Antimicrobial activity of kojic acid from endophytic fungus Colletotrichum gloeosporioides isolated from Sonneratia apetala,a mangrove plant of the Sundarbans

Objective: To isolate and evaluate the antimicrobial activity of the active principle(s) from the ethyl acetate(EtOAc) extract of endophytic fungus Colietotrichum gloeosporioides(C.gloeosporioides) isolated from Sonneratia apetala. Methods: Water agar technique was used to isolate the fungus, and both microscopic and molecular techniques were used for identification of the strain. Potato dextrose broth was used to grow the fungus in large-scale. Reversed-phase preparative HPLC analysis was performed to isolate the major active compound, kojic acid. The EtOAc extract and kojic acid were screened for their antimicrobial activity against two Grampositive and two Gram-negative bacteria as well as a fungal strain using the resazurin 96-well microtitre plate antimicrobial assay. Results: The fungus C. gloeosporioides was isolated from the leaves of Sonneratia apetala. Initial identification of the fugal isolate was carried out using spore characteristics observed under the microscope. Subsequently, the ITS1-5.8 S-ITS2 sequencing was employed for species-level identification of the fungus C. gloeosporioides. Five litres of liquid culture of the fungus produced approximately 610 mg of a mixture of secondary metabolites.Kojic acid(1) was isolated as the main secondary metabolite present in the fungal extract, and the structure was confirmed by 1 D, 2 D NMR and mass spectrometry. The EtOAc extract and compound 1 exhibited considerable antimicrobial activity against all tested microorganisms.Whilst the minimum inhibitory concentration(MIC) values from the EtOAc extract ranged between 2.4×10^(-4)mg/mL and 2.5 mg/mL, those of kojic acid(1) were between 0.125 mg/mL and1 mg/mL. The EtOAc extract and kojic acid(1) were most active against Pseudomonas aeruginosa(MIC = 2.4×10^(-4). mg/mL) and Micrococcus luteus(MIC = 0.125 mg/mL), respectively. Conclusions:The results revealed that the endophytic fungus C. gloeosporioides could be a good source of commercially important kojic acid, which exhibited antimicrobial properties.

Annotation on Mangrove Plants

This paper reviews and discusses the technical terms and definition of mangrove and mangal, as well as mangrove plant. The word mangrove has been used to refer either to the constituent plant of tropical and subtropical intertidal community or to the community itself, but this usage makes more confusion. Being leaved mangrove in the more limited sense for the constituent plant species, mangal was proposed by MacNae (1968) as a term for mangrove community, which has been universally applied to most previous studies and should be adopted now. Mangrove should be therefore defined as a tropical and subtropical tree restricted to intertidal zones, which possesses some morphological specializion and physiological mechanism adapted to its habitat, and mangal as a tropical and subtropical forest community restricted to marine intertidal zones and periodically inundeated by the tides. A new term "consortive plant" is proposed here for herb, liana, epiphyte or parasite, which is restricted in the strict mangrove habitat.

Evaluation of antiparasitic,anticancer,antimicrobial and hypoglycemic properties of organic extracts from Panamanian mangrove plants

Objective: To investigate 33 organic extracts of mangrove plants for: antiparasitic, anticancer, and antibacterial activities, as well as their ability to inhibit the activity of the α-glucosidase enzyme. Methods: Leaves from all different plant mangrove species located in five mangrove zones of the Pacific coast of Panama were collected according to standard procedures. Qualitative phytochemical analysis of the organic extracts was performed by thin layer chromatography. The antiparasitic activity against Plasmodium falciparum, Trypanosoma cruzi and Leishmania donovani, toxicity against Artemia salina, anticancer activity in MCF-7 cell line, and antibacterial activity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa of all organic extract were investigated according protocols stablished in our institution. Finally, the ability to inhibit the enzymatic activity of α-glucosidase was evaluated by monitoring the hydrolysis of p-nitrophenyl α-Dglucopyranoside. Results: Thirty-three different samples belonging to nine different species of vascular plants with seeds of true mangroves were collected. Triterpenoids, phenolics, and tannins were the main groups of compounds found in the sampled mangroves. Saponins, quinones, and coumarins were found in less than 50%of the samples. Laguncularia racemosa showed moderate activity against Plasmodium falciparum. None of the extracts presented anticancer activity. Rhizophora mangle exhibited potent activity against Staphylococcus aureus and Bacillus subtilis [(90.41 ±7.33)% and(96.02±6.14)% of inhibition]; Avicennia germinans and Conocarpus erectus had activity against Escherichia coli[(71.17±6.15)% and(60.60±5. 13)% of inhibition,respectively]. About 60% of the mangroves showed α-glucosidase inhibitory activity. In particular, extracts from Laguncularia racemosa, Pelliciera rhizophorae, Conocarpus erectus, Mora oleifera, and Tabebuia palustris species showed α-glucosidase inhibitory potential, with IC_(50) values of(29.45±0.29),(20.60±0.70),(730.06±3.74),(25.59±0.37), and(853.39±5.30) μg/mL, respectively. Conclusions: Panamanian mangroves are mainly a promising potential source of hypoglycemic compounds, specifically α-glucosidase inhibitors.These results highlight the therapeutic virtues of extracts from American mangrove plants.

