In vitro antioxidant and antimicrobial activity of Prunus africana (Hook. f.) Kalkman (bark extracts) and Harrisonia abyssinica Oliv. extracts (bark extracts): A comparative study

Abstract

Background: Plants are new sources of antibacterial agents, hence the need to determine and evaluate the antibacterial properties, antioxidant activity and gas chromatography – mass spectrometer (GC-MS) profile of medicinal plants. Methodology: In this study, sequential extraction of Prunus africana and Harrisonia abyssinica was used to obtain ethyl acetate and methanol extracts. Antioxidant activity was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH), whereas the total phenolic and total flavonoid contents were estimated using Folin-Ciocalteu and aluminium chloride, respectively. Antibacterial properties of the extracts against Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, Escherichia coliand Candida albicans were estimated using the disc diffusion method and compared against streptomycin. Results: Screening of crude methanolic extracts revealed the presence of secondary metabolites which was further confirmed by Fourier transform infrared (FT-IR) characterisation that revealed the presence of H-bonded OH functional groups. The extracts revealed that P. africana had a higher total phenolic and total flavonoid contents compared to H. abyssinica. Methanolic extracts of both plants had moderate activity against selected microorganisms and both inhibited DPPH radical scavenging activity. GC-MS analysis of P. africana and H. abyssinica extracts revealed the presence of several phytochemicals that have been reported to have medicinal uses. Total phenolic and flavonoid contents showed positive correlations with the DPPH radical scavenging activity and negative correlations with EC50. Conclusion: Prunus africana and H. abyssinica extracts had moderate antimicrobial properties against the selected microorganisms because of the presence of secondary metabolites.

Effect of Indigenous and Introduced Arbuscular Mycorrhizal Fungi on Growth and Phytochemical Content of Vegetatively Propagated Prunus africana (Hook. f.) Kalkman Provenances

“…The listed properties of P. africana barks are attributed to different types of phytochemical compounds. Our study targeted three phytochemical compounds namely tannins, flavonoids and phenols; tannins in P. africana have been reported to be having antimicrobial and antioxidant properties [50]. We observed no significant difference between treatments on the tannins content, except the treatment MM which shows a higher concentration.…”

“…Previous reports and/or studies have mentioned the presence of this group of phytochemical compounds in P. africana extracts [5,51]. Also known to have antioxidant activities, phenol, especially flavonoids play a key role in management of prostate conditions [50,[52][53][54]. The flavonoid and total phenol contents were significantly higher in CT compared to other mycorrhizal treatments.…”

Synthesis and Characterization of Silver Nanoparticles from Ethanolic Extracts of Leaves of Annona muricata: A Green Nanobiotechnology Approach

“…The 13 mm KBr pellets were prepared in a standard device under a pressure of 75 kN cm -2 for 3 min. The spectral resolution was set at 4 cm -1 and the scanning range from 400 to 4000 cm -1 [56]. The representative FTIR spectra of the recovered and dried AgNPs synthesized from ethanolic extracts of fruits of Annona muricata were recorded and the major and minor peaks were manifested and identified accordingly.…”

Synthesis and characterization of dialdehyde cellulose nanofibers from O. sativa husks

“…The pellets were prepared in a standard device under a pressure of 75 kN/cm 2 for 3 min. The spectral resolution was set at 4 cm −1 and the scanning range from 400 to 4000 cm −1 [23,24]. The crystallinity index of the oxidized fibers was identified using STOE STADIP P X-ray Powder Diffraction System (STOE & Cie GmbH, Darmstadt, Germany).…”