No description available.

The objectives of this study were to investigate the characteristics and mechanism of gonad maturation including identified maturation inducing steroids and its physiological role in the final oocyte maturation (FOM) in yellowfin porgy. yellowfin porgy, Acanthopagrus latus are functional male for the first year of life but begin to change sex during the second year. Only 30~50% of cultured yellowfin porgy are change into females in 2-year-old, while 80% fish become females at 3-year-old. Vitellogenesis were observe between August and November and have the highest gonadosomatic index (GSI %) at 6.88 % and 14.35 % in 2 and 3-year-old female yellowfin porgy respectively. Highest serum levels of T occurred simultaneously during spawning season in one and two years of age in functional male, while highest level concentration E2 were observed at the same time in two and three years old female fish. GSI increased 1.5-fold during FOM and reach 2-fold at germinal vesicle breakdown stage (GVBD). Oogenesis in 3-year-old female yellowfin porgy was divided into three stages¡F(1) previtellogenic stage from February to July with the primary oocytes¡F(2) vitellogenic stage from August to October and with full growth oocyte of diameter at 400

Several terpenoids isolated from a Formosan gorgonian coral Isis hippuris have shown significant cytotoxic activity against various cancer cell lines. In our studies, the EtOAc and n-Hexane extracts showed potent cytotoxic response toward P-388, A549 and HT-29 cancer cell lines. In order to search other active components, we have studied the chemical constituents of I. hippuris from a Green Island specimen. Thus, the investigation on the chemical content of this extract was carried out. After our hard working, we haved isolated eleven new steroids (1- 11) , A-nor-2-carboxy-22-epi-hippurin-1 (1)¡B2a-acetoxy-3a-hydroxy- 11b-hydroxy-24-methyl-22,25-epoxy-5a-furostan-18,20b-lactone (2)¡B2a,3a-dihydroxy-11b-hydroxy-24-methyl-22,25-epoxy-5a-furostan-18,20b-lactone (3)¡B2a-hydroxy-3a-acetoxy-11b-hydroxy-24-methyl-22, 25-epoxy-5a-furostan-18,20b-lactone (4)¡B2a-hydroxy-3a-acetoxy-24- methyl-11b,18;18,20b;22,25-triepoxy-5a-furostane (5)¡B2a-acetoxy- 3a-hydroxy-24-methyl-11b,18;18,20b;22,25-triepoxy-5a-furostane (6)¡Bhippuristerone K (7)¡Bhippuristerone L (8)¡B hippuristerol F (9)¡B1a, 3b,5b,11a-tetrahydroxy gorgostan-6-one (10)¡B22-epi-hippuristan-11-one (11). We also isolated two known compounds, 22-epi- hippuristanol (19)¡B 2-desacetyl-22-epi-hippurin-1 (25). The structures of new compounds (1-11) were elucidated by spectroscopic evidences (IR, MS, 1D NMR, 2D NMR) and the comparison of literature. Among those, the stereochemistry of compound 1, with a new skeleton, were confirmed by single-crystal X-ray diffraction analyses. Unfortunately, because of the poor yield, the cytotoxicity test can not be carry out. But now, we try to get enough by semisynthesis.

Investigation on the chemical constituents of the EtOH extract of the soft coral Lobophytum sarcophytoides, collected off the coast of Dongsha Atoll, Taiwan, has led to the isolation of ten natural compounds 1¡V10, including four new cembrane-type diterpenoids, Sarcophytolins A¡VD (1¡V4) and one new polyhydroxylated steroid 23, 24-Dimethyl-cholesta-5, 16-diene-3£], 20£\-diol (5) along with five know compounds 6¡V10¡CThe structure of compounds 1¡V10 were established by detailed spectral data analysis (IR, MS, 1D, 2D NMR) and by comparison of the spectral data with those of the related known compounds. The relative stereochemistries of compound 5 was further confirmed by X-ray single-crystal diffraction analysis. The cytotoxicity of compounds 1¡V10 against the Daoy (human medulloblastoma), Hep-2 (human laryngeal carcinoma), MCF-7 (human breast adenocarcinoma), CCRF-CEM (human T-cell acute lymphoblastic leukemia), and DLD-1/WiDr (human colon adenocarcinoma) tumor cell lines were determined. Compounds 6, 8, 9, and 10 exhibited moderate cytotoxicities against the tested tumor cells. Furthermore, compounds 1, 2, 4, 6, and 10 were found to show significant activity against the accumulation of the pro-inflammatory iNOS protein at 10 £gM.

