Brucine

Abstract: Publisher Summary In phenol-disulfonic acid method for nitrate, the nitration of phenol-2,4-disulfonic acid yields an orange-brown solution. This can be measured on a colorimeter with a blue filter. In brucine method for nitrate, nitration of brucine yields an orange-brown solution which can be determined on a colorimeter with a blue filter. Xylen-l-ol method for nitrate depends on the formation of 5-nitro-2,4-xylen- 1-ol, which is volatile in steam and is distilled into dilute sodium hydroxide with which it forms a red salt. This can be determined colorimetrically with a green filter. Nitrite determination by diazotization and coupling reactions based on the formation of a red AZO compound. This involves, first, the reaction in acid solution of a primary amine such as sulfanilic acid or sulfanilamide with nitrite to form a diazonium salt. The latter is then coupled to an aromatic amine to yield the red AZO dye whose concentration can be determined in a colorimeter.

Abstract: To further understand the purpose of the traditional processing method of the seeds of Strychnos nux-vomica L. (Loganiaceae) as well as analgesic and anti-inflammatory activities of brucine and brucine N-oxide extracted from this medicinal plant, various pain and inflammatory models were employed in the present study to investigate their pharmacological profiles. Both brucine and brucine N-oxide revealed significant protective effects against thermic and chemical stimuli in hot-plate test and writhing test. However, on different phases they exerted analgesic activities in formalin test. Brucine N-oxide showed stronger inhibitory effect than brucine in carrageenan-induced rat paw edema, both of them significantly inhibited the release of prostaglandin E2 in inflammatory tissue, reduced acetic acid-induced vascular permeability and the content of 6-keto-PGF1a in Freund's complete adjuvant (FCA) induced arthritis rat's blood plasma. In addition, brucine and brucine N-oxide were shown to reduce the content of 5-hydroxytryptamine (5-HT) in FCA-induced arthritis rat's blood plasma, while increase the content of 5-hydroxytryindole-3-acetic acid (5-HIAA) accordingly. These results suggest that central and peripheral mechanism are involved in the pain modulation and anti-inflammation effects of brucine and brucine N-oxide, biochemical mechanisms of brucine and brucine N-oxide are different even though they are similar in chemical structure.

Abstract: To screen the anti-tumor effects of the four alkaloids: brucine, strychnine, brucine N-oxide and isostrychnine from the seed of Strychnos nux-vomica, MTT assay was used to examine the growth inhibitory effects of these alkaloids on human hepatoma cell line (HepG2). Brucine, strychnine and isostrychnine revealed significant inhibitory effects against HepG2 cell proliferation, whereas brucine N-oxide didn't have such an effect. In addition, brucine caused HepG2 cell shrinkage, membrane blebbing, apoptotic body formation, all of which are typical characteristics of apoptotic programmed cell death. The results of flow cytometric analysis demonstrated that brucine caused dose-dependent apoptosis of HepG2 cells through cell cycle arrest at G0/G1 phase, thus preventing cells entering S or G2/M phase. Immunoblot results revealed that brucine significantly decreased the protein expression level of cyclooxygenase-2, whereas increased the expression caspase-3 as well as the caspase-3-like protease activity in HepG2 cells, suggesting the involvement of cyclooxygenase-2 and caspase-3 in the pro-apoptotic effects exerted by brucine. Therefore, this paper indicate that the major alkaloids present in the seed of Strychnos nux-vomica are effective against HepG2 cells proliferation, among which brucine proceed HepG2 cells death via apoptosis, probably through the participation of caspase-3 and cyclooxygenase-2.

Abstract: In radioligand binding studies, it has been reported that brucine, N-chloromethyl brucine, and brucine N-oxide increased the affinity of acetylcholine for M1, M3, and M4 muscarinic receptors, respectively, in a manner consistent with the predictions of the ternary complex allosteric model. We now demonstrate an equivalent ability of these three allosteric agents to modulate the actions of acetylcholine in functional studies in membranes and in whole cells. The enhancing actions of brucine and brucine N-oxide on acetylcholine (ACh) potency at M1 and M4 receptors respectively have been confirmed in guanosine-5'-O-(3-[35S]thio)triphosphate, GTPase, cAMP, and intracellular Ca2+ mobilization assays of function. In general, neither the basal nor the maximally stimulated response to ACh is affected. The subtype-selective allosteric effects of N-chloromethyl brucine on M2 and M3 receptors were shown to be qualitatively and quantitatively the same in guanosine-5'-O-(3-[35S]thio)triphosphate functional assays, in terms of both its affinity and cooperativity with ACh, as those found in binding assays. Neutral cooperativity of N-chloromethyl brucine with ACh on M4 receptor function was also observed, thereby demonstrating its "absolute subtype selectivity": a lack of action at any concentration at M4 receptors and an action at M2 and M3 receptors. The enhancing action of N-chloromethyl brucine on neurogenically released ACh binding at M3 receptors was also detected in whole tissue as an increased contraction of the isolated guinea pig ileum to submaximal electrical stimulation. In conclusion, these functional studies confirm that brucine analogs are allosteric enhancers of ACh affinity at certain muscarinic receptor subtypes.