The incubation of 13α,17-dihydroxystemodane with Cephalosporium aphidicola.

The biotransformation of 13α,17-dihydroxystemodane (3) with the fungus Cephalosporium aphidicola afforded 13α,17,18-trihydroxystemodane (4), 3ß,13α,17-tri-hydroxystemodane (5), 13α,17-dihydroxy-stemodan-18-oic acid (6), 3ß,11ß,13α,17-tetra-hydroxystemodane (7), 11ß,13α,17,18-tetrahydroxystemodane (8) and 3ß,13α,17,18-tetra-hydroxystemodane (9). The hydroxylation at C-18 of the substrate points to a biosynthetically-directed transformation, because aphidicolin (2) is hydroxylated at this carbon. However, the C-3(ß) and C-11(ß) hydroxylations seem to indicate a xenobiotic biotransformation.

A chemotaxonomic study of nine Canarian Sideritis species.

Nine taxa of the Sideritis genus, Sideritis argosphacelus var. spicata, Sideritis candicans var. eriocephala,Sideritis discolor, Sideritis kuegleriana, Sideritis lotsyi, Sideritis lotsyi var. mascaensis, Sideritis marmorea, Sideritis soluta and Sideritis tenoi, which are endemic from the Canary Islands, have been chemically studied. The diterpene sicanatriol 7beta,18-diacetate was obtained from S. argosphacelus var. spicata, whilst a nor-diterpene, epiadejone, and the 3(2H)-benzofuranone solutin have been found in S. soluta. Another diterpene, sidendrodiol 18-monoacetate, has been isolated from S. argosphacelus var. spicata, for the first time as a natural product. Known sesquiterpenes, diterpenes, triterpenes, sterols, flavones, coumarins and other aromatic derivatives have also been isolated. These studies support the botanical division of the genus into two subgenera, Sideritis and Marrubiastrum, the three sections of the latter subgenus, Cretica, Empedocleopsis and Marrubiastrum, and the elevation of S. argosphacelus var. spicata, S. candicans var. eriocephala and S. lotsyi var. mascaensis to the rank of species.

Biotransformation of two ent-Pimara-9(11),15-diene derivatives by Gibberella fujikuroi.

The incubation of 19-hydroxy-13-epi-ent-pimara-9(11),15-diene (4) with Gibberella fujikuroi gave 8 alpha,19-dihydroxy-9 alpha,11alpha-epoxy-13-epi-ent-pimara-15-ene (6), 7-oxo-11 alpha,19-dihydroxy-13-epi-ent-pimara-8(9),15-diene (7), 7-oxo-11beta,19-dihydroxy-13-epi-ent-pimara-8(9),15-diene (9), and 8 alpha,19-dihydroxy-9 alpha,11 alpha:15,16-diepoxy-13-epi-ent-pimarane (11), while the feeding of 13-epi-ent-pimara-9(11),15-diene-19-oic acid (5) with this fungus afforded 1-oxo-2 alpha,9 alpha-dihydroxy-13-epi-ent-pimara-11,15-dien-19-oic acid (13), 1-oxo-2 beta,9 alpha-dihydroxy-13-epi-ent-pimara-11,15-dien-19-oic acid (14), 13-epi-ent-pimara-9(11),15-dien-1,19-dioic acid 1,2-lactone (15), and 1-oxo-12 beta-hydroxy-13-epi-ent-pimara-9(11),15-dien-19-oic acid (16). In both biotransformations, the main reaction was the epoxidation of the 9(11)-double bond, followed by rearrangement to afford allylic alcohols. The formation of lactone 15 represents the first time that a Baeyer-Villiger oxidation has been observed in a microbiological transformation with this fungus.

The microbiological transformation of 7alpha-hydroxy-ent-kaur-16-ene derivatives by Gibberella fujikuroi.

