Antioxidant and anti-inflammatory potential of some dietary cucurbits

Abstract

Objective: The inflammatory problems and associated diseases in the gastrointestinal tract are known to exist in a sizable fraction of the population. It results due to complex interaction between food, enteric microbes and the host. Therefore, the cucurbits as an easily digestible diet were evaluated for their antioxidant and anti-inflammatory activities. Methods: Antioxidant properties of cucurbits (Lagenaria siceraria, Ls; Cucurbita pepo, Cp; Luffa cylindrical, Lc) were evaluated in vitro following xylenol orange or Amplex® Red dye method. Anti-inflammatory properties of cucurbits with respect to cyclooxygenase (COX)-1 and 2 were studied and interleukin (IL)-1β and tumor necrosis factor (TNF)-α in serum samples of lipopolysaccharide (LPS)-inflamed mice. Results: The inhibition rate of superoxide radicals by Ls, Cp and Lc was 40, 36 and 31%, respectively, at a concentration of 0.08 mg/ml. The perhydroxyl radical scavenging activity was in a declining order and maximum effect was exhibited by Ls. With respect to COX-1 inhibition, IC50 for indomethacin, Cp, Lc and Ls were estimated to be 0.0154, 0.026, 0.0337 and 0.0335 mg/µl; and IC50 against COX-2 were 0.0427, 0.023, 0.0183 and 0.0150 mg/µl, respectively. In vivo study revealed that Ls, Lc, indomethacin and Cp correspondingly down-regulated the expression of IL-1β by 52, 68, 75 and 126 pg/100 µl, significantly less than control (260 pg/100 µl). TNF-α was also reduced significantly more by Ls, Lc, indomethacin and Cp by 12, 16, 20 and 26 pg/100 µl, respectively, than control (46 pg/100 µl). Conclusion: The dietary cucurbits seem to have potential for developing a non-toxic therapeutic product.