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Biomedical subjects

P G Waterman

Publications and source records attributed to P G Waterman.

At least 19 recordsLinked to original sources
PubMed2004

Screening of some Australian Flacourtiaceae species for in vitro antioxidant, cytotoxic and antimicrobial activity.

A total of 27 methanol extracts obtained from different plant parts of 10 species of rain forest trees belonging to four genera of the Flacourtiaceae and originating from Australia were investigated. In vitro cytotoxicity was measured by an ATP Lite-M assay method against the mouse P388 lymphocytic leukemia cell line. The total antioxidant activity has been assessed based on scavenging activity of stable ABTS free radicals. The minimum inhibition concentration (MIC) was determined by the dilution method performed in 96 well plates against four different microbes. The leaf extract of Casearia sp. (RB 3051), mature stem extract of Casearia grayi and stem extract of Scolopia braunii were found to have most antioxidant activity (IC50 = 2.9 microg/ml), cytotoxic activity (LC50 = 0.89 microg/ml) and antimicrobial activity against all four different microbes, respectively. The results obtained suggested that among the four genera studied Casearia is the most promising in respect of finding significant antioxidant, cytotoxic and also antimicrobial activity.

Animals↗
PubMed2003

Alkaloids and limonoids from Bouchardatia neurococca: systematic significance.

Five alkaloids, four beta-indoloquinazoline and one furoquinoline, and four terpenoids, three limonoids and one modified sesquiterpene, have been obtained from the aerial parts of Bouchardatia neurococca (Rutaceae). Two of the alkaloids, 1,2-dihydroxyrutaecarpine and 2-(2-[3-formylindolyl])-(3H)-quinazolin-4-one (bouchardatine), and two of the limonoids, 23-oxo-21xi-hydroxy-21,23-dihydroveprisone (veprisonic acid) and 21-oxo-23xi-hydroxy-21,23-dihydroveprisone (isoveprisonic acid) are new. The pattern of secondary metabolites isolated is rather unusual in the Rutaceae and is reminiscent of Tetradium, a genus with which Bouchardatia has not previously been associated.

Alkaloids↗
PubMed2001

Flavones and phenylpropenoids in the surface exudate of Psiadia punctulata.

Three flavones, 5,7-dihydroxy-2',3',4',5'-tetramethoxyflavone, 5,4'-dihydroxy-7,2',3',5'-tetramethoxyflavone, and 5,7,4'-trihydroxy-2',3',5'-trimethoxyflavone were isolated from the leaf exudate of Psiadia punctulata, together with the previously reported 5-hydroxy-7,2',3',4',5'-pentamethoxyflavone and 5,7,3'-trihydroxy-2',4',5'-trimethoxyflavone. The two phenylpropenoids, Z-docosyl-p-coumarate and E-docosyl-p-coumarate were also isolated. The structures were determined on the basis of spectroscopic evidence.

Asteraceae↗
PubMed2001

3-Monoterpenyl-2,4-dioxygenated quinoline alkaloids from the aerial parts of Halfordia kendack.

The aerial parts of Halfordia kendack (Rutaceae) have yielded the known alkaloid trans-erioaustralasine ([rel]-1-acetoxymethyl-4.8'-epoxy-3-(1'beta,2'beta-epoxy-3'beta,4'alpha-para-menthyl-3'-yl)quinolin-2-one) together with four new alkaloids. The latter were characterised by spectroscopic methods as trans-deacetoxyerioaustralasine ([rel]-1-methyl-4.8'-epoxy-3-(1'beta,2'beta-epoxy-3'beta,4'alpha-para-menthyl-3'-yl)quinolin-2-one), trans-deacetoxyerioaustralasine hydrate ([rel]-1-methyl-4.8'-epoxy-3-(1'alpha,2'alpha-dihydroxy-3'beta,4'alpha-para-;menthyl-3'-yl)quinolin-2-one), trans-erioaustralasine hydrate ([rel]-1-acetoxymethyl-4.8'-epoxy-3-(1'alpha,2'alpha-dihydroxy-3'beta,4'alpha-para-menthyl-3'-yl)quinolin-2-one) and trans-1-epi-deacetoxyerioaustralasine hydrate ([rel]-1-acetoxymethyl-4.8'-epoxy-3-(1'beta,2'alpha-dihydroxy-3'beta,4'alpha-para-menthyl-3'-yl)quinolin-2-one).