The biotransformation of 7alpha-hydroxy-ent-kaur-16-ene (epi-candol A) by the fungus Gibberella fujikuroi gave 7alpha,16alpha,17-trihydroxy-ent-kaur-16-ene and a seco-ring B derivative, fujenoic acid, whilst the incubation of candicandiol (7alpha,18-dihydroxy-ent-kaur-16-ene) and canditriol (7alpha,15alpha,18-trihydroxy-ent-kaur-16-ene) afforded 7alpha,18,19-trihydroxy-ent-kaur-16-ene and 7alpha,11beta,15alpha,18-tetrahydroxy-ent-kaur-16-ene, respectively. The presence of a 7alpha-hydroxyl group in epi-candol A avoids its biotransformation along the biosynthetic pathway of gibberellins, and directs it to the seco-ring B acids route. The 15alpha-hydroxyl group in canditriol inhibits oxidation at C-19 and direct hydroxylation at C-11(beta). The formation of fujenoic acid, from 7alpha-hydroxy-ent-kaur-16-ene, probably occurs via 7alpha-hydroxykaurenoic acid and 7-oxokaurenoic acid, with subsequent hydroxylation at the C-6(beta) position.

The microbiological transformation of two 15beta-hydroxy-ent-kaurene diterpenes by Gibberella fujikuroi.

The incubation of 15beta-hydroxy-3-oxo-ent-kaur-16-ene (1) with the fungus Gibberella fujikuroi afforded 11beta-hydroxy-3,15-dioxo-ent-kaurane (6), 11beta,15beta-dihydroxy-3-oxo-ent-kaur-16-ene (8), 7beta,11beta,15beta-trihydroxy-3-oxo-ent-kaur-16-ene (9), 7alpha,11beta-dihydroxy-3,15-dioxo-ent-kaurane (7), and 7alpha,11beta,15beta-trihydroxy-3-oxo-ent-kaur-16-ene (10). The incubation of 15beta-hydroxy-ent-kaur-2,16-diene (3) with the same fungus yielded 7alpha,11beta-dihydroxy-15-oxo-ent-kaur-2-ene (12), 7alpha,11beta,15beta-trihydroxy-ent-kaur-2,16-diene (13), 7beta,15beta-dihydroxy-ent-kaur-2,16-dien-19,6-olide (14), 1beta,7beta,15beta-trihydroxy-ent-kaur-2,16-dien-19-oic acid (15), 7alpha,11beta,16alpha-trihydroxy-15-oxo-ent-kaur-2-ene (17), and 7alpha,15beta,17-trihydroxy-11beta,16beta-epoxy-ent-kaur-2-ene (19). These results indicated that a 3-oxo group in ent-kaur-16-ene derivatives inhibits the oxidation at C-19, typical of the biosynthetic pathway of gibberellins and kaurenolides, while a 2,3-double bond or a 15beta-OH does not. In both substrates a 15beta-alcohol directs hydroxylations at C-11(beta) and C-7(alpha), while in those with a 2,3-double bond the functionalization of C-1(beta) is favored.

The microbiological transformation of the diterpenes dehydroabietanol and teideadiol by Mucor plumbeus.

The microbiological transformation of dehydroabietanol (18-hydroxy-dehydroabietane) by Mucor plumbeus led to 2alpha,18-dihydroxy-abieta-8,11,13,15-tetraene, 2alpha,15-dihydroxy-dehydroabietanol, 2alpha-hydroxy-15-methoxy-dehydroabietanol, 7beta-hydroxy-2-oxo-dehydroabietanol, 15-hydroxy-2-oxo-dehydroabietanol and 15,16-dihydroxy-2-oxo-dehydroabietanol, whilst that of teideadiol (1alpha,18-dihydroxy-dehydroabietane) gave 2alpha-hydroxy-teideadiol, 7alpha-hydroxy-teideadiol and 7beta-hydroxy-teideadiol. Thus, 2alpha- and 7beta-hydroxylation occur in both biotransformations and the 15-hydroxylation is inhibited in the biotransformation of teideadiol by the presence of a 1alpha-alcohol.

On the ent-kaurene diterpenes from Sideritis athoa.

The structure of a diterpene, which has been isolated form Sideritis athoa, has been corrected from 3beta,18-dihydroxy-ent-kaur-16-ene to 1alpha,18-dihydroxy-ent-kaur-16-ene (canadiol).

Microbial transformation of 18-hydroxy-9,13-epi-ent-pimara-7,15-diene by Gibberella fujikuroi.

