Dejan Stojković

Chemical features of Ganoderma polysaccharides with antioxidant, antitumor and antimicrobial activities

Ganoderma genus comprises one of the most commonly studied species worldwide, Ganoderma lucidum. However, other Ganoderma species have been also reported as important sources of bioactive compounds. Polysaccharides are important contributors to the medicinal properties reported for Ganoderma species, as demonstrated by the numerous publications, including reviews, on this matter. Yet, what are the chemical features of Ganoderma polysaccharides that have bioactivity? In the present manuscript, the chemical features of Ganoderma polysaccharides with reported antioxidant, antitumor and antimicrobial activities (the most studied worldwide) are analyzed in detail. The composition of sugars (homo- versus hetero-glucans and other polysaccharides), type of glycosidic linkages, branching patterns, and linkage to proteins are discussed. Methods for extraction, isolation and identification are evaluated and, finally, the bioactivity of polysaccharidic extracts and purified compounds are discussed. The integration of data allows deduction of structure-activity relationships and gives clues to the chemical aspects involved in Ganoderma bioactivity.

In situ antioxidant and antimicrobial activities of naturally occurring caffeic acid, p-coumaric acid and rutin, using food systems.

BACKGROUND Three pure compounds that naturally occur in plants were of particular interest to our study regarding the possibility of using them as food preservatives: p-coumaric acid (found in peanuts, tomatoes, carrots, garlic, wine, vinegar, etc.), caffeic acid (found in argan oil, oats, wheat, rice and olive oil) and rutin (found in asparagus, citrus fruits, berries, apple, apricot, asparagus, beef and beer). In the following study we investigated in situ antioxidant and antimicrobial activities of three pure compounds, namely caffeic acid, p-coumaric acid and rutin, naturally occurring in plants. RESULTS Two food systems were used in order to obtain information on how these compounds react in actual food systems rather than microbiological media. The results indicated good antioxidant activity in in situ food systems. For tested phenolic compounds it was further shown that they successively inhibited the development of the isolated food contaminant Staphylococcus aureus in chicken soup. Panelist found that organoleptic characteristics of chicken soup and pork meat improved after treatment with phenolics. CONCLUSION Our findings alone, along with the potential use of phenolic compounds that are widespread in nature, may imply their potential use as preservatives in the food industry.

Satureja horvatii essential oil: In vitro antimicrobial and antiradical properties and in situ control of Listeria monocytogenes in pork meat

The dominant compounds in Satureja horvatii oil were p-cymene (33.14%), thymol (26.11%) and thymol methyl ether (15.08%). The minimum inhibitory concentration (MIC) varied from 0.03 to 0.57 mg/mL for bacteria, and from 0.56 to 2.23 mg/mL for yeast strains, while minimum bactericidal/yeast-cidal concentration (MBC/MYC) varied from 0.07 to 1.15 mg/mL and 1.11 to 5.57 mg/mL for bacteria and yeasts, respectively. The antiradical potential of the essential oil was evaluated using hydroxyl radical (•OH) generated in Fenton reaction. The meat preserving potential of essential oil from Satureja horvatii was investigated against L. monocytogenes. Essential oil successfully inhibited development of L. monocytogenes in pork meat. Sensorial evaluation on flavor and color of meat was performed. The color and flavor of meat treated with essential oil improved after 4 days of storage. S. horvatii essential oil can act as a potent inhibitor of food spoiling microorganisms, in meat products and also can be a useful source of natural antioxidants.

Antibacterial activity of Veronica montana L. extract and of protocatechuic acid incorporated in a food system.

This study was designed to evaluate the antibacterial activity of the Veronica montana L. water extract and its main phenolic compound, protocatechuic acid. The antibacterial activity was determined by microdilution assay against six strains of Gram-positive and Gram-negative bacteria. Listeria monocytogenes was the most sensitive of the tested bacterial species. Antibacterial preserving properties of protocatechuic acid were also evaluated after its incorporation in cream cheese, using L. monocytogenes as commonly cheese contaminant. The compound successfully inhibited L. monocytogenes development in cream cheese, at room temperature and in refrigerator (25°C and 4°C, respectively), after 3days of inoculation. Sensory evaluation was carried out in order to validate the mentioned food system. A possible mode of action of the tested compound towards bacterial cells was assessed and appears to be direct lysis of pathogenic cytoplasmic membrane. Prediction of pharmacokinetic properties was also performed using computational analyzes. The obtained results can serve as an important platform for the development of effective natural preservatives.

Cultivated strains of Agaricus bisporus and A. brasiliensis: chemical characterization and evaluation of antioxidant and antimicrobial properties for the final healthy product – natural preservatives in yoghurt

Agaricus bisporus (J. E. Lange) Emil J. Imbach and Agaricus brasiliensis Wasser, M. Didukh, Amazonas & Stamets are edible mushrooms. We chemically characterized these mushrooms for nutritional value, hydrophilic and lipophilic compounds. The antioxidant and antimicrobial activities of methanolic and ethanolic extracts were assessed. Hepatotoxicity was also evaluated. The ethanolic extract of both species was tested for inhibition of Listeria monocytogenes growth in yoghurt. Both species proved to be a good source of bioactive compounds. A. brasiliensis was richer in polyunsaturated fatty acids and revealed the highest concentration of phenolic acids, and tocopherols. A. bisporus showed the highest monounsaturated fatty acids and ergosterol contents. A. brasiliensis revealed the highest antioxidant potential, and its ethanolic extract displayed the highest antibacterial potential; the methanolic extract of A. bisporus revealed the highest antifungal activity. A. brasiliensis possessed better preserving properties in yoghurt.

