Steroidal Saponins from Furcraea hexapetala Leaves and Their Phytotoxic Activity.

Four new steroidal saponins (1-4) along with 13 known saponins were isolated from the leaves of Furcraea hexapetala. The new compounds were identified as (20R,22R,25R)-3ß-hydroxy-5α-spirostan-12-one 3-O-{α-l-rhamnopyranosyl-(1→4)-O-ß-d-glucopyranosyl-(1→3)-O-[ß-d-glucopyranosyl-(1→3)-O-ß-d-glucopyranosyl-(1→2)]-O-ß-d-glucopyranosyl-(1→4)-O-ß-d-galactopyranoside} (1), (25R)-3ß-hydroxy-5α-spirost-20(21)-en-12-one 3-O-{α-l-rhamnopyranosyl-(1→4)-O-ß-d-glucopyranosyl-(1→3)-O-[ß-d-glucopyranosyl-(1→3)-O-ß-d-glucopyranosyl-(1→2)]-O-ß-d-glucopyranosyl-(1→4)-O-ß-d-galactopyranoside} (2), (25R)-5α-spirostan-3ß-ol 3-O-{ß-d-glucopyranosyl-(1→2)-O-ß-d-glucopyranosyl-(1→2)-O-ß-d-glucopyranosyl-(1→4)-O-ß-d-galactopyranoside} (3), and (25R)-5ß-spirostan-3ß-ol 3-O-{ß-d-glucopyranosyl-(1→6)-O-ß-d-galactopyranoside} (4) by spectroscopic analysis, including one- and two-dimensional NMR techniques, mass spectrometry, and chemical methods. The phytotoxicity of the isolated compounds against the standard target species Lactuca sativa was evaluated. Structure-activity relationships for these compounds with respect to phytotoxic effects are discussed.

Phytotoxic steroidal saponins from Agave offoyana leaves.

A bioassay-guided fractionation of Agave offoyana leaves led to the isolation of five steroidal saponins (1-5) along with six known saponins (6-11). The compounds were identified as (25R)-spirost-5-en-2α,3ß-diol-12-one 3-O-{α-l-rhamnopyranosyl-(1→3)-O-ß-d-glucopyranosyl-(1→2)-O-[ß-d-xylopyranosyl-(1→3)]-O-ß-d-glucopyranosyl-(1→4)-O-ß-d-galactopyranoside} (1), (25R)-spirost-5-en-3ß-ol-12-one 3-O-{α-l-rhamnopyranosyl-(1→3)-O-ß-d-glucopyranosyl-(1→2)-O-[ß-d-xylopyranosyl-(1→3)]-O-ß-d-glucopyranosyl-(1→4)-O-ß-d-galactopyranoside} (2), (25R)-spirost-5-en-3ß-ol-12-one 3-O-{ß-d-xylopyranosyl-(1→3)-O-ß-d-glucopyranosyl-(1→2)-O-[ß-d-xylopyranosyl-(1→3)]-O-ß-d-glucopyranosyl-(1→4)-O-ß-d-galactopyranoside} (3), (25R)-26-O-ß-d-glucopyranosylfurost-5-en-3ß,22α,26-triol-12-one 3-O-{α-l-rhamnopyranosyl-(1→3)-O-ß-d-glucopyranosyl-(1→2)-O-[ß-d-xylopyranosyl-(1→3)]-O-ß-d-glucopyranosyl-(1→4)-O-ß-d-galactopyranoside} (4) and (25R)-26-O-ß-d-glucopyranosylfurost-5-en-3ß,22α,26-triol-12-one 3-O-{ß-d-xylopyranosyl-(1→3)-O-ß-d-glucopyranosyl-(1→2)-O-[ß-d-xylopyranosyl-(1→3)]-O-ß-d-glucopyranosyl-(1→4)-O-ß-d-galactopyranoside} (5) by comprehensive spectroscopic analysis, including one- and two-dimensional NMR techniques, mass spectrometry and chemical methods. The phytotoxicity of the isolated compounds on the standard target species Lactuca sativa was evaluated.

Bioactive steroidal saponins from Agave offoyana flowers.

