title: Isolation of opioid-active compounds from Tabernaemontana pachysiphon leaves.
abstract: A procedure for prefractionation of crude plant extracts by centrifugal partition chromatography (CPC) has been developed to enable rapid identification of known-positive compounds or false-positive compounds and to increase the chance of identifying minor unknown-active compounds. The study explored the use of CPC as a tool in the prefractionation step before investigation of bioactivity. Fractions obtained by CPC from an ethanolic extract of Tabernaemontana pachysiphon Stapf (Apocynaceae) were screened by means of an opiate-receptor-binding assay and an adenosine A1-receptor-binding assay. Fractions containing fatty acids, which had false-positive effects on the assay, were identified, as were unknown-positive fractions from which two opioid-active compounds, tubotaiwine and apparicine, were subsequently isolated. The affinities (Ki) of tubotaiwine and apparicine at the opiate receptor were 1.65 +/- 0.81 and 2.65 +/- 1.56 micromol, respectively. Both alkaloids had analgesic activity in the abdominal constriction test in mice. CPC prefractionation led to the rapid isolation of two opioid-active compounds, tubotaiwine and apparicine, from the unknown-positive fraction; false-positive fractions were rapidly identified. Both tubotaiwine and apparicine had affinity for adenosine receptors in the micromolar range and also had in-vivo analgesic activity in mice.
authors.affiliation: Leiden/Amsterdam Centre for Drug Research, Gorlaeus Laboratories, Leiden University, The Netherlands.
authors.forename: K
authors.initials: K
authors.lastname: Ingkaninan
authors.forename: A P
authors.initials: AP
authors.lastname: Ijzerman
authors.forename: T
authors.initials: T
authors.lastname: Taesotikult
authors.forename: R
authors.initials: R
authors.lastname: Verpoorte
mesh_terms: D000470:Alkaloids / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology; D000701:Analgesics, Opioid / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D002540:Cerebral Cortex / Q000378:metabolism; D005260:Female; D066298:In Vitro Techniques; D008024:Ligands; D019684:Magnoliopsida / Q000737:chemistry*; D008297:Male; D051379:Mice; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology; D018515:Plant Leaves / Q000737:chemistry; D011869:Radioligand Assay; D011957:Receptors, Opioid / Q000378:metabolism; D018047:Receptors, Purinergic P1 / Q000378:metabolism
chemical_list: D000470:Alkaloids; D000701:Analgesics, Opioid; D008024:Ligands; D010936:Plant Extracts; D011957:Receptors, Opioid; D018047:Receptors, Purinergic P1; C008811:pericalline; C404563:tubotaiwine