scholarly journals New perspectives of purple starthistle (Centaurea calcitrapa) leaf extracts: phytochemical analysis, cytotoxicity and antimicrobial activity

AMB Express ◽  
2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Ivica Dimkić ◽  
Marija Petrović ◽  
Milan Gavrilović ◽  
Uroš Gašić ◽  
Petar Ristivojević ◽  
...  

Abstract Ethnobotanical and ethnopharmacological studies of many Centaurea species indicated their potential in folk medicine so far. However, investigations of different Centaurea calcitrapa L. extracts in terms of cytotoxicity and antimicrobial activity against phytopathogens are generally scarce. The phenolic profile and broad antimicrobial activity (especially towards bacterial phytopathogens) of methanol (MeOH), 70% ethanol (EtOH), ethyl-acetate (EtOAc), 50% acetone (Me2CO) and dichloromethane: methanol (DCM: MeOH, 1: 1) extracts of C. calcitrapa leaves and their potential toxicity on MRC-5 cell line were investigated for the first time. A total of 55 phenolic compounds were identified: 30 phenolic acids and their derivatives, 25 flavonoid glycosides and aglycones. This is also the first report of the presence of centaureidin, jaceidin, kaempferide, nepetin, flavonoid glycosides, phenolic acids and their esters in C. calcitrapa extracts. The best results were obtained with EtOAc extract with lowest MIC values expressed in µg/mL ranging from 13 to 25, while methicillin resistant Staphylococcus aureus was the most susceptible strain. The most susceptible phytopathogens were Pseudomonas syringae pv. syringae, Xanthomonas campestris pv. campestris and Agrobacterium tumefaciens. The highest cytotoxicity was recorded for EtOAc and Me2CO extracts with the lowest relative and absolute IC50 values between 88 and 102 µg/mL, while EtOH extract was the least toxic with predicted relative IC50 value of 1578 µg/mL. Our results indicate that all tested extracts at concentration considered as non-toxic can be one of great importance in combat towards phytopathogenic and human pathogenic strains, as well as natural sources of antimicrobials.

2014 ◽  
Vol 81 (1) ◽  
pp. 432-440 ◽  
Author(s):  
T. Sotelo ◽  
M. Lema ◽  
P. Soengas ◽  
M. E. Cartea ◽  
P. Velasco

ABSTRACTGlucosinolates (GSLs) are secondary metabolites found inBrassicavegetables that confer on them resistance against pests and diseases. Both GSLs and glucosinolate hydrolysis products (GHPs) have shown positive effects in reducing soil pathogens. Information about theirin vitrobiocide effects is scarce, but previous studies have shown sinigrin GSLs and their associated allyl isothiocyanate (AITC) to be soil biocides. The objective of this work was to evaluate the biocide effects of 17 GSLs and GHPs and of leaf methanolic extracts of different GSL-enrichedBrassicacrops on suppressingin vitrogrowth of two bacterial (Xanthomonas campestrispv. campestris andPseudomonas syringaepv. maculicola) and two fungal (AlternariabrassicaeandSclerotiniascletoriorum)Brassicapathogens. GSLs, GHPs, and methanolic leaf extracts inhibited the development of the pathogens tested compared to the control, and the effect was dose dependent. Furthermore, the biocide effects of the different compounds studied were dependent on the species and race of the pathogen. These results indicate that GSLs and their GHPs, as well as extracts of differentBrassicaspecies, have potential to inhibit pathogen growth and offer new opportunities to study the use ofBrassicacrops in biofumigation for the control of multiple diseases.


PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12097
Author(s):  
Yaowanoot Promnuan ◽  
Saran Promsai ◽  
Wasu Pathom-aree ◽  
Sujinan Meelai

