Antioxidant and Antimicrobial Activity of Secondary Metabolites Extracted from Bakery Yeast Saccharomyces cerevisiae

Background: Actinobacteria are widespread and live in a variety of habitats. Today, these bacteria are very important due to the production of various secondary metabolites with different biological activities. The present study aimed to isolate strains of Actinobacteria from different habitats (the Persian Gulf, Gandom Beryan area in the Lut Desert, and some plant roots). The anticancer and antimicrobial activities of secondary metabolites of these isolates were also investigated. Methods: Samples were taken from water of the Persian Gulf, soil of Gandom Beryan area in the Lut Desert, and plant roots. For isolation of Actinobacteria, samples were cultured in ISP2, ISP4, AIA, Gauze, M1, ISP3, and GYP media. Bacterial strains were identified based on the colony and bacterial morphology and confirmed using the specific primers for Actinobacteria. The anticancer and antimicrobial activities of crude metabolite extracts and supernatant of the isolates were evaluated on MCF-7 and Staphylococcus aureus PTCC 112 and Pseudomonas aeruginosa PTCC 1214 strains. Results: The results showed that the supernatants of 7 isolates (ga31, ez, sa, mar2, rz, ga33, and ga5) and the metabolite extracts of 4 strains (ga31, ga5, rz, and ez) had anticancer activity. Overall, ga31 was the best strain with anticancer activity of more than 75%. When evaluating the antimicrobial activity of bacterial secondary metabolites, we found that only two strains (ga31 and ga5) had antimicrobial activity against S. aureus PTCC 1112. Conclusions: In general, strain ga31, which has high anticancer and antimicrobial activities, could be a good candidate for new trials in the pharmaceutical industry.

BackgroundProstate cancer is a significant global health concern, particularly among ageing male populations, with a disproportionately higher burden in sub-Saharan Africa. Conventional treatments, though effective, are costly and cause devastating side effects which limit their clinical benefits. Hence, this study evaluated the in vitro antiprostate cancer properties and secondary metabolites of dichloromethane and ethyl acetate lead extracts of Vitex doniana to explore safer and efficacious natural alternatives based on ethnomedicinal claims.MethodsPhytochemical profiling was conducted using gas chromatography-mass spectrometry (GC-MS) analysis to identify secondary metabolites in the extracts. The cytotoxic effects of the extracts were determined through the MTT assay using Vero CCL-81 cells and DU-145 cells. The expression profile of the selected genes (ar, bcl2, caspase-3, cdk1, and p53) in DU-145 cells treated with the study extracts was investigated using RT-qPCR.ResultsGC-MS analysis revealed 10 secondary metabolites in the dichloromethane extract and 27 secondary metabolites in the ethyl acetate extract of V. doniana leaves, with the majority being sesquiterpenes, diterpenoids, and phytosterols. The dichloromethane and ethyl acetate leaf extracts of V. doniana exhibited low cytotoxicity against normal mammalian epithelial cells (Vero CCL-81), with CC50 values of 1,238.85 μg/mL and 964.81 μg/mL, respectively. Besides, the ethyl acetate leaf extract of the studied plant demonstrated potent anti-prostate cancer activity against DU-145 cells, with an IC50 of 35.68 μg/mL and a high selectivity index (SI) of 27.04. Likewise, the dichloromethane leaf extract of this plant displayed cytotoxic effects (IC50: 287.01 μg/mL) and a selectivity index of 4.32. The reference drug (Doxorubicin) showed a higher toxicity against Vero CCL-81(IC50: 0.41 μg/mL) and DU-145 (IC50: 0.28 μg/mL) cells and a lower selectivity index of 1.46. The DU-145 cells treated with the studied plant extracts exhibited notable upregulation of ar and bcl2, and normalization of caspase 3, cdk1 and p53 expression.ConclusionThe studied plant extracts possess in vitro anti-prostate cancer properties and could be promising candidates for further preclinical studies aimed at developing novel botanical-based therapies for the management of prostate cancer.