The incubation of the diterpene 18-dihydroxy-9,13-epi-ent-pimara-7,15-diene (3) with the fungus Gibberella fujikuroi gave 14 metabolites, 4 and 6-18. The carbons functionalized were the C-20 methyl and all the secondaries, except C-12. The main reaction observed was the epoxidation of the 7,8-double bond, which rearranged to form 7-keto derivatives, such as 10-17, or the allylic alcohol 18. Compound 9 was the only one obtained in which the 7,8-double bond of the substrate remained unaltered. This work confirms that, in the feeding of this type of diterpene with this fungus, the oxidation at C-19, typical of the biosynthesis of gibberellins from ent-kaur-16-ene, is inhibited.

The biotransformation of the diterpene 2beta-hydroxy-ent-13-epi-manoyl oxide by Gibberella fujikuroi.

Incubation of the diterpene 2beta-hydroxy-ent-13-epi-manoyl oxide with Gibberella fujikuroi afforded in good yield 2beta,6beta-dihydroxy-ent-13-epi-manoyl oxide, 2beta,12beta-dihydroxy-ent-13-epi-manoyl oxide and 2beta,20-dihydroxy-ent-13-epi-manoyl oxide, confirming that although ent-13-epi-manoyl oxide is a final metabolite of a biosynthetic branch in this fungus, more polar derivatives of this compound can be transformed by this micro-organism.

Efficacy of Rhizophora mangle aqueous bark extract in the healing of open surgical wounds.

Thirty-seven patients with open wounds from surgical intervention of pilonidal cyst (14; 37.8%) or pilonidal fistula (23; 62.2%) were enrolled on a voluntary basis in a comparative blinded clinical trial and randomly assigned to a topical treatment with a Rhizophora mangle aqueous bark extract once a day or twice a day or mercurocrome twice a day. The efficacy of the treatments was evaluated weekly from day 10 to 12 until 6 weeks after surgery by measuring the area of the wounds by image digital planimetry and the tolerability by recording adverse effects. The initial size of the wounds was taken in consideration as covariable in the Generalized Lineal Model used. A thin dark red colored film covering the wound was observed in all the cases treated with the extract. The wound areas of the groups treated with the extract once or twice per day showed a greater reduction (P < 0.05) compared to the group treated with mercurocrome. No differences between the two regimes of application of the extract of R. mangle were observed. No subject showed any sign of adverse effects and no secondary infections were observed.

Antibacterial activity of Rhizophora mangle bark.

The aqueous extract of Rhizophora mangle bark, also formulated to ensure physical and chemical stability, was found to inhibit the growth of seven bacteria frequent in infected wounds.

Prótesis parcial removible semirrígida: evaluación clínica de cinco años de uso / Semirigid removable partial denture: a five-year clinical evaluation

Se evalúan los resultados obtenidos con el uso de prótesis parcial removible semirrígida, con retenedores directos DPA, realizadas en forma sistemática durante un período de 5 años en la Clínica de Prótesis II de la Facultad de Odontología de Montevideo. De 462 prótesis clase I de Kennedy resueltas (82 por ciento del total) se tomó una muestra de 3 por ciento, para analizar mediante un cuestionario y un examen clínico específicos, la repercusión ecológica de los retenedores DPA, referidos a incidencia de caries y enfermedad periodontal; a nivel del terreno protético se buscaron signos de trauma periodontal, cambios óseos y mucosos, se valoró la opinión de los pacientes sobre eficacia y confort del tratamiento protético

Investigación clínica del registro de la centricidad mandibular / A clinical research of the mandibular centricity record

El registro de la centricidad mandibular, ha sido tratado con múltiples enfoques, destacándose la existencia de diferentes criterios para ubicar la mandíbula (Escuela Gnatológica: relación céntrica - Escuela Miocéntrica: posición muscular) así como múltiples técnicas para encontrarlas (técnicas pasivas y activas). Actualmente existe una convergencia entre ambas escuelas que fundamenta la búsqueda de la P.M.O., que es la más fisiológica y estable para el sistema estomatognático. Del estudio experimental de las técnicas de Ramfjord, Lengua, Jig, Calibrador, se deduce que la diferencia de resultados de su uso no tiene importancia clínica significativa para el odontólogo general o el estudiante de odontología