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Apart from boosting flavor, herbs and spices are also known for their preservative, antioxidant, antimicrobial and other medicinal properties. Bioactive metabolites with aspiring prospect have guided the present study to screen for antibacterial and antioxidant activity of three Zingiberplants available in Bangladesh. For that purpose, rhizomes of Zingiber officinale, Z. montanumand Z. zerumbetwere extracted with ethanol as solvent system for bioactivity analysis. Antioxidant activity was assessed by employing DPPH free radical scavenging assay, reducing power assay and ferric reducing antioxidant power (FRAP) assay. Z. officinaleextract demonstrated the highest free radical scavenging activity (IC50: 43.65 µg/ml), reducing power (EC50: 189.026 µg/ml) and FRAP value (137.18 ± 0.116 µM Fe(II)/100 µg dry weight of extract). Moreover, total phenolic, flavonoid and tannin content were determined which significantly correlated (Pearson correlation) with the antioxidant activities. For the evaluation of antibacterial activity, zone of inhibition (ZOI) was measured by disc diffusion bioassay against four Gram positive bacteria Bacillus megaterium, Staphylococcus aureus, Micrococcusspp., and S. epidermidisas well as ten Gram negative bacteria Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, S. paratyphi, Vibrio cholera, Shigella dysenteriae, S. flexneri, Proteusspp., Mycobacteriumspp., and Campylobacterspp. Z. montanumextract exhibited significant activity against E. coli(13.67 ± 0.577 mm ZOI) and Micrococcusspp. (14.33 ± 0.763 mm ZOI) if compared to standard erythromycin with ZOI 15.33 ± 0.577 mm and 15.67 ± 0.577 mm, respectively. Furthermore, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of Z. montanumextract were determined against B. megaterium, Micrococcusspp., E. coliand S. paratyphi.Thus, Z. officinaleand Z. montanumextracts could be utilized as source and template for the synthesis of potential drugs and food supplements as well.

Endophytic fungi reside in the intercellular space of plant nourished by the plant. In return, they provide bioactive molecules which can play critical roles on plant defense system. Fifty six endophytes were isolated from the leaves, root, bark and fruits of Sonneratia apetala, a pioneer mangrove plant in the Sundarbans, Bangladesh. A total of 56 isolates were obtained and 12 different species within 8 genera were identified using morphological and molecular characteristics. Antimicrobial activity of ethyl acetate (EtOAc) and methanolic (MeOH) extracts of these 12 different species were analyzed by resazurin assay and the minimum inhibitory concentrations (MICs) were determined. The fungal extracts showed antimicrobial activities against more than one tested bacterium or fungus among 5 human pathogenic microbes, i.e. Escherichia coliNCTC 12241, Staphylococcus aureusNCTC 12981, Micrococcus lutusNCTC 7508, Pseudomonas aeruginosaNCTC 7508 and Candida albicansATCC 90028. Overall, methanolic extracts showed greater activity than that of ethyl acetate extracts. Of the isolates identified, Colletotrichum gloeosporioides, Aspergillus nigerand Fusarium equisetiwere the most active isolates and showed activity against microorganisms under investigation. Methanolic extracts of C. gloeosporioidesand A. nigershowed the lowest MIC (0.0024 mg/mL) against P. aeruginosa. The study indicates that endophytic fungi isolated from S. apetalaspecies possess potential antimicrobial properties, which could be further investigated.

The antioxidant and anti-inflammatory potential of Heritiera fomesethanolic extract was evaluated.Query Ethanolic extraction of dried and grinded plant leaves and bark was performed. Antioxidant activity was evaluated by 1, 1-diphenyl-2-picryl-hydrazil (DPPH) free radical scavenging assay, ferric reducing antioxidant power (FRAP) and β-carotene bleaching inhibition assay. Total phenolic and flavonoid content were also determined. Anti-inflammatory activity was evaluated by in vitro human RBC membrane stabilizing assay and in vivo mice paw edema test. Ethanolic bark and leaf extracts of H. fomes(S1 and S2, respectively) showed significant scavenging effect on DPPH scavenging 68.51 µg/ml for S1 and 108.64 µg/ml for S2. Potent reduction potential (FRAP) was observed in S1 (83.75 mM of ferrous equivalent) while the FRAP of standard ascorbic acid was found 86.66 μM of ferrous equivalent. S1 also exhibited 87.43% β-carotene bleaching inhibition as comparable to standard butylated hydroxytoluene with 98.85% inhibition. Substantial phenolic and flavonoid content was also observed in S1 (136.83 μg gallic acid equivalent/g of extract and 76.67 μg quercetin equivalent/g of extract, respectively). S1 could provide 61.73% and 53.27% protection of RBC membrane in hypotonicity and heat induced lysis of RBC, respectively while the standard diclofenac sodium provided 91.66% and 86.66% protection, respectively. Furthermore, 44.16% reduction in mice paw edema at 40 μg/kg bw concentration was observed in S1 as compared to standard indomethacine (53.54% in 10 μg/kg bw concentration). The results revealed that the bark extract (S1) of H. fomespossesses significant antioxidant and anti-inflammatory activity.