In vitro-in vivo availability of metformin hydrochloride-PLGA nanoparticles in diabetic rats in a periodontal disease experimental model.

CONTEXT: Metformin is an important oral anti-hyperglycemic used in diabetes. Polylactic-co-glycolic acid (PLGA) has been widely used due to its reliability in controlling the release of drugs. OBJECTIVE: This study evaluates the in vitro-in vivo availability of metformin hydrochloride-loaded polylactic-co-glycolic acid. MATERIAL AND METHODS: In vitro metformin release (Met-free or PLGA + Met-12.5 mg/mL per 360 min) was evaluated using static Franz vertical diffusion cells. The in vivo study was performed with two control groups (validation bioanalytical method) and two experimental groups of diabetic male Wistar rats treated with PLGA + Met 10 mg/kg or Met 100 mg/kg by oral gavage. Diabetes was induced by streptozotocin (40 mg/kg) through the penile vein. Blood samples were collected 0.5, 1, 4, 7, 10, 12, 18, 24, 36, 48 and 72 h and analysed by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). RESULTS: PLGA + Met 10 mg/kg was released in the in vitro assay suggesting a parabolic diffusion kinetic model (K -0.0619-0.5h) with a 100% release profile in 10 h by controlled diffusion. The in vivo assay showed the apparent volume of distribution Vz/F (PLGA + Met 10 mg/kg, 40971.8 mL/kg vs. Met 100 mg/kg, 2174.58 mL/kg) and mean residence time MRTinf (PLGA + Met 10 mg/kg, 37.66 h vs. Met 100 mg/kg, 3.34 h). DISCUSSION AND CONCLUSIONS: The formulation modifies pharmacokinetics parameters such as apparent distribution volume and mean residence time. The PLGA + Met 10 mg/kg had a slower elimination rate compared to Met 100 mg/kg in diabetic rats in a periodontal disease experimental model.

Production and Characterization of Chitooligosaccharides: Evaluation of Acute Toxicity, Healing, and Anti-Inflammatory Actions.

The search for promising biomolecules such as chitooligosaccharides (COS) has increased due to the need for healing products that act efficiently, avoiding complications resulting from exacerbated inflammation. Therefore, this study aimed to produce COS in two stages of hydrolysis using chitosanases derived from Bacillus toyonensis. Additionally, this study aimed to structurally characterize the COS via mass spectrometry, to analyze their biocompatibility in acute toxicity models in vivo, to evaluate their healing action in a cell migration model in vitro, to analyze the anti-inflammatory activity in in vivo models of xylol-induced ear edema and zymosan-induced air pouch, and to assess the wound repair action in vivo. The structural characterization process pointed out the presence of hexamers. The in vitro and in vivo biocompatibility of COS was reaffirmed. The COS stimulated the fibroblast migration. In the in vivo inflammatory assays, COS showed an antiedematogenic response and significant reductions in leukocyte migration, cytokine release, and protein exudate. The COS healing effect in vivo was confirmed by the significant wound reduction after seven days of the experiment. These results indicated that the presence of hexamers influences the COS biological properties, which have potential uses in the pharmaceutical field due to their healing and anti-inflammatory action.

Isoquinoline alkaloids reduce beta-amyloid peptide toxicity in Caenorhabditis elegans.

Alzheimer's disease (AD) is a multifactorial health problem widespread over the world. Regarding the historical importance of the alkaloids in the central nervous system pharmacology they remain as promising drug candidates against AD. Seven alkaloids from Amaryllidaceae and Fabaceae were evaluated in vivo, in vitro and in silico targets related to the AD pathophysiology. Erythraline and erysodine showed the greatest potential compared to Memantine, a drug currently used in AD therapy, by delaying the Aß1-42-induced paralysis in the transgenic strain CL2006 Caenorhabditis elegans, an alternative model to assess the impairment of beta-amyloid peptide deposition. The in vitro inhibition of the acetylcholinesterase was observed for the first time for Erythrina alkaloids; however Lycorine was the most active. Docking simulation contributed to comprehend this potential by showing a hydrophobic interaction between acetylcholinesterase and Lycorine in the amino acid residue TRP 84 as well as hydrogen bonds with TRY 121 and ASP 72.

Mangaba (Hancornia speciosa Gomes) fruit juice decreases acute pulmonary edema induced by Tityus serrulatus venom: Potential application for auxiliary treatment of scorpion stings.

