Desmethoxyabresoline and 10-epi-desmethoxyabresoline,new ester alkaloids in Heimia salicifolia

Two new ester alkaloids, desmethoxyabresoline and 10-epi-desmethoxyabresoline, have been isolated from young seedlings of Heimia salicifolia and have been synthesized. Chemical and physical properties of the natural and synthetic isomers are in agreement. The presence of these alkaloids adds support to the postulate that the biphenyl system of the lythraceous alkaloids is derived from trans-cinnamate esters of phenylquinolizidinols.     

The effect of light on the production of Heimia alkaloids

Alkaloid extracts obtained from light- and dark-grown shoot cultures of Heimia salicifolia were partially fractionated and semi-quantitatively analysed for phenyl- and biphenylquinolizidine alkaloids. The concentrations of the two structural types of alkaloids in extracts of shoots grown with illumination increase over a 4 week culture period. In extracts obtained from shoots grown in darkness for 4 weeks, however, we observed substantial decreases in the concentrations of both the phenyl- and biphenylquinolizidine alkaloids. We observed that growth in the dark for periods of up to 9 weeks resulted in a further reduction in the levels of biphenyl alkaloids relative to those of the phenylquinolizidinols.     

Biscoclaurine alkaloids in callus tissues of Stephania cepharantha

Although callus tissues derived from tubers of Stephania cepharantha cannot synthesize the main alkaloids of the original plant, cepharanthine and isotetrandrine, they are able to synthesize biscoclaurine alkaloids, berbamine and aromorine, the latter not being found in the original plant. These results suggest that enzymes controlling specific methylation and methylenedioxy group formation are absent from the callus. The maximum content of total alkaloid in the callus tissues subcultured for 9 months was more than 3 times that of original plant. Alkaloid content was affected by addition of various auxins, IAA being most effective.     

Quaternary alkaloids of Thalictrum foliolosum

The isolation and identification of eleven alkaloids from the quaternary alkaloid fraction of a root extract of Thalictrum foliolosum are described     

Lupin alkaloids from sophora chrysophylla

A new lupin alkaloid, (?)-mamanine N-oxide, was isolated from Sophora chrysophylla together with 18 known alkaloids including some unusual lupin alkaloids such as kuraramine, lamprolobine, epilamprolobine, epilamprolobine N-oxide, (+)-mamanine and (?)-pohakuline. It was also shown that the alkaloid constituents of S. chrysophylla differed considerably in the leaves, stems and seeds.     

Alkaloid distribution and catabolism in Cephalotaxus harringtonia

Cephalotaxus harringtonia produces a variety of antitumor alkaloids that are distributed throughout the tree. In a young plant grown in a controlled environment, the concentration of free alkaloids (homoerythrina alkaloids and cephalotaxine) did not increase with age, whereas the concentration of cephalotaxine esters (harringtonine, deoxyharringtonine, isoharringtonine and homoharringtonine) increased roughly 5-fold. Total alkaloid concentrations increased in the older leaves of the plant and decreased in the older stems. Physiological stress (pruning) causes hydrolysis of part of the stored alkaloid esters to free cephalotaxine within one week. In 4 out of 5 field-grown trees environmental factors caused complete ester hydrolysis and, in addition, the oxidation of cephalotaxine to 11-hydroxycephalotaxine and drupacine and of homoerythrina alkaloid to its epoxy derivative. This shows that the alkaloids in this perennial tree are not inert storage products, but are under metabolic control.     

Tropane alkaloids from Anthocercis and Anthotroche

In addition to known tropane alkaloids, 3α-iso-butyryloxytropan-6β-ol and 3α-n-butyryloxytropane have been characterized as respective components of the aerial parts of two subspecies of Anthocercis albicans. Aponoratropine, not previously recorded as a natural product, has been detected in the leaves of Anthotroche myoporoides and A. walcottii; similarly aponorhyoscine is indicated as a component of the roots of a subspecies of Anthocercis genistoides.     

New alkaloids from Strychnos icaja

The alkaloids of Strychnos icaja (Loganiaceae) have been studied. An extract from Zaire leaf material yielded nine alkaloids, comprising novacine, the new base 21,22-α-epoxy-4,14-dihydroxy-3-methoxy-N-methyl-sec.-pseudostrychnine, and seven others of known structure previously obtained from the plant. Cameroun leaf material gave five alkaloids, of which one, 21,22-α-epoxy-3,4-dimethoxy-N-methyl-sec.-pseudostrychnine, is new. Fruits from Gabon afforded eight alkaloids; two of them are new and are formulated as 21,22-α-epoxy-4-methoxy-N-methyl-sec.-pseudostrychnine and the corresponding 14-hydroxy derivative.     

Distribution of alkaloids in Anthocercis littorea and A. viscosa

The distribution of tropane alkaloids in organs of Anthocercis littorea and A. viscosa is reported. The following alkaloids have been isolated: atropine (hyoscyamine), apoatropine, noratropine (norhyoscyamine), littorine, hyoscine, norhyoscine, meteloidine, 3α, 6β-ditigloyloxytropan-7β-ol, 6β-tigloyloxytropan-3α-ol, 3α-tigloyloxytropane, tigloidine, tropine, ψ-tropine, (?)-tropan-3α-6β-diol, cuscohygrine and unknown bases.     

