Streptomyces smyrnaeus UKAQ_23, isolated from the mangrove-sediment, collected from Jubail,Saudi Arabia, exhibited substantial antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA), including non-MRSA Gram-positive test bacteria. The novel isolate, under laboratory-scale conditions, produced the highest yield (561.3 ± 0.3 mg/kg fermented agar) of antimicrobial compounds in modified ISP-4 agar at pH 6.5, temperature 35 °C, inoculum 5% v/w, agar 1.5% w/v, and an incubation period of 7 days. The two major compounds, K1 and K2, were isolated from fermented medium and identified as Actinomycin X2 and Actinomycin D, respectively, based on their structural analysis. The antimicrobial screening showed that Actinomycin X2 had the highest antimicrobial activity compared to Actinomycin D, and the actinomycins-mixture (X2:D, 1:1, w/w) against MRSA and non-MRSA Gram-positive test bacteria, at 5 µg/disc concentrations. The MIC of Actinomycin X2 ranged from 1.56–12.5 µg/ml for non-MRSA and 3.125–12.5 µg/ml for MRSA test bacteria. An in-silico molecular docking demonstrated isoleucyl tRNA synthetase as the most-favored antimicrobial protein target for both actinomycins, X2 and D, while the penicillin-binding protein-1a, was the least-favorable target-protein. In conclusion, Streptomyces smyrnaeus UKAQ_23 emerged as a promising source of Actinomycin X2 with the potential to be scaled up for industrial production, which could benefit the pharmaceutical industry.

One new monoterpene glucoside and five dihydroflavonols were isolated for the first time from the aerial parts of Pulicaria jaubertii and identified as p-menthane-2-O-β-D-glucopyranoside [1], dihydroquercetin (taxifolin) [2], 7,3'-di-O-methyltaxifolin [3], 3'-O-methyltaxifolin [4], 7-O-methyltaxifolin (padmatin) [5] and 7-O-methyl-dihydrokampferol (7-O-methylaromadenderin) [6]. The structures of these compounds were unambiguously assigned on the basis of NMR spectroscopic data ((1)H, (13)C, DEPT, HSQC, HMBC) and MS analysis. 2D-NMR methods required revision of assignments of H-6 and H-8 for dihydroflavonol compounds. Possible cytotoxic activity as well as blood pressure (BP) lowering activity were tested. The alcoholic extract showed cytotoxic activity against prostate carcinoma (PC-3), breast carcinoma (MCF-7) and hepatocellular carcinoma (HepG-2) human cell lines with IC50 19.1, 20.0 and 24.1 μg, respectively. The higher dose levels of the alcoholic extract significantly reduced normal BP of rats in a dose-dependent manner.

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Background:Isolation and structure elucidation of flavan-3-ol constituents from the leaves of Ficus spragueana and their cytotoxic activity.Materials and Methods:Different open silica gel column chromatographic techniques with different solvent systems were used for the separation of the constituents of the ethyl acetate-soluble fraction of the alcoholic extract of Ficus spragueana leaves. The structures of these compounds were assigned on the basis of spectroscopic analyses and comparison with literature data. MTT colorimetric assay method (Viability assay) was used for the evaluation of cytotoxic activity of compound 1 against human breast cancer (MCF-7) and human liver cancer (HepG2) cell lines.Results:The isolation of one flavan-3-ol dimer and was identified as (-)-afzelechin-(4α→8)-epicatechin 1, and two flavan-3-ol monomers and were identified as (-)-epiafzelechin 2 and (-)-epicatechin 3. Compound 1 was relatively inactive against human breast cancer (MCF-7) cell line at the tested concentrations as compared with the standard. However, at a concentration (50 ΅g) it was found to give inhibition upon the proliferation of examined human liver (HepG2) tumor cell line.Conclusions:Compound 1 is a new flavan-3-ol dimer and it showed a potent cytotoxic activity against human liver (HepG2) tumor cell line.

Suaeda vermiculata, a halophyte consumed by livestock, is also used by Bedouins to manage liver disorders. The aqueous-ethanolic extract of S. vermiculata, its subsequent fractions, and pure compounds, i.e., pheophytin-A (1), isorhamnetin-3-O-rutinoside (2), and quercetin (3), were evaluated for their hepatoprotective efficacy. The male mice were daily fed with either silymarin, plant aq.-ethanolic extract, fractions, pure isolated compounds, or carboxyl methylcellulose (CMC) for 7 days ( n = 6 /group, p.o.). On the day 7th of the administrations, all, except the intact animal groups, were induced with hepatotoxicity using paracetamol (PCM, 300 mg/kg). The anesthetized animals were euthanized after 24 h; blood and liver tissues were collected and analysed. The serum aspartate transaminase (AST) and alanine transaminase (ALT) levels decreased significantly for all the S. vermiculata aq.-ethanolic extract, fraction, and compound-treated groups when equated with the PCM group ( p < 0.0001 ). The antioxidant, superoxide dismutase (SOD), increased significantly ( p < 0.05 ) for the silymarin-, n-hexane-, and quercetin-fed groups. Similarly, the catalase (CAT) enzyme level significantly increased for all the groups, except for the compound 2-treated group as compared to the CMC group. Also, the glutathione reductase (GR) levels were significantly increased for the n-butanol treated group than for the PCM group. The oxidative stress biomarkers, lipid peroxide (LP) and nitric oxide (NO), the inflammatory markers, IL-6 and TNF-α, and the kidney’s functional biomarker parameters remained unchanged and did not differ significantly for the treated groups in comparison to the PCM-induced toxicity bearing animals. All the treated groups demonstrated significant decreases in cholesterol levels as compared to the PCM group, indicating hepatoprotective and antioxidant effects. The quercetin-treated group demonstrated significant improvement in triglyceride level. The S. vermiculata aq.-ethanolic extract, fractions, and the isolated compounds demonstrated their hepatoprotective and antioxidant effects, confirming the claimed traditional use of the herb as a liver protectant.

