Background: Microalgae is one of the major sources of natural compounds with antimicrobial activity. The metabolite profiling of the extracts could identify the bioactive compounds based on methanol (MET), ethanol (ETH), chloroform (CHL), hexane (HEX) and water (W) solvent systems. The microalgal crude extracts in co-application with silver nanoparticles (AgNPs) had enhanced antimicrobial activity with potential to overcome the global problem of microbial antibiotic resistance. Results: Chlorella sp. exhibited the highest lipid, N. oculata the highest total saturated fatty acids (TSFA), and T. suecica the highest mono-unsaturated (MUFA) and poly-unsaturated fatty acids (PUFA). The highest carbohydrate, protein and total phenolics contents (TPCs) were attained by N. oculata. The highest total flavonoids contents (TFCs), and chlorophyll a and b were in T. suecica, while comparable level of carotenoids were found in all species. For high-performance thin-layer chromatography (HPTLC) analyses, the eicosapentaenoic acid (EPA) with high peaks were detected in T. suecica-HEX and N. oculata-CHL; and β-carotene in Chlorella sp.-ETH. The gas chromatography-mass spectrometry (GC-MS) analyses showed high 13-docosenamide (Z)-in T. suecica-HEX; phytol in N. oculata-HEX; and neophytadiene in Chlorella sp.-ETH. The AgNPs-MCEs-MET and HEX at the 1.5:1 ratios exhibited strong activities against Bacillus subtilis, Streptococcus uberis, and Salmonella sp.; and the AgNPs-T. suecica-HEX and MET and AgNPs-Chlorella sp.-HEX at the 1.5:1 ratios exhibited activities against Klebsiella pneumoniae. Conclusion: Different bioactive components were detected in the MCEs based on the HPTLC and GC-MS analyses. Significant antimicrobial activities against the pathogenic microbes were demonstrated by the synergistic effects of the MCEs in co-application with the AgNPs. This could be beneficial in the fight against sensitive and multidrugresistant bacteria.
Mangrove plants are endowed with various biologically active compounds which have potent antibacterial and antioxidant properties. In present study, a bioactivity-guided fractionation for antibacterial and antioxidant active metabolites from the twigs of Avicennia officinalis collected from Kuala Selangor Nature Park, Selangor, Malaysia gave 13 major fractions. The antibacterial activity of A. officinalis fractions using well-diffusion showed strong selectivity on the Gram-positive bacteria (Staphylococcus epidermidis, S. aureus and Bacillus subtilis) with minimum inhibition concentration (MIC) values of 0.156-5.00 mg/mL. However, no antibacterial activities were observed on the Gram-negative bacteria (Vibrio cholera, Enterobacter cloacae and Escherichia coli). The active antibacterial fractions were further isolated using several chromatographic techniques to give two naphthofuranquinones, namely, avicenol C (1) and stenocarpoquinone B (2). Meanwhile, the antioxidant activity of A. officinalis fractions were evaluated using DPPH radical scavenging assay exhibited low antioxidant activities. Molecular structure of the naphthofuranquinones was elucidated using 1D and 2D NMR spectroscopy.
Objective: This study aimed to investigate the anti-inflammatory activity of methanol extract and fractions of bacteria associated with sponge (Haliclona amboinensis) and to evaluate their effect in reducing NO production and inhibiting cyclooxygenase-1 (COX-1), cyclooxgenase-2 (COX-2) and secretory phospholipase A2 (sPLA2) activity.Methods: All bacterial isolates were cultured and supernatants were collected for the extraction of secondary metabolites using diaion HP-20 to obtain methanol extracts. Evaluation of cytotoxicity property was carried out on macrophage cell lines (RAW264.7) by 3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyl tetrazoliumbromide assay. Anti-inflammatory screening was done by inducible nitric oxide assay on RAW264.7 cell lines with lipopolysaccharide (LPS) stimulation. Dianion HP-20 was used to remove salt content. A selected methanol extract was subjected to further fractionations by C-18 reverse phase and their anti-inflammatory potential was evaluated by COX-1 and COX-2, and sPLA2 enzymatic assay.Results: Seven methanol extracts showed no cytotoxic property against RAW 264.7 cell line (inhibitory concentration 50% > 30 µg/ml) and selected for anti-inflammatory screening assay. Result showed methanol extract HM 1.2 reduced NO production >80% and it has been selected for phytochemical screening, further fractionations and assay. Phytochemical screening showed alkaloids and terpenoids present in the HM 1.2. The HM 1.2 and its fractions (F1, F2, F1C1, F1C2, F1C3, and F1C4) were proven to inhibit COX-1, COX-2, and sPLA2 activity in the range of 60.516-116.886%, 20.554-116.457%, and 70.2667-114.8148%, respectively. Conclusions:This study revealed that bacteria associated with H. amboinensis have produced anti-inflammatory activity via reducing NO production and inhibiting COX-1, COX-2, and sPLA2 activity.
Background: Quercus infectoria galls (QI) extracts were previously reported to have cytotoxicity effects towards human cervical cancer cells, HeLa. However, the underlying molecular mechanisms of the extracts have been poorly determined. Objective: The present study was undertaken to examine the effect of ethyl acetate extracts of QI (EAQI) on cell cytotoxicity and induction of apoptosis in HeLa cells. Materials and Method: The in vitro cytotoxicity was investigated by using the MTT [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide] assay and the OD values were read at 570 nm. Meanwhile the induction of apoptosis was measured by using acridine orange and propidium iodide (AO/PI) staining, flow cytometry analysis of annexin V/PI staining and cell cycle distribution. Results: MTT assay showed that EAQI exhibited cytotoxicity effect on HeLa cells with IC 50 of 11.50 ± 0.50 µg/ml. HeLa cells underwent apoptosis in response to EAQI treatment, demonstrated by an increase in the percentage of apoptotic cell stained with AOPI from 1.00% to 10.33% compared to untreated cell population (p<0.05) at 72 hours of treatment. The evidence of early apoptosis in treated cells were also observed in annexin V/PI staining. Furthermore, an increase of cell population in sub G0/G1 phase revealed that apoptosis as the mode of cell death in HeLa cells treated with EAQI. Conclusion: These findings indicated that EAQI significantly inhibits HeLa cell growth through induction of apoptosis. Further studies are needed to confirm the mechanism of cell death by expression of apoptotic cascade in HeLa cells treated with EAQI.
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