Angiotensin-converting enzyme inhibitors from plants: A review of their diversity, modes of action, prospects, and concerns in the management of diabetes-centric complications / 中西医结合学报

Angiotensin-converting enzyme (ACE) inhibitors are antihypertensive medications often used in the treatment of diabetes-related complications. Synthetic ACE inhibitors are known to cause serious side effects like hypotension, renal insufficiency, and hyperkalaemia. Therefore, there has been an intensifying search for natural ACE inhibitors. Many plants or plant-based extracts are known to possess ACE-inhibitory activity. In this review, articles focusing on the natural ACE inhibitors extracted from plants were retrieved from databases like Google Scholar, PubMed, Scopus, and Web of Science. We have found more than 50 plant species with ACE-inhibitory activity. Among them, Angelica keiskei, Momordica charantia, Muntingia calabura, Prunus domestica, and Peperomia pellucida were the most potent, showing comparatively lower half-maximal inhibitory concentration values. Among the bioactive metabolites, peptides (e.g., Tyr-Glu-Pro, Met-Arg-Trp, and Gln-Phe-Tyr-Ala-Val), phenolics (e.g., cyanidin-3-O-sambubioside and delphinidin-3-O-sambubioside), flavonoids ([-]-epicatechin, astilbin, and eupatorin), terpenoids (ursolic acid and oleanolic acid) and alkaloids (berberine and harmaline) isolated from several plant and fungus species were found to possess significant ACE-inhibitory activity. These were also known to possess promising antioxidant, antidiabetic, antihyperlipidemic and anti-inflammatory activities. Considering the minimal side effects and lower toxicity of herbal compounds, development of antihypertensive drugs from these plant extracts or phytocompounds for the treatment of diabetes-associated complications is an important endeavour. This review, therefore, focuses on the ACE inhibitors extracted from different plant sources, their possible mechanisms of action, present status, and any safety concerns.

Optimization of cultural conditions affecting growth and improved bioactive metabolite production by a subsurface aspergillus strain TSF 146.

The aim of this study was to optimize cultural conditions for optimum growth and bioactive metabolite production by Aspergillus strain TSF 146, isolated from the subsurface soils of Brahmaputra plains, Assam, India. Agar disc diffusion assay was used to examine the antagonistic activity of the strain. The effect of different culture media, temperature, pH, incubation period, shaking, inoculum size and various carbon and nitrogen sources on the mycelial growth and bioactive metabolite production in a fixed volume of culture broth were studied. Aspergillus strain TSF 146 grew well and produced optimum bioactive metabolites in Potato dextrose broth medium at 25 °C on the 14th day of the incubation. The optimal mycelial growth, however, was obtained at pH 5.5. Sucrose (2.0 g/l) and asparagine (1.0 g/l) were the best carbon and nitrogen sources respectively for optimum growth and production of active metabolites by the isolate. Inoculum size of 2x1010 spores/ml with periodic shaking at 150 rpm optimized production of bioactive molecules. The results of the present investigation indicated that cultural conditions like carbon, nitrogen and mineral sources as well as physical factors such as temperature, pH, incubation period, inoculum size and shaking greatly affected the growth and production of bioactive metabolites by Aspergillus strain TSF 146.

Characterization of cytotoxic compound from mangrove derived fungi Irpex hydnoides VB4

<p><b>OBJECTIVE</b>To investigate the cytotoxic activity of endophytic fungi isolated from mangrove fungi.</p><p><b>METHODS</b>In the present study the DNA was isolated and the ITS region of 5.8s rRNA was amplified using specific primers ITS 1 and ITS4 and sequence was determined using automated sequencers. Blast search sequence similarity was found against the existing non redundant nucleotide sequence database thus, identified as Aspergilus flavus, Hyporcaea lixii, Aspergillus niger, Eutorium amstelodami, Irpex hydnoides and Neurospora crassa. Among the seven isolates, one fungi Irpex hydnoides was selected for further studies. The fungi were grown in sabouraud broth for five days and filtrate were separated and subjected to ethyl acetate for further studies.</p><p><b>RESULTS</b>Nearly half (49.25%) of the extracts showed activity (IC50 of 125µg/mL). These values were within the cutoff point of the National Cancer Institute criteria for cytotoxicity (IC50<20 µg/mL) in the screening of crude plant extracts. The GC MS analysis revealed that the active principals might be Tetradecane (6.26%) with the RT 8.606.</p><p><b>CONCLUSIONS</b>It is clear from the present study that mangrove fungi with bioactive metabolites can be expected to provide high quality biological material for high throughout biochemical, anti cancer screening programmes. The results help us conclude that the potential of using metabolic engineering and post genomic approaches to isolate more novel bioactive compounds and to make their possible commercial application is not far off.</p>

Preliminary research of bioactive metabolite produced by marine actinomyces M326 / 中国海洋药物

Objective To study bioactive metabolite produced by marine actinomyces M326.Methods Based on the index of antimicrobial activity,the relation between activity of metabolite and conditions of culture in different media and time were researched,and the stability of bioactive metabolite treated with different temperatures and pH were obseved,and the bioactive ingredients were extracted and separated by organic solvent and by macroporous resin.Results The GBP medium made by artificial seawater or distilled water were suitable for production of strong bioactive metabolites.The antimicrobial substances were stable under pH 2～11 and were heat-resistant under strong acidic condition.It could not be extracted by usual organic solvent,but could be absorbed by AB-8 macroporous resin under alkaline situation.Conclusion The metabolites have strong activity against gram-positive bacteria and have different antimicrobial activities against gram-negative bacteria and drug-resistant strains moreover,the polarity of antimicrobial substances is strong.