Antimicrobial Activity and Chemical Constitution of the Crude, Phenolic-Rich Extracts of Hibiscus sabdariffa, Brassica oleracea and Beta vulgaris

Abstract

Crude, phenolic-rich extracts (CPREs) were isolated from different sources, such as Hibiscus sabdariffa (H. sabdariffa), Brassica oleracea var. capitata f. rubra (B. oleracea) and Beta vulgaris (B. vulgaris) and characterized. These CPREs showed potential antibacterial and antifungal activities. H. sabdariffa CPRE (HCPRE) is the most potent, as it inhibited all tested bacteria and fungi. Total anthocyanins content (TAC), total phenolic content (TPC) and total flavonoid content (TFC) were estimated in all three CPREs. H. sabdariffa contained 4.2 mg/100 g TAC, 2000 mg/100 g of TPC and 430 mg/100 g of TFC in a dry weight sample. GC–MS analysis of HCPRE showed 10 different active compounds that have antimicrobial effects against pathogenic bacteria and fungi, especially alcoholic compounds, triazine derivatives and esters. Scanning and transmission electron microscopy images of Staphylococcus aureus DSM 1104 and Klebsiella pneumonia ATCC 43816 treated with HCPRE (50 μg/mL) exhibited signs of asymmetric, wrinkled exterior surfaces, cell deformations and loss of cell shapes; and adherence of lysed cell content led to cell clumping, malformations, blisters, cell depressions and diminished cell numbers. This indicates death of bacterial cells and loss of cell contents. Aspergillus ochraceus EMCC516 (A. ochraceus, when treated with 100 μg/mL of HCPRE showed irregular cell organelles and cell vacuolation.

Identification and Testing of Antidermatophytic Oxaborole-6-Benzene Sulphonamide Derivative (OXBS) from Streptomyces atrovirens KM192347 Isolated from Soil

“…differs according to both solvents used and chemical nature of the antifungal agent produced [43]. These results support previous studies in this respect [44].…”

“…Streptomycete isolates were inoculated as spore suspension onto starch nitrate agar media and incubated at 30 • C for 14 days. An agar cylinders (8mm) were cut out by a sterile metallic cork borer and transferred over dermatophyte selective medium (soybean dextrose agar) that were pre-seeded with the indicator dermatophytes [44,54]. Plates were kept at 4 • C for 4 h to allow the diffusion of fungal metabolites, then incubated at 28 • C for three weeks.…”

Inhibition of Staphylococcus aureus LC 554891 by Moringa oleifera Seed Extract either Singly or in Combination with Antibiotics

“…Therefore, the identification of these bacteria was carried out by API kits (Biomerieux, Montalieu-Vercieu, France), which approved that the 18 presumptive S. aureus bacteria belong to S. aureus . These API-identification kits were used successfully for bacterial identification [ 8 , 10 , 11 ]. Identification of bacteria using API-kits is a well-established method for characterization and classification of bacteria to the species level as API-strips give accurate identification based on standardized extensive database (APIWEB TM serve) in safe and quick procedures as provided by Biomereux Company (Montaliea, France) [ 1 , 8 , 10 ].…”

“…It is necessary to investigate those plants to improve the quality of healthcare. The novel antimicrobial compounds from essential oils are potential inhibitors against bacterial pathogens [ 10 ].…”

“…Therefore, inhibition of S. aureus by other alternatives is mandatory. In this regard, plant extracts are used nowadays, Moringa oleifera extracts of either leaves or seeds inhibited different pathogenic bacteria in vitro, HB and garlic extracts are used also as an antibacterial agent [ 9 , 10 , 11 ]. This is to concur with the international interest to inhibit the multidrug resistant bacteria, in general, and S. aureus in particular.…”