Leaf alkaloids of Rauwolfia volkensii

Thirteen alkaloids were isolated and identified from the leaves of Rauwolfia volkensii. The alkaloids included E-seco heteroyohimbine, heteroyohimbine, sarpagan, dihydroindole, pleiocarpamine, picrinine and akuammicine types together with peraksine.     

Three new alkaloids from Buxus papillosa

Three new steroidal alkaloids have been obtained from Buxus papillosa Schneider. These are (?)-cyclobuxupaline-C (IV)(+)-cyclopapilosine-D (VII) and (+)-buxamine-C (IX). A known alkaloid also present is desoxy-16-buxidienine (X).     

Alkaloids of formosan Fissistigma and Goniothalamus species

Separation of the basic fractions from Formosan Fissistigma glaucescens, F. oldhamii and Goniothalamus amuyon afforded one new quaternary phenanthrene alkaloid, N-methylatherosperminium (15), along with the known alkaloids, (?)-discretamine (1), (?)-tetrahydropalmatine (2), palmatine (3), (?)-asimilobine (4), (?)-norannuradhapurine (5), (?)-crebanine (6), (?)-calycinine (fissoldine, fissistigine A) (7a), (?)-anolobine (8), (?)-xylopine (9), (?)-anonaine (10a), oxocrebanine (11), liriodenine (12), atherosperminine (13), N-noratherosperminine (14) and (+)-O-methylflavinantine (O-methylpallidine) (16).     

The alkaloids of Aspidosperma cuspa: 16-epi-isositsirikine,a new indole base

Aspidosperma cuspa Blake contains kopsanone, epikopsanol, kopsanol, aspidodasycarpine and 16-epi-isositsirikine. Both chemical and botanical data support the allocation of this species to a unique series within the genus.     

Alkaloid catabolism and mobilization in catharanthus roseus

The catabolic turnover of vindoline and catharanthine, indole-dihydroindole alkaloids produced by Catharanthus roseus, occurs much more rapidly in apical cuttings than in intact plants. The implication of the results is that such alkaloids may participate actively in the plant's biochemical processes under certain conditions, in contradistinction to the general belief that plant alkaloids are metabolically insignificant.     

Peptide alkaloids of Scutia buxifolia

Two new components, the peptide alkaloid scutianine D and scutianene C have been isolated from Scutia buxifolia and their structures elucidated. The configuration of some of the asymmetric centers of scutianine A has been determined by gas chromatography.     

Lupin alkaloids from flowers of Echinosophora koreensis

(?)-Methyl 12-cytisineacetate (2) was isolated from methanol extracts of fresh flowers of Echinosophora koreensis together with seven known lupin alkaloids. Ethyl 12-cytisineacetate (3) was also isolated from ethanol extracts of the same flowers. Compounds 2 and 3 were artifacts and (?)-12-cytisineacetic acid (4) is assumed to be the principal source of 2 and 3. The variations in alkaloid content during growth of the flowers and the seedlings were also examined.     

Pyrrolizidine alkaloids from Senecio cacaliaster

Four pyrrolizidine alkaloids have been isolated from Senecio cacaliaster and their structures analysed by spectroscopic methods (IR, mass, ¹H, ¹³CNMR). One of them is new and the name sencalenine (3) is proposed. Alkaloids O⁷-senecioylretronecine (1) and 7-senecioyl-9-sarracinylretronecine (2) have recently been identified elsewhere. The fourth is bulgarsenine (4) which was isolated from a Senecio species before.     

Biosynthesis of pyridine alkaloids from Tripterygium wilfordii

Nicotinic acid-6-¹⁴C and nicotinamide adenine dinucleotide-carbonyl-¹⁴C were rapidly metabolized in T. wilfordii Hook. with formation of all compounds in the pyridine nucleotide cycle. Nicotinic acid-6-¹⁴C and the nicotinamide moiety of NAD were efficiently incorporated into wilfordic acid and hydroxywilfordic acid, the pyridinium moieties of the ester alkaloids. The structures of wilfordic acid and hydroxywilfordic acid were confirmed using GLC-MS. The molecular formulae of the four isolated alkaloids were determined by high resolution MS and agreed with earlier results based on elemental analysis.     

Morphine metabolism and normorphine in Papaver somniferum

Normorphine has been established as an active metabolite of morphine in P. somniferum. This was done by, (a) demonstrating the presence of normorphine throughout the life cycle of the plant, (b) finding normorphine-¹⁴C after feeding morphine-¹⁴C via the roots, and (c) exposing opium poppies to ¹⁴CO₂ under steady state conditions which led to morphine and normorphine of the same specific activity. Feeding normorphine-¹⁴C showed that the N-demethylation step is irreversible. A sensitive procedure was developed for the detection of normorphine in the presence of large amounts of morphine; using this procedure, normorphine was found in raw opium. These results indicate that the major, if not the sole, morphine degradative pathway involves an initial demethylation to normorphine, which is subsequently degraded to non-alkaloidal metabolites. The high rates of turnover observed led to the conclusion that the morphine alkaloids do play an active metabolic role, perhaps as specific methylating agents.