Plants produce many secondary metabolites, which reveal biological activity

Background: Adansonia digitata L. (Malvaceae), also known as baobab, is a tree attracting recent interest especially due to the high nutritional value of the fruit pulp. However, few studies are reported on the secondary metabolite content, showing high variability depending on the geographic region. Methods: In this study, the chemical profiles of Malian commercial baobab fruits and leaves, focused on phenolic content, were investigated by HPLC coupled with a photodiode array (PDA)/UV and an electrospray ionization (ESI) mass spectrometer (MS) and gas chromatography (GC)/MS. In addition, the extracts of fruit pulps obtained from three different markets (Fruits 1, 2, and 3) were evaluated for their total phenolic content (TPC), antioxidant activity and α-glucosidase inhibition. Results: Baobab fruit pulps were found to be rich in procyanidins and flavonol glycosides, with tiliroside as the major constituent. The baobab leaves showed a similar profile respect to the fruits, but with more detected phenolics. All fruit pulp extracts exerted antioxidant activity (highest for Fruit 3) and higher α-glucosidase inhibition than acarbose used as standard. Conclusions: This study confirmed the variability of baobab with different origins and indicated Malian species baobab as a promising source of health-promoting substances.

The present study aimed to investigate the phytochemical profile of leaf methanol extracts of fourteen Smallanthus sonchifolius (yacon) landraces and their antioxidant, anticholinesterase and antidiabetic activities that could lead to the finding of more effective agents for the treatment and management of Alzheimer’s disease and diabetes. For this purpose, antioxidant activity was assessed using different tests: ferric reducing ability power (FRAP), 2,2-diphenyl-1-picryl hydrazyl (DPPH), nitric oxide (˙NO) and superoxide (O₂˙⁻) scavenging and lipid peroxidation inhibition assays. Anticholinesterase activity was investigated by quantifying the acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities, whereas antidiabetic activity was investigated by α-amylase and α-glucosidase inhibition tests. To understand the contribution of metabolites, phytochemical screening was also performed by high performance liquid chromatography-diode array detector (HPLC-DAD) system. Among all, methanol extract of PER09, PER04 and ECU44 landraces exhibited the highest relative antioxidant capacity index (RACI). ECU44 was found to be rich in 4,5-di-O-caffeoylquinic acid (CQA) and 3,5-di-O-CQA and displayed a good α-amylase and α-glucosidase inhibition, showing the lowest IC₅₀ values. Flavonoids, instead, seem to be involved in the AChE and BChE inhibition. The results of this study revealed that the bioactive compound content differences could be determinant for the medicinal properties of this plant especially for antioxidant and antidiabetic activities.

Today’s human society, product of decades of progress in all fields of knowledge, would have been unimaginable without the discovery of antibiotics and more generally of antimicrobials. However, from the beginning, the scientific community was aware that microorganisms through various strategies were able to hinder and render vain antibiotic action. Common examples are the phenomena of persistence, tolerance, and resistance, up to the creation of the feared bacterial biofilms. Antibiotics are a precious but equally labile resource that must be preserved but at the same time reinforced to safeguard their effectiveness. Nanoparticulate systems such as nanobactericides, with their inherent antibacterial activity, and nanocarriers, which operate as drug delivery systems for conventional antibiotics, are innovative therapies made available by nanotechnology. Inorganic nanoparticles are effective both as nanobactericides (AgNPs, ZnONPs, and TiO₂NPs) and as nanocarriers (AgNPs, AuNPs, ZnONPs, and TiO₂NPs) against sensitive and multi-drug-resistant bacterial strains. Liposomes are among the most studied and flexible antibiotic delivery platforms: conventional liposomes allow passive targeting at the mononuclear phagocytic system (MPS); “stealth” liposomes prevent macrophage uptake so as to eradicate infections in tissues and organs outside MPS; thanks to their positive charge, cationic liposomes interact preferentially with bacterial and biofilm surfaces, acting as innate antibacterials as well as drug delivery systems (DDS); fusogenic liposomes have fluid bilayers that promote fusion with microbial membranes; and finally, ligand-targeted liposomes provide active targeting at infection sites. Dendrimers are among the most recent and attractive nanoparticulate systems, thanks to their multibranched nanoarchitecture, which equipped them with multiple active sites for loading antibiotics and also interacting with bacteria. Finally, nanoantibiotics represent a new hopeful generation of antibiotic candidates capable of increasing or even restoring the clinical efficacy of “old” antibiotics rendered useless by the resistance phenomena.