scholarly journals Reproducibility challenges in the search for antibacterial compounds from nature

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0255437
Author(s):  
Nelson E. Masota ◽  
Gerd Vogg ◽  
Knut Ohlsen ◽  
Ulrike Holzgrabe
Keyword(s):  
Escherichia Coli ◽  
Plant Species ◽  
Plant Extracts ◽  
Antibacterial Activities ◽  
Bacterial Isolates ◽  
Research Papers ◽  
Related Factors ◽  
Antibacterial Compounds ◽  
Growth State ◽  
Related Plant

Background Reproducibility of reported antibacterial activities of plant extracts has long remained questionable. Although plant-related factors should be well considered in serious pharmacognostic research, they are often not addressed in many research papers. Here we highlight the challenges in reproducing antibacterial activities of plant extracts. Methods Plants with reported antibacterial activities of interest were obtained from a literature review. Antibacterial activities against Escherichia coli and Klebsiella pneumoniae were tested using extracts’ solutions in 10% DMSO and acetone. Compositions of working solutions from both solvents were established using LC-MS analysis. Moreover, the availability of details likely to affect reproducibility was evaluated in articles which reported antibacterial activities of studied plants. Results Inhibition of bacterial growth at MIC of 256–1024 μg/mL was observed in only 15.4% of identical plant species. These values were 4–16-fold higher than those reported earlier. Further, 18.2% of related plant species had MICs of 128–256 μg/mL. Besides, 29.2% and 95.8% of the extracts were soluble to sparingly soluble in 10% DMSO and acetone, respectively. Extracts’ solutions in both solvents showed similar qualitative compositions, with differing quantities of corresponding phytochemicals. Details regarding seasons and growth state at collection were missing in 65% and 95% of evaluated articles, respectively. Likewise, solvents used to dissolve the extracts were lacking in 30% of the articles, whereas 40% of them used unidentified bacterial isolates. Conclusion Reproducibility of previously reported activities from plants’ extracts is a multi-factorial aspect. Thus, collective approaches are necessary in addressing the highlighted challenges.

scholarly journals Studies on Phytochemical, Nutraceutical Profiles and Potential Medicinal Values of Allium sativum Linn (Lilliaceae) on Bacterial Meningitis

2019 ◽  
pp. 1-15 ◽  
Author(s):  
Kokori Bajeh Tijani ◽  
Abdullahi Attah Alfa ◽  
Abdullahi Aminu Sezor
Keyword(s):  
Escherichia Coli ◽  
Streptococcus Pneumoniae ◽  
Klebsiella Pneumoniae ◽  
Bacterial Meningitis ◽  
Haemophilus Influenzae ◽  
Allium Sativum ◽  
Antibacterial Activities ◽  
Phytochemical Screening ◽  
Bacterial Isolates ◽  
Neisseria Meningitides

The studies on phytochemical, nutraceutical profiles and potential medicinal values of Allium sativum linn (lilliaceae) on bacterial meningitis were evaluated against bacterial meningitis pathogens. The methods employed in this study were validation of phytochemical screening which was done according to standard methods, determination of nutritional composition was carried out using analytical automated instruments (Atomic Absorption Spectrometers) and evaluation of in vitro antibacterial activities of the extracts against clinical isolates using agar-well diffusion and broth dilution methods. The clinical isolates of meningitis pathogens, Streptococcus pneumoniae, Neisseria meningitides, Klebsiella pneumoniae, Haemophilus influenzae and Escherichia coli were obtained from Ahmadu Bello University Teaching Hospital (ABUTH), Shika-Zaria. The collected bulbs of A. sativum (600 g) were washed and air dried under shade for 2 hours and the dry scaly outer covering was peeled-off to obtain the fresh garlic cloves which were then divided into three parts of 200 g each. These three portions were crushed separately for cold extraction. The first portion was homogenized and poured into a muslin cloth to squeeze out the juice, while second and third portions were homogenized and submerged into 500 ml of 96% ethanol and 500 ml of distilled water respectively for 24 hours and both filtered after thorough shaking. The first and second portions were freeze dried, while the third portion was evaporated over water bath at 50°C to obtain the powdered yield. The phytochemical screening of A. sativum extracts (JEAS, EEAS and AEAS) revealed the presence of alkaloids, carbohydrates, cardiac glycosides, fats & oils, flavonoids, saponins and steroidal terpenoids. The results obtained as nutritional profiles from analytical automated machines analysis showed that A. sativum contained all classes of food nutrients such as carbohydrate, protein, fat and oils, dietary fibres, and vitamins together with zeolite herbominerals (nanopharmacologic effects). JEAS and EEAS extracts were potent in (0.94 ± 0.01 minutes), (0.99±0.04) and antibacterial activities while and AEAS (1.20±0.04) showed low activity, inhibiting the clinical bacterial isolates Neisseria meningitides, Streptococcus pneumoniae, Haemophilus influenzae and Escherichia coli with diameter of zone of inhibition ranging from 15-36 mm at concentrations of 10, 15, 20 and 25 mg/ml. It produced significant (p<0.05) antibacterial activity while EEAS and AEAS showed low activities, except Klebsiella pneumoniae which was resistant to the three extracts concentrations used. The extracts inhibited the growth of the bacterial isolates in a concentration dependent manner with MICs ranging between 0.04-1.56 mg/ml while MBCs was 0.10-2.50 mg/ml respectively the findings from this study could be of interest and suggest the need for further investigations with a view to use the plant in novel drug development for BM therapy. The outcome of this study could therefore justify the ethnomedical and folkloric usage of A. sativum to treat bacterial meningitis locally.

