A possible general mechanism for ultrasound-assisted extraction (UAE) suggested from the results of UAE of chlorogenic acid from Cynara scolymus L. (artichoke) leaves.

The use of ultrasound-assisted extraction (UAE) for the extraction of chlorogenic acid (CA) from Cynara scolymus L., (artichoke) leaves using 80% methanol at room temperature over 15 min gave a significant increase in yield (up to a 50%) compared with maceration at room temperature and close to that obtained by boiling over the same time period. A note of caution is introduced when comparing UAE with Soxhlet extraction because, in the latter case, the liquid entering the Soxhlet extractor is more concentrated in methanol (nearly 100%) that the solvent in the reservoir (80% methanol) due to fractionation during distillation. The mechanism of UAE is discussed in terms of the effects of cavitation on the swelling index, solvent diffusion and the removal of a stagnant layer of solvent surrounding the plant material.

Naphthaquinones of Alkanna Orientalis (L.) Boiss

The roots of Alkanna orientalis (L.) Boiss yielded a- methyl-n-butyl alkannin (compound 1) and alkannin acetate (compound 2). The compounds were identified by UV; MS; 1H NMR and 13C NMR. Quantitative determination of a- methyl-n-butyl alkannin and alkannin acetate in Alkanna orientalis (L) Boiss roots was established by TLC densitometry

Isolation and NMR spectra of syringaresinol-beta-D-glucoside from Cressa cretica.

The isolation, (1)H-NMR and revised (13)C-NMR assignments of syringaresinol-beta-D-glucoside from Cressa cretica are reported.

Chemical and biological investigations on Zizyphus spina-christi L.

Different extracts and fractions of the leaves, fruits and seeds of Zizyphus spina-christi L. grown in Egypt were investigated in vitro for their antiviral, antifungal and antibacterial activities. The flavonoids quercetin, hyperoside, rutin and quercetin-3-O-[beta-xylosyl-(1-2)-alpha-rhamnoside] 4'-O-alpha- rhamnoside) were isolated.