Marcela Escobar

Leaves of Persea americana Mill. are a potential source of bioactive compounds; however, current knowledge is limited by the lack of studies that simultaneously evaluate multiple cultivars and leaf developmental stages under comparable field conditions, as well as by inconsistent sampling criteria across studies. This study aimed to assess how leaf developmental stage and cultivar influence phenolic composition and antioxidant activity in avocado leaves grown under field conditions. Total polyphenols, total flavonoids, quercetin-3-O-galactoside, and chlorogenic acid were selected as representative compounds due to their relevance in plant defense and antioxidant capacity. These compounds, together with antioxidant activity, were quantified in young expanding (E1) and fully expanded (E6) leaves of seven avocado cultivars using spectrophotometric methods and HPLC-DAD, and analyzed through two-way ANOVA. Results showed that leaf developmental stage significantly influenced flavonoid content, chlorogenic acid, and antioxidant activity, which were consistently higher in E1 leaves. In contrast, total polyphenol content exhibited cultivar-dependent responses, increasing toward E6 only in specific genotypes, while quercetin-3-O-galactoside remained stable across developmental stages but varied among cultivars. Overall, the results indicate that phenolic metabolism in avocado leaves is regulated by both developmental stage and genotype in a compound-specific manner, with no consistent pattern associated with racial background. From a practical perspective, these findings provide a basis for selecting leaf material according to the intended application: young leaves for higher antioxidant capacity and flavonoid content, and specific cultivars at advanced stages for higher total polyphenol accumulation, supporting the functional valorization of avocado leaves as a source of bioactive compounds.

Gonadotropin-releasing hormone (GnRH) is one of the most fascinating neuroendocrine peptides: It is essential for maintaining the reproductive state of vertebrates and also displays high sequence homology to the tridecapeptide mating pheromone of the yeast, S. cerevisiae . In spite of its highly conserved role in vertebrate reproduction, recent studies in zebrafish show that the loss of function of genes encoding Gnrh isoforms does not cause infertility. Here we first investigated whether Phoenixin, a novel peptide acting in the reproductive pathway of vertebrates, is the hormone that has replaced Gnrh in zebrafish. While loss of function of the phoenixin gene affected female differentiation, we observed no defects in fertility. We next reconsidered the GnRH pathway and turned to the natural world, where fishes use waterborne hormones to control reproduction. Thus, we investigated whether exogenous Gnrh affects the hypothalamic-pituitary axis. Here we show that fish isolated from their conspecifics and kept in artificial water devoid of fish odors, mounted sex–appropriate pituitary responses when Gnrh was added to the water. Furthermore, blocking the access of water to the olfactory organs eliminated these responses. We then analyzed Gnrh signaling by knocking out the gene encoding gnrh-receptor3 ( gnrh-r3 ) and, surprisingly, found that fish homozygous for a gnrh-r3 null mutation were almost completely infertile: males did not produce sperm and females produced but a few mature oocytes. Finally, we found that Gnrh was present in nanomolar concentrations in the water that houses the fish, thus supporting the hypothesis that waterborne Gnrh from conspecifics plays a key role in regulating zebrafish reproduction in the absence of the endogenous ligand.

Integrating traditional herbal extracts into modern biomaterials offers a promising route for advanced wound care. A standardized Buddleja globosa Hope extract (BG-126), recognized for its therapeutic value, was incorporated into polymeric scaffolds with variable composition to explore their potential in promoting wound healing and controlling infections. This work aimed to identify the polymeric composition of a scaffold with BG-126 that maximizes its compatibility and antimicrobial properties. Scaffolds were developed by lyophilization using a Box–Behnken design (BBD) with chitosan, hyaluronic acid, and gelatin content as study factors. Thirteen scaffold formulations were tested for their antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa, including biofilm forms, as well as for their biocompatibility with normal human fibroblasts. Structural and physical properties, such as the moisture content and swelling capacity, were evaluated. The best-performing scaffold was analyzed using Raman spectroscopy. The chitosan content was strongly associated with antimicrobial efficacy, while gelatin enhanced fibroblast compatibility (R² ≥ 0.9). No correlations were identified between the polymeric content and biofilm inhibition or physical properties. BG-126-loaded scaffolds reduced planktonic and biofilm proliferation and improved fibroblast compatibility compared to the control scaffold (without BG-126). The results support the rational design of botanical-loaded scaffolds with targeted properties for wound healing.