Design of composite microparticle systems based on pectin and waste material of propolis for modified l-alanyl-l-glutamine release and with immunostimulant activity

Tolerability of glutamine supplementation in older adults: a double-blind placebo-controlled randomized clinical trial

In this double-blind placebo-controlled randomized investigation, we assessed the tolerability of glutamine in older adults recruited from three daycare centers. The relevance of studying glutamine supplementation in elderly patients lies in its potential to provide a well-tolerated intervention. Glutamine, a crucial amino acid, plays a vital role in various physiological processes, including immune function and protein synthesis. Understanding its impact on older adults is essential, given the potential implications for their health and well-being. Participants received a daily dose of 12.4 g of oral effervescent glutamine (EGln group) or maltodextrin (placebo group) for 60 days. Fifteen patients from each group completed the study. The mean ages were 77.0±9.1 and 79.0±6.9 years for the EGln and placebo groups, respectively. We evaluated body mass index, aminogram, hemogram, plasma levels of glucose, prealbumin, albumin, urea, creatinine, uric acid, C-reactive protein, vitamin D, calcium, sodium, potassium, and the plasma activities of aspartate aminotransferase and alanine aminotransferase. Notably, we quantified a broad array of inflammatory markers and growth factors providing a holistic understanding of the potential effects of glutamine supplementation. The results demonstrated that oral glutamine did not induce significant changes in any evaluated parameters, and no adverse effects were reported. This finding suggested that the dosage of glutamine used in this study was well-tolerated and safe. This information contributes to the broader understanding of glutamine supplementation, emphasizing its safety and supporting its potential as a viable intervention for maintaining health in aging individuals.

Clean Production of l-Alanyl-l-glutamine by an Efficient Yeast Biocatalyst Expressing α-Amino Acid Ester Acyltransferase without N-Glycosylation

l-Alanyl-l-glutamine (Ala-Gln) is a widely used value-added dipeptide whose production relies heavily upon an efficient biocatalyst. The currently available yeast biocatalysts that express α-amino acid ester acyltransferase (SsAet) possess relatively low activity, which may be attributed to glycosylation. Here, to promote SsAet activity in yeast, we identified the N-glycosylation site as the Asn residue at position 442 and subsequently eliminated the negative effect of N-glycosylation on SsAet by removing artificial and native signal peptides to obtain K3A1, a novel yeast biocatalyst with significantly improved activity. Additionally, the optimal reaction conditions of strain K3A1 were determined (25 °C, pH 8.5, AlaOMe/Gln = 1:2), resulting in a maximum molar yield and productivity of approximately 80% and 1.74 g·(L·min)^-1, respectively. Therefore, we developed a promising system to cleanly produce Ala-Gln in a safe, efficient, and sustainable manner, which may contribute to the future industrial production of Ala-Gln.

Design and characterization of polymeric microneedles containing extracts of Brazilian green propolis

Microneedles (MNs) are a means to break the protective skin barrier in a minimally invasive way. By creating temporary micropores, they make biologically active agents available in the skin layers. Propolis (PRP) is a gum resin with a complex chemical composition, produced by bees Apis mellifera L. and showing several therapeutic properties (i.e., antibacterial, antiviral, antifungal, anti-inflammatory, healing, and immunomodulatory properties). The administration of PRP extracts by conventional routes has some disadvantages, such as running off over the skin in liquid or emulsion form. When taken orally, the extracts have a strong and unpleasant taste. The aim of this work was to fabricate and characterize microneedles containing polyvinyl alcohol, polyvinylpyrrolidone, poloxamer P407, and an ethanolic or glycolic extract of PRP. Also, the obtained structures were microscopically and mechanically characterized. The results of the mechanical analysis showed that formulations containing 3% of P407 presented the highest compression values in a hard surface, which was also confirmed by the height and base values of the morphological analysis and by the microscopy images. It was possible to design MNs and select the best formulations for future tests. MNs containing an ethanolic extract of PRP showed to be better structured than MNs containing a glycolic extract of PRP. The MNs obtained in these studies proved to be a promising platform for the topical application of PRP.

Effervescent Glutamine Formulation Improves the Beneficial Effects of Antiretroviral Therapies on Immune Function in HIV/AIDS Carrier Patients

The impact of oral supplementation with an effervescent glutamine formulation on the beneficial effects of antiretroviral therapies was evaluated in people living with HIV/AIDS. For this purpose, 12 HIV/AIDS carrier patients with CD4⁺ T cell counts <500, and who had received the same antiretroviral therapy for at least 1 year before starting this investigation were selected. The patients were required to dissolve the effervescent glutamine formulation (supplied in sachets) in water immediately before oral ingestion (12.4 g), once a day, after lunch or after dinner during 30 days. CD4⁺ T cell counts, complete blood cell counts, serum cytokines, and amino acids levels were quantified; biochemical and toxicological measurements were performed. The numbers of CD4⁺ T cells were increased (P < .05), and the serum C-reactive protein levels decreased (P < .01) after the administration of effervescent glutamine formulation. Serum levels of interferon-gamma inducible protein-10, RANTES, and macrophage inflammatory protein-1β were decreased after the treatment with effervescent glutamine formulation. No changes were observed in the serum levels of amino acids, hematological, toxicological, and biochemical parameters. In conclusion, the treatment during 30 days with effervescent glutamine formulation was well tolerated, promoted reduction of inflammation, and improved the beneficial effects of antiretroviral therapies in HIV/AIDS carrier patients.

Biological Activity and Pharmacological Application of Pectic Polysaccharides: A Review

Pectin is a polymer with a core of alternating α-1,4-linked d-galacturonic acid and α-1,2-l-rhamnose units, as well as a variety of neutral sugars such as arabinose, galactose, and lesser amounts of other sugars. Currently, native pectins have been compared to modified ones due to the development of natural medicines and health products. In this review, the results of a study of the bioactivity of pectic polysaccharides, including its various pharmacological applications, such as its immunoregulatory, anti-inflammatory, hypoglycemic, antibacterial, antioxidant and antitumor activities, have been summarized. The potential of pectins to contribute to the enhancement of drug delivery systems has been observed.