Objective: To find a new natural source of antioxidant, the phenolic contents and antioxidant activities of some secondary metabolites extracted from roots of Ziziphus lotus were evaluated. Methods: The total polyphenol contents were determined spectrophotometrically. Pyrrocatechol, catechin and cyanidin equivalents were used for these parameters. The antioxidant activities of the extracts were determined by several in vitro systems of assays, namely DPPH radical scavenging activity method, b-Carotene Bleaching assay (BCB), Ferric Reducing Antioxidant Power assay (FRAP) and Total Antioxidant capacity test (TAC). Results: The quantitative estimation showed that the roots of Z. lotus were rich in polyphenols (20.09 mg PE/g DW) and proanthocyannidins (1.56%) and they contained a small amount of flavonoids (0.02 mg CE/g DW). The most fractions exhibited high antioxidant activities, and some even showed higher potency than the standard synthetic antioxidants in some instances. In DPPH assay, all extracts had shown significant inhibition (58.535 -94.730% at 1 mg/mL). In addition, the IC 50 values ranged from 0.211 to 0.816 mg/mL, compared to 0.110, 0.214, 0.214 and 0.413 mg/mL for gallic acid, tannic acid, butylated-hydroxyanisol and ascorbic acid respectively. In (BCB) assay, the extracts showed strong inhibition (55.55 -100.00% at 1 mg/mL) and the IC 50 values ranging from 0.123 to 0.850 mg/mL compared to 0.433 mg/mL for gallic acid. A dose dependant curve was obtained for all extracts in the FRAP assay. However, the antioxidant potencies of ascorbic acid and extracts were comparable at low concentrations. The majority of extracts showed the highest value of antioxidant activity, based on TAC test (0.073 -0.398 mg ascorbic acid / mg extract). Conclusion: The results indicate that Z. lotus roots could be an important sources of natural antioxidants.

No abstract

Zizyphus lotus (Zl) is used widely as a source of food and for the treatment of various ailments. Therefore, we investigated the biological activities of Zl against obesity and related disorders. Hence, male Wistar rats received either control diet, high fat diet (HFAD), or HFAD supplemented with the Zl pulp (HFADP) for 14 weeks. RAW 264.7 cells were used for the determination of antiinflammatory activities in vitro. It was observed that HFDP resulted in significantly reduced weight, blood sugar, and oxidative stress than HFAD. In addition, Zl extract co‐treatment with LPS reduced the mRNA expression of MCP‐1, pro‐inflammatory cytokines (IL‐6, TNF‐α), and increased the level of IL‐10, an antiinflammatory cytokine, in LPS‐stimulated RAW 264.7 cells. Moreover, nitric oxide synthesis and the expression of iNOS were decreased by Zl extract in RAW 264.7 cells. Zl extract also possessed a significant antioxidant capacity and ferric‐reducing power. Our results validate the traditional use of Zl. Practical applications Zizyphus lotus is commonly used as food in different countries and is easily available. Scientific validation of the traditional use of plants can be significant in the prevention and treatment of different disorders. Naturally occurring products are generally safe to use, have fewer side effects, and can be self‐administered. Hence, specialized health‐care supervision is not necessary. Our study supports the traditional use of Zizyphus lotus to prevent and decrease obesity and related disorders.