Reversal of cholera toxin-induced secretion in rat ileum by luminal berberine

In Vitro and In Vivo Evaluations of Berberine-Loaded Microparticles Filled In-House 3D Printed Hollow Capsular Device for Improved Oral Bioavailability

The low oral bioavailability, short biological half-life, high dose, and frequent dosing of berberine (BBR) contribute to its restricted clinical use despite its extensive pharmacological activity. Thus, the objective of this study was to formulate sustained-release microparticles (MPs) using a pH-independent release polymer and to evaluate their potential to improve the oral bioavailability of BBR. BBR loaded MPs were prepared using the emulsion crosslinking method and evaluated for particle size, circularity, morphology, entrapment efficiency, solid-state analysis, swelling index, and in vitro BBR release study fitted with different models of release kinetics. The MPs exhibited desired particle sizes ranges between 11.09-11.62 μm and were almost spherical in shape, as confirmed by the circularity value and micrographic images. A loss of BBR crystallinity was observed after encapsulation in MPs, as evident from various solid-state analyses. The final optimized batch (F3) showed highest % BBR entrapment efficiency value of 81.63% ± 4.9. The in vitro BBR release performance in both acidic and alkaline media showed the desired sustained release behavior from the crosslinked MPs, where the maximum BBR release was observed at alkaline pH, which is in accordance with the swelling study data. In the in vivo study, the oral absorption profiles of BBR from both pristine and MPs formats were investigated using in-house prototyped 3D printed hollow capsules as a unit dose carrier. In vivo data showed sustained and prolonged absorption behavior of BBR from MPs compared to their pristine counterparts, which resulted in a cumulative increment of relative oral bioavailability to mitigate the aforementioned issues related to BBR. Graphical Abstract.

Berberis vulgaris and its constituent berberine as antidotes and protective agents against natural or chemical toxicities

Berberis vulgaris L (B. vulgaris) and its main constituent berberine have been used in traditional medicine for a long time. This medicinal plant and berberine have many properties that have attracted the attention of researchers over the time. According to several studies, B. vulgaris and berberine exhibited anti-inflammatory, antioxidant, anticonvulsant, antidepressant, anti-Alzheimer, anti-cancer, anti-arrhythmic, antiviral, antibacterial and anti-diabetic effects in both in vitro and invivo experiments. In regard to many reports on protective effects of B. vulgaris and berberine on natural and chemical toxins, in the current review article, the inhibitory effects of these compounds against natural, industrial, environmental and chemical toxicities with focus on cellular mechanism have been categorized. It has been mentioned that berberine could ameliorate toxicity of chemical toxins in brain, heart, kidney, liver and lung in part through antioxidant, anti-inflammatory, anti-apoptotic, modulation of mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) signaling pathways.

Weak C-H···X (X = O, N) hydrogen bonds in the crystal structure of dihydroberberine

Dihydroberberine (systematic name: 9,10-dimethoxy-6,8-dihydro-5H-1,3-dioxolo[4,5-g]isoquinolino[3,2-a]isoquinoline), C20H19NO4, a reduced form of pharmacologically important berberine, crystallizes from ethanol without interstitial solvent. The molecule shows a dihedral angle of 27.94 (5)° between the two arene rings at the ends of the molecule, owing to the partial saturation of the inner quinolizine ring system. Although lacking classical O-H or N-H donors, the packing in the crystalline state is clearly governed by C-H···N and C-H···O hydrogen bonds involving the two acetal-type C-H bonds of the 1,3-dioxole ring. Each dihydroberberine molecule is engaged in four hydrogen bonds with neighbouring molecules, twice as donor and twice as acceptor, thus forming a two-dimensional sheet network that lies parallel to the (100) plane.

Mechanical and electrophysiological effects of 8-oxoberberine (JKL1073A) on atrial tissue

The effects of 8-oxoberberine (JKL1073A) on contractions and electrophysiological characteristics of atrial tissues were examined. In driven left atria of the rat JKL1073A (10-100 microM) increased twitch tension dose-dependently. In spontaneously beating right atria, JKL1073A increased twitch tension but decreased beating rate slightly. The positive inotropic and the negative chronotropic effect of 30 microM JKL1073A was not affected by prazosin (1 microM), propranolol (1 microM) and 3-isobutyl-1-methyl-xanthine (10 microM) but significantly suppressed by 4-aminopyridine (2 mM 4-AP). Current-clamp study revealed that JKL1073A prolonged rat atrial action potential duration (APD). This prolongation of APD by JKL1073A was decreased by pretreating the cells with 2 mM 4-AP. Voltage-clamp study showed that JKL1073A inhibited the integral of the transient outward current (I(to)) dose-dependently with a KD value of 3.66 +/- 0.93 microM in rat atrial myocytes. The equilibrium dissociation constant (Kd) for JKL1073A bindings to open state I(to) was 0.50 +/- 0.08 microM. The suppression of I(to) by 3 microM JKL1073A was accompanied by shortening of its inactivation time constant from 52.5 +/- 0.9 ms to 16.8 +/- 0.7 ms. V(0.5) for the steady-state inactivation curve of I(to) was shifted from -25.7 +/- 3.3 mV to -34.8 +/- 3.2 mV. In human atrial cells, similar inhibition of I(to) and prolongation of APD by JKL1073A was found. The KD value of JKL1073A for inhibition of the integral of I(to) in human atrial cells is 4.03 +/- 0.02 microM. The Kd for bindings to open state I(to) is 0.5 microM. Currents through K1 channels of rat and human atrial myocytes were not inhibited by JKL1073A at concentrations up to 10 microM. These results indicate that JKL1073A exerts a positive inotropic effect by inhibition of I(to). JKL1073A inhibit I(to) by binding to open state channels or shifting of the steady-state inactivation curve of I(to).

Clinical trial of berberine in acute watery diarrhoea

Four hundred adults presenting with acute watery diarrhoea were entered into a randomised, placebo controlled, double blind clinical trial of berberine, tetracycline, and tetracycline and berberine to study the antisecretory and vibriostatic effects of berberine. Of 185 patients with cholera, those given tetracycline or tetracycline and berberine had considerably reduced volume and frequency of diarrhoeal stools, duration of diarrhoea, and volumes of required intravenous and oral rehydration fluid. Berberine did not produce an antisecretory effect. Analysis by factorial design equations, however, showed a reduction in diarrhoeal stools by one litre and a reduction in cyclic adenosine monophosphate concentrations in stools by 77% in the groups given berberine. Considerably fewer patients given tetracycline or tetracycline and berberine excreted vibrios in stools after 24 hours than those given berberine alone. Neither tetracycline nor berberine had any benefit over placebo in 215 patients with non-cholera diarrhoea.