The Punica granatum L. (pomegranate) by-product POMx was partitioned between water, EtOAc and n-BuOH, and the EtOAc and n-BuOH extracts were purified by XAD-16 and Sephadex LH-20 column chromatography to afford ellagic acid (1), gallagic acid (2), punicalins (3), and punicalagins (4). Compounds 1 - 4 and the mixture of tannin fractions (XAD-16 eluates) were evaluated for antioxidant, antiplasmodial, and antimicrobial activities in cell-based assays. The mixture of tannins (TPT), XAD-EtOAc, XAD-H2O, XAD-PJ and XAD-BuOH, exhibited IC50 values against reactive oxygen species (ROS) generation at 0.8 - 19 microg/mL. Compounds 1 - 4 showed IC50 values of 1.1, 3.2, 2.3 and 1.4 microM, respectively, against ROS generation and no toxicity up to 31.25 microg/mL against HL-60 cells. Gallagic acid (2) and punicalagins (4) exhibited antiplasmodial activity against Plasmodium falciparum D6 and W2 clones with IC50 values of 10.9, 10.6, 7.5 and 8.8 microM, respectively. Fractions XAD-EtOAc, XAD-BuOH, XAD-H2O and XAD-PJ compounds 1 - 4 revealed antimicrobial activity when assayed against Escherichia coli, Pseudomonas aeruginosa, Candida albicans, Cryptococcus neoformans, methicillin-resistant Staphylococcus aureus (MRSA), Aspergillus fumigatus and Mycobacterium intracellulare. Compounds 2 and 4 showed activity against P. aeruginosa, C. neoformans, and MRSA. This is the first report on the antioxidant, antiplasmodial and antimicrobial activities of POMx isolates, including structure-activity relationships (SAR) of the free radical inhibition activity of compounds 1 - 4. Our results suggest a beneficial effect from the daily intake of POMx and pomegranate juice (PJ) as dietary supplements to augment the human immune system's antioxidant, antimalarial and antimicrobial capacities.

A comparison of the product yield, total phenolics, total flavonoids, and antioxidant properties was done in different leafy vegetables/herbs (basil, chard, parsley, and red kale) and fruit crops (bell pepper, cherry tomatoes, cucumber, and squash) grown in aeroponic growing systems (AG) and in the field (FG). An average increase of about 19%, 8%, 65%, 21%, 53%, 35%, 7%, and 50% in the yield was recorded for basil, chard, red kale, parsley, bell pepper, cherry tomatoes, cucumber, and squash, respectively, when grown in aeroponic systems, compared to that grown in the soil. Antioxidant properties of AG and FG crops were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DDPH) and cellular antioxidant (CAA) assays. In general, the study shows that the plants grown in the aeroponic system had a higher yield and comparable phenolics, flavonoids, and antioxidant properties as compared to those grown in the soil.

As part of our search for new antifungal agents from natural resources, 22 C-27 steroidal saponins and 6 steroidal sapogenins isolated from several monocotyledonous plants were tested for their antifungal activity against the opportunistic pathogens Candida albicans, Candida glabrata, Candida krusei, Cryptococcus neoformans, and Aspergillus fumigatus. The results showed that the antifungal activity of the steroidal saponins was associated with their aglycone moieties and the number and structure of monosaccharide units in their sugar chains. Within the 10 active saponins, four tigogenin saponins (compounds 1 to 4) with a sugar moiety of four or five monosaccharide units exhibited significant activity against C. neoformans and A. fumigatus, comparable to the positive control amphotericin B. The antifungal potency of these compounds was not associated with cytotoxicity to mammalian cells. This suggests that the C-27 steroidal saponins may be considered potential antifungal leads for further preclinical study.

Many health benefits of pomegranate products have been attributed to the potent antioxidant action of their tannin components, mainly punicalagins and ellagic acid. While moving through the intestines, ellagitannins are metabolized by gut bacteria into urolithins that readily enter systemic circulation. In this study, the antioxidant properties of seven urolithin derivatives were evaluated in a cell-based assay. This method is biologically more relevant because it reflects bioavailability of the test compound to the cells, and the antioxidant action is determined in the cellular environment. Our results showed that the antioxidant activity of urolithins was correlated with the number of hydroxy groups as well as the lipophilicity of the molecule. The most potent antioxidants are urolithins C and D with IC(50) values of 0.16 and 0.33 microM, respectively, when compared to IC(50) values of 1.1 and 1.4 microM of the parent ellagic acid and punicalagins, respectively. The dihydroxylated urolithin A showed weaker antioxidant activity, with an IC(50) value 13.6 microM, however, the potency was within the range of urolithin A plasma concentrations. Therefore, products of the intestinal microbial transformation of pomegranate ellagitannins may account for systemic antioxidant effects.

Phytochemical investigation of the fruits of Schisandra chinensis led to the isolation of 13 lignans including schisandrene (13), a new lignan based on a dibenzocyclooctadiene backbone with an exocyclic double bond. Its structure and absolute configuration were established using NMR, MS, and CD data. Antioxidant activity of the lignans was evaluated using a DCFH-DA cellular-based assay. The structure-activity relationships of the dibenzocyclooctadiene lignans showed that the exocyclic methylene functionality was essential for antioxidant activity, with the benzoyloxy group probably enhancing such effects.