Cytotoxic Pregnane Steroidal Glycosides from Chonemorpha megacalyx.

Three new C21 pregnane steroids, chonemorphols A-C (1, 3, and 4), 11 new C21 steroidal glycosides, chonemorphosides A-K (2 and 5-14), and 11 known compounds (15-25) were obtained from the vines and leaves of Chonemorpha megacalyx Pierre. Their structures were established using extensive spectroscopic data. The X-ray crystallographic data of 1 and 3 permitted definition of their absolute configurations. Notably, 1 and 2 possessed an uncommon 6/5/6/5/5-fused steroidal ring system. Compound 7 displayed significant cytotoxicity against several cancer cell lines with IC50 values of 2.0-3.6 µM.

Histopathological effects and immunolocalization of periplocoside NW from Periploca sepium Bunge on the midgut epithelium of Mythimna separata Walker larvae.

Periplocoside NW (PSNW) with pregnane glycoside skeleton is a novel insecticidal compound isolated from the root bark of Periploca sepium Bunge. This compound has a potent stomach poisoning activity against several insect pests. In this study, we observed the intoxication symptoms, investigated the histopathological effects and carried out immuno-electron microscopic localization of PSNW on the midgut epithelium of oriental armyworm Mythimna separata Walker larvae for better understanding its action mechanism against insects. Ultrastructural observations showed that cell damages caused by PSNW in the midgut of M. separata larvae are related to the degeneration of brush border microvilli. The dissolution of cytoskeletal structures in the interior and on the surface of microvilli was responsible for the decrease in size and eventual disappearance of microvilli when bubbles of cytoplasmic substances protrude into the midgut lumen of M. separata, thus resulting in cell death. The immuno-electron microscopic localization research showed that gold particle appeared on the microvilli layer of the midgut of M. separate larvae firstly. The density of gold particle gradually added with the time, and finally microvilli layer was destructed severely. Meantime, the gold particles were also presented to the intracellular organelle membrane and the organelles also were destructed. Therefore, we proposed that this membrane system on insect midgut epithelium cells is the initial acting site of PSNW against insects.

Cytotoxic cholestane and pregnane glycosides from Tribulus macropterus.

The methanol extract of the whole parts of Tribulus macropterus Boiss. (family Zygophyllaceae) showed cytotoxic activity against a human tumour cell line (hepatocyte generation 2, HepG2) (IC50 = 2.9 microg/ml). The n-butanolic fraction obtained from successive fractionation of the methanolic extract exhibited activity against HepG2 (IC50 = 2.6 microg/ml). Therefore, this fraction was subjected to separation using different chromatographic techniques. Five compounds, 1-5, were isolated and identified as: (22S,25S)-16beta,22,26-trihydroxy-cholest-4-en-3-one-16-O-beta-D-glucopyranosyl-(1-->3)-beta-D-xylopyranoside (1), (22S,25S)-16beta,22,26-trihydroxy-cholest-4-en-3-one-16-O-beta-D-glucopyranosyl-(1-->3)-beta-D-glucopyranoside (2), sucrose (3), D-pinitol (4) and 3beta-hydroxy-5a-pregn-16(17)en-20-one-3-O-beta-D-xylopyranosyl-(1-->2)-[beta-D-xylopyranosyl-(1-->3)]-beta-D-glucopyranosyl-(1-->4)-[alpha-L-rhamnopyranosyl-(1-->2)]-beta-D-ga-lactopyranoside (5) on the basis of spectroscopic and chemical data. The three steroidal compounds 1, 2 and 5 were also tested against the same cell line HepG2 and their IC50 values were 2.4, 2.2 and 1.1 microg/ml, respectively.

Insecticidal Pregnane Glycosides from the Root Barks of Periploca sepium.

To explore novel lead compounds for botanical pesticides from natural sources, a new pregnane glycoside (periplocoside) P2 as well as its isomer, a known pregnane glycoside P1, were isolated from the root barks of Periploca sepium using a bioactivity-guided method, and their structures were confirmed by ID NMR, 2D NMR, IR, ESI-MSn and HRMS. Their insecticidal activities were evaluated against 3rd instar larvae of M separata, and the results indicated that P2 exhibited excellent insecticidal activity with LC50 values of 2.9 and 2.2 mg/mL after 24 and 48 h, respectively, much lower than those of the positive control celangulin-V (24.7 and 21.0 mg/mL after 24 and 48 h, respectively). This work demonstrated that pregnane glycosides from Periploca sepium could be promising lead compounds for developing botanical pesticides urgently needed in agriculture.