Assignment of the absolute stereochemistry of an unusual diterpenoid from the mangrove plant Excoecaria agallocha L.

An unusual diterpenoid excoagallochaol A （1）, together with epi-β-amyrin （2）, epitaraxerol （3）, epi-a-amyrin （4）, epilupeol （5）, betulin （6）, betulinic acid （7）, lupenone （8）, betulone （9）, betulonic acid （10）, （9Z,12Z,15Z）-2,3-dihydroxypropyl octadecatrienoate （11）, and （9Z,12Z）-2,3-dihydroxypropyl octadecadienoate （12）were isolated from the stems of Excoecaria agallocha L. Their structures were elucidated by spectroscopic analyses, and the absolute stereochemistry of 1 was assigned using Mosher method. Compounds 4, 8, 10-12 were isolated from the genus Excoecaria for the first time.

Phenolic glucopyranosides from the Chinese mangrove plant Excoecaria agallocha L.

Chemical examination of a Chinese mangrove plant Excoecaria agallocha L.led to the isolations of a new glucoside named l-（3,5-dimethoxy-4-hydroxybenzyl）-6-O-galloyl-l-O-β-D-glucopyranoside（1）,together with 10 known glycosides including 3,5-dimethoxy-4-hydroxybenzyl-l-O-β-D-glucopyranoside（2）,hydrangeifolin I（3）,（2-methoxy-5-hydroxymethyl-phenyl） -l-O-β-D-（6-Ogalloyl） glucopyranoside（4）,（3,5-dimethoxy-4-hydroxyphenyl）-l-O-β-D-（6-O-galloyl） glucopyranoside （5）,3-methoxy-4-hydroxyphenyl l-O-β-D-（6-O-galloyl） glucopyranoside（6）,3,4,5-trimethoxyphenyl-（6-O-galloyl）-O-β-D-glucopyranoside （7）,koaburaside（8）,koaburaside monomethyl ether（9）,cuneatasides D（10）,and（？）-isosyringin（11）.Their structures were determined through the extensive spectroscopic analysis and comparison with the reported data in literature. Compounds 2-6,8-11 were isolated from the genus Excoecaria for the first time.

A new linear monoterpene from the Chinese mangrove plant Cerbera manghas L.

The current study aimed to investigate the chemical components of the Chinese mangrove plant Cerbera manghas L., collected in Hainan Island.Repeated column chromatography was performed for the isolation and purification.Compounds were identified by the analysis of their 1D and 2D NMR data as well as IR and MS spectral data.A new linear monoterpene,named （2E,6S）-8-hydroxy-2-hydroxymethyl-6-rnethyl-2-octenoic acid（1）,together with cerbinal（2）,cerberidol（3）,2α,3β,24-trihydroxyolea- 12en-28oic acid（4）,4,4,9,7- tetrahydroxy-3,3 -dimethoxy-7,9-epoxylignan （5）, （-）-olovil （6）, （＋）-cycioolivil （7）, naringenin-7-glucoside （8）, aromadendrin （9）, naringenine （10）, and （＋）-dihydroquercetin （11） were isolated from the EtOH and CH2Cl2 extracts. Compounds 4, 5, 8-11 were isolated from this plant for the first time.

Two new diterpenoids from the endophytic fungus Trichoderma sp.Xy24 isolated from mangrove plant Xylocarpus granatum

Two new harziane diterpenoids, named（9R,10R）-dihydro-harzianone（1） and harzianelactone（2）, were isolated from the endophytic fungus Trichoderma sp. Xy24 by using various column chromatography techniques. Their structures were determined on the basis of extensive spectroscopic（HR-ESI-MS, 1D NMR, 2D NMR and CD） analyses. Among them, 1 was the reductive product of harzianone and 2 was the Baeyer–Villiger monooxygenase catalyzed oxidation product of harzianone. Compound 1 exhibited cytotoxic activity against He La and MCF-7 cell lines with IC（50） values of 30.1 μmol/L and 30.7 μmol/L,respectively.

Antimicrobial Compounds from Mangrove Plants:A Pharmaceutical Prospective

Mangroves are salt-tolerant forest ecosystem that extends between tropical and subtropicalintertidal regions of the world. Mangroves are biochemically unique vegetation that produce wide array of naturalproducts with immense medicinal potential. These plants are the most valuable resources and provide economicand ecological benefits to the coastal people. Natural products from these plants are of great interest as theyprovide innumerable direct and indirect benefits to human beings for the discovery of novel antimicrobial andother bioactive compounds. They possess active metabolites with some novel chemical structures that belong todiverse chemical classes such as alkaloids, phenol, steroids, terpenoids and tannins. Several mangrove specieshave been used in traditional medicine or have few applications as insecticide and pesticide. To date, severalmangroves, and their associated species and solvent extracts are screened for antimicrobial activity along withthe presence of potent bioactive compounds. The present article emphasizes and creates awareness aboutthe potential mangrove plants and their associates as a source of biologically active compounds with potentantimicrobial properties. This paper also elaborates the mechanisms of action and various methods for screeningof antimicrobial compounds.