bis (2-ethylhexyl hydroxypyridine oxide, 1 2-benzenedicarboxylic acid mono (2-ethylhexyl) ester, Phthalic acid 6-ethyl-3-Octyl heptyl ester and Phthalic acid dodecyl nonyl ester which may possess antibacterial and antifungal properties. Keywords: Oscillatoria sp., MFC, MIC, MBC, Cytotoxicity

Antifungal activity of crude extracts from brown and red seaweeds by a supercritical carbon dioxide technique against fruit postharvest fungal diseases

Fungal infections are the main cause of decay on fresh fruit during postharvest phase determining severe losses. Postharvest control is performed by fungicides, but their intense use have aroused issue relating to environmental protection and human health prompting to search alternative control means. The use of biofuel-used seaweed extracts by a supercritical carbon dioxide technique could be a valid alternative during postharvest handling of fresh fruit. The aim of this work was to assess the in vitro and in vivo activity of extracts from two brown seaweeds (Laminaria digitata and Undaria pinnatifida) and three red seaweeds (Porphyra umbilicalis, Eucheuma denticulatum and Gelidium pusillum) against three postharvest pathogens (Botrytis cinerea, Monilinia laxa and Penicillium digitatum) using three concentrations of extract (10, 20 and 30gL−1). The total content of fatty acids of the extracts was determined by CG-MS, those of polysaccharides by HIC, and phenolic compounds (phlorotannins) by HPLC-DAD. Twenty fatty acids were quantified in the extracts, while three polysaccharides categories and three phlorotannins classes were identified only in brown seaweed extracts. L. digitata, U. pinnatifida and P. umbilicalis showed the highest antifungal efficacy on in vitro cultures of the pathogens. L. digitata and U. pinnatifida completely inhibited mycelia growing and conidial germination of B. cinerea and M. laxa at the highest dose tested and strongly reduced those of P. digitatum. P. umbilicalis extract strongly inhibited mycelia and conidia growth on all the fungi. E. denticulatum and G. pusillum showed a lower but still significant reduction of mycelia growing and conidia germination on all the pathogens. In trials performed in vivo on wounded fruit, L. digitata, U. pinnatifida and P. umbilicalis extracts strongly suppressed grey mould on strawberries, brown rot on peaches, and green mould on lemons at 30gL−1 dose both in preventive and curative treatments; E. denticulatum and G. pusillum poorly reduced disease development. In all cases, a dose-effect of the treatments was observed with an increase of fruit decay inhibition and reduction of disease severity as the dose of extract applied over the wound increased. Moreover, an increased peroxidase activity in the strawberries/B. cinerea and peaches/M. laxa systems by preventive treatment with 30gL−1 extract was observed. The antifungal activity could be mainly ascribed to a direct toxicity of fatty acids found at the highest concentrations in L. digitata, U. pinnatifida and P. umbilicalis rather than to those of phenolic compounds and phlorotannins; but it could be related to possible peroxidase-mediated systemic resistance mechanisms elicited by the polysaccharides.

Antifungal activity of sterols and dipsacus saponins isolated from Dipsacus asper roots against phytopathogenic fungi

The in vivo antifungal activity of crude extracts of Dipsacus asper roots was evaluated against the phytopathogenic fungi Botrytis cinerea, Colletotrichum coccodes, Blumeria graminis f. sp. hordei, Magnaporthe grisea, Phytophthora infestans, Puccinia recondita and Rhizoctonia solani using a whole-plant assay method. Ethyl acetate and acetone extracts, at 1000μg/mL, suppressed the development of tomato gray mold (TGM) and tomato late blight (TLB) by 90%. Through bioassay-guided isolation, five antifungal substances were isolated from the D. asper roots and identified as β-sitosterol (1), campesterol (2), stigmasterol (3), cauloside A (4) and a novel dipsacus saponin, named colchiside (3-O-β-d-xylopyranosyl-23-O-β-d-glucopyranosyl-28-O-β-d-(6-O-acetyl)-glucopyranosyl hederagenin) (5). Of those, cauloside A (4) displayed the greatest antifungal efficacy against rice blast, TGM and TLB. Colchiside (5) moderately suppressed the development of TLB, but exhibited little effect against the other diseases. The synergistic effects of the isolated compounds against TLB were also assessed. Synergistic and additive interactions were observed between several of the sterol compounds. This study indicated that the crude extracts of, and bioactive substances from, the roots of D. asper suppress TGM and TLB. In addition, cauloside A (4) and colchiside (5) could be used as antifungal lead compounds.

