Applications of the method of molecular rotation differences in structural and stereochemical problems in triterpenes

The specific rotation data of some triterpenoid alcohols and their simple functional derivatives have been correlated by the Barton and Jones method of molecular rotation differences (MRD). Cases in the literature in which the recorded specific rotation data are erroneous have been indicated for possible correction.     

13C NMR spectra of olean-18-ene derivatives

The ¹³C NMR signals of sixteen derivatives of olean-18-ene-triterpenes have been assigned.     

Bioactive Compounds with Added Value Prepared from Terpenes Contained in Solid Wastes from the Olive Oil Industry

Starting from solid wastes from two‐phase olive‐oil extraction, the pentacyclic triterpenes oleanolic acid and maslinic acid were isolated. These natural compounds were transformed into methyl olean‐12‐en‐28‐oate ( 5 ), which then was transformed into several seco‐C‐ring triterpene compounds by chemical and photolytic modifications. The triene seco‐products were fragmented through several oxidative procedures to produce, simultaneously, cis‐ and trans‐decalin derivatives, both potential synthons for bioactive compounds. The chemical behavior of the isolated fragments was investigated, and a suitable approach to several low‐molecular‐weight terpenes was performed. These are interesting processes for the value‐addition to solid waste from the olive‐oil industry.     

Triterpenoids and triterpenoid saponins from the aerial parts of Fagonia indica Burm

As part of our search of new bioactive compounds from indigenous medicinal plants, phytochemical investigation of the aerial parts of Fagonia indica Burm led to the isolation of seven compounds including two new compounds, namely, indicacin (1) and fagonicin (2), and five known compounds (3–7) from the methanol extract. Compounds 6 and 7 are hitherto unreported from this plant. The structures of the new compounds were elucidated from their spectral data, mainly HREIMS, 1D NMR (¹H, ¹³C NMR, and DEPT) and 2D NMR (COSY, NOESY, HSQC and HMBC), and by comparison with the literature data. The new compounds 1 and 2 were assayed for their cytotoxicity against human colorectal cancer cell line H-29. Compound 1 exhibited 51.40% cytotoxicity at 6.25 μM/mL dose whereas compound 2 demonstrated 39.3% cytotoxicity at the same dose.     

Application of mass spectrometry in structural problems in triterpenes

Mass spectral data on 105 pentacyclic triterpenoids have been collated and analysed.From this analysis, it has been possible to identify base peaks which are characteristic of specific stereoskeletons.