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Chromatographic investigation of fruits obtained from Citrullus colocynthis, growing in Saudi Arabia, led to isolation of two compounds; Cucurbitacin E glucoside (Cu E, 1), and Cucurbitacin I glucoside (Cu I, 2). The chemical structures of 1 and 2, were elucidated by spectroscopic analyses include; 1D ((1)H and (13)C) and 2D (COSY, HMQC and HMBC) NMR and ESI-MS spectroscopy. The in vitro cytotoxic activity against hepatoma cell line (HepG2) and mice-bearing tumor of Ehrlich's ascites carcinoma (EAC) of the compounds were estimated. Both compounds had potent inhibitory activity on HepG2 with IC(50) 3.5 and 2.8 nmol/mL, respectively. In addition to these activities, the in vivo study employing EAC, showed the capability of both compounds to prolong the survival time, life span and normalize the biochemical parameters of the infected mice with EAC., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Background: Macroalgae can be viewed as a potential antioxidant and anti-inflammatory sources owing to their capability of producing compounds for its protection from environmental factors such as heat, pollution, stress, oxygen concentration, and UV radiations., Objective: To isolate major compounds which are mainly responsible for the pharmacological activity of brown alga under investigation, Sargassum sp., Materials and Methods: Algal material was air dried, extracted with a mixture of organic solvents, and fractionated with different adsorbents. The structures of obtained pure compounds were elucidated with different spectroscopic techniques, and two pure materials were tested for protection of DNA from damage, antioxidant, antitumor, and cytotoxicity., Results: Four pure compounds were obtained, of which fucosterol (1) and fucoxanthin (4) were tested; it was found that fucoxanthin has strong antioxidant and cytotoxicity against breast cancer (MCF-7) with IC(50) = 11.5 μg/ml., Conclusion: The naturally highly conjugated safe compound fucoxanthin could be used as antioxidant and as an antitumor compound.

Separation of the extract of the underground tubers of Cyperus conglomeratus Rottb. (family Cyperaceae) afforded, in addition to known compounds, two novel flavans, which were identified, by one and two dimensional NMR, MS and IR spectra, as 5-hydroxy-7,3',5'-trimethoxyflavan and 5,7-dihydroxy-3',5'-dimethoxy-6-prenylflavan.