Alkaloids↗
PubMed2001

Polyphenols from Eucalyptus consideniana and Eucalyptus viminalis.

From the leaves of Eucalyptus consideniana and E. viminalis, known hydrolysable tannins, galloyl esters and ellagitannins, were isolated. Flavonol glycosides were also isolated from the leaves of E. consideniana. The spectral data of the dimeric ellagitannin, oenothein B (1), are reported.

Flavonoids↗
PubMed2001

Polyphenols from Eucalyptus ovata.

From the leaves of Eucalyptus ovata 13 known compounds, four flavonol glycosides and nine tannins, including the trimer gallocatechin-(4alpha-8)-gallocatechin-(4alpha-8)-catechin (1), were isolated. The spectral data of the peracetate derivative of the trimer are reported.

Catechin↗
PubMed2000

3,5-Dimethoxy-3-(1,1-dimethylprop-2-enyl)-3,4-dihydropsoralen-4-one: an unusual furanocoumarin derivative from Halfordia kendack.

The aerial parts of Halfordia kendack (Rutaceae) have yielded a new furanocoumarin derivative which has been identified as 3,5-dimethoxy-3-(1,1-dimethylprop-2-enyl)-3,4-dihydropsoralen-4-one on the basis of spectroscopic and X-ray examination. This new compound, present in high concentration, is probably formed from a 4-O-prenylated precursor furanocoumarin via a Claisen rearrangement. No trace of the putative precursor was found in this sample.

Crystallography, X-Ray↗
PubMed2000

Flavonoids from the stem bark of Lonchocarpus xuul.

The stem bark of Lonchocarpus xuul (Leguminosae) has yielded four flavonoids which have been identified by spectroscopic methods as the novel 4beta,5-dimethoxy-6",6"-dimethyl-2H-pyrano-(2",3":7,6)-fl avan (xuulanin), 3beta,4beta,5-trimethoxy-6",6"-dimethyl-2H-pyrano-(2",3":7,6 )-flavan (3beta-methoxyxuulanin). 4beta-ethoxy-5-methoxy-6",6"-dimethyl-2H-pyrano-(2",3":7,6)- flavan (4beta-demethylxuulanin-4beta-ethyl ether), and the known 5,7-dihydroxy-6,8-di(3-methylbut-2-enyl)flavanone (spiniflavanone-B). The ethyl derivative is considered likely to be an artefact.

Fabaceae↗
PubMed2000

Flavanone, triterpene and chromene derivatives from the stems of Paramignya griffithii.

Five compounds, including three that are novel, were isolated from the stems of Paramignya grifithii (Rutaceae). Two new and one known prenylated flavanones were characterized as 3',4'-dihydroxy-7-methoxy-8-(3-methylbut-2-enyl)-furano(4",5":6,5)-flava-adicin. In addition, a triterpene, 3-oxo-tirucalla-7,24-diene-21-al, and a novel chromene, 6-(2-hydroxyethyl)-2,2-dimethyl-2H-1-benzopyran, were identified.

Benzopyrans↗
PubMed2000

(Rel)-1beta,2alpha-di-(2,4-dihydroxy-6-methoxybenzoyl)-3beta, 4alpha-di-(4-methoxyphenyl)-cyclobutane and other flavonoids from the aerial parts of Goniothalamus gardneri and Goniothalamus thwaitesii.

