Bioactivity and chemical characterization of Opuntia macrorhiza Engelm. seed oil: potential food and pharmaceutical applications.

In the food industry, there is a continuous search for ingredients that might provide advantageous properties to food products, either considering their nutritional value or bioactivity, as well as flavouring and technological aspects. Crude oils are good examples of this type of ingredient, especially if obtained from nonconventional sources. Accordingly, the Opuntia macrorhiza Engelm. seed oil (OMSO) was chemically characterized and evaluated for different in vitro and in vivo bioactivities. OMSO presented physicochemical characteristics appropriate to be considered as an edible oil, namely low acidity value, stability to oxidation (high peroxide value and low K232 and K270 values), and high contents of unsaturated fatty acids (as shown by the iodine value) and saponifiable matter. Furthermore, this natural oil, owing to its rich phytochemical profile, showed relevant antioxidant activity (especially in lipid peroxidation inhibition assays), α-glucosidase inhibitory activity, cytotoxicity against human tumour cell lines, antibacterial (mainly against Gram positive species) and antifungal properties, as well as anti-inflammatory and analgesic activities. Furthermore, OMSO did not show any sign of acute toxicity on animals, highlighting its possible use in different applications, considering that this natural product is not expected to induce the adverse effects typically associated with synthetic bioactive agents (e.g., ampicillin, amphotericin B, or lysine acetylsalicilate).

Antioxidant, anti-inflammatory, and antiproliferative activities of organic fractions from the Mediterranean brown seaweed Cystoseira sedoides.

The present study was conducted to evaluate the antioxidant, anti-inflammatory, and antiproliferative activities of organic fractions from Cystoseira sedoides (Desfontaines) C. Agardh . Various fractions of C. sedoides (chloroform (F-CHCl3), ethyl acetate (F-AcOEt), and methanol (F-MeOH)) were screened for total phenol content, as well as antioxidant activity, using the stable radical 1,1-diphenyl-2-picrylhydrazyl (DPPH), and assays for determining the reducing power of these fractions. The anti-inflammatory properties of these fractions were assessed using the carrageenan-induced rat paw oedema model. The antiproliferative activity of C. sedoides fractions was evaluated on normal Madin-Darby canine kiney (MDCK), and fibroblast cells and on cancer cell lines (A549, MCF7, and HCT15), using the ability of the cells to metabolically reduce 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) formazan dyes. The F-CHCl3 and F-AcOEt fractions showed significant total phenolic content at 55.09 and 61.30 mg gallic-acid equivalent/g dried sample, respectively. Using the DPPH method, the F-CHCl3 and the F-AcOEt fractions exhibited the strongest radical scavenging activity, with IC50 120 µg/mL for F-CHCl3 and 121 µg/mL for F-AcOEt, which approaches the activity of the powerful antioxidant standard, Trolox (IC50 = 90 µg/mL). The reducing power of the samples was in the following order: F-AcOEt > F-CHCl3  > F-MeOH fraction. The F-CHCl3 and F-AcOEt fractions of C. sedoides tested at different doses (25 and 50 mg/kg, intraperitoneally (i.p)), exhibited a dose-dependent reduction of rat paw oedema. The percentage of inhibition of oedema, 3 h after carrageenan injection, ranged from 67.71% to 73.49% and from 67.74% to 74.58%, for F-CHCl3 and F-AcOEt, respectively. Their effects are comparable with that of lysine acetylsalicylate (300 mg/kg body mass; i.p.), which is used as a reference drug with the ability to inhibit oedema by 66.14%. Our results revealed that the F-CHCl3 and F-AcOEt fractions from C. sedoides showed important antiproliferative properties towards all of the cancer cell lines studied here, as judged by their IC50 values, which ranged from 52.6 to 66.5 µg/mL for A549; 22.4 to 70.2 µg/mL for MCF7, and 250.6 to 255.3 µg/mL for HCT15. Moreover, no visible destruction or alteration of normal cells was observed, even at 500 µg/mL F-CHCl3 or F-AcOEt. These results suggest that C. sedoides fractions might be used as a potential source of natural antioxidant, anti-inflammatory, and antitumor agents. The purification and determination of the chemical structures of the compounds in these active fractions are under investigation. The results could provide a compound(s) with a promising role in future medicines and nutrition, when used either as a drug or a dietary supplement.