Spectroscopic examination of purified extracts of the rumen content of sheep intoxicated by Brachiaria decumbens revealed the presence of two spirostanes, identified as epi-sarsasapogenin and epi-smilagenin. Sarsasapogenone was obtained by the oxidation of sarsasapogenin. The reduction of sarsasapogenone using lithium aluminum hydride yielded isomeric products, sarsasapogenin (20%) and epi-sarsasapogenin (80%).
Spectroscopic examinations of purified extracts of the rumen content of sheep intoxicated by Brachiaria decumbens revealed the presence of a mixture of sapogenins, identified as 3-spirostanols. These isomeric steroid sapogenins (C27H44O3) are believed the toxic principles in causing toxicity in sheep after feeding on B. decumbens.
Centella asiatica (L.) Urban (Apiaceae), a small annual plant that grows in India, Sri Lanka, Malaysia, and other parts of Asia, is well-known as a medicinal herb with a long history of therapeutic uses. The bioactive compounds present in C. asiatica leaves include ursane-type triterpene sapogenins and saponins-asiatic acid, madecassic acid, asiaticoside, and madecassoside. Various bioactivities have been shown for these compounds, although most of the steps in the biosynthesis of triterpene saponins, including glycosylation, remain uncharacterized at the molecular level. This chapter describes an approach that integrates partial enzyme purification, proteomics methods, and transcriptomics, with the aim of reducing the number of cDNA candidates encoding for a glucosyltransferase involved in saponin biosynthesis and facilitating the elucidation of the pathway in this medicinal plant.
Introduction: This study aims to build a standardization method for preparation of effective powder from
FSA and to quantify diosgenin in FSA. Methodology: One kg of FS were used in this study. Setting: BMS, KOM
and KOP, IIUM Kuantan campus. FS were washed with distilled water to exclude any foreign matter, and
were then air dried. FS-powder were put in distilled water in a ratio of 1 g of powder in 20 ml of distilled
water and were shaken at room temperature for 24 hours. Ten mg of hydrolyzed extract sample was diluted
in 10 ml volumetric flask with methanol for 15 minutes. Chromatographic estimation was performed using
an equilibrated reverse phase Eclipse XDB-C18 column (particle size 5 µg, 4.6 mm x 150 mm). Results: One
gram of FSA extract was hydrolyzed to produce sapogenins and 46.6% was recovered. A calibration curve
that was constructed based on five dilutions of diosgenin standard at concentrations of 2, 5, 10, 20, 30 and
50 ppm produced a linear graft (r = 0.999). The concentration of diosgenin in FSA extract as calculated using
the regression analysis was found to be 29.66 µg/ml, 13.81 % w/w on dried weight basis. Conclusion:
Preparation and standardization of effective powder from FSA are the corner stone of many scientific
researches in IIUM and Malaysia. Diosgenin is available in the FSA in adequate concentration. The adequate
amount of diosgenin in the FSA will guide us to do further study in the way of preparation of a natural
product that can be used in the field of reversible anti-fertility therapy.
The LHb expression is up-regulated during puberty in female zebrafish. However, the molecular mechanism underlying how LHb expression is regulated during puberty remains largely unknown. In this study, we found that the mRNA expression levels of lhb, fshb and cyp19a1b were up-regulated along with the puberty onset in zebrafish. Among the three nuclear estrogen receptors (nERs), the esr2b is the only type whose expression is significantly up-regulated during puberty onset in the pituitary. However, in situ hybridization results revealed that lhb mRNA was colocalized with esr1 and esr2a but not esr2b. Exposure to estradiol (E2) significantly stimulates LHb expression in both wild-type and kiss1-/-;kiss2-/-;gnrh3-/- triple knockout pubertal zebrafish. Moreover, exposure of cultured pituitary cells to E2 increased the LHb expression, indicating that the estrogenic effect on LHb expression could be acted at the pituitary level. Finally, we cloned and analyzed the promoter of lhb by luciferase assay. Our results indicated that the E2 responsive regions of lhb promoter for ERα and ERβ2 are identical, suggesting that ERα and ERβ2 could bind to the same half ERE region of the promoter of lhb, exhibiting a classical ERE-dependent pathway. In summary, we demonstrate that E2 could directly act on the pituitary level to stimulate LHb transcription during puberty in zebrafish.