The genus Avicennia comprises eight species of mangrove trees that occur in intertidal zones of estuaries and seabeds found in tropical and temperate regions spanning throughout the world. The plan...

https://www.tandfonline.com/doi/pdf/10.1080/21553769.2016.1235619

The genus Avicennia, a pioneer group of dominant mangrove plant species with potential medicinal values: a review

Avicennia officinalis (AO) is an evergreen mangrove tree that finds a prominent place in folk medicine. In this study, we have quantified 2 significant phytochemicals viz., phenols and flavonoids and studied the antibacterial activity of extracts of AO fruits in ethyl acetate, acetone, methanol and ethanol against 8 pathogenic bacterial species E. coli , En. aerogenes , K. pneumoniae , P. aeruginosa , B. subtilis , L. delbrueckii , S. aureus and  Strep. pyogens . Phenols and flavonoids were quantified Spectrophotometrically. Total phenolic content (TPC) ranged from 125-350mg of GAE/g of crude extract and the flavonoid levels were in the range of 60-192 mg of rutin equivalent/g of dry sample. The methanol and ethanol extracts showed highest levels of TPC, while acetone extract was identified to contain comparatively elevated amounts of flavonoids. Antibacterial activity of all the extracts was screened against the selected strains by agar well diffusion method. All the extracts exhibited different degrees of inhibition against the bacterial strains tested.  Their MIC values ranged between 1.25-5.0mg/100µl. Methanol and Ethanol extracts showed strong inhibitory activities against both Gram negative and Gram positive bacterial strains compared to those of other extracts. However, ethyl acetate infusion restricted its activity only against the Gram positive bacterial strains tested. Strains of E. coli , En. aerogenes (Gram negative) S. aureus and  Strep. pyogens (Gram positive) were inhibited by acetone extract. This study provides the necessary data for isolation and characterization of individual broad spectrum antibacterial compounds from different extracts of AO fruits. The study also supports the potentiality of AO in folk medicine. Keywords:  Avicennia officinalis , Phenols, Flavonoids, Antibacterial

Quantification of phytochemicals and antibacterial activity of fruit extract of avicennia officinalis

Avicennia officinalis (AO) belongs to family Avicenniaceae. It finds a prominent place in folk medicine. Hence the present work was carried out for the identification of bioactive principles in the fruits of Avicennia officinalis and screened for the antibacterial activity against selected test cultures. The methanolic extracts has high efficacy against the test cultures. The methanolic extracts were further purified by column chromatography. With the aid of 1H NMR, 13C NMR and GC-MS analysis. The structure of the compounds were detected as Phenols namely 1, 2, 3 Benzene triol and 4, 4’-(1-methylethyldiene)bis2-methyl and both the compounds exhibited antibacterial activity. This report of ours is the first one regarding the 1, 2, 3 Benzene triol and 4, 4’-(1-methylethyldiene) bis 2-methyl in the plant Avicennia officinalis.

Identification of bioactive principles of avicennia officinalis fruit extract in methanol and screening for antibacterial activity

Objectives: Stem infusions of Derris trifoliata L (DT) finds a prominent place in folk medicine. In this study, we qualitatively screened the ethyl acetate, acetone, methanol and ethanol extracts of DT stem for secondary metabolites like alkaloids, flavonoids, saponins, and tannins. Biological activities such as antioxidant and antibacterial potentials were also quantified in these extracts. Methods: Phytochemicals in the respective solvent extracts of DT were determined by standard procedures. Total antioxidant activity was quantified Spectrophotometrically by FRAP assay. Antibacterial strength was assessed against selected 6 bacterial species Escherichia coli (MTCC 7410), Enterobacter aerogenes (MTCC 7324), Enterobacter cloacae (MTCC 7408), Bacillus subtilis (MTCC 736), Enterococcus faecalis (MTCC9845), and Streptococcus pyogenes (MTCC 1928) by agar well diffusion method and compared with gentamicin and tetracyclin. The Minimum Inhibitory Concentration (MIC) was determined by serial dilution method. Results: Phytochemical screening showed that the crude extracts were found to be positive to alkaloids, flavonoids, saponins and tannins. Antioxidant activity of the extracts was expressed as FRAP units and it varies amid the solvents used. Methanol extracts showed highest level of antioxidant activity (632), while ethyl acetate extract was identified to contain lower antioxidant activity (196). Extracts of DT exhibited different degrees of anti bacterial activity and varied from solvent to solvent. Among the extracts, methanol extract exhibited maximum antibacterial activity against the tested gram positive species than that of gram negative cultures. The MIC values were found to be between 1.25 to 5mg/100µl. Conclusion: This study provides the necessary data for isolation and characterization of bioactive principles that possess the antioxidant and antibacterial activity from different extracts of DT stem.