Evaluation of antimicrobial activity of secondary metabolites of fungi isolated from Sultanate Oman soil

Attention is being diverted toward the bioprospecting of newer bioactive compounds from marine endophytic fungi. This is because marine fungi have shown a large chemo-diversity of untapped important secondary metabolites needed for drug development. In the present study, the secondary metabolites of a mangrove-derived endophytic fungus Pseudopestalotiopsis species isolated from the root of Rhizophora racemosa were investigated for antimicrobial and antioxidant activities. The fungal isolation, taxonomic identification, fermentation, extraction, and isolation of the fungal secondary metabolites were carried out using standard techniques. The fermentation product was subjected to fractionation. The crude extract and its fractions were screened for antimicrobial and antioxidant assays. The active extracts and fractions exhibited good antimicrobial activities against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas oleaginous, and Candida albicans with MIC values that ranged between 0.06 to 1 mg/mL. The Gram negatives were the most susceptible bacteria while C. albicans was the most susceptible fungi. Moderately low antioxidant activities were recorded in the DPPH and FRAP assays. The chromatographic separation and HPLC analysis of the fungal secondary metabolites yielded compounds: Palitantin (A), Cytosporin D (B), Cytosporin K (C), and Fusarielin (D). These compounds have been previously reported to possess varying pharmacological activities which include antimicrobial and antioxidant activities. Thus, The results of this study show that these compounds may, in part, account for the anti-microbial and antioxidant effect of the root of Rhizophora racemosa ethno medically.

Objectives: Globally, scientific evaluation of traditional uses of herbal medicine, isolation, and characterization of bioactive constituents from herbs are some of the leading research areas. Spermacoce hispida (SH) is well known for its hypolipidemic and anti-obesity activity. The aim of this study is to qualitatively analyze the presence of primary and secondary metabolites in various extracts of SH seeds and to examine the presence of bioactive principles of chloroform extract from SH seeds.Methods: Physicochemical analysis such as ash content, acid-soluble ash, water-soluble ash, moisture content, fiber content, ethanol soluble extractive value, and water-soluble extractive value for seeds of SH was determined as per WHO guidelines. Cold percolative extracts of seeds of SH with different solvents were carried out. Preliminary phytochemical analysis for the presence of various primary and secondary metabolites in extracts was determined. Gas chromatography mass spectrometry (GC-MS) analysis of chloroform extract was carried out.Results: Physicochemical analysis values were found to be present in permissible level (<5%). Yield of ethyl acetate (4.9/100 g), ethanolic (4.2/100 g), and hydroalcoholic extract (4.0/100 g) of seeds of SH was found to be higher than that of extract obtained by soaking with different low polar solvents. Secondary metabolites such as phenol, flavonoid, and tannin are present in ethyl acetate, ethanolic, hydroalcoholic extract. Fat and alkaloid are present in chloroform extract. GC-MS spectra show the presence of 30 different bioactive constituents. Among them, n-hexadecanoic acid was found to constitute (5.83%) highest peak area than the remaining compounds.Conclusion: Seeds of SH is a rich source of primary and secondary metabolites and various bioactive phytoconstituents.

MEASUREMENT OF THE SENSORY QUALITY OF STRAWBERRIES

MALAGASY AROMATIC PLANTS: ESSENTIAL OILS, ANTIOXIDANT AND ANTIMICROBIAL ACTIVITIES

Background: People have become interested in consuming high-quality, safe, natural foods with the increased spread of green consumerism worldwide. Methods: Prepare a coating solution from leaves of spearmint Mentha spicata with glycerol, estimate the antimicrobial activity and application of this coated on apricots and study the effect on weight loss, soluble solids content, antioxidant activity and sensory evaluation. Result: The qualitative detection of the bioactive compounds of the spearmint M. spicata leaves showed its continent included tannins, alkaloids, flavonoids, coumarins, terpenes, and saponins. The used concentrations of 12.5 and 25 mg mL-1 from spearmint coating solution (SCS) showed a non-significant effect at (P≤0.05). In comparison, the 50 and 100 mg mL-1 showed a significant effect at (P≤0.05) as antimicrobial activity against Escherichia coli, Pseudomonas aeruginosa, Bacillus cereus and Staphylococcus aureus. The weight loss of coated apricots after storage for 30 d at 4°C was 20.06, 18.52, 14.84 and 13.42%. Also, the soluble solids content was 17.3, 16.7, 14.1 and 13.9%. The antioxidant activity (Inhibition%) was increased to 30, 34, 39 and 47% using SCS of 12.5, 25, 50 and 100 mg mL-1 as a coating material. The sensory evaluation found significant differences at (P≤0.05) between treatments for all characteristics. The coating kept the consumer’s acceptance of consuming these fruits through characteristics of appearance, aroma and taste after storage for 30 d at 4°C.