Background:Many plants growing in Saudi Arabia are used in folk medicine for treatment of several diseases.Objective:Information of the chemical constituents and biological activities of plants is desirable for the discovery of therapeutic agents and discovering the actual value of folkloric remedies.Materials and Methods:The compounds were isolated and purified using silica gel column chromatography and preparative high-performance liquid chromatography-diode array detector (HPLC-DAD) Method. The alcoholic extracts of these plants were evaluated for biological activities.Results:Isolation and characterization of 1-feruloyl-β-D-glucopyranoside (1) as well as new secondary metabolite tryptophan methyl ester (2) were isolated for the 1st time from the Horwoodia dicksoniae. The three flavones were isolated from Rumex cyprius identified as isoorientin (3), vitexin (4), and Cynarosid (5). The structures of these compounds were characterized by nuclear magnetic resonance and mass spectrometry analysis and comparing with literature. The compounds were isolated and purified using silica gel column chromatography and preparative HPLC-DAD Method. The alcoholic extracts of these plants were evaluated for antimicrobial activities against two Gram-positive bacteria, two Gram-negative bacteria, and four pathogenic fungi. Both plants showed good activities against Syncephalastrum racemosum and Streptococcus pneumoniae with minimal inhibitory concentrations (MICs) 0.98 and 1.95 μg/mL, respectively. H. dicksoniae showed good activity against Aspergillus fumigates with an MIC 1.95 μg/mL. The two extracts showed also effective free radical scavenging activities in the 1,1-diphenyl-2-picrylhydrazyl assay. H. dicksoniae exhibited remarkable cytotoxic activity against Human breast cancer mammary cancer cells-7, Human liver cancer human hepatoma carcinoma cells-2, and human lung carcinoma (A-549) cell lines.Conclusions:It was suggested that further work should be carried out to isolate, purify, and characterize the active constituents responsible for the activity of these plants.SUMMARY New secondary metabolite Tryptophane methyl ester as well as 1-feruloyl-β-D-glucopyranoside were isolated for the first time from the HD.Isoorientin, vitexin and Cynarosid were isolated from RC.HD exhibited good activity against Aspergillus fumigates with an MIC 1.95 µg mL-1.HD showed significant cytotoxic activity against Human breast cancer (MCF-7), Human liver cancer (HepG-2) and Human lung carcinoma (A-549) cell lines.

Six flavonoids present in Pulicaria jaubertii, i.e., 7,3′-di-O-methyltaxifolin (1), 3′-O-methyltaxifolin (2), 7-O-methyltaxifolin (3), taxifolin (4), 3-O-methylquercetin (5), and quercetin (6), were tested for their anticancer activities. The methylated flavonoids, compounds 1–3 and 5, were evaluated for their anticancer activities in comparison to the non-methylated parent flavonoids taxifolin (4) and quercetin (6). The structures of the known compounds were reconfirmed by spectral analyses using 1H and 13C NMR data comparisons and HRMS spectrometry. The anticancer activity of these compounds was evaluated in colon cancer, HCT-116, and noncancerous, HEK-293, cell lines using the MTT antiproliferative assays. The caspase-3 and caspase-9 expressions and DAPI (4′, 6-diamidino-2-phenylindole) staining assays were used to evaluate the apoptotic activity. All the compounds exhibited antiproliferative activity against the HCT-116 cell line with IC50 values at 33 ± 1.25, 36 ± 2.25, 34 ± 2.15, 32 ± 2.35, 34 ± 2.65, and 36 ± 1.95 μg/mL for compounds 1 to 6, respectively. All the compounds produced a significant reduction in HCT-116 cell line proliferation, except compounds 2 and 6. The viability of the HEK-293 normal cells was found to be significantly higher than the viability of the cancerous cells at all of the tested concentrations, thus suggesting that all the compounds have better inhibitory activity on the cancer cell line. Apoptotic features such as chromatin condensation and nuclear shrinkage were also induced by the compounds. The expression of caspase-3 and caspase-9 genes increased in HCT-116 cell lines after 48 h of treatment, suggesting cell death by the apoptotic pathways. The molecular docking studies showed favorable binding affinity against different pro- and antiapoptotic proteins by these compounds. The docking scores were minimum as compared to the caspase-9, caspase-3, Bcl-xl, and JAK2.