A Targeted and an Untargeted Metabolomics Approach to Study the Phytochemicals of Tomato Cultivars Grown Under Different Salinity Conditions.

In this study, we evaluated the effect of increasing the salinity of irrigation water on the metabolic content and profiles of two tomato cultivars ('Jaune Flamme' (JF) and 'Red Pear' (RP)) using targeted and untargeted metabolomics approaches. Irrigation of tomato plants was performed with four different salt concentrations provided by chloride (treatment 1) and sulfate (treatment 2) salts. Targeted analysis of the methanolic extract resulted in the identification of nine major polyphenols. Among them, chlorogenic acid, rutin, and naringenin were the prominent compounds in both cultivars. In addition, the quantification of 18 free amino acids from both tomato cultivars showed that different salinity treatments significantly enhanced the levels of glutamine, glutamic acid, and γ-aminobutyric acid (GABA). Using the untargeted metabolomic approach, we identified 129 putative metabolites encompassing a diverse array of phytochemicals including polyphenols, organic acids, lipids, sugars, and amino acids. Principal component analysis (PCA) of mass spectral data acquired under positive and negative ionization modes showed a clear separation between the two cultivars. However, only positive ionization showed separation among different salinity treatments. Unsupervised and supervised learning algorithms were applied to mine the generated data and to pinpoint metabolites different from the two cultivars. These findings suggest that different salinity conditions significantly influenced the accumulation of phytochemicals in tomato cultivars. This study will help tomato breeding programs to develop value-added tomato cultivars under varying environmental conditions.

An Untargeted Metabolomics Approach to Study the Variation between Wild and Cultivated Soybeans.

The differential metabolite profiles of four wild and ten cultivated soybeans genotypes were explored using an untargeted metabolomics approach. Ground soybean seed samples were extracted with methanol and water, and metabolic features were obtained using ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry (UHPLC-HRMS) in both positive and negative ion modes. The UHPLC-HRMS analysis of the two different extracts resulted in the putative identification of 98 metabolites belonging to several classes of phytochemicals, including isoflavones, organic acids, lipids, sugars, amino acids, saponins, and other compounds. The metabolic profile was significantly impacted by the polarity of the extraction solvent. Multivariate analysis showed a clear difference between wild and cultivated soybean cultivars. Unsupervised and supervised learning algorithms were applied to mine the generated data and to pinpoint metabolites differentiating wild and cultivated soybeans. The key identified metabolites differentiating wild and cultivated soybeans were isoflavonoids, free amino acids, and fatty acids. Catechin analogs, cynaroside, hydroxylated unsaturated fatty acid derivatives, amino acid, and uridine diphosphate-N-acetylglucosamine were upregulated in the methanol extract of wild soybeans. In contrast, isoflavonoids and other minor compounds were downregulated in the same soybean extract. This metabolic information will benefit breeders and biotechnology professionals to develop value-added soybeans with improved quality traits.

Oxidative Stress and Antioxidants-A Critical Review on In Vitro Antioxidant Assays.

Antioxidants have been widely studied in the fields of biology, medicine, food, and nutrition sciences. There has been extensive work on developing assays for foods and biological systems. The scientific communities have well-accepted the effectiveness of endogenous antioxidants generated in the body. However, the health efficacy and the possible action of exogenous dietary antioxidants are still questionable. This may be attributed to several factors, including a lack of basic understanding of the interaction of exogenous antioxidants in the body, the lack of agreement of the different antioxidant assays, and the lack of specificity of the assays, which leads to an inability to relate specific dietary antioxidants to health outcomes. Hence, there is significant doubt regarding the relationship between dietary antioxidants to human health. In this review, we documented the variations in the current methodologies, their mechanisms, and the highly varying values for six common food substrates (fruits, vegetables, processed foods, grains, legumes, milk, and dairy-related products). Finally, we discuss the strengths and weaknesses of the antioxidant assays and examine the challenges in correlating the antioxidant activity of foods to human health.

Extractability of Curcuminoids Is Enhanced with Milk and Aqueous-Alcohol Mixtures.