scholarly journals In Vitro Antibacterial Activities of Various Ethanolic Medicinal Plant Extracts Against Some Human Pathogenic Bacteria

2020 ◽  
Vol 8 (6) ◽  
pp. 1272-1276
Author(s):  
Samir K. Ali ◽  
Ghorbat S. Ali ◽  
Berivan Abdulrahman Abdullah
Keyword(s):  
Medicinal Plant ◽  
Plant Extracts ◽  
Pathogenic Bacteria ◽  
Antimicrobial Agents ◽  
Nigella Sativa ◽  
Antibacterial Activities ◽  
Diffusion Method ◽  
Bacterial Isolates ◽  
Foeniculum Vulgare ◽  
Medicinal Plant Extracts

The widespread use of antibiotics often causes increase in the bacterial drugs resistance and causes many side effects in humans. Medical plants have antimicrobial effects against most pathogenic bacteria and can serve as harmless replacement to antibiotics. The aim of this study was to assess the antibacterial effect of five medicinal plant prevailed in Kurdistan region namely; Cinnamon (Cinnamomum cassia (L.) D.Don), Nigella (Nigella sativa L.), Allium (Allium hirtifolium Boiss.), Carrot (Daucus carota L.), and Fennel (Foeniculum vulgare Mill.) against pathogenic Gram positive bacteria (Staphylococcus aureus), and pathogenic Gram negative bacteria (Salmonella typhi and Escherichia coli). The evaluation of antibacterial activity for these plant extracts was carried out using agar-well diffusion method. Results showed that minimum inhibitory concentration (MIC) of A. hirtifolium against tested bacterial isolates were (25 mg/mL), the lowest MIC values for S. aureus were (25 mg/mL) observed with C. cassia, N. sativa and F. vulgare ethanolic extracts and the lowest MIC of D. carota against bacterial isolates were (50 mg/mL), Also, it was observed that S. aureus was more sensitive than S. typhi and E. coli to plant extracts. The ethanol plant extracts had potential antibacterial activities. However, further studies are required to identify the active compounds which could be used for the preparation of new antimicrobial agents and control the bacterial infectious diseases.

scholarly journals Atividade Antibacteriana dos Extratos Etanolícos do Caule e da Folha de Qualea parviflora Mart. (Pau-terra)

UNICIÊNCIAS ◽  
2019 ◽  
Vol 23 (1) ◽  
pp. 43
Author(s):  
Daniel David Franczak ◽  
Roberta Carreto ◽  
Vivian Tallita Pinheiro Santana ◽  
Geny Silva De Souza
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Streptococcus Pyogenes ◽  
Plant Extracts ◽  
Inhibitory Action ◽  
Secondary Compounds ◽  
Antibacterial Activities ◽  
Antimicrobial Treatment ◽  
Gram Positive ◽  
Gram Negative

