Microemulsions strongly promoted the activity of α-bisabolol against different Leishmania species and its skin permeation.

This study aimed to develop microemulsions (MEs) containing α-bisabolol for the topical treatment of cutaneous leishmaniasis (CL). Initially, pseudoternary phase diagrams were developed using α-bisabolol as the oil phase, Eumulgin® CO 40 as the surfactant, Polymol® HE as the co-surfactant, and distilled water as the aqueous phase. Two transparent liquid systems (TLS) containing 5% of α-bisabolol were selected and characterized (F5E25 and F5EP25). Next, skin permeation and retention assays were performed using Franz cells. The interaction of the formulation with the stratum corneum (SC) was evaluated using the FTIR technique. The cytotoxicity was evaluated in murine peritoneal macrophages. Finally, the antileishmanial activity of microemulsions was determined in promastigotes and amastigotes of L. amazonensis (strain MHOM/BR/77/LTB 0016). As a result, the selected formulations showed isotropy, nanometric size (below 25 nm), Newtonian behavior and pH ranging from 6.5 to 6.9. The MEs achieved a 2.5-fold increase in the flux and skin-permeated amount of α-bisabolol. ATR-FTIR results showed that microemulsions promoted fluidization and extraction of lipids and proteins of the stratum corneum, increasing the diffusion coefficient and partition coefficient of the drug in the skin. Additionally, F5E25 and F5EP25 showed higher activity against promastigotes (IC50 13.27 and 18.29, respectively) compared to unencapsulated α-bisabolol (IC50 53.8). Furthermore, F5E25 and F5EP25 also showed antileishmanial activity against intracellular amastigotes of L. amazonensis, with IC50 50 times lower than free α-bisabolol and high selectivity index (up to 15). Therefore, the systems obtained are favorable to topical administration, with significant antileishmanial activity against L. amazonensis promastigotes and amastigotes, being a promising system for future in vivo trials.

Influence of Lemongrass Essential Oil (Cymbopogon flexuosus) Supplementation on Diabetes in Rat Model.

(1) Background: Species of the genus Cymbopogon and its essential oil are known for their antioxidant and hypoglycemic effects. This study aimed to investigate the impact of the essential oil of Cymbopogon flexuosus (EOCF), and its major component, citral, on glycemic, lipid, antioxidant parameters, and oxidative stress in a type 1 diabetes (DM1) rat model. (2) Methods: Initially, EOCF was analyzed by Gas chromatography-mass spectrometry (GC-MS) and the antioxidant activity of EOCF and citral was evaluated. Next, male Wistar rats (3 months old, 200-250 g) induced with DM1 using Streptozotocin (STZ) were divided into four groups: negative control supplemented with an 80% Tween solution, two groups of animals supplemented with EOCF (32 mg/kg and 64 mg/kg) and with citral (32 mg/kg), and treated for 14 days. Measurements of blood glucose levels and body weight were taken; after euthanasia, biochemical markers, including lipid profile, uric acid, alanine aminotransferase (ALT), and aspartate aminotransferase (AST), were evaluated. (3) Results: The predominant compounds in EOCF were α-citral (53.21%) and neral (19.42%), constituting 72.63% citral. EOCF showed good antioxidant activity, significantly greater than citral. EOCF supplementation demonstrated a mitigating effect on glycemic, lipid, and hepatic abnormalities induced by DM1. (4) Conclusions: EOCF emerges as a promising therapeutic option for the management of DM1.