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Mankind is facing an unprecedented threat of existence due to the antibiotic resistance developed by bacteria. The unripe fruits of Diospyros malabarica (Desr.) Kostel. (family: Ebenaceae) can be considered as one of the natural sources to tackle this issue. The present study is designed to assess the antimicrobial activity of D. malabarica seed and flesh ex-tracts. Herein, D. malabarica extracts were prepared using polar solvents (i.e., water and 70% ethanol) and their antimicrobial activity as well as in vivo toxicity was investigated. Their antibacterial activity was investigated against gram positive (Bacillus subtilis) and gram negative (Escherichia coli DH5α, and Salmonella typhi) bacteria at different time points. All the extracts showed the highest antibacterial activity after 2 hours of incubation. The aqueous seed extract showed the maximum zone of inhibition (i.e., ~13 mm) against Bacillus subtilis with a minimum inhibitory concentration (MIC) value of 2 μg/μl. The an-tibacterial propensity was also confirmed through trypan blue dye exclusion assay, CellToxTM Green assay, and lipid peroxidation (LPO) assay. On the other hand, the etha-nolic seed extract demonstrated higher antifungal activity through inhibition of mycelial growth. All the extracts showed excellent hemocompatibility against both human and rat red blood cells (RBCs). They also did not show any toxicity to rat liver and kidneys. Taken together, this study demonstrates that the aqueous and ethanolic extracts of D. malabarica seed and flesh could be an effective source of natural antimicrobial agents with no cytotox-ic activity.

Among metallic nanoparticles, silver nanoparticles (AgNPs) have a wide spectrum of medical applications. Herein, biogenic silver nanoparticles (bAgNPs) were prepared from extracts of Caesalpinia di...

Among metallic nanoparticles, silver nanoparticles (AgNPs) have a wide spectrum of medical applications. Herein, biogenic silver nanoparticles (bAgNPs) were prepared from extracts of

Diospyros malabarica (Deshi Gab) belonging to the family “Ebenaceae” grows well in the humid tropical climate of Bangladesh. In order to investigate the phytoconstituents both qualitatively and quantitatively, the seed and flesh extracts of D. malabarica were prepared using two polar solvents (i.e., water and 70% ethanol) and a nonpolar solvent (i.e., hexane). The maximum yield was obtained for aqueous and ethanolic seed extracts indicating that most of the phytoconstituents present in D. malabarica fruit are polar. The qualitative phytochemical analysis of the extracts revealed the presence of diverse amount of phytoconstituents in the extracts. On the other hand, the quantitative phytochemical analysis for phenols, tannins, flavonoids, alkaloids, saponin, proteins, reducing sugar and vitamin C revealed that the maximum amount of phenols, tannins, flavonoids and reducing sugar were present in aqueous seed extract. However, the maximum amount of total protein and vitamin C was found in ethanolic seed extract. D. malabarica seed powder contained more amount of alkaloids (i.e., 13.6%) than that of flesh (i.e., 3.4%). However, the content of saponin was more in flesh extract (0.74%) when compared to that of seed extract (0.42%). In vitro antioxidant properties of the extracts were also investigated by DPPH free radical scavenging assay, FRAP assay and reducing power assay. The highest antioxidant activity was observed for aqueous seed extract followed by the ethanolic seed, ethanolic flesh, and aqueous flesh extracts. The lowest antioxidant activity was obtained for hexane flesh extract. Furthermore, the lowest (i.e., 44.70 μg/ml) as well as the highest (2359.66 μg/ml) IC50 values were obtained for aqueous seed and hexane flesh extracts, respectively.

Biogenic nanoparticles are the smartest weapons to deal with the multidrug-resistant “superbugs” because of their broad-spectrum antibacterial propensity as well as excellent biocompatibility. The aqueous biogenic silver nanoparticles (Aq-bAgNPs) and ethanolic biogenic silver nanoparticles (Et-bAgNPs) were synthesized using aqueous and ethanolic extracts of Andrographis paniculata stem, respectively, as reducing agents. Electron microscopic images confirmed the synthesis of almost spherical shaped biogenic silver nanoparticles (bAgNPs). The zeta potentials of the nanoparticles were negative and were −22 and −26 mV for Aq-bAgNPs and Et-bAgNPs, respectively. The antibacterial activity of bAgNPs was investigated against seven pathogenic (i.e., enteropathogenic Escherichia coli, Salmonella typhi, Staphylococcus aureus, Vibrio cholerae, Enterococcus faecalis, Hafnia alvei, Acinetobacter baumannii) and three nonpathogenic (i.e., E. coli DH5α, E. coli K12, and Bacillus subtilis) bacteria at different time points (i.e., 12, 16, 20, and 24 h) in a dose-dependent manner (i.e., 20, 40, and 60 μg) through broth dilution assay, disk diffusion assay, CellToxTM Green uptake assay, and trypan blue dye exclusion assay. The lowest minimum inhibitory concentration value for both the bAgNPs was 0.125 μg. Et-bAgNPs showed the highest antibacterial activity against S. aureus at 60 μg after 16 h and the diameter of inhibited zone was 28 mm. Lipid peroxidation assay using all the bacterial strains revealed the formation of malondialdehyde–thiobarbituric acid adduct due to the oxidation of cell membrane fatty acids by bAgNPs. The bAgNPs showed excellent hemocompatibility against human as well as rat red blood cells. Furthermore, there was no significant toxicity observed when the levels of rat serum ALT, AST, γ-GT (i.e., liver function biomarkers), and creatinine (i.e., kidney function biomarker) were determined.