In this study, we evaluated the extractability of three curcuminoids (curcumin, demethoxycurcumin, and bisdemethoxycurcumin) from turmeric powder in several solvents using high-performance liquid chromatography (HPLC) with the diode-array detection method. These solvents include water, milk (homogenized, 2% reduced fat, low fat, fat free, soy, almond, coconut, and milkadamia), and aqueous ethanols (0%, 4%, 10%, 20%, 30%, 40%, 50%, and 100%). Ambient water was able to extract only 0.55 mg/g of curcuminoids, whereas warm water extracted more than four-fold higher amounts (2.42 mg/g). Almond, coconut, and milkadamia milk were able to extract only small amounts of curcuminoids at ambient temperatures (0.01-0.07 mg/g). The extractability of curcuminoids in these milk types did not improve, even in warm conditions (0.08-0.37 mg/g). Whereas dairy and soy milk extracted 6.76-9.75 mg/g of curcuminoids under ambient conditions, their extractability increased significantly in warm conditions by 30-100% higher (11.7-14.9 mg/g). The solubility of curcuminoids also varied remarkably in different proportions of aqueous-alcohol mixtures. With 4% ethanol, only 1.7 mg/g of curcuminoids were extracted, and the amounts improved with the increase in ethanol content up to 50% (32.2 mg/g), while 100% ethanol extracted a similar amount as 50% ethanol (34.2 mg/g). This study suggests that the extractability of curcuminoids from turmeric will be dependent on the type of diets consumed with the turmeric supplements.

Metabolic Interaction between Ammonia and Baicalein.

Ammonia is treated as a primary waste product of cellular metabolism in vivo and can contribute to the alteration of neurotransmission, oxidative stress, and cerebral edema and astrocyte swelling when its concentration in the brain is high. The objective of this study was to determine whether bioactive polyphenol baicalein had the capacity to trap ammonia in vitro and in vivo. Under in vitro conditions, baicalein rapidly reacted with ammonia to generate two monoaminated products and one diaminated product under different reaction times. These three major aminated products were purified from the reaction mixture, and their structures were characterized as 5-NH2-baicalein, 6-NH2-baicalein, and 5,6-di-NH2-baicalein based on the analysis of their HR-MS and 1D- and 2D-NMR data. In mice, both 5-NH2-baicalein and 6-NH2-baicalein were detected in 24 h fecal and urine samples collected from mice treated with baicalein (200 mg/kg) through oral gavage, and 6-NH2-baicalein was also detected in mouse plasma and brain samples collected at 0.5 h after baicalein treatment. Significant amounts of 6-NH2-baicalein were detected in all mouse samples including feces, urine, plasma, and brain. The levels of 6-NH2-baicalein in feces and urine were significantly higher than those of 5-NH2-baicalein. Furthermore, the average level of 6-NH2-baicalein was very close to that of baicalein (3.62 vs 3.77 ng/g) in mouse brain, suggesting it is possible that baicalein has the capacity to be absorbed rapidly into the circulation system and then cross the blood-brain barrier into the brain to detoxify ammonia in the blood and brain. In conclusion, this study confirmed that baicalein, a flavonoid with a vic-trihydroxyl structure on the A-ring, has the potential to detoxify ammonia and treat ammonia-associated chronic diseases.

Precision Research on Ginger: The Type of Ginger Matters.

Ginger is a widely consumed spice and possesses numerous pharmacological properties. However, studies addressing the efficacy of ginger in humans have been inconsistent. Many confounding factors need to be considered when evaluating the health effects from ginger against chronic diseases, especially the levels of bioactive components in the ginger formulations used in human trials. Gingerols, the major compounds in fresh ginger, are liable to dehydrate and convert to shogaols, the major compounds in dried ginger, as a result of the instability of ß-hydroxyl ketone when exposed to heat and/or acidic conditions. As a result of various heating and processing methods, the concentrations of gingerols and shogaols in ginger products vary significantly. Increasing evidence has shown that gingerols and shogaols have different bioactivities, molecular targets, and metabolic pathways, suggesting the importance of identifying the optimal oral ginger composition for a specific disease. In this perspective, we highlighted differences in the composition between fresh ginger and dry ginger, bioactivities, molecular targets, and metabolic pathways of gingerols and shogaols as well as future perspectives regarding precision research on ginger.

Inhibitory Effects of Linear Lipopeptides From a Marine Bacillus subtilis on the Wheat Blast Fungus Magnaporthe oryzae Triticum.