The role of progesterone metabolites in breast cancer: potential for new diagnostics and therapeutics.

Proliferative changes in the normal breast are known to be controlled by female sex steroids. However, only a portion of all breast cancer patients respond to current estrogen based endocrine therapy, and with continued treatment nearly all will become unresponsive and experience relapse. Therefore, ultimately for the majority of breast carcinomas, explanations and treatments based on estrogen are inadequate. Recent observations indicate that 5alpha-pregnane and 4-pregnene progesterone metabolites may serve as regulators of estrogen-responsive as well as unresponsive human breast cancers. The conversion of progesterone to the 5alpha-pregnanes is increased while conversion to the 4-pregnenes is decreased in breast carcinoma tissue, as a result of changes in progesterone metabolizing 5alpha-reductase, 3alpha-hydroxysteroid oxidoreductase (3alpha-HSO) and 20alpha-HSO activities and gene expression. The 5alpha-pregnane, 5alpha-pregnane-3,20-dione (5alphaP) stimulates, whereas the 4-pregnene, 3alpha-hydroxy-4-pregnen-20-one (3alphaHP), inhibits cell proliferation and detachment, by modulation of cytoskeletal and adhesion plaque molecules via the MAP kinase pathway and involving separate and specific plasma membrane-based receptors. The promotion of breast cancer appears to be related to changes in in situ concentrations of cancer-inhibiting and cancer-promoting progesterone metabolites. New diagnostic and therapeutic possibilities for breast cancer are suggested.

Cytotoxicity of pregnane glycosides of Cynanchum otophyllum.

Fourteen new pregnane glycosides, including nine caudatin glycosides (1-9), three qinyangshengenin glycosides (10-12), one kidjoranin glycosides (13) and one gagaminin glycosides (14), along with twelve known analogs (15-26) were isolated from roots of Cynanchum otophyllum Schneid. Their structures were deduced by detailed analysis of 1D and 2D NMR spectra, as well as HRESIMS. In this study, all pregnane glycosides obtained (1-26) were evaluated for their cytotoxic activities using three cancer cell lines (HepG2, Hela, U251). As results, except 6 and 10, other twenty-four pregnane glycosides showed cytotoxicities at different degrees against three cell lines.

Anaesthetic, cardiovascular and respiratory effects of a new steroidal agent CT 1341: a comparison with other intravenous anaesthetic drugs in the unrestrained cat.

1. The anaesthetic, cardiovascular, respiratory and adverse effects produced by the intravenous injection of CT 1341, thiopentone, methohexitone, pentobarbitone, propanidid and ketamine have been compared in unrestrained cats prepared with chronically implanted venous and arterial cannulae. Aortic blood pressure and heart rates were monitored before, during and after loss of consciousness.2. CT 1341 produced rapid induction of anaesthesia followed by moderately rapid recovery, was active over a wide range of doses and caused minimal respiratory depression and few adverse effects. It caused an initial short-lasting tachycardia and fall in aortic blood pressure succeeded by a secondary depressor response.3. The safety margin was narrower with the barbiturate drugs than with CT 1341, and large doses induced apnoea and respiratory depression. Small doses of methohexitone elicited excitatory effects and large doses caused severe respiratory and circulatory depression, and recovery from anaesthesia was protracted.4. Propanidid induced short-lasting light anaesthesia. The safety margin was narrowest with this drug and induction was associated with adverse circulatory, respiratory and other effects.5. Ketamine was active over a wide range of doses but exhibited qualitatively different properties from the other anaesthetics. Induction was slower after small doses and these produced circulatory stimulation, catatonia and bizarre behavioural effects. Large doses caused respiratory and circulatory depression and recovery was protracted.6. It is concluded that CT 1341 has a wider therapeutic latitude, produces less respiratory depression and has other advantages over the currently used intravenous anaesthetics.

Trichilone, a new C21 steroid from Trichilia connaroides.

Phytochemical investigation of the leaves of Trichilia connaroides led to the isolation of a new pregnane, trichilone (1), featuring a 2-methoxycyclopent-2-enone moiety, along with a related known compound, 3beta,4alpha-dihydroxypregnane-16-one (2). The structure of 1 was established on the basis of extensive spectroscopic analysis. Compound 1 showed significant root-growth inhibition activity against Amaranthus. mangostanus with an IC50 value of 23.1 ppm.

Polyoxypregnane glycosides from Caralluma retrospiciens.