Challenges in the Development of Antifungal Agents Against Candida: Scope of Phytochemical Research.

Infections caused by Candida have become a major source of morbidity and mortality. Limited numbers of drugs are available to treat these infections. Phytochemicals can be the major source of antifungal compounds. The aim of this publication was to review the current literature to assess the challenges and scope of phytochemical research in the development of new antifungal drugs. Literature describing cellular nature of Candida, the development of drug resistance and target sites for the new drugs were assessed. Publications reporting antifungal activities of crude extracts of plants, their essential oils and identified chemical constituents were also summarised. The results showed that the development of new antifungal agents from natural sources is a complex process due to the cellular nature of Candida and the types of infections caused, such as superficial to life threatening systemic mycosis which necessitate systemic and topical use of drugs. Efficacy of the drugs in the presence of body fluids, normal flora and medical devices can also pose a challenge. Synthetic, semi-synthetic and natural compounds can be screened for their antifungal activities against emerging target sites using new cost effective techniques to increase throughput. Their efficacy, substantivity and site specific desired drug delivery can be enhanced using nanotechnology, hydrogel formulation and bio-adhesive technology. Finally, partnership between academic research laboratories and pharmaceutical industries is also necessary. Many challenges are identified in the development of new antifungal drugs, however phytochemicals are still the major source of new antifungal drugs and should be strategically explored.

ANTIMICROBIAL ACTIVITY OF THREE INSECT SPECIES, CRUDE EXTRACTS AGAINTS CERTAIN MICROBIAL AGENTS.

The aim of the present study was to investigate the antibacterial and antifungal activities of crude extracts of the desert locust, Schistocerca gregaria, the cotton leaf worm, Spodoptera littoralis and the oriental hornet, Vespa orientalis using different solvents; methanol, petroleum ether and chloroform against Gram-positive bacteria; Micrococcus luteus and Staphylococcus aureus, Gram-negative bacteria, Pseudomonas aeruginosa and Escherichia coli and fungi; Penicillium chrysogenum and Candida albicans. Preparation of crude insect extracts from the whole body of the three species were firstly washed with 80 % ethanol as a disinfectant, then rinsed in distilled water, excess water was removed by filter paper, then homogenized in 10 ml of the first solvent, centrifuged at 13,000 r.p.m. for 30 min.at 4oC, supernatant was removed and used as first solvent extract, residue was soaked in the second solvent then centrifuged, The previous step was carried out with the remain solvent as mentioned before. All solvent extracts were dried by evaporation of solvents for usage in the antimicrobial activity tests. A strong effect against Gram-positive bacteria Micrococcus luteus and Staphylococcus aureus was observed by the extraction of desert locust by petroleum ether as an inhibition zone recorded 30±0.1mm and 32±0.4 mm, respectively. While the inhibition zone effect of the desert locust and the oriental hornet extracted by methanol was 23±0.2mm, 26±0.44mm and 24±0.26mm, 24±0.64mm, respectively. While the oriental hornet extracted by petroleum ether was 26±0.18 mm, 25±0.51mm. On the other hand, Escherichia coli inhibited by the oriental hornet extracts, while Pseudomonas aeruginosa inhibited by two oriental hornet extracted by methanol, petroleum ether and the desert locust extracted by chloroform, respectively. While all extracts except the oriental hornet extracted by chloroform have antifungal activity against Penicillium chrysogenum. Keywords: Antimicrobial activity, Crud extract, Insect, bacteria and fungi.

Antifungal and SAR potential of crude extracts derived from neem and ginger against storage carrot rot caused by Sclerotinia sclerotiorum

The in vitro and in vivo experiments were conducted to evaluate antifungal activity of crude extracts derived from neem (Azadirachta indica) leaves and ginger (Zingiber officinale) rhizomes against three isolates of Sclerotinia sclerotiorum, the causal agent of storage carrot (Daucus carota) rot. Ethyl acetate (EA) and ethanol were used as different solvents. Although plant extracts significantly reduced the mycelial growth of three isolates at volatile phase, highest inhibitory efficacy was observed at contact phase. Furthermore, all crude extracts were able to reduce carpogenic germination of sclerotia at concentrations 2g/l. The isolate 2 was found to be more inhibited in in vitro tests. At volatile phase, EA and ethanol extracts of ginger meaningfully reduced myceliogenic germination of sclerotia in three isolates. However, all plant extracts decreased the myceliogenic germination of sclerotia at contact phase at the concentration 10g/l. The results of in vivo tests showed that all plant extracts are able to decrease disease severity of carrot rot at the concentration 2g/l. In addition, the enzymatic analyses of phenylalanine ammonia layse, polyphenoloxidase and peroxidase in inoculated carrots after application of plant crude extracts indicated that neem extracts can be considered as resistance inducers against Sclerotinia carrot rot.