Introduction. Wild-crafting leads to the local extinction of many medicinal plants that are rich in phenolic substances. In vitro cultivation of cells and organs of higher plants can be the optimal solution to this problem. The research objective was to study the biosynthetic activity of in vitro extracts of wild Siberian plants.
 Study objects and methods. The study featured callus, cell suspension, and hairy root extracts of such Siberian medicinal plants as Eleutherococcus senticosus, Codonopsis pilosula, Platanthera bifolia, and Saposhnikovia divaricata. They were obtained by in vitro cultivation using modified nutrient media of Murashige and Skoog and Gamborg. The content of secondary metabolites was studied using the methods of thin-layer and high-performance liquid chromatography. A set of in vitro experiments tested the antioxidant and antimicrobial activity of the extracts.
 Results and discussion. All the samples demonstrated a high content of secondary metabolites of phenolic nature. Flavonoglycosides, apigenin, and rutin were found to be the predominant biologically active substances in the callus extracts. Flavonoglycosides dominated in the suspension extracts. The root extracts contained more caffeic acid, rutin, ecdysteroids, quercetin, apigenin, cardiofolin, and coleofolide than the callus and suspension cultures. The list of prevailing secondary metabolites in the root extracts included rutin, apigenin, coleofolide, and quercetin. All the extracts showed antimicrobial and antioxidant activity.
 Conclusion. All the extracts demonstrated good antioxidant and antimicrobial properties. Therefore, they can be used for the production of pharmaceuticals and biologically active food supplements as they can be helpful against infectious diseases, as well as oncological, cardiovascular, and neurodegenerative diseases linked to oxidative stress.

Introduction. The antibiotic resistance of Gram positive bacteria is a serious public health problem where some palliative measures can be found in the antimicrobial principles of filamentous fungi. Objective. To evaluate the antimicrobial activity of secondary metabolites of a clinical isolation of Aspergillus fumigatus on clinical strains of Staphylococcus aureus and Streptococcus pneumoniae. Methods. The liquid fermentation of A. fumigatus was carried out in a liquid broth sulfate, potato and dextrose; using ethyl acetate for the extraction of secondary metabolites. The antimicrobial activity considered as a halo greater than 6 mm was evaluated using the diffusion disk methodology. Results. A mean of 24,02 ± 2,51 mm and 23,62 ± 4,68 mm was obtained on sensitive and resistant Staphylococcus aureus, respectively. For Streptococcus pneumoniae sensitive and non-susceptible, the means were 25,82 ± 4,05 mm and 26,5 ± 5,39 mm, respectively. Conclusions. The crude extract of A. fumigatus has secondary metabolites of alkaloid nature and unsaturated sterols with antimicrobial activity.

Recently, “green chemistry” methods have been increasingly used to process agricultural waste in order to obtain products with high added value. In the presented work, the medium of subcritical water (SBW) was used to obtain (in the temperature range from 100 to 220 °C) extracts from the leaves of the olive (LO) of Olea europaea L. enriched with polyphenols and to assess their antioxidant activity (AOA). The use of medium of SBW for extraction processes allows not only to increase the extraction of secondary plant metabolites (SPM) from the plant matrix, but also to achieve a change in the phytochemical profile of extracts obtained in SBW. The dependence of the content of secondary plant metabolites (the sum of polyphenolic compounds and flavonoids) and AOA of extracts obtained at different temperatures in SBW and traditional aqueous-alcoholic extraction from olive leaves was studied. It was shown that the content of polyphenolic compounds and the AOA activity of the extracts depend on the extraction conditions. It has been demonstrated that the obtained extract from LO in medium of SBW at 220 °C contains the maximum amount of polyphenolic compounds and demonstrates the maximum AOA (EC50=26.9 μg/ml). The presented results demonstrate the promise of using SBW for obtaining extracts from LO with a high content of polyphenols for the development of pharmaceuticals and food additives with high AOA.

