Daniel Zaragoza-Puchol

Larrea ameghinoi Speg., an endemic species of Argentine Patagonia traditionally used in folk medicine to treat fever, stomach disorders, respiratory conditions, back pain, and as an emmenagogue, among others, still remains chemically and biologically underexplored compared to the other four members of the genus. This study aimed to perform a comprehensive metabolomic characterization of methanolic extracts from two populations (EMLaSAO and EMLaMAQ) using ultra-high-resolution liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (UHPLC–ESI–QTOF–MS) and to evaluate their antioxidant, antimicrobial, and enzyme-inhibitory activities of relevance to human health. Thirty-three compounds were tentatively identified by extensive UHPLC–MS analysis, including flavones, two major lignans, and oleanane-type triterpenes. Both extracts exhibited high phenolic content (215–239 mg of gallic acid equivalents (GAE)/g extract) and strong free radical scavenging activity, as evidenced by 2,2-diphenyl-1-picrylhydrazyl (DPPH, EC₅₀ ≈ 10 μg/mL), ferric-reducing antioxidant power (FRAP), and Trolox equivalent antioxidant activity (TEAC) assays. In addition, significant inhibition of butyrylcholinesterase (IC₅₀ ≈ 50 μg extract/mL) and α-glucosidase, together with selective antibacterial activity against methicillin-sensitive and resistant Staphylococcus aureus (MIC = 125 μg extract/mL), were recorded. These findings suggest that L. ameghinoi possesses a distinctive phytochemical composition conferring multitarget bioactivity, differing from other Larrea species dominated by lignans such as nordihydroguaiaretic acid (NDGA) and its derivatives. Overall, this work supports the potential of L. ameghinoi as a novel source of bioactive metabolites for managing oxidative stress-related disorders and opportunistic infections. This warrants future in vivo studies investigating biological activities associated with oxidative stress and their relevance to human health.

In this work, a decoction (DOe) and a methanolic global extract (MGEOe), obtained with the aerial parts of Oxalis erythrorhiza Gillies ex Hooker et Arnott (Oxalidaceae), were evaluated. The high-resolution liquid chromatography in conjunction with electrospray ionization quadrupole time-of-flight mass spectrometry (UHPLC-ESI-QTOF-MS) analysis showed forty compounds in MGEOe and twenty-nine in DOe, including flavones, C-glycosyl flavones, isoflavones, fatty acids, terpenes, phenolic acids, and sterols. The antioxidant properties were evaluated by DPPH, TEAC, FRAP, and ILP assays. Both DOe and MGEOe showed stronger antioxidant activities. The anti-inflammatory effects were evaluated by COX inhibition method, where DOe demonstrated a significant inhibitory effect. The cytotoxic effects were evaluated in the tumoral HCT-116 and non-tumoral HBL-100 cell lines, revealing a selective action from DOe and MGOe on cancer cells. DOe was evaluated in an animal model of insulin resistance, which is characterized by alterations in glucose and lipid metabolism, as well as cognitive impairments, including anxiety-like behavior and memory deficits. Male SD rats received sucrose (10% w/v, SUC), a half dilution of DOe (5% w/v) with sucrose (HDOeS) or DOe with sucrose (DOeS) from PND21 to PND61. Then, anxiety-like behavior and spatial memory were assessed using the open field (OF), elevated plus maze (EPM) and the novel object location (NOL) tests, respectively. Serum parameters basal glycemia, total cholesterol (TC) and tryglicerides were measured using commercial kits. The lipid peroxidation was determined in homogenates of cerebral cortex, hippocampus and hypothalamus by TBAR assay. Only HDOeS exhibited lower anxiety-like behavior in OF and improved performance in NOL compared to SUC. Furthermore, DOeS showed reduced serum parameters, while HDOeS presented lower TC levels than SUC. No differences were observed on TBAR assay. The beneficial properties of these preparations could be attributed to the identified metabolites. These findings highlighted O. erythrorhiza as a potential source of compounds to improve human health; however, further research is required to elucidate its mechanisms of action.

Plants in the Amaryllidaceae family synthesize a diversity of bioactive alkaloids. Some of these plant species are not abundant and have a low natural multiplication rate. The aims of this work were the alkaloids analysis of a Habranthus cardenasianus bulbs extract, the evaluation of its inhibitory activity against cholinesterases, and to test several propagation strategies for biomass production. Eleven compounds were characterized by GC-MS in the alkaloid extract, which showed a relatively high proportion of tazettine. The known alkaloids tazettine, haemanthamine, and the epimer mixture haemanthidine/6-epi-haemanthidine were isolated and identified by spectroscopic methods. Inhibitory cholinesterases activity was not detected. Three forms of propagation were performed: bulb propagation from seed, cut-induced bulb division, and micropropagated bulbs. Finally, different imbibition and post-collection times were evaluated in seed germination assays. The best propagation method was cut-induced bulb division with longitudinal cuts into quarters (T1) while the best conditions for seed germination were 0-day of post-collection and two days of imbibition. The alkaloids analyses of the H. cardenasianus bulbs showed that they are a source of anti-tumoral alkaloids, especially pretazettine (tazettine) and T1 is a sustainable strategy for its propagation and domestication to produce bioactive alkaloids.

In this work, we report the synthesis of a series of derivatives of N-benzyl-2-phenylethanamine which is the framework of norbelladine, the natural common precursor of the Amaryllidaceae alkaloids. These compounds were assessed in the inhibition of both AChE and BChE which are the enzymes responsible for the breakdown of acetylcholine and hence they constitute targets in the palliative treatment of Alzheimer's disease. In particular, brominated derivatives exhibited the lowest IC₅₀ values against AChE. Interestingly, the presence of iodine in one of the aromatic rings highly increased the inhibition of BChE compared to its analogues, with an IC₅₀ value similar to that of galantamine, which is the reference compound currently used in the treatment of AD. A possible mechanism of action for these compounds was determined by molecular modeling studies using combined techniques of docking and molecular dynamics simulations.