Wheat blast is a devastating fungal disease caused by a filamentous fungus, Magnaporthe oryzae Triticum (MoT) pathotype, which poses a serious threat to food security of South America and South Asia. In the course of screening novel bioactive secondary metabolites, we found that some secondary metabolites from a marine Bacillus subtilis strain 109GGC020 remarkably inhibited the growth of M. oryzae Triticum in vitro at 20 µg/disk. We tested a number of natural compounds derived from microorganisms and plants and found that five recently discovered linear non-cytotoxic lipopeptides, gageopeptides A-D (1-4) and gageotetrin B (5) from the strain 109GGC020 inhibited the growth of MoT mycelia in a dose-dependent manner. Among the five compounds studied, gageotetrin B (5) displayed the highest mycelial growth inhibition of MoT followed by gageopeptide C (3), gageopeptide D (4), gageopeptide A (1), and gageopeptide B (2) with minimum inhibitory concentrations (MICs) of 1.5, 2.5, 2.5, 10.0, and 10.0 µg/disk, respectively. Application of these natural compounds has also completely blocked formation of conidia in the MoT fungal mycelia in the agar medium. Further bioassay revealed that these compounds (1-5) inhibited the germination of MoT conidia and, if germinated, induced deformation of germ tube and/or abnormal appressoria. Interestingly, application of these linear lipopeptides (1-5) significantly suppressed wheat blast disease on detached wheat leaves. This is the first report of the inhibition of mycelial growth, conidiogenesis, conidial germination, and morphological alterations in the germinated conidia and suppression of wheat blast disease by linear lipopeptides from the strain of B. subtilis. A further study is needed to evaluate the mode of action of these natural compounds for considering them as biopesticides for managing this notorious cereal killer.

Biotransformation of Myricetin: A Novel Metabolic Pathway to Produce Aminated Products in Mice.

SCOPE: In this study, whether amination is a novel metabolic pathway of myricetin, one of the major dietary flavonoids found in fruits, vegetables, and tea, and whether the aminated metabolite of myricetin remains bioactive, are investigated. METHODS AND RESULTS: It is found that myricetin with a vic-trihydroxyl group on the B ring can chemically react with ammonia via the formation of myricetin quinone to generate the aminated product in vitro. As expected, the amination occurs on position 4´ of the B-ring of myricetin. The structure of this new product is confirmed by 1D and 2D nuclear magnetic resonance (NMR) spectroscopy and liquid chromatography-mass spectrometry and is named 4´-NH2 -myricetin. Using the synthetic 4´-NH2 -myricetin as a standard, the presence of this compound is searched for in fecal samples collected from myricetin-treated mice using LC-MS, and 4´-NH2 -myricetin is confirmed as the metabolite of myricetin in mice for the first time. Furthermore, two metabolites of myricetin, the mono-methylated myricetin and the microbial-derived metabolite 3,4,5-trihydroxyphenylacetic acid, are confirmed to be aminated in vivo based on LC-MS data analysis. After administration of different doses of myricetin through oral gavage, the amination of myricetin shows a dose-dependent response in feces. A similar trend is observed for the amination of the mono-methylated myricetin, but not for the microbial-derived metabolite 3,4,5-trihydroxyphenylacetic acid. In plasma, the trend of a dose-dependent response for the amination of myricetin and its mono methylated metabolite is observed, and the plasma concentration of the aminated 3,4,5-trihydroxyphenylacetic acid at 200 mg kg-1 dose is significantly higher than those at the 100 and 400 mg kg-1 doses. Interestingly, it is observed that the aminated myricetin retains the anti-inflammatory activity of myricetin. CONCLUSION: This result demonstrates that amination is a novel biotransformation mechanism of myricetin to produce aminated metabolites.

Anti-Staphylococcal Calopins from Fruiting Bodies of Caloboletus radicans.

Three new and seven known calopins were isolated from Caloboletus radicans. The structures of the new cyclocalopins, 8-deacetylcyclocalopin B (1), cyclocalopin A-15-ol (2), and 12,15-dimethoxycyclocalopin A (3), were mainly elucidated by NMR and MS data analysis. The stereochemistry of 1-3 was assigned based on NOE correlations and coupling constants and by comparison of their CD spectra with those of similar known calopins. While 1-10 were inactive against two cancer cell lines, they displayed anti-staphylococcal activity against methicillin-resistant Staphylococcus aureus strains (MRSA) with MIC values of 16-256 µg/mL. Moreover, some calopins were active against the fish pathogen Enterococcus faecalis F1B1.

