Antioxidant galloylated flavonol glycosides from Calliandra haematocephala.

Three new acylated quercetin rhamnosides have been isolated from the leaves and stem of Calliandra haematocephala Hassk. (Fabaceae) and their structures were established as quercitrin 2''-O-caffeate (1), quercitrin 3''-O-gallate (2) and quercitrin 2'',3''-di-O-gallate (3). Also, 17 known compounds were identified as gallic acid (4), methyl gallate (5), caffeic acid (6), myricitrin (7), quercitrin (8), myricetin 3-O-beta-D-4C1-glucopyranoside (9), afzelin (10), isoquercitrin (11), myricetin 3-O-(6''-O-galloyl)-beta-D-glucopyranoside (12), myricitrin 2''-O-gallate (13), quercitrin 2''-O-gallate (14), afzelin 2''-O-gallate (15), myricitrin 3''-O-gallate (16), afzelin 3''-O-gallate (17), 1,2,3,4,6-penta-O-galloyl-beta-D-4C1-glucopyranose (18), myricitrin 2'',3''-di-O-gallate (19), quercetin 3-O-methyl ether (20), for the first time from the genus Calliandra except for 6. Compounds 7, 8, 13, 14, 16 and 19 exhibited moderate to strong radical scavenging properties on lipid peroxidation, hydroxyl radical, superoxide anion generation and DPPH radical in comparison with that of quercetin as a positive control in vitro. Compounds 7 and 8 exhibited lethal effect towards brine shrimp Artemia salina.

Antiinflammatory and ulcerogenic activities of Salvia triloba extracts.

In continuation of our research on Salvia triloba, acute and chronic antiinflammatory and ulcerogenic activities of chloroform, ethanol, butanol and water extracts were detected at 25 mg/kg p.o. The chloroform extract showed the highest antiinflammatory activity in both acute and chronic models, while the ulcerogenic effects of all tested extracts were found to be less than that of acetyl salicylic acid.

Antioxidant activity and two new flavonoids from Washingtonia filifera.

Two new flavonoids, 8-hydroxyisoscoparin (1) and luteolin 7-O-glucoside 4''-sulfate (2), along with eight known flavonoids, including luteolin 7-O-glucoside 2''-sulfate, were isolated and identified from Washingtonia filifera. All compounds were characterized by (1)H-NMR, (13)C-NMR, CI-MS, FABMS and UV. The antioxidant activities of various W. filifera extracts were determined.

Phytochemical studies and effect on urine volume of Glossostemon bruguieri Desf. constituents.

Two new flavonoids, takakin 7-O-glucoside (1) and (2) bucegin 7-O-glucoside, and six other known compounds (3-8), takakin, isosctullarien, its 7-O-glucoside, takakin 8-O-glucoside, xanthotoxin and esculetin, were separated and identified from Glossostemon bruguieri. The new compounds were characterized using modern spectroscopic techniques, including UV spectroscopy, proton nuclear resonance (1HNMR), carbon thirteen nuclear resonance (13CNMR), homomolecular quantum coherance (HMQC), heteromolecular bonding connectivity (HMBC) and chemical ionization mass spectra (CI). The effect on rats urine volume of the plant powder, its ethanolic extract, (500 mg kg(-1)) along with four of the purified compounds (1,4-6), (100 mg kg(-1)) are described. Eight groups of albino rats (200-300 g body weight) (n=5 for each group) were used in the tests for a one-time treatment, and other seven groups (150-180 g body weight) (n=5 for each group) were tested using the same dose with repeated administration for 15 days. The rat sera were collected and used to determine liver and kidney functions based on alanine amino transferase (ALT) and aspartate amino transferase (AST) for both single and repeated administration. Levels of urea, creatinine and uric acid were determined for both sets of experiments. The toxic effects of both the powder and its alcoholic extract were also studied on mice to determine their LD50, both materials proved to be non-toxic up to 2500 mg kg(-1) body weight.

Phenolic constituents from the leaves of the carnivorous plant Nepenthes gracilis.

Plumbagin, isoshinanolone, epishinanolone, shinanolone, quercetin and kaempferol were isolated from the leaves of Nepenthes gracilis. Spectral data of shinanolone are presented.

Constituents from Salvia triloba.

Twelve hydrocarbons, four sterols, three triterpenes, nineteen fatty acids, two phenolic acids, and five flavonoids have been detected and identified in Salvia triloba. Among the isolated flavonoids, 8-methoxygenistein 7-O-alpha-L-rhamnoside 4'-O-beta-D-glucoside (1), is reported for the first time.

