Isolation and Antimicrobial Activities of Phytochemicals from Parinari curatellifolia (Chrysobalanaceae)

Enrichment of Cookies with Fruits and Their By-Products: Chemical Composition, Antioxidant Properties, and Sensory Changes

Cookies made from wheat have become increasingly popular as a snack due to their various advantages, such as their convenience as a ready-to-eat and easily storable food item, wide availability in different types, and affordability. Especially in recent years, there has been a trend towards enriching food with fruit additives, which increase the health-promoting properties of the products. The aim of this study was to examine current trends in fortifying cookies with fruits and their byproducts, with a particular focus on the changes in chemical composition, antioxidant properties, and sensory attributes. As indicated by the results of studies, the incorporation of powdered fruits and fruit byproducts into cookies helps to increase their fiber and mineral content. Most importantly, it significantly enhances the nutraceutical potential of the products by adding phenolic compounds with high antioxidant capacity. Enriching shortbread cookies is a challenge for both researchers and producers because the type of fruit additive and level of substitution can diversely affect sensory attributes of cookies such as color, texture, flavor, and taste, which have an impact on consumer acceptability.

Isolation of Bioactive Compounds, Antibacterial Activity, and Action Mechanism of Spore Powder From Aspergillus niger xj

Aspergillus fungi can produce a wide range of secondary metabolites, and they have represented a potential resource of novel bioactive compounds. Bacterial plant diseases have a serious impact on the sustainable development of agriculture worldwide, so it is necessary to use natural antibacterial compounds in microorganisms to control plant pathogens. This study was conducted to investigate the bioactive compounds of Aspergillus niger xj, three plant pathogens (Agrobacterium tumefaciens T-37, Erwinia carotovora EC-1, and Ralstonia solanacearum RS-2) were used as indicator bacteria, according to the biological activity tracking, five compounds were isolated from A. niger xj spore powder, and characterization of compounds was done by NMR (1H-NMR and 13C-NMR) and EI-MS and was identified as ergosterol (1), β-sitosterol (2), 5-pentadecylresorcinol (3), 5-hydroxymethyl-2-furancarboxylic acid (4), and succinimide (5). Compounds 3 and 5 were isolated from A. niger xj for the first time. The minimum inhibitory concentration (MIC) of five compounds against three plant pathogens was evaluated, the results showed that compound 4 exhibited the strongest antibacterial activity against tested bacteria, and RS-2 was the most sensitive to compound 4, showing the lowest MIC of 15.56 μg/ml. We concluded that the mechanism of action of the compound 4 against RS-2 might be described as compound 4 acting on bacterial protein synthesis and intracellular metabolism according to the results of the scanning electron microscopy observation, permeability of cell membrane and SDS-PAGE. These results indicated that compound 4 has good potential to be as a biocontrol agent. In conclusion, the results from this study demonstrated that the compounds with antibacterial activity are of great significance of the prevention and control of plant phytopathogenic bacteria, and they may be applicable to exploring alternative approaches to integrated control of phytopathogens.

Antibacterial activity of β-sitosterol isolated from the leaves of Odontonema strictum (Acanthaceae)

The observation of a dog eating the roots of Odontonema strictum in 2008 in Lubumbashi (DR. Congo) was the starting point of this research which later led to the isolation of β-sitosterol (BSL), a known phytosterol, isolated for the first time from the leaves of this tropical plant which has a large range of medicinal properties including anti-inflammation, anti-hypertension and antibacterial. The analysis of the ¹H NMR spectrum showed that the active compound contains 60% of BSL and 40% of stigmasterol. With a melting point (m.p.) of 134-136 °C and the R_f value 0.55 in EtOAc-hexane (1:3) on silica gel TLC, the active compound was confirmed to be BSL. Here, we determined the minimal inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of BSL on Staphylococcus aureus by the broth dilution method. The MIC and MBC were found to be 1.24 mg/mL and 2.208 mg/mL, respectively. For the crude extract, the MIC and MBC were 4.33 mg/mL and the MBC was 7.66 mg/mL, respectively. The Total antibacterial activity underlined the fact that the crude extract from 1 g of plant materials could be diluted 65 times and still retains the ability to inhibit the growth of S. aureus. This is the first report of the antibacterial activity of BSL from this plant.