ABSTRACT
The diterpenes ent-kaur-16-en-19-oic acid (1) and ent-beyer-15-en-19-oic acid (2) are the major constituents of a spasmolytic diterpenic mixture obtained from the roots of Viguiera hypargyrea, a Mexican medicinal plant. Microbial transformation of 1 and 2 was performed with Aspergillus niger. Two metabolites, ent-7alpha,11beta-dihydroxy-kaur-16-en-19-oic acid (4) and ent-1beta,7alpha-dihydroxy-kaur-16-en-19-oic acid (5), were isolated from the incubation of 1, and one metabolite, ent-1beta,7alpha-dihydroxy-beyer-15-en-19-oic acid (6), was isolated in high yield (40%) from 2. The structures were elucidated on the basis of spectroscopic analyses and confirmed by X-ray crystallographic studies. Compounds 1-4 and 6 and methyl ester derivatives 4a and 6a were evaluated for their ability to inhibit the electrically induced contraction of guinea-pig ileum. Compounds 1, 3, 4, 4a and 5 were significantly active. These results showed that dihydroxylation of 1 at 7beta, 11alpha-, and 1alpha, 7beta-positions resulted in a loss of potency.
Subject(s)
Aspergillus niger/metabolism , Asteraceae/chemistry , Diterpenes/metabolism , Parasympatholytics/pharmacology , Plant Extracts/metabolism , Animals , Biotransformation , Crystallography, X-Ray , Guinea Pigs , Hydroxylation , Ileum/drug effects , In Vitro Techniques , Molecular Structure , Muscle, Smooth/drug effects , Parasympatholytics/metabolism , Plant Extracts/chemistry , Plant Extracts/pharmacology , Plant RootsABSTRACT
The hypoglycemic effect of methanol leaf extracts from Cecropia obtusifolia and C. peltata was evaluated in healthy mice. A significant decrease (p < 0.05) in plasma glucose levels was recorded 2 and 4 h after a single oral administration of methanol extracts (1 g/kg). This effect was correlated with the chlorogenic acid contents in both species; C. peltata, containing 19.84 +/- 1.64 mg of chlorogenic acid/g of dried leaves produced the highest decrease (D(alpha 2,60) = 20.18, p < 0.05) of plasma glucose levels (52.8%). The extracts of C. obtusifolia from Tabasco and Veracruz, showed similar hypoglycemic effects (33.3% and 35.7%, respectively) and chlorogenic acid contents (Tukey(0.05) = 1.8859) (13.3 +/- 3.2 mg/g and 13.1 +/- 1.6 mg/g, respectively). The hypoglycemic effect produced by different doses (0.1, 0.25, 0.50, 0.75 and 1 g/kg body wt, p.o.) of C. peltata showed a lineal relationship with chlorogenic acid content, reaching an ED(50) = 0.540 g/kg body wt for extract, and an ED(50) = 10.8 mg/kg body wt for chlorogenic acid. These results suggest that C. peltata is a better hypoglycemic agent than C. obtusifolia, and it could be considered for developing a phytomedicinal product to carry out clinical trials.
Subject(s)
Cecropia Plant/chemistry , Chlorogenic Acid/analogs & derivatives , Chlorogenic Acid/pharmacology , Hypoglycemic Agents/chemistry , Hypoglycemic Agents/pharmacology , Animals , Blood Glucose/drug effects , Chlorogenic Acid/analysis , Dose-Response Relationship, Drug , Male , Mice , Mice, Inbred BALB C , Molecular Structure , Phytotherapy , Plant Extracts/chemistry , Plant Leaves/chemistryABSTRACT
A new spirostanol saponin, together with three known saponins, were isolated from the leaves of Solanum hispidum. The structure of the new saponin was elucidated as 6alpha-O-beta-D-quinovopyranosyl-(25S)-5alpha-spirostan-3beta-ol (1) on the basis of spectroscopic analysis (1H NMR, 13C NMR, 1H-1H COSY, HMQC, HMBC, and HRFABMS). All of the isolated compounds showed antimycotic activity. The most active compound was 6alpha-O-[beta-D-xylopyranosyl-(1-->3)-beta-D-quinovopyranosyl]-(25S)-5alpha-spirostan-3beta-ol (2) (MIC = 25 microg/mL against both Trichophyton mentagrophytes and T. rubrum). The structure-activity relationships of the isolated compounds and those isolated from S. chrysotrichum are discussed.