Kaempferol triosides from Reseda muricata.

A flavonoid trioside and its coumaryl ester together with seven known flavonoids and five phenolic acids were isolated from the leaves of Reseda muricata. Their structures were elucidated by spectroscopic methods including UV, FAB MS, 1H, 13C and 2D-NMR, DEPT, HMBC and HMQC experiments. The two compounds were identified as kaempferol 3-O-beta-D-glucopyranosyl-(1''' --> 2'')-O-alpha-L-rhamnopyranoside 7-O-beta-D-glucopyranoside and kaempferol 3-O-beta-D-glucopyranosyl-(1''' --> 2'')-O-alpha-L rhamnopyranoside 7-O-beta-D-(6''''-O-E-coumarylglucopyranoside), respectively.

15alpha-acetoxycleomblynol A from Cleome amblyocarpa.

Reinvestigation of the MeOH-CH(2)Cl(2) extract of the aerial parts of Cleome amblyocarpa led to isolation of a new dammarane triterpenoid, 15alpha-acetoxycleomblynol A, whose structure was determined to be 11alpha,15alpha-diacetoxybrachycarpon-22(23)-ene (1) by NMR data interpretation and X-ray analysis.

Selected topics from forty years of natural products research: betalains to flavonoids, antiviral proteins, and neurotoxic nonprotein amino acids.

The elucidation by NMR and chemical methods of the unique structure of betanidin, the aglycon of the red-violet beet pigment betanin, forty years ago at the University of Zürich, Switzerland, was the beginning of my plant chemistry research program. Many of the same chemical and spectral techniques developed in Zürich have been used at The University of Texas at Austin for the structure analysis of members of many other classes of natural products including especially flavonoids, terpenoids, and alkaloids. Investigations at UT-Austin have concerned many topics such as biochemical and molecular systematics, biosynthetic pathways, structure-activity relationships, and the medicinal importance of natural products and included studies of antiviral proteins in the genus Phytolacca and neurotoxic nonprotein amino acids from cycads and other sources. Following the betalain story and an account of the early development of my UT-Austin biochemical systematic program, the Phytolacca and neurotoxin investigations are discussed herein.

Eudesmane derivatives from Iva frutescens.

Re-investigation of the aerial parts of Iva frutescens resulted in the isolation of three sesquiterpenes, two of which are new natural products, and their structures were established by spectral data.

Identification of nonprotein amino acids from cycad seeds as N-ethoxycarbonyl ethyl ester derivatives by positive chemical-ionization gas chromatography-mass spectrometry.

Nonprotein amino acids from nine species of cycad seeds were analyzed as N-ethoxycarbonyl ethyl ester (ECEE) derivatives by positive chemical-ionization gas chromatography-mass spectrometry. Based on the retention times and mass spectrometry analyses, 12 nonprotein amino acids were identified in these seeds. In addition to the excitatory and putative neurotoxin beta-N-methylamino-L-alanine (BMAA), the known neurotoxin beta-N-oxalylamino-L-alanine (BOAA) was detected from the seeds of Macrozamia moorei and M. communis, and delta-N-oxalyl-ornithine was obtained from the Cycas revoluta seeds. A novel nonprotein amino acid named cycasindene, previously reported from C. revoluta, was also found in the seeds of members of the C. angulata and C. rumphii complex. Eight additional known nonprotein amino acids were also identified. This is the first report of the neurotoxin BOAA from cycad seeds.

Nonprotein amino acids from Cycas revoluta.

Two nonprotein amino acids, cycasindene and cycasthioamide, along with eight known nonprotein amino acids, were isolated from the seeds of Cycas revoluta Thunb. The structures of cycasindene and cycasthioamide were elucidated as 3-[3'-amino-indenyl-2]-alanine (1) and N-[glycinyl-alaninyl-11-thio]-5-one-pipecolic acid (2) by chemical and spectral methods.

Clerodane diterpenoids, long chain esters of coumaric acid and other compounds from Baccharis myrsinites.

A new clerodane diterpenoid and two new long chain esters of trans- and cis-coumaric acid, in addition to known triterpenoids and one known clerodane diterpenoid, have been isolated and characterized from Baccharis myrsinites. The structures were determined by spectroscopic techniques.

A new derivative of glucose and 2-C-methyl-D-erythritol from Ferula sinaica.

A new glucose derivative (1) and 2-C-methyl-D-erythritol (2) were isolated from the leaves of Ferula sinaica. The two structures were elucidated by highfield NMR spectroscopy, and that of 1 was confirmed by X-ray diffraction analysis.