Bacilotetrins A and B, Anti-Staphylococcal Cyclic-Lipotetrapeptides from a Marine-Derived Bacillus subtilis.

LC-MS and NMR spectroscopy guided metabolic profiling and dereplication of a crude extract obtained from the fermentation of a marine-derived bacterium, Bacillus subtilis, followed by chromatographic isolation yielded two new cyclic-lipotetrapeptides, bacilotetrins A (1) and B (2). Based on extensive 1D and 2D NMR and high-resolution ESIMS data analysis, the structures of 1 and 2 were elucidated, revealing the unique structures of these lipopeptides consisting of three leucines and a glutamic acid residue cyclized with a lipophilic 3-hydroxy fatty acid. The absolute stereochemistries at selected stereocenters in 1 and 2 were assigned by chemical derivatization and comparison to literature data. Compounds 1 and 2 exhibited anti-MRSA activity with MIC values of 8 to 32 µg/mL. However, these compounds showed no cytotoxicity when tested against prostate and liver cancer cell lines using the standard SRB assay.

Cytotoxic and antibacterial naphthoquinones from an endophytic fungus, Cladosporium sp.

OBJECTIVE: Endophytes have the potential to synthesize various bioactive secondary metabolites. The aim of the study was to find new cytotoxic and antibacterial metabolites from endophytic fungus, Cladosporium sp. isolated from the leaves of Rauwolfia serpentina (L.) Benth. ex Kurz. (Fam: Apocyanaceae). MATERIALS AND METHODS: The endophytic fungus was grown on potato dextrose agar medium and extracted using ethyl acetate. Secondary metabolites were isolated by chromatographic separation and re-crystallization, and structures were confirmed by 1H NMR, 13C NMR and mass spectroscopic data. The cytotoxicity was determined by WST-1 assay and brine shrimp lethality bioassay, while antibacterial activity was assessed by disc diffusion method. RESULTS: Two naphthoquinones, namely anhydrofusarubin (1) and methyl ether of fusarubin (2), were isolated from Cladosporium sp. The isolated compounds 1 and 2, by WST-1 assay against human leukemia cells (K-562) showed potential cytotoxicity with IC50 values of 3.97 µg/mL and 3.58 µg/mL, respectively. Initial screening of crude ethyl acetate extract and column fractions F-8 and F-10 exhibited noticeable cytotoxicity to brine shimp nauplii with LC50 values of 42.8, 1.2 and 2.1 µg/mL, respectively. Moreover, the isolated compound 2 (40 µg/disc) showed prominent activities against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Bacillus megaterium with an average zone of inhibition of 27 mm, 25 mm, 24 mm and 22 mm, respectively and the activities were compared with kanamycin (30 µg/disc). CONCLUSION: Our findings indicate that anhydrofusarubin (1) and methyl ether of fusarubin (2) might be useful lead compounds to develop potential cytotoxic and antimicrobial drugs.

Gageopeptins A and B, new inhibitors of zoospore motility of the phytopathogen Phytophthora capsici from a marine-derived bacterium Bacillus sp. 109GGC020.

The motility of zoospores is critical in the disease cycles of the peronosporomycetes that cause devastating diseases in plants, fishes, vertebrates, and microbes. In the course of screening for secondary metabolites regulating the motility of zoospores of Phytophthora capsici, we discovered two new inhibitors from the ethyl acetate extract of the fermentation broth of a marine-derived strain Bacillus sp. 109GGC020. The structures of these novel metabolites were elucidated as new cyclic lipopeptides and named gageopeptins A (1) and B (2) by spectroscopic analyses including high resolution MS and extensive 1D and 2D NMR. The stereoconfigurations of 1 and 2 were assigned based on the chemical derivatization studies and reviews of the literature data. Although compounds 1 and 2 impaired the motility of zoospores of P. capsici in dose- and time-dependent manners, compound 1 (IC50 = 1 µg/ml) was an approximately 400-fold stronger motility inhibitor than 2 (IC50 = 400 µg/ml). Interestingly, the zoospores halted by compound 1 were subsequently lysed at higher concentrations (IC50 = 50 µg/ml). Compounds 1 and 2 were also tested against some bacteria and fungi by broth dilution assay, and exhibited moderate antibacterial and good antifungal activities.