A resistência aos antimicrobianos por micro-organismos patogênicos é consequência, principalmente, do uso irracional de antibióticos e constitui uma ameaça para o controle das doenças infecciosas. Estudos das atividades antibacterianas de extratos de plantas podem fornecer alternativas para o tratamento antimicrobiano e, por isso têm despertado interesse pela investigação para o potencial da flora brasileira. Objetivou-se analisar a possível atividade antibacteriana da espécie Qualea parviflora Mart. (Pau-terra). Os ensaios foram realizados por difusão em discos previamente sensibilizados com extratos obtidos por maceração do caule e folhas nas concentrações de 50 e 100% (etanol 99,5ºGL como extrator). Realizaram-se testes para cepas Gram-positivas (Staphylococcus aureus e Streptococcus pyogenes) e Gram-negativas (Escherichia coli). Os discos sensibilizados foram dispostos nas placas de cultivo e essas incubadas a 37 ºC/24 horas. Os halos de inibição foram analisados por leitura visual. Os extratos concentrados (100%) da casca e folha apresentaram inibição contra Gram-positivas e Gram-negativas, sendo o obtido da folha mais eficaz. Na concentração de 50%, a inibição somente foi observada com o macerado das folhas. Os extratos da maceração das folhas apresentaram maior inibição contra Gram-negativos. A ação inibitória registrada para os extratos da Q. parviflora Mart. pode estar relacionada a sua composição fitoquímica, pois apresenta vários metabolitos secundários com atividade antimicrobiana. Porém, são necessários estudos complementares para comprovação da presença dos compostos secundários capazes de atuar na inibição de micro-organismos, além de testes como a microdiluição em caldo para auxiliar na confirmação da ação inibitória dos compostos presentes na Q. parviflora Mart.Palavras-chave: Antibiótico. Cerrado. Extratos Vegetais.AbstractAntimicrobial resistance to pathogens is mainly due to the irrational use of antibiotics and constitutes a threat to the control of infectious diseases. Studies of the antibacterial activities of plant extracts can provide alternatives for the antimicrobial treatment and, therefore, has aroused interest by the investigation for the potential of the Brazilian flora. It was aimed to  analyze the possible antibacterial activity of the species Qualea parviflora Mart. The tests were carried out by diffusion in disks previously sensitized with extracts obtained by stem maceration and leaves at concentrations of 50 and 100% (99.5 °GL ethanol as extractor). Tests were performed for Gram-positive strains (Staphylococcus aureus and Streptococcus pyogenes) and Gram-negative (Escherichia coli). The sensitized discs were placed in the culture plates and incubated at 37 °C / 24 hours. Inhibition halos were analyzed by visual reading. Concentrated (100%) extracts of bark and leaf showed inhibition against Gram-positive and Gram-negative, being the most effective leaf extract. At 50% concentration the inhibition was only observed with leaf maceration. Extracts from leaf maceration showed greater inhibition against Gram negative. The inhibitory action recorded for the extracts of Q. parviflora Mart. may be related to its phytochemical composition, since it presents several secondary metabolites with antimicrobial activity. However, further studies are necessary to prove the presence of secondary compounds capable to act in inhibition of microorganisms, as well as testing broth microdilution to assist in confirming the inhibitory action of the compounds present in Q. parviflora Mart. Keywords: Antibiotic. Cerrado. Plant Extracts.  AbstractAntimicrobial resistance to pathogens is mainly due to the irrational use of antibiotics and constitutes a threat to the control of infectious diseases. Studies of the antibacterial activities of plant extracts can provide alternatives for the antimicrobial treatment and, therefore, has aroused interest by the investigation for the potential of the Brazilian flora. It was aimed to  analyze the possible antibacterial activity of the species Qualea parviflora Mart. The tests were carried out by diffusion in disks previously sensitized with extracts obtained by stem maceration and leaves at concentrations of 50 and 100% (99.5 °GL ethanol as extractor). Tests were performed for Gram-positive strains (Staphylococcus aureus and Streptococcus pyogenes) and Gram-negative (Escherichia coli). The sensitized discs were placed in the culture plates and incubated at 37 °C / 24 hours. Inhibition halos were analyzed by visual reading. Concentrated (100%) extracts of bark and leaf showed inhibition against Gram-positive and Gram-negative, being the most effective leaf extract. At 50% concentration the inhibition was only observed with leaf maceration. Extracts from leaf maceration showed greater inhibition against Gram negative. The inhibitory action recorded for the extracts of Q. parviflora Mart. may be related to its phytochemical composition, since it presents several secondary metabolites with antimicrobial activity. However, further studies are necessary to prove the presence of secondary compounds capable to act in inhibition of microorganisms, as well as testing broth microdilution to assist in confirming the inhibitory action of the compounds present in Q. parviflora Mart. Keywords: Antibiotic. Cerrado. Plant Extracts.

