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At least 19 recordsLinked to original sources

PubMed1985

Is the Tecoma stans infusion an antidiabetic remedy?

The intravenous administration of Tecoma stans infusion in normal dogs produces an early hyperglycemic response and arterial hypotension followed by a slow decrease of the glucose blood values with a concomitant hypertriglyceridemia; no important changes in immunoreactive insulin were detected. Heart frequency was gradually increased after the first 60 min of drug administration and persisted for several hours. The effects observed on blood parameters seem to be related to hepatic glycogen metabolism, involving an activation of glycogenolysis. The late hypoglycemic effect of Tecoma stans infusion could be considered secondary to the observed hepatic glucose output. The study represents an attempt to elucidate the popularly attributed antidiabetic properties of this Mexican medicinal plant.

Animals↗

PubMedDate not supplied

(-)-delta-N-normethylskytanthine from Tecoma arequipensis.

Bark of Tecoma arequipensis yielded the major alkaloidal component (-)-delta-N-normethylskytanthine whose structure was proven by X-ray diffraction analysis of the N-thiourea derivative. The stereochemistry of 1 at all four centers was enantiomeric with that of skytanthine previously reported from Tecoma stans and Skytanthus acutus. Gc-ms of the crude base fraction indicated the presence of several related alkaloids as very minor constituents.

Alkaloids↗

PubMed1975

A new mode of ring cleavage of 2,3-dihydroxybenzoic acid in Tecoma stans (L.). Partial purification and properties of 2,3-dihydroxybenzoate 2,3-oxygenase.

2,3-Dihydroxybenzoic acid has been shown to be oxidized via the 3-oxoadipate pathway in the leaves of Tecoma stans. The formation of 2-carboxy-cis,cis-muconic acid, a muconolactone, 3-oxoadipic acid and carbon dioxide during its metabolism has been demonstrated using an extract of Tecoma leaves. The first reaction of the pathway, viz., the conversion of 2,3-dihydroxybenzoate to 2-carboxy-cis,cis-muconic acid has been shown to be catalysed by an enzyme designated as 2,3-dihydroxybenzoate 2,3-oxygenase. The enzyme has been partially purified and a few of its properties studied. The enzyme is very labile with a half-life of 3--4 h. It is maximally active with 2,3-dihydroxybenzoate as the substrate and does not exhibit any activity with catechol, 4-methyl catechol, 3,4-dihydroxybenzoic acid, etc. However, 2,3-dihydroxy-p-toluate and 2,3-dihydroxy-p-cumate are also oxidized by the enzyme by about 38% and 28% respectively, compared to 2,3-dihydroxybenzoate. Sulfhydryl reagents inhibit the enzyme reaction and the inhibition can be prevented by preincubation of the enzyme with the substrate. Substrate also affords protection to the enzyme against thermal inactivation. Sulfhydryl compounds strongly inhibit the reaction and the inhibition cannot be prevented by preincubation of the enzyme with its substrates. Data on the effect of metal ions as well as metal chelating agents suggest that copper is the metal cofactor of the enzyme. Evidence is presented which suggests that iron may not be participating in the overall catalytic mechanism.

Cations, Divalent↗

PubMed2003

Characterization and pharmacological actions of tecostanine, an alkaloid of Tecoma stans.

Tecostanine (1) was isolated from Tecoma stans leaves. Its sterochemistry was elucidated as well as its antihyperglycemic activity and its affinity to opioid and nicotinic receptors. The oxalate salt of 1 did not significantly affect blood glucose levels in normoglycaemic and hyperglycaemic rats. It did not appear to interact with opioid receptors (mu type) and showed only moderate affinity to the nicotinic receptor.

Alkaloids↗

PubMed2003

Isolation and pharmacological activities of the Tecoma stans alkaloids.

Tecoma stans is a plant traditionally used in Mexico for the control of diabetes. Amongst the alkaloids isolated from the plant harvested in Egypt, Tecomine was shown to be one of the compounds responsible for the hypoglycemic action. Given the interest in substances able to treat type II diabetes, we isolated the main alkaloids present in the plant growing in Egypt and Brazil and tested them in vivo on db/db mice. Contrary to previous literature reports on different animal models, Tecomine was unable to modify glycemia; the only effect seen being a decrease in plasma cholesterol levels. On the contrary, when tested in vitro on glucose uptake in white adipocytes, the compound showed a marked effect. The two other alkaloids isolated, namely 5beta-Hydroxyskitanthine, early called Base C, and Boschniakine were inactive both in vivo and in vitro assays.

