Tzy-Ming Lu

Antityrosinase and antioxidant effects of ent-kaurane diterpenes from leaves of Broussonetia papyrifera.

Three new ent-kaurane type diterpenes, broussonetones A-C (1-3), were isolated from leaves of Broussonetia papyrifera, together with seven known compounds, and their structures determined by 1D and 2D NMR and MS methods. Compounds 1-3 were marginal inhibitors of tyrosinase. Antioxidant assays showed them also to be inhibitors of xanthine oxidase. The mild inhibition of tyrosinase and significant inhibition of xanthine oxidase suggests that 1-3 could be useful ingredients in the development of skin-protecting cosmetics.

Immunomodulatory Activities of Medicinal Mushroom Grifola frondosa Extract and Its Bioactive Constituent

Grifola frondosa (GF), a high value medicinal mushroom in China and Japan, is popularly consumed as traditional medicines and health foods, especially for enhancing immune functions. In this study, our aim was to examine the immunomodulatory activities of GF and its bioactive compound ergosterol peroxide (EPO) in lipopolysaccharide (LPS)-induced human monocytic (THP-1) cells. At low concentrations, EPO but not other extracts showed a full protection against LPS-induced cell toxicity. EPO significantly blocked MyD88 and VCAM-1 expression, and cytokine (IL-1β, IL-6 and TNF-α) production in LPS-stimulated cells. It also effectively inhibited NF-κB activation, which was further confirmed with siRNA treatment. These results conclude that EPO may play an important role in the immunomodulatory activity of GF through inhibiting the production of pro-inflammatory mediators and activation of NF-κB signaling pathway.

A novel monoterpene-stilbene adduct with a 4,4-dimethyl-2,3-diphenylchromane skeleton from Artocarpus xanthocarpus.

Artoxanthochromane (1), a DielsAlder‐type conjugation product of 4‐isopropenylresorcinol and oxyresveratrol, was isolated from the heartwood of Artocarpus xanthocarpus and characterized. The structure of 1 was elucidated as 2‐(2,4‐dihydroxyphenyl)‐3‐(3,5‐dihydroxyphenyl)‐7‐hydroxy‐4,4‐dimethylchromane by 1D‐ and 2D‐NMR spectroscopy, and other spectral evidences. A plausible metabolic mechanism was proposed to illustrate the biosynthetic pathway of artoxanthochromane. This compound exhibited mild mushroom tyrosinase inhibitory, and weak free radical‐scavenging activities on ABTS+. and superoxide anion (O

Inhibitory potential of Grifola frondosa bioactive fractions on α‐amylase and α‐glucosidase for management of hyperglycemia

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Effects of Grifola frondosa non-polar bioactive components on high-fat diet fed and streptozotocin-induced hyperglycemic mice.

) free radicals.

Free-Radical-Scavenging, Antityrosinase, and Cellular Melanogenesis Inhibitory Activities of Synthetic Isoflavones.

This study examined the inhibitory effects of Grifola frondosa (GF), a medicinal mushroom popularly consumed in traditional medicine and health food, on digestive enzymes related to type 2 diabetes; chemical profiles and inhibitory kinetics of its bioactive fractions were also analyzed. Results showed that all GF extracts showed weak anti‐α‐amylase activity; however, strong anti‐α‐glucosidase activity was noted on GF n‐hexane extract (GF‐H). Further fractionation confirmed that compared with acarbose (a commercial α‐glucosidase inhibitor), the nonpolar fraction of GF possessed a stronger anti‐α‐glucosidase activity but a weaker anti‐α‐amylase activity. These activities were not derived from ergosterol and ergosterol peroxide, two major compounds of this fraction. The inhibitory kinetics of GF‐H on α‐glucosidase was competitive inhibition. GF‐H was as good as acarbose in inhibiting the starch digestion in vitro. Oleic acid and linoleic acid could be the major active constituents that have contributed to the potency of GF in inhibiting α‐glucosidase activity.

Transdermal delivery of capsaicin derivative-sodium nonivamide acetate using microemulsions as vehicles.

Abstract Context: Consumption of medicinal mushrooms for disease prevention and maintaining health has a very long history in Asia. Grifola frondosa (Fr) S.F. Gray (GF) (Meripilaceae) is a medicinal fungus popularly used for enhancing immune systems, lowering blood glucose, and improving spleen, stomach, and nerve functions. Objective: This study examines the hypoglycemic effects of GF in vitro and in vivo, and analyzes the chemical profiles of its bioactive components. Materials and methods: In vitro hypoglycemic effects of GF was evaluated enzymatically using α-amylase and α-glucosidase inhibition assays, whereas in vivo study was conducted on high-fat diet fed and streptozotocin (HFD + STZ)-induced hyperglycemic mice. GC-MS was used to determine the chemical profiles of bioactive components. Results: The non-polar fraction of GF exhibited a stronger anti-α-glucosidase activity (IC50: 0.0332 mg/ml) than acarbose, but its anti-α-amylase activity (IC50: 0.671 mg/ml) was weaker. Oral administration of GF at 600 mg/kg (GF600) significantly lowered the blood glucose, HbA1c, average blood glucose, and serum total cholesterol levels in hyperglycemic mice. Although GF was found to contain mainly oleic acid and linoleic acid, their levels in the fungus were low, suggesting that the effects of GF on HFD + STZ-induced hyperglycemic mice could be due to factors other than these fatty acids. Conclusion: These results conclude that GF possesses anti-α-glucosidase activity, and hypoglycemic effect in HFD + STZ-induced hyperglycemic mice.

Potential antioxidants and tyrosinase inhibitors from synthetic polyphenolic deoxybenzoins.

In this study, we examined the potential of synthetic isoflavones for application in cosmeceuticals. Twenty‐five isoflavones were synthesized and their capacities of free‐radical‐scavenging and mushroom tyrosinase inhibition, as well as their impact on cell viability of B16F10 murine melanoma cells and HaCaT human keratinocytes were evaluated. Isoflavones that showed significant mushroom tyrosinase inhibitory activities were further studied on reduction of cellular melanin formation and antityrosinase activities in B16F10 melanocytes in vitro. Among the isoflavones tested, 6‐hydroxydaidzein (2) was the strongest scavenger of both ABTS.+ and DPPH. radicals with SC50 values of 11.3±0.3 and 9.4±0.1 μM, respectively. Texasin (20) exhibited the most potent inhibition of mushroom tyrosinase (IC50 14.9±4.5 μM), whereas retusin (17) showed the most efficient inhibition both of cellular melanin formation and antityrosinase activity in B16F10 melanocytes, respectively. In summary, both retusin (17) and texasin (20) exhibited potent free‐radical‐scavenging capacities as well as efficient inhibition of cellular melanogenesis, suggesting that they are valuable hit compounds with potential for advanced cosmeceutical development.