€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€ *****AFRICAN JOURNAL OF MEDICINE AND MEDICAL SCIENCES***** BINUTU OA LAJUBUTU BA ANTIMICROBIAL POTENTIALS OF SOME PLANT SPECIES OF THE BIGNONIACEAE FAMILY. In: Afr J Med Med Sci (1994 Sep) 23(3):269-73 ISSN: 0309-3913 The methanol extracts of the leaves and stem bark of four Bignoniaceae plants Jacaranda mimosifolia D. Dol., Tecoma stans Linn., Tabebuia rosea (Bertol) D.C., and Crescentia cujete Linn. were studied for their antimicrobial activity using a wide range of Gram- positive and Gram-negative bacteria and fungi. Extracts of both the leaves and stem bark of majority of plant species studied showed variable but remarkable broad spectrum antimicrobial activity. However, methanol extracts of Tecoma stans leaves was found to be effective against only Candida albicans at the concentrations employed. It was observed that the extracts of stem bark generally showed better antimicrobial activity than those of the leaves and some organisms were selectively more sensitive to the extracts than others. Preliminary phytochemical screening of these plants revealed the presence of tannins, flavonoids, alkaloids, quinones and traces of saponins. The antimicrobial activity observed are discussed in relation to the chemical constituents reportedly isolated from these plants and their traditional uses. €€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€ *****ARCHIVOS DE INVESTIGACION MEDICA***** ROMAN-RAMOS R FLORES-SAENZ JL PARTIDA-HERNANDEZ G LARA-LEMUS A ALARCON-AGUILAR F EXPERIMENTAL STUDY OF THE HYPOGLYCEMIC EFFECT OF SOME ANTIDIABETIC PLANTS. In: Arch Invest Med (Mex) (1991 Jan-Mar) 22(1):87-93 ISSN: 0066-6769 The purpose of this work is to look for the hypoglycemic effect of 12 plants most used in Mexico for controlling diabetes mellitus. The studies were realized in 27 rabbits submitted weekly to glucose tolerance tests after gastric administration of water, tolbutamide or a preparation of the plant. The results showed that tolbutamide and studied plants (except Aloe barbadensis) decreased significantly (p less than 0.05) the area under glucose tolerance curve, in relation with the water control. The strongest effect was yielded by Psacalium peltatum (27.9%), followed by Curcubita ficifolia (26.4%), Lepechinia caulescens (26.0%), Opuntia streptacantha (21.4%), Slanum verbascifolum (21.1%), Teucrium cubense (19.4%), Cecropia obtusifolia (18.9%), Phaseolus vulgaris (18.5%), Tecoma stans (17.5%), Eriobotrya japonica (17.2%), Salpianthus macrodonthus (15.0%), tolbutamide (14.3%), and Aloe barbadensis (1.4%). Our results point out that the majority of the plants most used by the Mexican population to control diabetes mellitus have an evident hypoglycemic action. Registry Numbers: 64-77-7 (Tolbutamide) €€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€ *****EUROPEAN JOURNAL OF BIOCHEMISTRY***** SHARMA HK VAIDYANATHAN CS 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. In: Eur J Biochem (1975 Aug 1) 56(1):163-71 ISSN: 0014-2956 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. €€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€ *****JOURNAL OF ETHNOPHARMACOLOGY***** LOZOYA-MECKES M MELLADO-CAMPOS V IS THE TECOMA STANS INFUSION AN ANTIDIABETIC REMEDY? In: J Ethnopharmacol (1985 Sep) 14(1):1-9 ISSN: 0378-8741 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. Registry Numbers: 11061-68-0 (Insulin) €€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€ *****JOURNAL OF NATURAL PRODUCTS***** HARRIS GH FIXMAN EC STERMITZ FR CASTEDO L (-)-DELTA-N-NORMETHYLSKYTANTHINE FROM TECOMA AREQUIPENSIS. In: J Nat Prod (1988 May-Jun) 51(3):543-8 ISSN: 0163-3864 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. Registry Numbers: 116183-67-6 (N-normethylskytanthine) €€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€ Rao MM Kingston DG PLANT ANTICANCER AGENTS. XII. ISOLATION AND STRUCTURE ELUCIDATION OF NEW CYTOTOXIC QUINONES FROM TABEBUIA CASSINOIDES In: J Nat Prod (1982) 45(5):600-604 An alcoholic extract of the stem bark of Tabebuia cassinodes showed slight but reproducible activity in the P-388 in vivo bioassay. Purification and recrystallization yielded three new cytotoxic furonaphthaquinones. Two of these showed significant activity in the KB cell culture assay. This may be significant since the related compound lapachol showed sufficient in vivo activity to reach clinical trials at the NCI. (11 Refs) €€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€