Studies directed toward the total synthesis of the cytotoxic steroidal alkaloid cortistatin A were carried out. In a model system, it was determined that a sequence of reactions involving a lithiocyclopropene addition-intramolecular [4 + 2] cycloaddition cascade and subsequent cyclopropylcarbinyl rearrangement allowed for ready access to the BCD rings of the core steroid. Implementation of this methodology en route to the fully functionalized natural product proved an effective means for the elaboration of the A ring carbocyclic framework. / text

Not available / text

No description available.

Dorsal raphe nucleus (DRN) neurons projects to widespread areas throughout the brain and are involved in many physiological functions and neuropsychiatric disorders. In particular, DRN serotonin (5-HT) neurons are thought to be implicated in major depressive disorder (MDD) as are steroid hormones. Therefore, the aim of this thesis was to assess the effects of some neurosteroids on DRN neurons in non-anaesthetized rats. Initially, we examined electrophysiological properties of dorsal raphe cells across the sleep---wake cycle in non-anaethetized rats. In this first study we characterized six distinct neuronal populations in the DRN based on spike waveform and firing pattern. We then examined the effects of DHEA-S and testosterone (T) on the firing properties of DRN neuronal populations previously characterized. We observed that most populations exhibited an initial decrease in firing activity following one week of treatment. However, there was a great variability in responses across the populations.

Solasodine, a steroidal alkaloid, is used by the pharmaceutical industry in certain parts of the world, as a raw material in the synthesis of steroid drugs. The compound is contained in many members of the genus Solanum, including S. mauritianum Scop., a common weed in South Africa. The levels of solasodine in three culture systems of S. mauritianum under various cultural conditions were examined. A high performance liquid chromatographic (HPLC) method was developed for the detection of solasodine. In order that low-cost, fixed wavelength ultra-violet detectors could be used, which would make the technique more widely applicable, a derivatization step, namely benzoylation, was included in the sample preparation. An extraction and purification protocol was then established, that complemented the HPLC technique and allowed successful detection of solasodine levels in a whole range of different sample types, including callus, suspension cultured cells, roots, stems and leaves. The three culture systems examined were callus, suspension and hairy root cultures. The callus system was used to establish which cultural parameters affected solasodine content in vitro to the greatest extent. A control culture was grown on a MURASHIGE and SKOOG (1962) medium (excluding glycine) supplemented with 3 % sucrose, 0.1 g I ¯¹ myo-inositol and lacking hormones. This culture contained an average of 9.2 μg g ¯¹ DW of solasodine. Many factors, including alteration of the carbon : nitrogen ratio and substitution of Gelrite for agar as the gelling agent, had no significant effect on the solasodine content of the callus or its growth. Greatly increased solasodine productivity of the callus was recorded when glucose was substituted for sucrose, the medium strength was reduced by half, or certain combinations of the hormones benzyladenine and naphthaleneacetic acid were added to the medium. The maximum levels of solasodine recorded in these cultures, on a per gram dry weight basis, equalled those of the vegetative parts of an intact S. mauritianum plant, but were approximately three times lower than those of the green berries. Suspension cultures could not be grown on the same medium as the callus cultures. Substitution of the vitamin complement of MURASHIGE and SKOOG (1962) with the so-called RT vitamin complement of KHANNA and STAB A (1968), resulted in successful growth and maintenance of S. mauritianum suspension cultures. The auxin, 2,4-dichlorophenoxyacetic acid (1 mg I ¯¹) was included in the medium. None of the suspension cultures grown on this medium, or slight modifications thereof, contained any trace of solasodine. This system could therefore not be used for the synthesis of solasodine in vitro. Hairy root cultures were initiated by inoculation of an excised hypocotyl of an in vitro-grown seedling of S. mauritianum with a 48 hour culture of Agrobacterium rhizogenes LBA 9402. Transformation frequency was extremely low. The transformed roots could be excised and grown successfully on a phytohormone-free medium, either in the solid or liquid form. Solasodine was extracted from hairy roots grown in a full-strength liquid MURASHIGE and SKOOG (1962) medium (excluding glycine) supplemented with 3 % sucrose and 0.1 g I ¯¹ myo-inositol, a half-strength such medium and a full-strength medium with 3 % glucose substituting for 3 % sucrose. In the latter medium, growth was very poor, whereas in the other two media, growth was very rapid . Both solasodine content (126 μg g¯¹DW) and root growth were greatest in the full-strength medium supplemented with 3 % sucrose. This level of solasodine was greater than that found in any of the callus cultures or vegetative parts of the plant and approached that of the green berries of S. mauritianum. Overall, of the culture types of S. mauritianum tested, the hairy root culture system appears to be most favourable for the in vitro production of solasodine. / Thesis (Ph.D)-University of Natal, Pietermaritzburg, 1993.

Thesis (Ph. D.)--McMaster University (Canada), 1990. / Source: Dissertation Abstracts International, Volume: 62-13, Section: A, page: 0000.