Investigation into the presence of Monatin in related plant species

Planta Medica ◽  
2008 ◽  
Vol 74 (09) ◽  
Author(s):  
N Moodley ◽  
V Maharaj
Keyword(s):  
Plant Species ◽  
Related Plant

Antibacterial Activities of Sirih Merah (Piper crocatum) Leaf Extracts

2019 ◽  
Vol 5 (3) ◽  
pp. 1-10
Author(s):  
Puspa Julistia Puspita ◽  
Mega Safithri ◽  
Nirmala Peni Sugiharti
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Antibacterial Agent ◽  
Leaf Extract ◽  
Antibacterial Activities ◽  
Leaf Extracts ◽  
Herbal Plants

Piper crocatum is one of medicinal herbal plants with a large number of benefits. Usually herbal plants have activity as antibacterial agent. Therefore, the objectives of this research were to obtain information on antibacterial activities of the leaf extracts of Piper crocatum againts four types of bacteria, in that Staphylococcus, Bacillus substilis, Escherichia coli, and Pseudomonas aeruginosa and then to analyze the phytochemistry of the leaf extracts of Piper crocatum. The leaves of Piper crocatum were extracted by maceration and reflux using ethanol 30%. The assays of the antibacterial activities and phytochemistry on the extracts were carried out using the method of Maria Bintang. Results showed that the yield of the extraction using ethanol by maceration method was 20.8%. Meanwhile, using the reflux method, the yield was obtained about 26.25%. The phytochemistry analysis showed that the leaf extracts of Piper crocatum contained alkaloid, steroid and tanin. According to this study, it was found that the leaf extract of Piper crocatum can be used to inhibit the growth of B. subtilis and P. aeuruginosa, but can not inhibit the growth of E.coli and S. aureus.

Antibacterial Flavonoids Against Oral Bacteria of Enterococcus Faecalis ATCC 29212 from Sarang Semut (Myrmecodia pendans) and Its Inhibitor Activity Against Enzyme MurA

2019 ◽  
Vol 16 (3) ◽  
pp. 290-296 ◽  
Author(s):  
Dikdik Kurnia ◽  
Eti Apriyanti ◽  
Cut Soraya ◽  
Mieke H. Satari
Keyword(s):  
Enzyme Activity ◽  
Enterococcus Faecalis ◽  
Ethyl Acetate Fraction ◽  
Antibacterial Activities ◽  
Oral Bacteria ◽  
Diffusion Method ◽  
Enzyme Activity Assay ◽  
Antibacterial Compounds ◽  
Ic50 Values ◽  
Positive Controls

Background: A significant number of antibiotics are known to inhibit peptidoglycan synthesis in the cross-linking stage, while the drug fosfomycin is the only one known to inhibit MurA. Escalated antibiotic resistance has had an impact on the efficacy of fosfomycin, thus demanding the discovery of suitable substitutes with improved potential for MurA inhibition. The aim of this work is to isolate antibacterial compounds from Sarang Semut (Myrmecodia pendans) and to evaluate their antibacterial activity against pathogenic oral bacteria of Enterococcus faecalis ATCC 29212 and inhibitory activity against MurA enzyme. Methods: The antibacterial compounds from Sarang Semut were isolated by a bioactivity-guided separation method with various solvents and combination of column chromatography on normal and reverse phases. The compounds with concentrations of 1000 and 5000 ppm were assessed against E. faecalis ATCC 29212 by agar well diffusion method, with chlorhexidine and fosfomycin being used as positive controls. Results: Two antibacterial compounds isolated from Sarang Semut were identified as two new flavonoids derivates of 1 (10 mg) and 2 (4 mg). Both compounds were tested for antibacterial activities against E. faecalis. MIC values of compounds 1 and 2 were 8.15 and 8.05 mm at 1000 ppm and 8.62 and 8.55 mm at 5000 ppm, respectively. MBC values were 156 and 625 ppm for 1 and 625 and 2500 ppm for 2, respectively. In an inhibitory murA enzyme activity assay, compounds 1 and 2 were shown to inhibit the enzyme activity by IC50 values of 21.7 and 151.3 ppm. Conclusion: The study demonstrated that ethyl acetate fraction of Sarang Semut contained antibacterial flavonoids as active constituents that showed activity against E. faecalis. These results showed the plant’s potential in herbal medicine and the development of new antibacterial agent for pathogenic dental caries.