This study aimed to investigate cultivable actinomycetes associated with rare honey bee species in Thailand and their antagonistic activity against plant pathogenic bacteria. Actinomycetes were selectively isolated from the black dwarf honey bee (Apis andreniformis). A total of 64 actinomycete isolates were obtained with Streptomyces as the predominant genus (84.4%) followed by Micromonospora (7.8%), Nonomuraea (4.7%) and Actinomadura (3.1%). All isolates were screened for antimicrobial activity against Xanthomonas campestris pv. campestris, Pectobacterium carotovorum and Pseudomonas syringae pv. sesame. Three isolates inhibited the growth of X. campestris pv. campestris during in vitro screening. The crude extracts of two isolates (ASC3-2 and ASC5-7P) had a minimum inhibitory concentration (MIC) of 128 mg L−1against X. campestris pv. campestris. For isolate ACZ2-27, its crude extract showed stronger inhibitory effect with a lower MIC value of 64 mg L−1 against X. campestris pv. campestris. These three active isolates were identified as members of the genus Streptomyces based on their 16S rRNA gene sequences. Phylogenetic analysis based on the maximum likelihood algorithm showed that isolate ACZ2-27, ASC3-2 and ASC5-7P were closely related to Streptomyces misionensis NBRC 13063T (99.71%), Streptomyces cacaoi subsp. cacaoi NBRC 12748T (100%) and Streptomyces puniceus NBRC 12811T (100%), respectively. In addition, representative isolates from non-Streptomyces groups were identified by 16S rRNA gene sequence analysis. High similarities were found with members of the genera Actinomadura, Micromonospora and Nonomuraea. Our study provides evidence of actinomycetes associated with the black dwarf honey bee including members of rare genera. Antimicrobial potential of these insect associated Streptomyces was also demonstrated especially the antibacterial activity against phytopathogenic bacteria.


Author(s):  
Vipul Kumar ◽  
Anurag Chakraborty ◽  
Manpreet Kaur ◽  
Sony Pandey ◽  
Manoj Kumar Jena

Objective: This study was focused on to compare the antimicrobial activity of methanolic leaf extracts of tulsi and neem.Methods: We have chosen tulsi (Ocimum sanctum) and neem (Azadirachta indica) to compare their antimicrobial activity toward Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. Phytochemical extracts have been made by the use of methanol as solvent and dried leaf powder by the cold maceration extraction process. Phytochemical analysis for some secondary metabolites has been done using standard protocols. Nutrient agar plates were inoculated with the above-mentioned microorganisms by spreading bacterial inoculum on the surface of the media. Wells (6 mm in diameter) were punched in the agar. The phytochemical extracts of neem and tulsi were allowed to diffuse into the medium, and after incubation of 24 h at 37°C, the zones of inhibition were observed.Results: Statistical analysis showed that tulsi was more effective toward S. aureus while neem was more effective toward E. coli. Minimum inhibitory concentration (MIC) of tulsi for both the microorganisms was 0.4 g/ml, and the MIC of neem for both the microorganisms was 0.2 g/ml. When both the tulsi and neem extract were mixed with each other for every concentration at equal volume, they have shown better effects in comparison to individual neem or tulsi extract and also the MIC got reduced to 0.2 g/ml for both the bacteria.Conclusions: Leaf extracts of both the A. indica and O. sanctum have shown antimicrobial activity against E. coli and S. aureus. A. indica has higher antimicrobial activity against S. aureus, whereas the O. sanctum was found to be more effective against E. coli (indicated by the zone of inhibition). When both the extracts were mixed with each other, they have shown a better effect toward both bacteria.


2018 ◽  
Vol 11 (1) ◽  
pp. 15-19
Author(s):  
S.M. Zakari ◽  
A.A. Aliko ◽  
H Haruna ◽  
A Muazu

This study was embarked upon to evaluate the efficacy of aqueous extracts of Senna tora leaf against Perenospora parasitica, causing downy mildew on cabbage. Phytochemical analysis of the leaf extracts revealed the presence of some secondary metabolites (Tannins, Saponins, Flavonoid, Glycosides, Alkaloids, Phenolic compounds and Carbohydrates) which have been reported to have antimicrobial effects. Assays were performed using extract concentrations of 1000, 500, 250, 125 mg/ml by agar well diffusion technique. Results obtained, revealed a significant difference in diameter of mycelial zone of inhibition between the concentrations. Highest zone of inhibition was recorded at 1000 and 500 mg/ml (20 and 15 mm) respectively. Minimum Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration (MFC) were determined and recorded at 250 mg/ml. The antifungal screening revealed that the extract exhibited inhibitory activities at varying concentrations against the downy mildew pathogen. These activities observed could be attributed to the presence of active metabolites contained in the extract.Keywords: Aqueous leaf extract, Downy mildew, Perenospora parasitica and Senna tora


