Bebeerine

Screening an In-House Isoquinoline Alkaloids Library for New Blockers of Voltage-Gated Na(+) Channels Using Voltage Sensor Fluorescent Probes: Hits and Biases.[Pubmed:35807390]

Molecules. 2022 Jun 28;27(13):4133.

Voltage-gated Na(+) (Na(V)) channels are significant therapeutic targets for the treatment of cardiac and neurological disorders, thus promoting the search for novel Na(V) channel ligands. With the objective of discovering new blockers of Na(V) channel ligands, we screened an In-House vegetal alkaloid library using fluorescence cell-based assays. We screened 62 isoquinoline alkaloids (IA) for their ability to decrease the FRET signal of voltage sensor probes (VSP), which were induced by the activation of Na(V) channels with batrachotoxin (BTX) in GH3b6 cells. This led to the selection of five IA: liriodenine, oxostephanine, thalmiculine, protopine, and Bebeerine, inhibiting the BTX-induced VSP signal with micromolar IC(50). These five alkaloids were then assayed using the Na(+) fluorescent probe ANG-2 and the patch-clamp technique. Only oxostephanine and liriodenine were able to inhibit the BTX-induced ANG-2 signal in HEK293-hNa(V)1.3 cells. Indeed, liriodenine and oxostephanine decreased the effects of BTX on Na(+) currents elicited by the hNa(V)1.3 channel, suggesting that conformation change induced by BTX binding could induce a bias in fluorescent assays. However, among the five IA selected in the VSP assay, only Bebeerine exhibited strong inhibitory effects against Na(+) currents elicited by the hNav1.2 and hNav1.6 channels, with IC(50) values below 10 microM. So far, Bebeerine is the first BBIQ to have been reported to block Na(V) channels, with promising therapeutical applications.

Comparative phytochemical investigation of the sources of ayurvedic drug patha: a chromatographic fingerprinting analysis.[Pubmed:20582188]

Indian J Pharm Sci. 2010 Jan;72(1):39-45.

Standardization of herbal drugs based on their chemical and biological activity profile is an important prerequisite for acquiring the herbal market. The main problem encountered in standardization of Ayurvedic drugs is proper identification of the source plant. The present study was aimed to establish identification characters, quality control parameters, chemical and biological parameters for roots of three plants Cissampelos pareira, Cyclea peltata and Stephania japonica (Fam. Menispermaceae) which are being used as source of Patha, in the market. All the three plant were subjected for evaluation of quality control parameters as per WHO guidelines and root extracts and total alkaloidal fractions were subjected for HPTLC and HPLC fingerprinting analysis using a marker compound Bebeerine isolated from roots of Cissampelos pareira. The parameters studied clearly indicated the significant differences among the three plant materials. The roots of Cissampelos pareira can be distinguished from other two plants by presence of high concentration of alkaloids especially the presence of high concentration of pharmacologically active alkaloid Bebeerine, which was found to be present in very low concentration in Stephania japonica and absent in roots of Cyclea peltata. The roots of Cyclea peltata were found to contain high concentration of saponins and comparatively in low concentration in Cissampelos pareira where as it was found to be absent in roots of Stephania japonica.

Natural probes for cholinergic sites: L-bebeerine actions on the neuromuscular transmission, the nicotinic receptor/ionic channel complex, and contraction of skeletal muscles.[Pubmed:10797870]

Acta Physiol Pharmacol Ther Latinoam. 1999;49(4):268-78.

The mechanisms underlying the muscle relaxant activity of 1-Bebeerine (BB), a tertiary alkaloid isolated from the roots of Chondrodendron platyphyllum, were examined in mammalian and amphibian skeletal muscles. Injections of BB (0.05-1 g/kg, i.p.) in rats caused a dose-related flaccid paralysis and respiratory arrest at high doses. In isolated rat diaphragm and toad sartorius muscles, BB depressed the indirectly elicited muscle twitches (IC50: 228 microM and 5.4 microM, respectively, at 22 degrees C) and blocked the nerve-elicited muscle action potential. The neuromuscular blockade was not reversed by neostigmine (10 microM). High concentrations of BB (170 and 340 microM) caused muscle contracture unrelated to the junctional blockade, and intensified by increasing the bath temperature. Analysis of the contraction properties showed that BB (40 and 80 microM) increased the twitch/tetanus ratio (46% and 125%) and prolonged the relaxation time; the falling phase of the directly elicited action potential in toad sartorius muscle fibers was slower probably by a decreased potassium conductance. BB (0.1-340 microM) reduced the binding of [125l]alpha--bungarotoxin to the junctional ACh receptor of the rat diaphragm (IC50: 47.7 microM, at 37 degrees C. At low concentrations BB (1.5-15 microM) induced either opening or blockade of the ACh receptor-ionic channel. The results showed that BB blocked noncompetitively the neuromuscular transmission through a mechanism that affects the ACh recognition site and the ionic channel properties. The alkaloid also produced muscle contracture and changed the contractile properties through its extra-junctional action at the calcium handling by the sarcoplasmic reticulum or the contractile machinery.