Antinociceptive activity of Maytenus rigida stem bark

Antispasmodic effect of 4'-methylepigallocatechin on guinea pig ileum

The antispasmodic effect of 4'-methylepigallocatechin (MEC), which was isolated from Maytenus rigida Mart (Celestraceae), was investigated in vitro in guinea pig intestinal segments. In the isolated ileum, MEC (1 nM-100 μM) did not modify the ileal spontaneous tonus or the electrically elicited contractions. MEC (8 μM) significantly (p<0.01) reduced the submaximal contractions induced by histamine (2 μM), carbachol (100 μM) and BaCl₂ (0.03 M). An additive relaxing action (p<0.001) was observed by co-incubation of verapamil (10 nM) and MEC (8 μM). Although MEC (1 nM-100 μM) did not modify the contractions elicited by 60 mM KCl, it significantly reduced the CaCl₂ contractile response without changing the EC₅₀ (effective concentration of CaCl₂ causing 50% of maximum response). In brief, these results show that MEC has a potent ileal spasmolytic effect and blocks spasms induced by specific and nonspecific stimuli. Importantly, the spasmolytic effects were attained at low concentrations and might be related to the symptomatic relief of abdominal pain that is obtained from the use of the M. rigida stem bark.

Isolation of active constituents from cherry laurel (Laurocerasus officinalis Roem.) leaves through bioassay-guided procedures

ETHNOPHARMACOLOGICAL RELEVANCE

The fresh leaves of Laurocerasus officinalis Roem. (Rosaceae) are externally used against pain and feverish symptoms in Turkish folk medicine.

AIM OF THE STUDY

Effects of the extracts, fractions and isolated compounds from the leaves of L. officinalis were investigated using in vivo models of inflammation and pain in mice.

METHODS

The crude ethanolic extract from the leaves of plant was sequentially fractionated into five subextracts; explicitly, n-hexane, chloroform, ethyl acetate (EtOAc), n-butanol, and remaining water extracts. Further studies were carried out on the most active EtOAc subextract was further subjected to fractionation through column chromatography. For the anti-inflammatory activity, carrageenan-induced hind paw edema and acetic acid-induced increase in capillary permeability models, and for the antinociceptive activity p-benzoquinone-induced writhing test in mice were employed.

RESULTS

Ethanolic extract of the leaves was shown to possess significant inhibitory activity in the assay methods without inducing any gastric damage. Through bioassay-guided fractionation and isolation procedures three phenolic compounds, 2-O-β-D-glucopyranosyl-2-hydroxyphenyl-acetic acid (1), kaempferol-3-O-β-D-xylopyranosyl-(1→2)-O-β-D-glucopyranoside (2) and (+)-catechin (3) were isolated from the active fraction and their structures were elucidated by spectral techniques (1D and 2D NMR, ESIMS).

CONCLUSION

The experimental data verified that Laurocerasus officinalis leaves displayed remarkable anti-inflammatory and antinociceptive activity.

Bioactivity guided evaluation of anti-inflammatory and antinociceptive activities of Arceuthobium oxycedri (D.C.) M. Bieb

ETHNOPHARMACOLOGICAL RELEVANCE

Arceuthobium oxycedri (D.C.) M. Bieb. (Loranthaceae) or dwarf mistletoe is a rare semi-parasitic plant that lives on the branches of Juniperus oxycedrus as the host plant. In Turkish folk medicine, the plant is prescribed as a panacea for every kind of diseases, including, against infectious and inflammatory disorders of upper respiratory system and gastro-intestinal complaints or as a hypotensive remedy.

AIM OF THE STUDY

In the current study, in vivo anti-inflammatory and antinociceptive effects of Arceuthobium oxycedri have been investigated.

MATERIAL AND METHODS

The crude ethanolic extract of the whole plant was sequentially fractionated into five subextracts; explicitly, n-hexane, chloroform, ethyl acetate (EtOAc), n-butanol, and remaining water extracts. Further studies were carried out on the most active subextract, i.e. the EtOAc subextract, was further subjected to fractionation through successive column chromatographic applications on Silica gel 60, Sephadex LH-20 and LiChropep RP-18. For the activity assessment, each extract or fraction was submitted to bioassay systems; carrageenan-induced hind paw edema model for anti-inflammatory activity and p-benzoquinone induced abdominal contraction test for antinociceptive activity assessment.

RESULTS

Among the extracts obtained, the ethanolic extract, EtOAc and n-butanol subextracts showed significant inhibitory activity in the bioassay systems. From the EtOAc subextract, a major component was isolated and its structure was determined as (+)-catechin by means of spectral techniques.

CONCLUSION

Present study confirms the claimed utilization of the plant against inflammatory complaints in Turkish folk medicine.

Tea catechins' affinity for human cannabinoid receptors

Among the many known health benefits of tea catechins count anti-inflammatory and neuroprotective activities, as well as effects on the regulation of food intake. Here we address cannabimimetic bioactivity of catechin derivatives occurring in tea leaves as a possible cellular effector of these functionalities. Competitive radioligand binding assays using recombinant human cannabinoid receptors expressed in Chem-1 and CHO cells identified (-)-epigallocatechin-3-O-gallate, EGCG (K(i)=33.6 microM), (-)-epigallocatechin, EGC (K(i)=35.7 microM), and (-)-epicatechin-3-O-gallate, ECG (K(i)=47.3 microM) as ligands with moderate affinity for type 1 cannabinoid receptors, CB1. Binding to CB2 was weaker with inhibition constants exceeding 50 microM for EGC and ECG. The epimers (+)-catechin and (-)-epicatechin exhibited negligible affinities for both CB1 and CB2. It can be concluded that central nervous cannabinoid receptors may be targeted by selected tea catechins but signaling via peripheral type receptors is less likely to play a major role in vivo.

Endogenous opiates and behavior: 2007

This paper is the thirtieth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2007 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses.