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

Mangroves being stress tolerant plants possess unique metabolites with significant amount of bioactive compounds which could be isolated and evaluated for possible drug development with suitable biotechnology tools. The mangrove genus Xylocarpus comprises of four species viz. Xylocarpus granatum (Koenig), X. moluccensis (lamk.) and X. mekongensis Pierre and X. rumphii. However, X. rumphii is a less abundant mangrove plant. There have been reports that different species of Xylocarpus are used ethnomedicinallly for treatment of various diseases such as fever, malaria, cholera, diarrhoea, swelling of breast, elephantiasis, inflammation, dyslipidemia, pain, hyperglycaemia etc. Recent studies revealed that the extracts from different parts of the plant such as leaves, stem, bark and fruits possess phytoconstituents like alkaloids, glycosides, steroids, limnoids, terpenoids, flavonoids, tannins and other phenolics. Further, it has been established that the different solvent extracts of the plants have exhibited antimicrobial and antidiarrhoeal activities against a number of human pathogens which could be correlated to their phytoconstituents such as flavonoids, alkaloids, limnoids, tannins etc. The present study is aimed at compiling information on phytochemical, pharmacological and ethnomedicinal properties of mangrove plants of genus Xylocarpus, with a view to critically assess the legitimacy of the use of these plants for antimicrobial and antidiarrhoeal activities as well as providing directions for further research.

Ethnomedicinal, Antimicrobial and Antidiarrhoeal Studies on the Mangrove Plants of the Genus Xylocarpus: A Mini Review

Scaevola spinescens (Goodeniaceae) has been traditionally used by indigenous Australians to treat various ailments including cancer, thus it is necessary to identify optimum extraction conditions for bioactive components from this plant. This study investigated the effects of different extraction conditions on Total Phenolic Content (TPC), antioxidant capacity (ABTS, DPPH, CUPRAC, FRAP assays) and anti-cancer activity (MTT assay) of S. spinescens. The results showed that optimal extraction conditions for TPC using water were 80°C, 15 min and ratio of 20:1 mL/g. However, the aqueous extract prepared under optimal conditions had lower TPC and less antioxidant capacity than those of the organic solvent extracts. The acetone extract displayed the greatest TPC as well as the highest antioxidant capacity and anti-cancer activity against a panel of cancer cell lines, including cancers of the pancreas, breast, lung, brain, skin, colon and ovary. Therefore, further investigations should be conducted to identify key bioactive compounds as potential anti-cancer agents.

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Phenolic Compounds, Antioxidant and Anti-Cancer Properties of the Australian Maroon Bush Scaevola spinescens (Goodeniaceae)

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

Background: Xylocarpus granatum has been used as a medicinal plant by coastal communities, which may indicate that this plant is a potential source of pharmaceuticals. Methods: Xylocarpus granatum leaf extract was tested as an antimicrobial agent for pathogens infecting tiger shrimp post-larvae. Of the treatments applied to the post-larvae, 25 were crudely extracted with ethanol, distilled water, and seawater solvent given by immersion. Vibrio harveyi and Saprolegnia sp. were microbial species used for the test. Results: X. granatum extract had the potential to inhibit V. harveyi and Saprolegnia sp., reducing infection and improving the survival of shrimp. Shrimp soaked with X. granatum extract had a total Vibrio count ranging from 14.67x10 3 to 22.67x10 3 CFU/ml. The survival rate of shrimp was recorded as 53.33% to 78.67% and 54.67% to 76.00% due to V. harveyi , and Saprolegnia sp infection, respectively. The relative percentage of the survival of shrimp protected from V. harveyi and Saprolegnia sp infection in treatments compared to negative controls ranged from 40.61% to 72.89% and 35.84% to 66.12%, respectively. Conclusions: Leaf extracts of X. granatum , which might have better antimicrobial activities to prevent tiger shrimp from pathogenetic infection, were consecutively extracted ethanol at 800-1,000 ppm, distilled water at 800-1,000 ppm, and seawater at 1,000 ppm.

Antimicrobial of nyirih (Xylocarpus granatum) against pathogens of tiger shrimp post-larvae

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.

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

Many efforts have been made to discover new antimicrobial compounds from different sources such as microorganisms, animals and plants. One of such resources is folk medicines. Systematic screening may result in the identification of novel and effective compounds. The increasing prevalence of multidrug resistant strains of bacteria and the recent appearance of strains with reduced susceptibility to antibiotics raises the specter of untreatable bacterial infections and adds urgency to the search for new infection-fighting strategies. Mangroves are the plants found in the intertidal zones of sheltered shores and have been used in the treatment of human diseases for many centuries in naturopathy because of their diverse habitat. Xylocarpus moluccensis belongs to Meliaceae family. The present study mainly focused to determine the effect of X. moluccensis leaf and stem organic and aqueous solubles against medically important drug resistant Gram positive bacteria viz., Bacillus cereus, Bacillus subtilis, Staphylococcus aureus and Gram negative bacteria viz., Escherichia coli, Klebsiella pneumoniae and drug sensitive Gram positive Bacillus subtilis, Gram negative Enterobacter aerogenes and Pseudomonas aeruginosa by agar well diffusion method. All the extracts were found effective against the tested drug resistant and drug sensitive strains. Among the extracts, acetone, ethanol, methanol and water extracts exhibited maximum activity against drug resistant E. coli, B. subtilis, B. cereus and drug sensitive P. aeruginosa and B. subtilis. Phytochemical diversity might be responsible for the antibacterial activity of acetone, ethanol, methanol and water extracts of X. moluccensis.

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P. Satya Veni

Papers

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

Antibacterial and Phytochemical Screening of Xylocarpus moluccensis Leaf and Stem on Selected Drug Resistant and Sensitive Bacteria