Six related polyoxypregnane glycosides were isolated and characterised from Caralluma retrospiciens leaves. The compounds were identified as 12beta-benzoyloxy-8beta,14beta-dihydroxypregn-20-one-3-O-[3-O-methyl-6-deoxy-beta-D-allopyranosyl-(1 --> 4)-beta-D-cymaropyranosyl-(1 --> 4)-]-beta-D-cymaropyranoside], 12beta-benzoyloxy-8beta,14beta-dihydroxypregn-20-one-3-O-[beta-D-glucopyranosyl-(1 --> 4)-3-O-methyl-6-deoxy-beta-D-allopyranosyl-(1 --> 4)-beta-D-cymaropyranosyl-(1 --> 4)-beta-D-cymaropyranoside], 12beta-benzoyloxy-8beta,14beta-dihydroxypregn-20-one-3-O-[beta-D-glucopyranosyl-(1 --> 4)-3-O-methyl-6-deoxy-beta-D-galactopyranosyl-(1 --> 4)-3-O-methyl-6-deoxy-beta-D-galactopyranoside], 12beta-benzoyloxy-8beta,14beta-dihydroxypregn-20-one-3-O-[beta-D-glucopyranosyl-(1 --> 6)-beta-D-glucopyranosyl-(1 --> 4)-3-O-methyl-6-deoxy-beta-D-galactopyranosyl-(1 --> 4)-3-O-methyl-6-deoxy-beta-D-galactopyranoside], 12beta-benzoyloxy-11alpha-isovaleroyloxy-8beta,14beta-dihydroxypregn-20-one-3-O-[beta-D-glucopyranosyl-(1 --> 4)-3-O-methyl-6-deoxy-beta-D-galactopyranosyl-(1 --> 4)-3-O-methyl-6-deoxy-beta-D-galactopyranoside], and 12beta-benzoyloxy-11alpha-isovaleroyloxy-8beta,14beta-dihydroxypregn-20-one-3-O-[beta-D-glucopyranosyl (1 --> 4)-3-O-methyl-6-deoxy-beta-D-allopyranosyl-(1 --> 4)-beta-D-cymaropyranosyl-(1 --> 4)-beta-D-cymaropyranoside]. The structures were determined by detailed analysis of one- and two-dimensional NMR spectra as well as by chemical means. The compounds showed cytotoxic activities towards brine shrimp having IC50 values of 1.19 x 10(-4), 8.83 x 10(-5), 2.64 x 10(-4), 2.26 x 10(-4), 2.39 x 10(-4) and 1.70 x 10(-4) M, respectively. This is the first report of the isolation of these compounds from a natural source.

Functional, biochemical, and morphological hepatobiliary effects in rats chronically exposed to a steroidal antiandrogen.

Yellow-brown deposits in intrahepatic bile ducts and portal macrophages were observed for male, but not female, Sprague- Dawley rats fed zanoterone, a steroidal antiandrogen, for >=3 months. The lesion did not affect biliary canaliculi and was associated with changes of biliary epithelium, portal chronic inflammation, and bile duct proliferation. Deposit formation was assumed to be related to a gender-related anomaly in bile composition and/or flow. Therefore, the pathogenesis of the lesion was investigated in male, female, and orchiectomized rat. Hepatobiliary structure and function were evaluated after 3 months of treatment and 3 months of reversibility. Drug biliary disposition was evaluated at 3 months. Sulfobromophthalein clearance, bile flow, and plasma concentration and biliary excretion rate of cholesterol were increased at the end of the treatment phase without significant sex-related differences. These effects are consistent with the hepatic enzyme induction potential of the drug, were accompanied by perivenous hepatocellular hypertrophy and increased liver weights, and were no longer observed at the end of the recovery phase. Histomorphologic evidence of cholestasis was observed for most intact and orchiectomized males, the lesion being slightly less pronounced for the latter. Deposits were present at the end of the recovery phase, but were confined to macrophages in all but one case. The lesion differed from a protoporphyria, or precipitates of bile pigments, cholesterol, or proteins. The drug was extensively metabolized with major gender-related differences. Glucuronides of a 16- hydroxy- and another unidentified metabolite were the major metabolites found in bile of males, while a 15-hydroxy-glucuronide was the major metabolite for females. The concentration and biliary excretion of the 16-hydroxy- glucuronide markedly increased after chronic exposure. A possible explanation for pigment deposition in males is that the drug is converted to a metabolite(s) which is excreted at a rate beyond the solubilization potential of bile and, therefore, precipitates in bile ducts.