The secondary metabolites profiling of Nymphaea nouchali stem (NNSE) extract was carried out using a high-resolution mass spectroscopic technique. The antioxidant effects of NNSE, as well as the underlying mechanisms, were also investigated in tert-butyl hydroperoxide (t-BHP)-stimulated oxidative stress in RAW264.7 cells. Tandem mass spectroscopy with (−) negative mode tentatively revealed the presence of 54 secondary metabolites in NNSE. Among them, phenolic acids and flavonoids were predominant. Phenolic acids (brevifolincarboxylic acid, p-coumaroyltartaric acid, niazinin B, lalioside, 3-feruloylquinic acid, and gallic acid-O-rutinoside), flavonoids (elephantorrhizol, apigenin-6-C-galactoside 8-C-arabinoside, and vicenin-2), sialic acid (2-deoxy-2,3-dehydro-N-acetylneuraminic acid), and terpenoid (α-γ-onoceradienedione) were identified in NNSE for the first time. Unbridled reactive oxygen species/nitrogen species (ROS/RNS) and redox imbalances participate in the induction and development of many oxidative stress-linked diseases. The NNSE exhibited significant free radical scavenging capabilities and was also able to reduce t-BHP-induced cellular generation in RAW264.7 cells. The NNSE prevented oxidative stress by inducing the endogenous antioxidant system and the levels of heme oxygenase-1 (HO-1) by upregulating Nrf2 through the modulation of mitogen-activated protein kinases (MAPK), such as phosphorylated p38 and c-Jun N terminal kinase. Collectively, these results indicate that the NNSE exhibits potent effects in preventing oxidative stress-stimulated diseases and disorders through the modulation of the MAPK/Nrf2/HO-1 signaling pathway. Our findings provide new insights into the cytoprotective effects and mechanisms of Nymphaea nouchali stem extract against oxidative stress, which may be a useful remedy for oxidative stress-induced disorders.

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This work was aimed to study the effect of natural polyphenol extract (Acacia catechu) on physicochemical properties of starch/PVA-based film. Acacia catechu extracts were incorporated in the starch/PVA-(60 : 40%) based films at different concentrations (0.1% to 15%) to the total weight of starch/PVA-based film. The tensile strength (TS) of the starch/PVA blend film was 24 MPa and significantly increased (33.8 MPa) by the addition of acacia (0.5%). Different percentages of urea (1% to 15%) were incorporated in the starch/PVA/acacia-based film. The best tensile strength (11 MPa) and elongation at break (59%) were obtained at 5% urea concentration. This 5% urea-incorporated film was irradiated at different radiation doses; the film showed the best results at 100 krad (tensile strength 15 MPa and elongation at break 69%). Molecular interactions due to incorporation of Acacia catechu were supported by FTIR spectroscopy. Thermal properties (TG/DTA) of all the films were carried out successfully. Water absorption trend of all the films was comparatively high. Urea-incorporated film degraded 94%, and irradiated urea incorporated film degraded 91% within 70 days into the soil.

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