Nutrients and non-nutrients composition and bioactivity of wild and cultivated Coprinus comatus (O.F.Müll.) Pers.

Mushrooms have been reported as sources of biomolecules with various potential. Coprinus comatus was studied to obtain information about this species, comparing cultivated and wild samples. Free sugars, fatty acids, tocopherols, organic acids and phenolic acids were analyzed by chromatographic techniques coupled to different detectors. C. comatus methanolic extract was tested for its antioxidant potential (reducing power, radical scavenging activity and lipid peroxidation inhibition) and antimicrobial properties (tested towards Gram positive and negative bacteria, and microfungi). The toxicity for liver cells was tested in porcine liver primary cells. Both studied samples revealed similar nutritional value and energy contribution. The cultivated sample revealed the highest content in free sugars, monounsaturated fatty acids and tocopherols, while the wild mushroom was richer in saturated and polyunsaturated fatty acids, organic acids and phenolic compounds. The cultivated species also revealed the highest antioxidant potential and antimicrobial activity (with exception towards Gram negative bacteria and Aspergillus ochraceus). Both species revealed no toxicity towards porcine liver cells. The present study proved that cultivated and wild mushrooms from the same species could be excellent options as food and as sources of nutritional and bioactive compounds. Furthermore, differences in wild and cultivated samples were comparatively investigated for the first time.

Susceptibility of pathogenic bacteria and fungi to essential oils of wild Daucus carota

The compositions of the essential oils of wild Daucus carota L. (Apiaceae) from the ripe fruits, unripe fruits, flowers, root, leaves, and stem, collected in Serbia, were analyzed by GC and GC/MS. The oils from all samples contained α-pinene (7.05–51.23%) and sabinene (2.68–36.69%) as major constituents. The other dominant compound in ripe and unripe fruits essential oil was α-muurolene (8.23–10.97%). Antibacterial and antifungal properties of these oils, against eight bacterial and eight fungal strains, were tested by a microdilution technique. The most prominent biological activity was achieved by isolated essential oils of ripe and unripe fruits of D. carota.

Laetiporus sulphureus, edible mushroom from Serbia: investigation on volatile compounds, in vitro antimicrobial activity and in situ control of Aspergillus flavus in tomato paste.

The volatile compounds of fruiting bodies of wild Laetiporus sulphureus (Bull.) Murrill, growing on willow trees from Serbia, were isolated and extracted using methanol, acetone and dichloromethane and investigated by GC/MS-SPME. A total of 56 components were identified in the extracts. Hydrocarbons predominated (76.90%, 77.20%, and 43.10%) in dichloromethane, acetone and methanol extracts, respectively. Fatty acids, esters and sesquiterpenes were present in amounts equal or lower than 2.00%. Ketones were represented with moderate amount with the exception of methanol extract where it reached as much as 28.90% of the total investigated compounds. Extracts were also tested for antimicrobial activity with and without the addition of food additive - potassium disulfite in vitro against eight bacterial and eight fungal species, and in situ in tomato paste against Aspergillus flavus. All the tested extracts showed good antimicrobial activity, but methanol extract with addition of E224 showed the best antimicrobial activity in vitro. In situ results indicate complete inhibition of A. flavus growth in tomato paste after 15 days of the treatment. This study is the first report on volatile composition of L. sulphureus growing wild in Serbia. We describe for the first time the application of its extract as antifungal food preservative.

Mycotherapy of Cancer: An Update on Cytotoxic and Antitumor Activities of Mushrooms, Bioactive Principles and Molecular Mechanisms of their Action

Mycotherapy is defined as the study of the use of extracts and compounds obtained from mushrooms as medicines or health-promoting agents. The present review updates the recent findings on anticancer/antitumor agents derived from mushroom extracts and their metabolites. The increasing number of studies in the past few years revealed mushroom extracts as potent antitumor agents. Also, numerous studies were conducted on bioactive compounds isolated from mushrooms reporting the heteropolysaccharides, β-glucans, α-glucans, proteins, complexes of polysaccharides with proteins, fatty acids, nucleoside antagonists, terpenoids, sesquiterpenes, lanostanoids, sterols and phenolic acids as promising antitumor agents. Also, molecular mechanisms of cytotoxicity against different cancer cell lines are discussed in this review. Findings with Antrodia camphorata and Ganoderma lucidium extracts and isolated compounds are presented, as being the most deeply studied previously.

A detailed comparative study between chemical and bioactive properties of Ganoderma lucidum from different origins

Abstract A detailed comparative study on chemical and bioactive properties of wild and cultivated Ganoderma lucidum from Serbia (GS) and China (GCN) was performed. This species was chosen because of its worldwide use as medicinal mushroom. Higher amounts of sugars were found in GS, while higher amounts of organic acids were recorded in GCN. Unsaturated fatty acids predominated over saturated fatty acids. GCN revealed higher antioxidant activity, while GS exhibited inhibitory potential against human breast and cervical carcinoma cell lines. No cytotoxicity in non-tumour liver primary cell culture was observed for the different samples. Both samples possessed antibacterial and antifungal activities, in some cases even better than the standard antimicrobial drugs. This is the first study reporting a comparison of chemical compounds and bioactivity of G. lucidum samples from different origins.