Isolation and characterisation of altissimin: a novel cytotoxic flavonoid C-apioglucoside from Drimia altissima (Asparagaceae).

Flavonoids are a class of biologically active compounds with various proven nutraceutical benefits. In flavonoid C-glycosides, the aglycones are attached to sugar residues via cleavage-resistant C-C bonds which alter typical flavonoid pharmacokinetic properties. In these compounds, the combination of biological activities from the flavonoid moieties and sugar residues create unique and more diverse biological functions than those of O-glycosylated and unsubstituted flavonoids. Through a series of reverse phase chromatography techniques and various spectroscopic methods, the phytochemical investigation of Drimia altissima (L.F.) Ker Gawl., a specie from the Asparagaceae family, led to the isolation and chemical characterisation of a novel C-glucosylflavonoid, altissimin, with a unique apioglucoside arrangement to the apigenin aglycone. Altissimin was found to possess strong in vitro anti-proliferative activity against HeLa cervical cancer cells.

In Vitro Evaluation of the Phytopharmacological Potential of Sargassum incisifolium for the Treatment of Inflammatory Bowel Diseases.

Background: Comprised of Crohn's disease and ulcerative colitis, inflammatory bowel diseases (IBD) are characterized by chronic inflammation of the gastro-intestinal tract, which often results in severe damage to the intestinal mucosa. This study investigated metabolites from the South African endemic alga, Sargassum incisifolium, as potential treatments for IBD. Phytochemical evaluation of S. incisifolium yielded prenylated toluhydroquinones and toluquinones, from which semi-synthetic analogs were derived, and a carotenoid metabolite. The bioactivities of S. incisifolium fractions, natural products, and semi-synthetic derivatives were evaluated using various in vitro assays. Methods: Sargahydroquinoic acid isolated from S. incisifolium was converted to several structural derivatives by semi-synthetic modification. Potential modulation of IBD by S. incisifolium crude fractions, natural compounds, and sargahydroquinoic acid analogs was evaluated through in vitro anti-inflammatory activity, anti-oxidant activity, cytotoxicity against HT-29 and Caco-2 colorectal cancer cells, and PPAR-γ activation. Results: Sargahydroquinoic acid acts on various therapeutic targets relevant to IBD treatment. Conclusions: Conversion of sargahydroquinoic acid to sarganaphthoquinoic acid increases peroxisome proliferator activated receptor gamma (PPAR-γ) activity, compromises anti-oxidant activity, and has no effect on cytotoxicity against the tested cell lines.