Phytochemical analysis of the essential oil of Thymus serpyllum L. growing wild in Estonia

Variations in the essential oil composition of Thymus serpyllum L., growing wild in Estonia (33 samples) and in some other countries (Russia, Latvia and Armenia, seven samples) were determined. The oil were obtained from Estonia (46 samples) in yields 0.6-4.4 and 1.9-8.2 mL kg(-1) in other countries. The T. serpyllum herb grown in Estonia usually did not confirmed to the EP standard in the aspect of the essential oil contents (3.0 mL kg(-1)). Variations in the essential oil composition of wild thyme were studied using capillary gas chromatographic methods. A total of 94 components were identified. Thymol and carvacrol, mentioned in literature as principial components, are not the main components of the essential oil of wild thyme growing in Estonia. (E)-nerolidol, caryophyllene oxide, myrcene and borneol chemotypes of wild thyme drug are distinguishable. The chemical composition of samples from Russia, Latvia and Armenia is very variable.     

Convergence of Collocation Method with Delta Functions for Integral Equations of First Kind

Integral equations of first kind with periodic kernels arising in solving partial differential equations by interior source methods are considered. Existence and uniqueness of solution in appropriate spaces of linear analytic functionals is proved. Rate of convergence of collocation method with Dirac’s delta-functions as the trial functions is obtained in case of uniform meshes. In case of an analytic kernel the convergence rate is exponential.     

Nanoformulation and Evaluation of Oral Berberine-Loaded Liposomes

Berberine (BBR) is a poorly water-soluble quaternary isoquinoline alkaloid of plant origin with potential uses in the drug therapy of hypercholesterolemia. To tackle the limitations associated with the oral therapeutic use of BBR (such as a first-pass metabolism and poor absorption), BBR-loaded liposomes were fabricated by ethanol-injection and thin-film hydration methods. The size and size distribution, polydispersity index (PDI), solid-state properties, entrapment efficiency (EE) and in vitro drug release of liposomes were investigated. The BBR-loaded liposomes prepared by ethanol-injection and thin-film hydration methods presented an average liposome size ranging from 50 nm to 244 nm and from 111 nm to 449 nm, respectively. The PDI values for the liposomes were less than 0.3, suggesting a narrow size distribution. The EE of liposomes ranged from 56% to 92%. Poorly water-soluble BBR was found to accumulate in the bi-layered phospholipid membrane of the liposomes prepared by the thin-film hydration method. The BBR-loaded liposomes generated by both nanofabrication methods presented extended drug release behavior in vitro. In conclusion, both ethanol-injection and thin-film hydration nanofabrication methods are feasible for generating BBR-loaded oral liposomes with a uniform size, high EE and modified drug release behavior in vitro.