scholarly journals Effects of Plant Age and Root Damage on Internalization of Shiga Toxin-Producing Escherichia coli in Leafy Vegetables and Herbs

Horticulturae ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 68
Author(s):  
Yi-Ju Wang ◽  
Amanda J. Deering ◽  
Hye-Ji Kim
Keyword(s):  
Escherichia Coli ◽  
Plant Species ◽  
Shiga Toxin ◽  
Production Systems ◽  
Plant Age ◽  
Leafy Vegetables ◽  
Root Damage ◽  
Hygiene Practices ◽  
Hydroponic Systems ◽  
Stx1 Gene

Our previous study reported that fresh produce grown in aquaponic and hydroponic systems can pose potential food safety hazards due to an accidental introduction of contaminated fish and cross-contamination between the systems. In this study, we examined the effects of plant species and age on the likelihood and level of internalization of Shiga toxin-producing Escherichia coli (STEC) in aquaponic and hydroponic systems. Four plant species, basil (Ocimum basilicum L. cv. Genovese), cilantro (Coriandrum Sativum L.), lettuce (Lactuca sativa cv. Cherokee), and kale (Brassica oleracea var. sabellica), received root damage treatment as seedlings before transplanting or mature plants at three weeks after transplanting by cutting off 1-cm tips of one-third of the roots. Enrichments and selective media were used for the isolation, and presumptive positive colonies were confirmed by PCR for the presence of stx1 gene in plant tissues, recirculating water, and fish feces collected at four weeks after transplanting. In hydroponic systems, STEC was found neither in the solution nor in the roots and leaves of all four plant species, possibly through improved sanitation and hygiene practices. However, consistent with our previous findings, STEC was found in the water, on the plant roots, and in the fish feces in aquaponic systems, even after thorough sanitation prior to the study. Regardless of plant age, STEC was internalized in the roots of all plant species when the roots were damaged, but there was no difference in the degree of internalization with STEC among plant species. STEC was present in the leaves only when seedlings received root damage treatment and were grown to maturity, indicating that root damage allows STEC to internalize in the roots within a week, but a longer period is required for STEC to internalize into the leaves. We concluded that root damage on seedlings can cause the internalization of E. coli O157:H7 in the edible parts of leafy vegetables and herbs in soilless production systems.

Plant leaf recognition with shallow and deep learning: A comprehensive study

2020 ◽  
Vol 24 (6) ◽  
pp. 1311-1328
Author(s):  
Jozsef Suto
Keyword(s):  
Machine Learning ◽  
Plant Species ◽  
Research Area ◽  
Research Papers ◽  
Plant Leaf ◽  
Leaf Characteristics ◽  
The Past ◽  
The Earth ◽  
Test Sets ◽  
Comprehensive Study

Nowadays there are hundreds of thousands known plant species on the Earth and many are still unknown yet. The process of plant classification can be performed using different ways but the most popular approach is based on plant leaf characteristics. Most types of plants have unique leaf characteristics such as shape, color, and texture. Since machine learning and vision considerably developed in the past decade, automatic plant species (or leaf) recognition has become possible. Recently, the automated leaf classification is a standalone research area inside machine learning and several shallow and deep methods were proposed to recognize leaf types. From 2007 to present days several research papers have been published in this topic. In older studies the classifier was a shallow method while in current works many researchers applied deep networks for classification. During the overview of plant leaf classification literature, we found an interesting deficiency (lack of hyper-parameter search) and a key difference between studies (different test sets). This work gives an overall review about the efficiency of shallow and deep methods under different test conditions. It can be a basis to further research.

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