Bioguided studies of flowers of Agave offoyana allowed the isolation of five steroidal saponins never described previously, Magueyosides A-E (1-5), along with six known steroidal saponins (6-11). The structures of compounds were determined as (25R)-spirost-5-en-2α,3ß-diol-12-one 3-O-{ß-d-xylopyranosyl-(1→3)-O-ß-d-glucopyranosyl-(1→2)-O-[ß-d-xylopyranosyl-(1→3)]-O-ß-d-glucopyranosyl-(1→4)-O-ß-d-galactopyranoside} (1), (25R)-spirost-5-en-2α,3ß-diol-12-one 3-O-{ß-d-glucopyranosyl-(1→2)-O-[ß-d-xylopyranosyl-(1→3)]-O-ß-d-glucopyranosyl-(1→4)-O-ß-d-galactopyranoside} (2), (25R)-spirost-5-en-2α,3ß,12ß-triol 3-O-{ß-d-glucopyranosyl-(1→2)-O-[ß-d-xylopyranosyl-(1→3)]-O-ß-d-glucopyranosyl-(1→4)-O-ß-d-galactopyranoside} (3), (25R)-5α-spirostan-2α,3ß-diol-12-one 3-O-{ß-d-xylopyranosyl-(1→3)-O-ß-d-glucopyranosyl-(1→2)-O-[ß-d-xylopyranosyl-(1→3)]-O-ß-d-glucopyranosyl-(1→4)-O-ß-d-galactopyranoside} (4), and (25R)-5α-spirostan-2α,3ß-diol-9(11)-en-12-one 3-O-{ß-d-xylopyranosyl-(1→3)-O-ß-d-glucopyranosyl-(1→2)-O-[ß-d-xylopyranosyl-(1→3)]-O-ß-d-glucopyranosyl-(1→4)-O-ß-d-galactopyranoside} (5), by comprehensive spectroscopic analysis, including one- and two-dimensional NMR techniques, mass spectrometry and chemical methods. The bioactivities of the isolated compounds on the standard target species Lactuca sativa were evaluated. A dose-dependent phytotoxicity and low dose stimulation were observed.

Teriparatide efficacy in the treatment of severe hypocalcemia after kidney transplantation in parathyroidectomized patients: a series of five case reports.

BACKGROUND: Teriparatide is a recombinant human parathormone (PTH 1-34) currently approved for the treatment of osteoporosis with high risk of fracture. In this study, we analyze the efficacy and safety profile of teriparatide therapy in severe and prolonged hypocalcemia after kidney transplantation in patients previously submitted to parathyroidectomy. METHODS: The authors report results from a series of five hemodialyzed patients (mean age: 50±15 years; three female) previously submitted to parathyroidectomy to control secondary hyperparathyroidism. All patients had developed severe refractory hypocalcemia (calcium minimum levels: 5±1.4 mg/dL) early after kidney transplantation. The effect of teriparatide in calcemia and phosphatemia levels was analyzed, and variations in calcium and vitamin D analog requirements were analyzed. Secondary effects and serum creatinine changes were also ascertained. RESULTS: Teriparatide therapy was initiated 32±14 days after the development of hypocalcemia. As a result, calcemia levels increased (median±standard deviation [SD]: 6.7±0.8 vs. 8.5±0.8 mg/dL, P=0.024) allowing suspension of intravenous calcium in two patients and reduction of calcitriol doses (mean±SD: 1.1±0.38 vs. 0.55±0.27 µg/day, P=0.004). In addition, phosphatemia levels (median±SD: 5.1±1.5 vs. 3.9±0.5 mg/dL, P=0.09) and calcium carbonate requirements (mean±SD: 13.8±9.4 vs. 7.2 ±3.7 g/day, P=0.9) exhibited declining trends. No secondary effects were observed and creatinemia remained stable. CONCLUSIONS: Our data strongly suggest that refractory hypocalcemia after kidney transplantation in patients with low PTH levels can be successfully treated with teriparatide. PTH analog therapy leads to faster normalization of calcemia, permits earlier suspension of intravenous calcium supplementation, and reduces calcitriol requirements.

Characterization of three saponins from a fraction using 1D DOSY as a solvent signal suppression tool. Agabrittonosides E-F. Furostane saponins from Agave brittoniana Trel. spp. Brachypus.

A careful NMR analysis, especially by 1D TOCSY and 1D ROESY, of a refined saponin fraction allowed us to determine the structure of three saponins from a polar extract of Agave brittoniana Trel. spp. Brachypus leaves. The use of 1D DOSY for the suppression of the solvent signal was useful to obtain the chemical shifts of anomeric signals. A full assignment of the (1)H and (13)C spectral data for the new saponins, agabrittonosides E-F (1-2) and the well-known Karatavioside C (3) and their methoxyl derivatives, is reported. The structures were established using a combination of 1D and 2D ((1)H, (1)H-COSY, TOCSY, ROESY, g-HSQC, g-HMBC and g-HSQC-TOCSY) NMR techniques and ESI-MS. In addition, the methoxylation of these furostane saponins in the presence of MeOH was studied.

Characterization of the fraction components using 1D TOCSY and 1D ROESY experiments. Four new spirostane saponins from Agave brittoniana Trel. spp. Brachypus.

A careful NMR analysis, especially 1D TOCSY and 1D ROESY, of two refined saponin fractions allowed us to determine the structures of four new saponins from a polar extract of the Agave brittoniana Trel. spp. Brachypus leaves. A full assignment of the 1H and 13C spectral data for these new saponins, agabrittonosides A-D (1-4), and one previously known saponin, karatavioside A (5) is reported. Their structures were established using a combination of 1D and 2D (1H, 1H-COSY, TOCSY, ROESY, g-HSQC, g-HMBC and g-HSQC-TOCSY) NMR techniques and ESI-MS. Moreover, the work represents a new approach to structural elucidation of saponins in refined fractions by NMR investigations.