Ieodoglucomide C and Ieodoglycolipid, New Glycolipids from a Marine-Derived Bacterium Bacillus licheniformis 09IDYM23.

Chemical examination of the ethyl acetate extract from the fermentation broth of the marine-derived bacterium Bacillus licheniformis resulted in the isolation of two new glycolipids, ieodoglucomide C (1) and ieodoglycolipid (2). The structural characterization of 1 and 2 was achieved by extensive spectroscopic evidence, including 2D NMR experiments. A combination of chemical derivatization techniques followed by NMR studies, LC-MS data analysis and a literature review was deployed for the establishment of the stereo-configurations of 1 and 2. Compounds 1 and 2 exhibited good antibiotic properties against Staphylococcus aureus, Bacillus subtilis, Bacillus cereus, Salmonella typhi, Escherichia coli and Pseudomonas aeruginosa with MICs ranging from 0.01 to 0.05 µM. Furthermore, the antifungal activity of 1 and 2 was evaluated against plant pathogenic fungi Aspergillus niger, Rhizoctonia solani, Botrytis cinerea and Colletotrichum acutatum as well as the human pathogen Candida albicans. Compounds 1 and 2 inhibited the mycelial growth of these pathogens with MIC values of 0.03-0.05 µM, revealing that these compounds are good candidates for the development of new fungicides.

Non-cytotoxic antifungal agents: isolation and structures of gageopeptides A-D from a Bacillus strain 109GGC020.

Antifungal resistance and toxicity problems of conventional fungicides highlighted the requirement of search for new safe antifungal agents. To comply with the requirement, we discovered four new non-cytotoxic lipopeptides, gageopeptides A-D, 1-4, from a marine-derived bacterium Bacillus subtilis. The structures and stereochemistry of gageopeptides were determined by NMR data analysis and chemical means. Gageopeptides exhibited significant antifungal activities against pathogenic fungi Rhizoctonia solani, Botrytis cinerea, and Colletotrichum acutatum with minimum inhibitory concentration (MIC) values of 0.02-0.06 µM. In addition, these lipopeptides showed significant motility inhibition and lytic activities against zoospores of the late blight pathogen Phytophthora capsici. These compounds also showed potent antimicrobial activity against Gram positive and Gram negative bacteria with MIC values of 0.04-0.08 µM. However, gageopeptides A-D did not exhibit any cytotoxicity (GI50 > 25 µM) against cancer cell lines in sulforhodamine B (SRB), 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT), and WST-1 ((4-[3-4-iodophenyl]-2-(4-nitrophenyl)-2H-5-tetrazolio)-1,3-benzene disulfonate)) assays, demonstrating that these compounds could be promising candidates for the development of non-cytotoxic antifungal agents.

Gageostatins A-C, antimicrobial linear lipopeptides from a marine Bacillus subtilis.

Concerning the requirements of effective drug candidates to combat against high rising multidrug resistant pathogens, we isolated three new linear lipopeptides, gageostatins A-C (1-3), consisting of hepta-peptides and new 3-ß-hydroxy fatty acids from the fermentation broth of a marine-derived bacterium Bacillus subtilis. Their structures were elucidated by analyzing a combination of extensive 1D, 2D NMR spectroscopic data and high resolution ESIMS data. Fatty acids, namely 3-ß-hydroxy-11-methyltridecanoic and 3-ß-hydroxy-9,11-dimethyltridecanoic acids were characterized in lipopeptides 1 and 2, respectively, whereas an unsaturated fatty acid (E)-7,9-dimethylundec-2-enoic acid was assigned in 3. The 3R configuration of the stereocenter of 3-ß-hydroxy fatty acids in 1 and 2 was established by Mosher's MTPA method. The absolute stereochemistry of amino acid residues in 1-3 was ascertained by acid hydrolysis followed by Marfey's derivatization studies. Gageostatins 1-3 exhibited good antifungal activities with MICs values of 4-32 µg/mL when tested against pathogenic fungi (R. solani, B. cinerea and C. acutatum) and moderate antibacterial activity against bacteria (B. subtilis, S. aeureus, S. typhi and P. aeruginosa) with MICs values of 8-64 µg/mL. Futhermore, gageostatins 1-3 displayed cytotoxicity against six human cancer cell lines with GI50 values of 4.6-19.6 µg/mL. It is also noteworthy that mixed compounds 1+2 displayed better antifungal and cytotoxic activities than individuals.