2020 ◽  
Vol 16 ◽  
Author(s):  
V. Vanitha ◽  
S. Vijayakumar ◽  
S. Rajalakshmi

Aim: To investigate the antimicrobial efficacy of various solvents leaf extracts of Aegle marmelos, Plumbago zeylanica and Rhinacanthus nasutus against human pathogenic organisms such as Acinetobacter baumannii, Salmonella enteriditis, Bacillus cereus, Streptococcus pneumonia, Mycobacterium tuberculosis and Aspergillus fumigatous by agar well diffusion method. Background: Also, this is the first time report on MIC and MBC/MFC activities and identify the phytochemicals and functional groups using HPLC, GC-MS and FT-IR analysis. Objective: Minimum inhibitory concentration (MIC), minimum bactericidal (MBC/MFC) values were also carried out by the micro dilution method. Methods: Ethyl acetate extract of P. zeylanica showed better antimicrobial activity against the tested pathogens, especially for S. pneumoniae (40 mm) followed by ethyl acetate extract of R. nasutus (36 mm) against S. pneumoniae. While least inhibition was observed for aqueous extract of P.zeylanica against S. enteritis (10 mm). Results: The MIC ranged from 3.75 µg/ml to 60µg/ml and MBC/MFC 7.5 µg/ml to 60 µg/ml. Phytochemical analysis exhibited the presence of alkaloids, steroids, saponins, flavonoids, tannins, terpenes, phenolics and cardiac glycoside in all samples of selected plant extracts. Tannins, phenolics and glycoside were found only in the ethyl acetate extract of P.zeylanica. HPLC and GC-MS analysis of ethyl acetate leaf extract of P. zeylanica exposed ten major peaks and eleven compounds respectively. Chemical nature of the leaf extract was analysed by FT-IR spectrum. Conclusion: Ethyl acetate leaf extract of P. zeylanica showed better antimicrobial activity than other extracts as well as standard drugs. Therefore, this plant could be studied in detail for the identification of active biomolecules for antimicrobial agents.


2020 ◽  
Vol 10 (3-s) ◽  
pp. 159-168
Author(s):  
Saliha Laouicha ◽  
Abderrahmane Senator ◽  
Abdallah Kherbache ◽  
Hamama Bouriche

Arbutus unedo L. is a plant widely distributed in the Mediterranean basin and North Africa, frequently used in traditional folk medicine to treat diabetes and arterial hypertension. This study aims to evaluate the phenolic composition and antioxidant activity of ethyl acetate (EA.E) and n-butanolic (But.E) extracts prepared from leaves of Arbutus unedo. Total phenolic and flavonoids contents were determined spectrophotometrically. The antioxidant activity was evaluated using DPPH•, OH•, H2O2, O•-2, ß-carotene bleaching and AAPH-induced erythrocyte oxidative hemolysis assays. The phytochemical analysis showed the presence of polyphenols and flavonoids in both extracts. The high amount was observed in EA.E which exerted the stronger antioxidant effect, with IC50 values of 3.43 μg/mL, 323.45 µg/mL, 38.40 µg/mL and 11.56 µg/mL, in DPPH•, OH•, O•-2 and H2O2 tests, respectively. Both extracts inhibited β-carotene bleaching, but EA.E is always more potent (92%) than But.E (85%). Furthermore, the EA.E showed the highest protective effect on erythrocyte hemolysis induced by AAPH, with half time hemolysis (HT50) of 122.02 min at 40 µg/mL. Taken together, this study showed that Arbutus unedo leaf extracts possess strong antioxidant potential, which may be attributed to the presence of a high amount of polyphenolic constituents. So, this plant might be exploited as a potential source of natural antioxidant agents for pharmaceutical and food applications. Keywords: oxidative stress, antioxidant, phenolic compounds, Arbutus unedo.