Scorpionism represents a serious public health problem due to its increasing incidence. In Brazil, Tityus serrulatus is a species of major medical importance, especially in children and the elderly, as envenomation may induce serious acute pulmonary edema. "Mangaba" (Hancornia speciosa Gomes) fruit juice is popularly used in the treatment of several inflammatory disorders. The objective of this study was to analyze the chemical composition of fruit juice of H. speciosa by HPLC-DAD-MS/MS, as well as to evaluate its anti-inflammatory potential and antioxidant activity, and analyze the biochemical and hematological parameters in acute pulmonary edema induced by T. serrulatus venom (TsV) in mice. Mice were challenged with TsV (30 µg/kg, subcutaneously) and were treated with dexamethasone (2 mg/kg, intraperitoneally) or fruit juice (pre- or post-treatment protocols, by intra-gastric route at 100 and 200 mg/kg), and 2 h later were anesthetized for blood, lung, and kidney collection, for several biochemical analyses. Results showed that the juice decreased edema, myeloperoxidase levels, vascular permeability, and production of cytokines (IL-1ß, IL-6, and TNF-α) in lung tissue. Also, the juice reduced the concentration of nitrite and malondialdehyde oxidative stress markers in renal tissue. Amylase, lactate dehydrogenase, aspartate aminotransferase, and creatine kinase seric levels were reduced when the animals were treated with the juice. HPLC-DAD-MS/MS analysis identified 13 phenolic derivatives. The results suggest that the juice was able to decrease the inflammatory effects induced by T. serrulatus, demonstrating that the use of juice can be relevant for the treatment of scorpion stings.

Local anti-inflammatory activity: Topical formulation containing Kalanchoe brasiliensis and Kalanchoe pinnata leaf aqueous extract.

Kalanchoe brasiliensis and Kalanchoe pinnata are used interchangeably in traditional medicine in the treatment of wound healing. In this context, the objective of the present study was to evaluate the local anti-inflammatory activity of a topical formulation containing aqueous extract of both species. The in vivo model used was ear edema induced by croton oil and paw edema induced by carrageenan. The Swiss mice treatments use formulations containing aqueous extract at different concentrations (1.25%, 2.5%, and 5%) or dexamethasone (1 mg/g), all administered topically and immediately after edema induction. The treatment with formulations containing aqueous extract of both species reduced ear and paw edema, besides that, the decrease in edema was evidenced by reduction of myeloperoxidase activity, IL-1ß, and TNF-α levels and increase IL-10 levels. In conclusion, the two species showed local anti-inflammatory activity; however K. brasiliensis showed a better result in both edematogenic models since it had activity in the lowest concentration.

Molecular basis of Tityus stigmurus alpha toxin and potassium channel kV1.2 interactions.

The Tityus stigmurus scorpion is widely distributed in the Northeast of Brazil and is the main causal agent of human envenoming. The venom produced by this scorpion includes neurotoxins, which are peptides belonging to Family 2 toxins and are able to interact with ion channels. The KTx subfamily displays selectivity and affinity for Kv channel subtypes and the result of this interaction is the blockade of potassium channels, impairing vital functions. We report the optimized structural model of a transcript encoding a potassium channel blocker toxin from T. stigmurus. LC-MS analysis confirmed the presence of the toxin in the venom and the three-dimensional structure was obtained by computational homology modeling and refined by molecular dynamic simulations. Furthermore, docking simulations were performed using a Shaker kV-1.2 potassium channel from rats as receptor model and the contacts were identified revealing which amino acid residues and interactions could be involved in its blockade. These residues were mapped and their contact and electrostatic interactions were evaluated revealing the influence of positive lysine residues and the additional contribution of an asparagine to the stabilization of the complex, bringing new insights into the mechanism of action of this toxin.

Isolation and Identification of the Five Novel Flavonoids from Genipa americana Leaves.

Genipa americana is a medicinal plant popularly known as "jenipapo", which occurs in Brazil and belongs to the Rubiaceae family. It is a species widely distributed in the tropical Central and South America, especially in the Cerrado biome. Their leaves and fruits are used as food and popularly in folk medicine to treat anemias, as an antidiarrheal, and anti-syphilitic. Iridoids are the main secondary metabolites described from G. americana, but few studies have been conducted with their leaves. In this study, the aim was to chemical approach for identify the main compounds present at the extract of G. americana leaves. The powdered leaves were extracted by maceration with EtOH: water (70:30, v/v), following liquid-liquid partition with petroleum ether, chloroform, ethyl acetate and n-butanol. A total of 13 compounds were identified. In addition three flavonoids were isolated from the ethyl acetate fraction: quercetin-3-O-robinoside (GAF 1), kaempferol-3-O-robinoside (GAF 2) and isorhamnetin-3-O-robinoside (GAF 3) and, from n-butanol fraction more two flavonoids were isolated, kaempferol-3-O-robinoside-7-O-rhamnoside (robinin) (GAF 4) and isorhamnetin-3-O-robinoside-7-rhamnoside (GAF 5). Chemical structures of these five flavonoids were elucidated using spectroscopic methods (MS, ¹H and 13C-NMR 1D and 2D). These flavonoids glycosides were described for the first time in G. americana.

In vitro metabolism of grandisin, a lignan with anti-chagasic activity.

Tetrahydrofuran lignans represent a well-known group of phenolic compounds capable of acting as antiparasitic agents. In the search for new medicines for the treatment of Chagas disease, one promising compound is grandisin which has shown significant activity on trypomastigote forms of Trypanosoma cruzi. In this work, the in vitro metabolism of grandisin was studied in the pig cecum model and by biomimetic phase I reactions, aiming at an ensuing a preclinical pharmacokinetic investigation. Although grandisin exhibited no metabolization by the pig microbiota, one putative metabolite was formed in a biomimetic model using Jacobsen catalyst. The putative metabolite was tested against T. cruzi revealing loss of activity in comparison to grandisin.