Antimicrobial activity in Asterceae: The selected genera characterization and against multidrug resistance bacteria

Glucose Uptake-Stimulating Metabolites from Aerial Parts of Centaurea sicula

A comprehensive phytochemical investigation of aerial parts obtained from Centaurea sicula L. led to the isolation of 14 terpenoids (1-14) and nine polyphenols (15-23). The sesquiterpenoid group (1-11) included three structural families, namely, elemanolides (1-6), eudesmanolides (7 and 8), and germacranolides (9-11) with four unreported secondary metabolites (5-8), whose structure has been determined by extensive spectroscopic analysis, including 1D/2D NMR, HR-MS, and chemical conversion. Moreover, an unprecedented alkaloid, named siculamide (24), was structurally characterized, and a possible biogenetic origin was postulated. Inspired by the traditional use of the plant and in the frame of ongoing research on compounds with potential activity on metabolic syndrome, all the isolated compounds were evaluated for their stimulation of glucose uptake, disclosing remarkable activity for dihydrocnicin (10) and the lignan salicifoliol (15).

A comprehensive review on Moringa oleifera nanoparticles: importance of polyphenols in nanoparticle synthesis, nanoparticle efficacy and their applications

Moringa oleifera is one of the popular functional foods that has been tremendously exploited for synthesis of a vast majority of metal nanoparticles (NPs). The diverse secondary metabolites present in this plant turn it into a green tool for synthesis of different NPs with various biological activities. In this review, we discussed different types of NPs including silver, gold, titanium oxide, iron oxide, and zinc oxide NPs produced from the extract of different parts of M. oleifera. Different parts of M. oleifera take a role as the reducing, stabilizing, capping agent, and depending on the source of extract, the color of solution changes within NP synthesis. We highlighted the role of polyphenols in the synthesis of NPs among major constituents of M. oleifera extract. The different synthesis methods that could lead to the formation of various sizes and shapes of NPs and play crucial role in biomedical application were critically discussed. We further debated the mechanism of interaction of NPs with various sizes and shapes with the cells, and further their clearance from the body. The application of NPs made from M. oleifera extract as anticancer, antimicrobial, wound healing, and water treatment agent were also discussed. Small NPs show better antimicrobial activity, while they can be easily cleared from the body through the kidney. In contrast, large NPs are taken by the mono nuclear phagocyte system (MPS) cells. In case of shape, the NPs with spherical shape penetrate into the bacteria, and show stronger antibacterial activity compared to the NPs with other shapes. Finally, this review aims to correlate the key characteristics of NPs made from M. oleifera extract, such as size and shape, to their interactions with the cells for designing and engineering them for bio-applications and especially for therapeutic purposes.

The chemical composition of the aerial parts essential oils of Centaurea erycina (Asteraceae), an endemic species of Sicily (Italy)

In the present study, the chemical composition of the essential oil from aerial parts of a very rare Centaurea species, not previously investigated, Centaurea erycina Raimondo and Bancheva, collected in Sicily, was evaluated by GC-MS. The new species, classified just twenty years ago, belongs to Centaurea cineraria group (sect. Pannophyllum Hayek, Asteraceae) and grows in an extremely limited area in the NW part of Sicily. The oil was shown to be rich of aldehydes (41.4%) and sesquiterpenes (33.4%). The main components of the essential oil were β-caryophyllene (13.4%), caryophyllene oxide (12.6%), hexanal (11.9%), and trans-2-hexenal (10.0%). Furthermore, a complete literature review on the composition of the essential oils of all the other taxa of Centaurea, belonging to sections Pannophyllum, studied so far, was carried out.

Centaurea polyacantha and C. maroccana: the chemical composition of the aerial parts essential oils of these Centaurea species (Asteraceae) collected in Morocco

In the present study, the chemical composition of the essential oil from the aerial parts of two Centaurea species not previously investigated, C. polyacantha Willd. (sect. Seridia, Asteraceae) and C. maroccana Ball. (sect. Calcitrapa, Asteraceae), collected in Morocco, was evaluated by GC-MS. The main components of the essential oil of the first one were limonene (18.2%), β-bisabolene (11.5%), (Z)-β-farnesene (8.6%), and spathulenol (8.3%), whereas the C. maroccana essential oil, practically devoid of terpenoids, was shown to be rich in some unusual Centaurea metabolites: 1-hexadecanol (24.9%), docosane (23.7%), and 1-octadecanol (19.5%). Furthermore, a complete literature review on the composition of the essential oils of all the other taxa of Centaurea, belonging to sections Seridia and Calcitrapa, studied so far, was performed.