Increasing dietary fiber intake is considered to be an effective way to prevent and relieve the diseases associated with high-income lifestyles. Compared with soluble dietary fiber, comprehensive evaluation about the effects of insoluble dietary fiber on hyperlipidemia is rarely studied. In the present study, the insoluble dietary fiber was extracted from defatted rice bran by enzymatic treatments (IDF-dRB), followed by investigation about the adsorption and antioxidant activities in vitro. Moreover, the alleviating effects of IDF-dRB on hyperlipidemia were evaluated and analyzed. As a result, IDF-dRB possessed good adsorption capacities of glucose and cholesterol, and also exhibited excellent properties in scavenging radicals. Furthermore, intervention with IDF-dRB significantly improved lipid and glucose metabolism and alleviated inflammation and oxidative stress in rats fed high-fat diet. It was also observed that IDF-dRB treatment could recover the decline in species of gut microbiota caused by high fat diet, increase the community richness, and modulate the metabolic function of gut microbiota. In conclusion, the results indicated that IDF-dRB could ameliorate hyperlipidemia from many aspects and offered some perspectives about the effects of diet intervention with insoluble dietary fiber. Practical Application: Rice bran and defatted rice bran are coproducts in the rice processing industry and potentially valuable for the preparation of insoluble dietary fiber. Here an insoluble dietary fiber IDF-dRB was extracted from defatted rice bran and showed good properties in improving lipid and glucose levels, alleviating inflammation and oxidative stress, and modulating gut microbiota in rats fed high-fat diet, suggesting the potential application in ameliorating hyperlipidemia.

Two new diterpenoids, hypoxyterpoids A (1) and B (2), and four new isocoumarin derivatives, hypoxymarins A–D (4–7), together, with seven known metabolites (3 and 8–13) were obtained from the crude extract of the mangrove-derived fungus Hypoxylon sp. The structures of the new compounds were elucidated on the basis of 1- and 2-dimensional (1D/2D) nuclear magnetic resonance (NMR) spectroscopic and mass spectrometric analysis. The absolute configurations of compounds 1, 2, 4, 5, and 7 were determined by comparison of experimental and calculated electronic circular dichroism (ECD) spectra, and the absolute configurations of C-4′ in 6 and C-9 in 7 were determined by [Rh2(OCOCF3)4]-induced ECD spectra. Compound 1 showed moderate α-glucosidase inhibitory activities with IC50 values of 741.5 ± 2.83 μM. Compounds 6 and 11 exhibited DPPH scavenging activities with IC50 values of 15.36 ± 0.24 and 3.69 ± 0.07 μM, respectively.

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