Cancer treatments usually cause adverse drug reactions. Therefore, safe anticancer drugs are needed in the treatment of cancer. One source of medicine that can be explored is plant. Extracts of longan leaves (Dimocarpus longan), jamaican cherry leaves (Muntingia calabura), and avocado leaves (Persea americana) have been tested for cytotoxic activity against several cancer cell lines. This study aims to determine the cytotoxic activity of ethanolic extract of longan leaves, jamaican cherry leaves, and avocado leaves against T47D and WiDr cells and to identify secondary metabolites in the extracts which have the highest activity. Ethanolic extract of longan leaves, jamaican cherry leaves, and avocado leaves were tested for their cytotoxic activity using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Identification of secondary metabolites in the ethanolic extract of avocado leaves was carried out by thin layer chromatography method using silica gel GF254 as the stationary phase and a mixture of n-hexane and acetone (6:4) as the mobile phase. Cytotoxic test results show that ethanolic extract of longan leaves and cherry leaves with concentration of up to 1600 μg/mL do not reduce the T47D and WiDr living cells to 50%. Avocado leaf extract decreases the percentage of living T47D cells and WiDr with IC50 values of 790.679 µg/mL and 1072.2 µg/mL, respectively. The ethanolic extract of avocado leaves contains flavonoid, phenolic, and terpenoid. Ethanolic extract of longan leaves, cherry leaves and avocado leaves do not have cytotoxic activity against T47D and WiDr cells.

The extracts of many plants used in traditional medicine contain curative agents that are used in many modern medicines. As part of the quest for potentially valuable plants of medicinal value, the plant species Phyllanthus amarus Schum. and Thonn. and Quassia amara L. were chosen based on ethno-pharmacological knowledge from Suriname, South America. Phyllanthus amarus (whole plant) was collected in the city Paramaribo and in the country, and Quassia amara (wood) was collected in the countryside of Suriname. The aim of this study was to optimize extraction methods in order to maximize the recovery of secondary metabolites in the crude extracts of P. amarus and Q. amara. This was accomplished by examining the influence of different extraction solvents on the presence of secondary metabolites in the extracts by thin layer chromatography (TLC), determining the most suitable mobile phase for the plant extracts, and determining the most suitable detection method. Ten grams of each species were extracted (w/v 1:10) with 50% methanol in water, 99% methanol, and 50% methanol in chloroform. Thin layer chromatography (TLC) was used to analyze the compounds in the plant extracts. In order to detect the most compounds, it was necessary to determine the optimal mobile phase (chloroform/methanol 9:1; 95:5; or 98:2) and most suitable detection method (I: UV-254 nm and Phosphomolybdic acid reagent; II: UV-365 nm and Dragendorff reagent; III: ethanolic sulfuric acid reagent; or IV: ethanolic sulfuric acid and UV-365 nm). For both plant species, crude extracts from methanol and chloroform-methanol yielded the highest number of fractions. Mobile phase chloroform/methanol 95:5 eluted the most fractions and had the best separation. Detection method I detected a wide variety of fractions/compounds. In the P. amarus extracts the following secondary metabolites were visualized: alkaloids, flavonoids, lignans, phenols and indole derivatives. In Q. amara extracts, alkaloids (e.g. β-carbolines, canthin-6-ones) and quassinoids were detected. Methanol as an extraction solvent gave the best recovery (extraction rate) of secondary metabolites in both plants, and it can be concluded that different extraction solvents influence the extraction rate. Optimized powder extracts were produced as determined by TLC analysis for future bioassay tests.

The influence of edible coatings enriched with citral and eugenol on the raspberry storage ability, nutritional and sensory quality

Antidiabetic, anti-oxidant and antimicrobial activities of Fadogia ancylantha extracts from Malawi