Antifungal activity of crude extract produced by Bacillus sp. associated with entomopathogenic nematode from media formulated by six nitrogen sources with fructose against Penicillium expansum

A specific symbiotic Bacillus species isolated from a rhabditid entomopathogenic nematode, Rhabditis (Oscheius) sp. was found to produce a number of bioactive compounds. The present study was conducted to determine the effect of six different nitrogen sources in combination with fructose on the production of antifungal crude extract by Bacillus sp. against Penicillium expansum. The yield of crude extract and antifungal activity against the test fungi differed significantly when the nitrogen sources in the fermentation media were changed. The highest yield was recorded for beef extract plus fructose (921 mg/L). The antifungal activity was higher in yeast extract plus fructose [P. expansum (46.5 ± 2.12 mm)], followed by beef extract. High performance liquid chromatography analysis of the crude antimicrobial substances revealed different peaks with different retention times indicating that they produced different compounds. When a carbon source was not included in the fermentation medium, the antimicrobial production was substantially reduced almost eight times. Carbon source in the fermentation medium plays a vital role in the production of antimicrobial substances. Yeast extract and fructose as nitrogen and carbon sources in the fermentation medium produced maximum antimicrobial activity.

Evaluation of Crude Extracts of <i>Mimosa pusica</i> LINN. against <i>Colletotrichum gloeosporioides</i> to Control Anthracnose

The antifungal activity of crude extracts of M. pudica Linn. was evaluated by determining the minimum inhibitory concentration (MIC) of the solvent extracts. Subsequently, an antifungal assay was carried out by determining the inhibition of radial growth in PDA plates added with plant extracts. MIC value of crude extracts was 15.00, 18.50 and 19.50 µg/mL for 95% ethanol, dichloromethane and acetone extracts, respectively. Concerning the inhibition of radial growth, ethanol crude extracts of M. Pudica was most effective and exhibited highest antifungal activity of 55.65% at 10.00 µg/mL, 54.02% at 1.00 µg/mL, 50.95% at 0.10 µg/mL, and 48.70% at 0.01 µg/mL against C. gloeosporioides., respectively. The highest yield was found in 95% ethanol at 73 mg/g. The higher yield was presented when the higher polar solvents were used in this experiment. Since factors such as solvent of extraction may influence the properties of derived crude extract, different extraction methods may be of interest for further trial.

Antibacterial and antifungal activity of crude extracts of Plumeria rubra L.

Petroleum ether, carbon tetrachloride, chloroform and ethyl acetate extracts of Plumeria rubra leaves were studied for their antimicrobial activities against eleven human pathogenic bacteria, viz., Shigella dysenteriae, S. sonnei, Salmonella typhi, S. paratyphi, Bacillus subtilis, B. megaterium, B. cereus, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Vibrio cholerae and four human pathogenic fungi, viz., Aspergillus niger, A. ochraceus, A. ustus and Candida albicans using disc diffusion and poisoned food method, respectively. Chloroform and ethyl acetate extract exhibited moderate to good antibacterial and antifungal activity against all the pathogens tested. The ethyl acetate extracts exhibited the largest zone of inhibition (25 mm in diameter with 2000 mg/disc extract) against E. coli. The highest inhibition of fungal radial mycelial growth (62.00% with 100 mg extract/ml medium) was recorded against A. ustus with ethyl acetate extract. The MICs were determined by broth macrodilution technique. The ethyl acetate extract exhibited the lowest MIC (750 mg/ml) against E. coli. However, for fungi the lowest MIC was 500 mg/ml against A. ustus with the same extract. DOI: http://dx.doi.org/10.3329/cujbs.v3i1.13409 The Chittagong Univ. J. B. Sci.,Vol. 3(1&2):87-94, 2008