Phytochemical Investigation and in vitro Antimicrobial and Antioxidant Activities Evaluation of Erianthemum aethiopicum Wiens and Polhill.

Background: Erianthemum aethiopicum Wiens and Polhill (Loranthaceae) is a parasitic plant native to north eastern Africa and Ethiopia. In Ethiopia, it is traditionally used to treat breast swelling, mastitis, morning illnesses and vomiting. Objective: This study aimed to screen the main phytochemical constituents; determine the total amounts of phenolics, flavonoids, and tannins; and evaluate the antimicrobial (against Escherichia coli, Staphylococcus sciuri, Candida glaebosa and Cryptococcus albidus) and antioxidant (against DPPH radical and ferric ion) activities of E. aethiopicum leaves extracts. Methods: Powdered E. aethiopicum leaves were macerated using n-hexane, chloroform, ethyl acetate, ethanol, and methanol. All crude extracts were qualitatively screened for phytochemical identification. The total phenolic, flavonoid, and condensed tannin contents of the chloroform, ethanol, and methanol extracts were determined by UV-Vis spectrophotometry. The n-hexane, chloroform, and methanol extracts were evaluated for their antimicrobial activity against the aforementioned microbes using agar disc diffusion and broth micro-dilution techniques. Chloroform, ethanol, and methanol extracts were also evaluated for antioxidant activity by DPPH and ferric ion reduction antioxidant power (FRAP) assays. Results: Methanol (17.56 ± 16%) and ethanol (16.45 ± 19%) showed better extraction efficiency. Flavonoids, polyphenols, tannins, terpenoids, saponins, and sterols were detected in all extracts. The highest total content of phenolics (22.63 ± 0.69 mgGAE/gDCE), flavonoids (5.38 ± 0.52 mgCE/gDCE) and tannins (39.18 ± 38 mg CE/g DCE), as milligram of gallic acid and catechin per gram of dried crude extract, were recorded in the methanolic extract. The methanolic extract also presented best anti -DPPH strength (IC50, 4.31 µg/mL) and ferric ion reduction power (absorbance of 0.71) though found weak compared to the ascorbic acid (IC50 of 0.49 µg/mL and absorbance of 0.93, respectively). Conclusion: All evaluated extracts displayed antifungal activity against both Cryptococcus albidus and Candida glaebosa strains (minimum inhibitory concentration values of 12.5-25 mg/mL), whereas they were found to have negligible activity against all tested bacterial strains. This report provides preliminary information for further phytochemical investigation of Erianthemum aethiopicum to isolate potential antioxidant and antifungal compounds.

Isolation, screening, and identification of chitinase-producing bacterial strains from riverbank soils at Ambo, Western Ethiopia.

Chitinases are hydrolytic enzymes that dissolve the glycosidic linkages in chitin. Chitin is a cell wall component of fungi and fund in exoskeleten of worms and arthropods. Chitinase has been applied in agriculture, as a biopesticide for the control of plant fungal infections, in medicine, and in waste management. This research aimed to isolate, screen, and identification of chitinase-producing bacteria from riverbank soils. Twenty nine chitinolytic bacteria were isolated from the river bank soil samples, from which 9 of them had strong chitinolytic properties. Chitinase production was determined by zones of hydrolysis produced after 96 h of incubation at 37 °C. The different bacterial isolates were characterized morphologically, microscopically, and biochemically and finally eight strain were identified at species level by Matrix Assisted Laser Desorption Ionization - Time of Flight Mass Spectrometry (MALDI-TOF MS). From the eight, bacterial isolates investigated in this study Stenotrophomonas maltophilia showed the highest chitinase enzyme activity (625 µg/mL) followed by Pseudomonas putida with the enzyme activity of (553 µg/mL) and the least enzyme activity was recorded for Lilliottia amnigena (80 µg/mL). An incubation temperature of 45 °C, neutral pH and an incubation period of 96 h are found to be the optimum condition for the chitinase enzyme production from Stenotrophomonas maltophilia. The results of this study indicated the possibility of the production of chitinase from the chitinolytic bacterial isolates, which was highly useful for a variety of applications, including biocontrol of harmful insects and pathogenic fungi as well as in the biochemical, pharmaceutical, and medical sectors.

Phytochemicals Analysis, In Vitro Antibacterial Activities of Extracts, and Molecular Docking Studies of the Isolated Compounds from Melhania zavattarii Cufod Leaves.

Melhania zavattarii Cufod is an endemic plant species to Ethiopia and is used to treat ailments related to kidney infection. The phytochemical composition and biological activity of M. zavattarii have been not reported yet. Therefore, the present work aimed to investigate phytochemical constituents and evaluate the antibacterial activity of different solvents' leaf extracts and analyze the molecular binding capacity of isolated compounds from the chloroform leaf extract of M. zavattarii. Accordingly, preliminary phytochemical screening was tested by using standard procedures and the result indicated that phytosterols and terpenoids as major and others like alkaloids, saponins, flavonoids, tannins, phlobatannin, and coumarins were detected as minor in extracts. Antibacterial activity of the extracts was evaluated using the disk diffusion agar method, and the activities revealed that chloroform extract showed the highest inhibition zones, 12.08 ± 0.38, 14.00 ± 0.50, and 15.58 ± 0.63 mm against Escherichia coli at 50, 75, and 125 mg/mL concentrations, respectively, compared to that of n-hexane and methanol extracts at respective concentrations. Methanol extract showed the highest zone of inhibition 16.42 + 0.52 against Staphylococcus aureus at 125 mg/mL concentration compared to that of n-hexane and chloroform extracts. Two compounds, namely, ß-amyrin palmitate (1) and lutein (2) were isolated and identified for the first time from the chloroform leaf extract of M. zavattarii, and structural elucidations of these compounds were accomplished by using spectroscopic methods (IR, UV, and NMR). For the molecular docking study, 1G2A, which is a protein of E. coli and chloramphenicol standard target, was selected. Binding energies of -9.09, -7.05, and -6.87 kcal/mol were calculated for ß-amyrin palmitate, lutein, and chloramphenicol, respectively. The drug-likeness property result indicated that both ß-amyrin palmitate and lutein violated two rules of Lipinski's rule of five with molecular weight (g/mol) > 500 and LogP > 4.15. In the near future, further phytochemical investigation and biological activity evaluation should be conducted on this plant.