Adipocytes↗

PubMed2000

Tecoma sambucifolia: anti-inflammatory and antinociceptive activities, and 'in vitro' toxicity of extracts of the 'huarumo' of peruvian incas.

Aqueous and alcoholic extracts of pods and flowers of Tecoma sambucifolia H.B.K. (Bignoniaceae) ('huarumo') were analysed to determine their anti-inflammatory activity (carrageenan-induced edema test), antinociceptive activity (acetic acid writhing test) and 'in vitro' toxicity in Chinese hamster ovary cells, human hepatome cells and human larynx epidermal carcinoma cells. The cytotoxic effects of both extracts were evaluated by two endpoint systems: neutral red uptake assay and tetrazolium assay. The results showed that all extracts have anti-inflammatory and antinociceptive activity, but the highest potency is that of the alcoholic extracts. There were significant differences in cytotoxicity between extracts and among the response of cells to them. The highest cytotoxicity was noted with the alcoholic extract, and the human hepatome cell line was the most sensitive, especially to the alcoholic extract of flowers. The aqueous pod extract appeared to have the best pharmaco-toxicological profile, since it provided a significant reduction of both pain and inflammation together with the lowest cytotoxicity.

Animals↗

PubMed1983

Purification and Characterization of a New Indole Oxygenase from the Leaves of Tecoma stans L.

A new indole oxygenase from the leaves of Tecoma stans was isolated and purified to homogenity. The purified enzyme system catalyzes the conversion of indole to anthranilic acid. It is optimally active at pH 5.2 and 30 degrees C. Two moles of oxygen are consumed and one mole of anthranilic acid is formed for every mole of indole oxidized. Dialysis resulted in complete loss of the activity. The inactive enzyme could be reactivated by the addition of concentrated dialysate. The enzyme is not inhibited by copper-specific chelators, non-heme iron chelators or atebrin. It is not a cuproflavoprotein, unlike the other indole oxygenases and oxidases.

Journal Article↗

PubMed2005

Extensive consumption of Tabebuia aurea (Manso) Benth. & Hook. (Bignoniaceae) nectar by parrots in a Tecoma savanna in the southern Pantanal (Brazil).

Neotropical parrots forage for various food items such as seeds, fruit pulp, flowers, young leaves, and even arthropods. While foraging, many species wander over large areas that include both open and closed habitats. In this study, I examined parrot foraging activity during a brief synchronous and massive flowering in August 1998 in a tecoma savanna (dominated by Tabebuia aurea) in the southern Pantanal. Six parrot species, ranging from the small Brotogeris chiriri to the large Amazona aestiva, foraged for T. aurea nectar, but Nandayus nenday was by far the major nectar consumer, and the results of each of their visits, like those of the other species, was damage of a substantial proportion of the existing flower crop. Parrots foraged mostly during the afternoon, when nectar concentration tended to be higher. Nevertheless, compared to bird-pollinated flowers, which produce copious nectar, T. aurea had a smaller mean nectar volume per flower. Hence, presumably the amount of damage wreaked by these parrots resulted from their efforts to obtain part of their daily energy and water requirements. Thus, the synchronous and massive flowering occurring in such a brief period in the dry season may be related to, among other factors, the necessity of satiating predators such as parrots, which are still abundant in the Pantanal.

Animals↗

PubMed2004

Role of phenolics and boron in reproductive success in seasonally transient sterile Tecoma stans L.

Quantitative and qualitative analysis of phenolics and boron in stigma of transient sterile Tecoma stans L. during seedless (May-July), partially seedbearing (August-November, April) and seedbearing periods (December-March) was made. UV absorption profile of stigmatic exudates indicated the presence of simple phenolics. Total phenolics were higher in stigma during seedless period. Thin layer chromatographic analysis of stigmatic extracts exhibited only three principal spots. Mass spectrophotometry showed the presence of derivatives of cinnamic acid, namely, caffeic acid in these spots. Quantity of boron in stigma during seedless period was lowest but the difference with other periods was not significant. It was suggested that the accumulation of higher quantity of caffeic acid in the stigma during seedless period due to high temperature (40 degrees-45 degrees C) could lead to inhibition of pollen germination in vivo, thereby rendering the plants seedless. This was confirmed by inhibition of in vitro pollen germination in the basal medium containing higher quantity of caffeic acid.

Bignoniaceae↗

PubMed1950