Gallotannins and flavonoids from Haematoxylon campechianum.

Two new compounds, 2,6-bis-O-digalloyl-3-O-galloylglucose and 2-O-trigalloyl-1,3,4,6-tetrakis-O-galloylglucose, along with four known gallotannins, were isolated and identified from the leaves of Haematoxylon campechianum. In addition, four known flavonoid and three simple phenolic compounds were also detected.

Nonprotein amino acids from seeds of Cycas circinalis and Phaseolus vulgaris.

Our chemical studies on Cycas circinalis seeds from Guam has provided two new nonprotein amino acids, N-(3'-one-5'-methyl)-hexylalanine and leucine betaine. N-methylisoleucine, previously reported as a component of naturally occurring peptides, has been isolated as a free amino acid from the seeds of Phaseolus vulgaris (pinto bean), together with S-methylcysteine, pipecolic acid and a dipeptide, gamma-glutamyl-leucine.

An unusual cycloartane triterpenoid from Cimicifuga foetida.

A new cycloartane triterpenoid glycoside has been isolated from the rhizomes of Cimicifuge foetida L. The spectroscopic characteristics of the new compound are different from previously described cycloartane triterpenoids because of the loss of the 24-isopropyl group as well as the presence of a 11 beta-OH group. Based on spectroscopic evidence, including a series of 2D-NMR analyses, the structure of the new triterpene is assigned as 24-des-isopropyl-7-ene-23-one-9,19; 16,24-dicycloart-3 beta,11 beta,16 alpha,24 alpha-tetraol 3-O-beta-D-xylopryanoside, named here as neocimiside. The structure of the aglycone of neocimiside was confirmed by X-ray analysis.

Protoplasts from Phytolacca dodecandra L'Herit (endod) and P. americana L. (pokeweed).

Pokeweed (Phytolacca americana L.) and endod (P. dodecandra L'Herit) produce ribosome-inactivating proteins which are sequestered in leaf cell walls. These proteins display strong antiviral activity. To aid in studying the antiviral mechanism, we developed protocols to isolate protoplasts from suspension culture cells and leaves. Ninety-five percent of pokeweed or endod culture cells were converted to protoplasts using 2% cellulase, 0.25% pectinase, 0.2 M mannitol, 2% sucrose, 15 mM CaCl2 Murashige and Skoog salts, pH 5.7. Viability was >85% after 24 h. Culture-derived protoplasts were purified by centrifugation through a 15% sucrose pad. Protoplasts collected from the supernatant were then pelleted in 0.3 M mannitol. Pokeweed leaves provided respectable yields (4×10(6) protoplasts/g f w) of partially-purified viable protoplasts when digested in solution containing 1% cellulase, 0.2% Pectolyase, 0.4 M mannitol, CPW salts, 0.5 mM MES, pH 5.6. We were unable to completely separate cell debris from mesophyll protoplasts, which were small and easily damaged by centrifugation. Endod leaves were found to be resilient to several digestion enzymes tested.

Enzymes of B-ring-deoxy flavonoid biosynthesis in elicited cell cultures of "old man" cactus (Cephalocereus senilis).

Elicited cell cultures of the cactus Cephalocereus senilis produce a group of flavonoids with unsubstituted B-rings, including an aurone which represents a new class of phytoalexin. Preliminary enzymological studies indicated that the chalcone synthase (CHS) and chalcone isomerase (CHI) from cultures of C. senilis were active with cinnamoyl-CoA and 2',4',6'-trihydroxychalcone, respectively, probable intermediates for synthesis of flavonoids with unsubstituted B-rings. We now demonstrate that the cultures contain two isoforms of CHI, both of which are induced by elicitor treatment and are active with both 2',4,4',6'-tetrahydroxy- and 2',4',6'-trihydroxychalcone. (Hydroxy)-cinnamate:CoA ligase in the cactus cultures was active with cinnamic, 4-coumaric, caffeic, ferulic, and 4-methoxycinnamic acids, but not sinapic acid. A single form of CoA ligase, as resolved by chromatofocusing analysis, was active against both cinnamate and 4-coumarate. Cinnamic acid 4-hydroxylase (CA4H) activity was induced by elicitor treatment. Thus, elicited cultures contain the necessary enzymatic activities for synthesis of B-ring-hydroxy and -deoxy flavonoids. Synthesis of only the deoxy class in response to elicitation may result from some form of metabolic compartmentation through which the CA4H reaction is bypassed, leading to formation of cinnamoyl CoA which may then be incorporated into B-ring deoxy flavonoids via nondiscriminating CHS and CHI activities.