Screening and evaluation for antibacterial and antioxidant potentials in stem extract of derris trifoliata l

The present study was conducted, to determine the bactericidal effects of aqueous and ethanol extracts of vegetative parts of Akaka plants Allium Akaka Gmel. On some standard pathogenic bacteria such as Staphylococcus aureus (ATCC 25923) ,Escherichia coli (ATCC 35218),Pseudomonas aeruginosa (ATCC 27853) and Klebsiella Pneumoniae (ATCC 1031) . Plant vegetative parts were extracted (crude extraction) using distilled water or ethanol (80%). Concentrations of 250, 500, 1000, 2000, 4000, 8000, 10000 and 20000 m g ml -1 or m g disc -1 using Disk Saturation Technic (DST)  and Disk Loading Technique (DLT) respectively and 20000 m g ml -1  delusions using Enzyme Linked Immunosorbent Assay (ELISA) were applied .Sterilized water and Streptomycin were used as control. Data was analyzed statistically using SPSS and treatment means were compared using Duncan Multiple Range Test at probability range 0.01. Results  showed that Akaka plant extracts contains antibacterial chemical compounds that affect bacterial growth. Minimum Inhibition Concentrations (MIC) of aqueous extract was 4000 m g disc -1 for Staphylococcus aureus and 8000 m g disc -1 for  other three bacteria using DLT. MIC of ethanol extract was 2.48 m g ml -1 for Staphylococcus aureus , Pseudomonas aeruginosa and Klebsiella pneumoniae and 4.95 m g : ml -1 for E. coli . Minimal Bactericidal Concentration (MBC) of ethanol extracts using ELISA Technique was 10000 m g ml -1 for Staphylococcus aureus and Klebsiella pneumoniae , 20000 m g ml -1 for E. coli and 625 m gml -1 for Klebsiella p neumonia e.

https://www.journals.uokufa.edu.iq/index.php/jkas/article/download/8213/_1

Effects of aqueous and ethanol extracts of Akaka plants Allium akaka Gmel on some standard pathogenic bacteria

Most of the human diseases are mediated by microorganisms. The discovery of antimicrobials provides an increasingly important tool to combat microbial diseases. Improp er usage of antimicrobials results in the developme nt of microbial resistance. Therefore, identification of new antimi crobial compounds is essential. Traditional medicin e still plays an important role in the health care in India and othe r countries. The mangrove ecosystem is a largely un explored source for the potential biologically active secondary metabol ites. Consequently, we set out to screen the stem o f Avicennia alba collected from the Coringa Mangrove Reserve Forest, Kakinada, East Godavari, Andhra Pradesh, India for antibacterial activity. In the present study, the stem extract of Avicennia alba in Hexane, Benzene, Chloroform, Ethylacetate, Methanol, Acetone, Absolute Alcohol & Water were screened for the antibacterial activity by Agar well diffusion method against selected microorganisms, viz, Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Klebsi ella pneumonia (drug resistant strains) Pseudomonas aeruginosa, Enterobacter aerogenes, Clo stridium perfringens & Bacillus subtilis (drug sensitive strains) . The extracts were also screened for secondary meta bolites like flavanoids, alkaloids, saponins, terpenoids, steroids and tanni ns. None of the extracts were found effective again st the tested drug resistant strains irrespective of Gram nature. Whil e, Methanol extract is active against E.aerogenes & Bacillus subtilis and Chloroform, Acetone, Absolute Alcohol & aqueous extracts exhibited only anti E. aerogenes activity. However, Hexane, Benzene & Ethyl acetate solubles does not show any activity on the tested cultures. Phytochemi cal studies support the antibacterial activity of methanol, ace tone, alcohol & water solubles of A.alba . This clearly indicates that the active principles of A.alba stem are positive against drug sensitive strains b ut not to the drug resistant strains.

V S Lakshmi

Papers

EVALUATION OF ANTIBACTERIAL ACTIVITY ON SELECTED BACTERIA AND SCREENING OF SECONDARY METABOLITES OF Avicennia Alba STEM