Author(s):  
SUDHAMA VN ◽  
RAMAKRISHNAN M

Objective: The objective of this study was to extract the phytochemicals from leaf and stem bark of Solanum pubescens, perform qualitative analysis, and evaluate antimicrobial activity of the phytochemicals against certain microbial pathogens. Methods: Leaf and stem bark of S. pubescens was subjected to phytochemical extractions using Soxhlet apparatus with five different solvents, identified the major constituents in different solvent extracts using standard protocols and investigated the potential antimicrobial activities of the extracts against certain selected bacterial and fungal pathogens by agar well diffusion method. Results: The maximum yield was in methanolic extracts of leaf and stem bark of the study plant such as 18.51 and 12.5%, respectively, followed by the hydroalcohol extracts (14.23 and 10.00%). Qualitative phytochemical analysis revealed maximum number of extracted bioactive compounds when compared to other similar studies. Among the five different solvent extracts of S. pubescens, n-hexane extract of stem bark was found to be active against all the bacterial pathogens and stem bark extracts made with methanol and hydroalcohol showed antifungal activity against all the four fungal pathogens tested. Leaf extracts made with solvents such as n-hexane and ethyl acetate showed inhibition against Klebsiella pneumoniae and Staphylococcus aureus, respectively, hydroalcohol extract was active against Pseudomonas aeruginosa and Salmonella typhimurium while none of the leaf extracts of the study plant showed inhibition zones against fungal pathogens tested. Conclusion: Multiple solvent extraction approach yielded the phytochemicals which are not yet reported and the antimicrobial activities of phytochemicals acknowledged their medicinal value.


2021 ◽  
Vol 3 (2) ◽  
pp. 44-48
Author(s):  
David Mutisya Musyimi ◽  
Marble Namarobe Namnabah

Medicinal plants have served as sources of medicine to treat and suppress the diseases, because many pathogens are gaining resistance to the current synthetic drugs. In addition, high cost and adverse side effects are commonly associated with popular Synthetic drugs. Therefore, there is need for continuous search for new drugs in order to overcome this emerging resistance. Plants synthesize bioactive compounds which are of great potential in agriculture, antimicrobial and anti-insect activity. The concentration of bioactive compounds in each plant species depends on the environmental conditions, age of the plant, relative humidity of harvested materials and method of extraction. Little is known on the phytochemical and antimicrobial potential of Alba and Rosea cultivars of Catharanthus roseus ethanol extracts. The leaves of Alba and Rosea cultivars were investigated for their phytochemical and antimicrobial properties. The study was conducted at Maseno University, Kenya. Plant Leaves were collected around Maseno University. Leaves of Alba and Rosea cultivars of Catharanthus roseus were air-dried in the shade, thereafter crushed into powder and ethanol extraction done using the Rotary evaporator. Antimicrobial activity of the pathogenic microorganisms was Candida albicans and Escherichia coli.  Disc diffusion method was used for antimicrobial tests. concentrations of ethanol leaf extracts consisted of 2.5, 5and 7.5 mg/mL with three replications.  Data on growth inhibition were subjected to analysis of variance (ANOVA) . Phytochemical analysis revealed the presence of tannins, flavonoids, terpenoids, saponins, alkaloids and phenols except steroids and glycosides. The ethanol leaf extracts were active against Candida albicans and and Escherichia coli. Alba leaves extracts showed higher inhibitory zones compared to Rosea leaves. The observed differences in antimicrobial activity could be due to differences in cell wall synthesis, structure and composition. The results of present study further confirm the use of these plants traditionally for the treatment of different ailments.


Author(s):  
B. A. Erinle ◽  
A. O. Ajayi ◽  
O. T. Osuntokun

Aim: Hyptis suaveolens is well known for its immense medicinal properties and are beneficial as folk medicine. The objective of the study is to investigate the efficacy of the leaves for it antimicrobial activity. Material and Methods: The leaves of Hyptis suaveolens was  subjected to extraction process using n-hexane, ethanol and distilled water as solvents and the antimicrobial activity was analyzed against different bacterial strains viz.; Escherichia coli, Proteus mirabilis, Streptococcus pneumoniae, Staphylococcus aureus, Klebsiella aerogenes, Pseudomonas aeruginosa, Salmonella typhi, Enterococcus faecalis by agar well diffusion method. Results: Aqueous extracts showed inhibitory effect against the different tested bacteria organisms with variable zone of inhibitory range 6 -21 mm. Conclusion: The aqueous extracts of Hyptis suaveolens exhibited the presence of highly effective bio-active compounds in these extracts. These can further be evaluated and characterize to improve upon what has been done to create a novel compound that can be useful for various medicinal purposes.


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