Gageotetrins A-C, noncytotoxic antimicrobial linear lipopeptides from a marine bacterium Bacillus subtilis.

Gageotetrins A-C (1-3), a unique class of linear lipopeptides, consisting of di- and tetrapeptides and a new fatty acid were isolated from a Marine Bacillus subtilis. The structures of 1-3 were assigned by spectroscopic data and their absolute stereochemistries were ascertained by chemical derivatization. Compounds 1-3 displayed good antimicrobial activities with MIC values of 0.01-0.06 µM. However, these compounds failed to register any cytotoxicity (GI50 > 30 µg/ml) against human cancer cell lines.

Antimicrobial gageomacrolactins characterized from the fermentation of the marine-derived bacterium Bacillus subtilis under optimum growth conditions.

Marine bacteria are a potential source of structurally diversified bioactive secondary metabolites that are not found in terrestrial sources. In our continuous effort to search for new antimicrobial agents from marine-derived bacteria, we isolated bacterial strain 109GGC020 from a marine sediment sample collected from Gageocho, Republic of Korea. The strain was identified as Bacillus subtilis based on a 16s rRNA sequence analysis. After a 7-day fermentation of the B. subtilis strain under optimum growth conditions three new and four known secondary metabolites were discovered using chromatographic procedures, and their biological activities were evaluated against both bacteria and crop-devastating fungi. The discovered metabolites were confirmed by extensive 2D NMR and high-resolution ESI-MS data analyses to have the structures of new macrolactin derivatives gageomacrolactins 1-3 and known macrolactins A (4), B (5), F (6), and W (7). The stereoconfigurations of 1-3 were assigned based on coupling constant values, chemical derivatization studies, and a literature review. The coupling constants were very crucial to determine the relative geometries of olefins in 1-3 because of overlap of the ¹H NMR signals. The NMR data of these compounds were recorded in different solvents to overcome this problem and obtain accurate coupling constant values. The new macrolactin derivatives 1-3 displayed good antibiotic properties against both Gram-positive (S. aureus, B. subtilis, and B. cereus) and Gram-negative (E. coli, S. typhi, and P. aeruginosa) bacteria with minimum inhibitory concentration (MIC) values of 0.02-0.05 µM. Additionally, the antifungal activities of 1-7 were evaluated against pathogenic fungi and found to inhibit mycelial growth of A. niger, B. cinerea, C. acutatum, C. albicans, and R. solani with MIC values of 0.04-0.3 µM, demonstrating that these compounds were good fungicides.

Ieodoglucomides A and B from a marine-derived bacterium Bacillus licheniformis.

Ieodoglucomides A (1) and B (2), unique glycolipopeptides consisting of an amino acid, a new fatty acid, a succinic acid, and a sugar, were isolated from a Marine-derived bacterium Bacillus licheniformis. The absolute stereochemistry of 1 and 2 was determined by deploying coupling constants, Marfey's and Mosher's methods, and literature reviews. Compounds 1 and 2 displayed moderate in vitro antimicrobial activity. Furthermore, ieodoglucomide B (2) exhibited cytotoxic activity against lung cancer and stomach cancer cell lines with GI(50) values of 25.18 and 17.78 µg/mL, respectively.

Cyclic ether-containing macrolactins, antimicrobial 24-membered isomeric macrolactones from a marine Bacillus sp.

Bioassay-guided isolation of bioactive metabolites from the ethyl acetate extract of a marine Bacillus sp. fermentation broth has led to the discovery of three new 24-membered macrolactones, macrolactins 1-3, which contain an oxetane, an epoxide, and a tetrahydropyran ring, respectively. The configurations of 1-3 were assigned by a combination of coupling constants, ROESY data analysis, and application of the modified Mosher's method. Compounds 1-3 showed in vitro antimicrobial activity.

Ieodomycins A-D, antimicrobial fatty acids from a marine Bacillus sp.

Bioassay-guided isolation of the EtOAc extract of a marine Bacillus sp., cultured in modified Bennett's broth medium, yielded four new antimicrobial fatty acids, named ieodomycins A-D. The planar structures of these new compounds were determined by extensive 1D and 2D NMR and HRESIMS spectroscopic data analysis. Their absolute configurations were elucidated by modified Mosher's method and literature data review. All four new compounds demonstrated antimicrobial activities in vitro.