The aerial parts of Goniothalamus gardneri (Annonaceae) has yielded the known flavonoids 2'-hydroxy-4,4',6'-trimethoxychalcone (flavokawain A), 2',4'-dihydroxy-4,6'-dimethoxydihydrochalcone, 4,2',4'-trihydroxy-6'-methoxydihydrochalcone, 5,7,4'-trimethoxyflavanone (naringenin trimethyl ether) and 7-hydroxy-5,4'-dimethoxyflavanone (tsugafolin) together with three novel compounds, the dimer characterised as (rel)-1beta,2alpha-di-(2,4-dihydroxy-6-methoxybenzoyl)-3beta,4alpha-di-(4-methoxyphenyl)-cyclobutane, 2',4'-dihydroxy-4,6'-dimethoxychalcone and 2'-hydroxy-4,4',6'-trimethoxydihydrochalcone. The last two have previously been synthesised but appear to be new natural products. A similar study of the aerial parts of G. thwaitesii led only to the isolation of the known flavonoids myricetin 4'-O-methyl ether-3-O-alpha-L-rhamnopyranoside (mearnsitrin) and myricetin-3-O-methyl ether (annulatin), together with the triterpenes friedelinol, friedelin and betulinic acid. All compounds were identified by spectroscopic analysis and, for known compounds, by comparison with published data.

Flavonoids↗
PubMed2000

Condensed tannins from Myrica gale.

From the aerial parts of the Myrica gale catechin, epicatechin, gallocatechin, epigallocatechin, epigallocatechin-3-O-gallate, gallocatechin-(4 alpha-8)-epicatechin, gallocatechin-(4 alpha-8)-epigallocatechin, and gallocatechin-(4 alpha-8)-gallocatechin-(4 alpha-8)-gallocatechin (1), were isolated. The 1H- and 13C-NMR data of the peracetate derivative of the trimer are reported.

Humans↗
PubMed2000

Novel oligorhamnosides from the stem bark of Cleistopholis glauca.

A reinvestigation of the stem bark of Cleistopholis glauca yielded 14 compounds, of which seven were either novel or had not been previously reported from this species. These were identified as the farnesane sesquiterpene methyl-(2E,6E)-10-oxo-3,7, 11-trimethyl-dodeca-2,6-dienoate (1); the azaanthracene alkaloid cleistopholine (4); two partially acetylated oligorhamnoside derivatives, 1-O-dodecanyl-2,3, 4-tri-O-acetyl-alpha-rhamnopyranosyl-(1-->3)-2, 4-di-O-acetyl-alpha-rhamnopyranosyl-(1-->3)-4-O-acetyl-alpha-rhamnopy ranosyl-(1-->4)-alpha-rhamnopyranoside (6) and 1-O-dodecanyl-2, 4-di-O-acetyl-alpha-rhamnopyranosyl-(1-->3)-2, 4-di-O-acetyl-alpha-rhamnopyranosyl-(1-->3)-4-O-acetyl-alpha-rhamnopy ranosyl-(1-->4)-alpha-rhamnopyranoside (8), for which the trivial names cleistetroside-7 and cleistetroside-6 were assigned, respectively; the dihydrobenzofuran neolignan rel-(2alpha, 3beta)-7-O-methylcedrusin (12); and the flavonoids dihydroquercetin (13) and quercetin (14). Structure assignments of all compounds were established by spectroscopic methods and comparison with published data. The chemosystematic significance of the occurrence of the isolated components is mentioned. Compounds 1, 6, and 8 are novel natural products.

Carbohydrate Sequence↗
PubMed2000

Isolation of 10-hydroxycoronaridine from Tabernaemontana penduliflora and its estrogen-like activity.

The methanol extract of Tabernaemontana penduliflora was found to appreciably inhibit [3H]-estradiol binding to estrogen receptors. Activity-guided fractionation led to the isolation of two known alkaloids, 10-hydroxycoronaridine (1) and its 10-O-methyl ether, voacangine (2). These alkaloids together with other related alkaloids were tested for their estrogenic activities. Among these molecules, 1 was found to be the most potent estrogen agonist and is distinctly more active than genistein.

Cell Division↗