Targeted isolation, identification, and antioxidant evaluation of aromatic polyketides from a plant-derived fungus Ophiobolus cirsii LZU-1509.

There are >350 species of the Ophiobolus genus, which is not yet very well-known and lacks research reports on secondary metabolites. Three new 3,4-benzofuran polyketides 1-3, a new 3,4-benzofuran polyketide racemate 4, two new pairs of polyketide enantiomers (±)-5 and (±)-7, two new acetophenone derivatives 6 and 8, and three novel 1,4-dioxane aromatic polyketides 9-11, were isolated from a fungus Ophiobolus cirsii LZU-1509 derived from an important medicinal and economic crop Anaphalis lactea. The isolation was guided by LC-MS/MS-based GNPS molecular networking analysis. The planar structures and relative configurations were mainly elucidated by NMR and HR-ESI-MS data. Their absolute configurations were determined by using X-ray diffraction analysis and via comparing computational and experimental ECD, NMR, and specific optical rotation data. 9 possesses an unreported 5/6/6/6/5 five-ring framework with a 1,4-dioxane, and 10 and 11 feature unprecedented 6/6/6/5 and 6/6/5/6 four-ring frames containing a 1,4-dioxane. The biosynthetic pathways of 9-11 were proposed. 1-11 were nontoxic in HT-1080 and HepG2 tumor cells at a concentration of 20 µM, whereas 3 and 5 exerted higher antioxidant properties in the hydrogen peroxide-stimulated model in the neuron-like PC12 cells. They could be potential antioxidant agents for neuroprotection.

Green tea polyphenols bind to soy proteins and decrease the activity of soybean trypsin inhibitors (STIs) in heated soymilk.

The interaction between epigallocatechin gallate (EGCG) and soy proteins at room temperature (25 °C) and after heating at 100 and 121 °C, and their effects on the inactivation of soybean trypsin inhibitors (STIs) in soymilk were investigated. The results of the nitroblue tetrazolium (NBT) staining assay showed that soy proteins can covalently bind to EGCG. The α/α' and A subunits in heated soymilk preferred to bind to EGCG because of their soluble state. More thiols were trapped when EGCG was added before thermal processing, and the free amino groups were depleted more with EGCG addition after heating. Circular dichroism and fluorescence spectroscopy showed that EGCG addition before or after heating induced different secondary and tertiary structural changes for soy proteins. The exposed aromatic amino acids preferred to react with EGCG before protein aggregation in the heating process. The random coil of soymilk proteins increased more when EGCG was added in soymilk after heating, resulting in more disordered structures in protein conformation. The binding between EGCG and soy proteins promoted protein aggregation, which was confirmed by the particle size distribution and gel electrophoresis. The trypsin and chymotrypsin inhibitory activity (TIA and CIA) in soymilk significantly reduced to 693 U mL-1 and 613 U mL-1, respectively, under the conditions of 2 mM EGCG addition after 100 °C heating for 10 min (p < 0.05). Consequently, the influence of EGCG on STI inactivation in soymilk only worked when EGCG was added after heating.

Pepsin Diffusivity and In Vitro Gastric Digestion of Soymilk as Affected by Binding of Tea Polyphenols to Soy Proteins.

This study aimed to investigate the effect of tea polyphenol extract (TPE) on the in vitro gastric digestion of soymilk. Fluorescence recovery after photobleaching was applied to measure pepsin diffusivity in soymilk. The characteristics of soymilk digesta were evaluated by gel electrophoresis, degree of hydrolysis (DH), molecular weight distribution, free amino acid analysis, particle size, antioxidant capacity, and trypsin/chymotrypsin inhibitor activity (TIA/CIA). The binding between soy proteins and tea polyphenols could significantly impair in vitro gastric digestion of soymilk by decreasing pepsin diffusivity from 91.3 to 70.3 µm2/s and DH from 17.13 to 13.93% with 1.2 mg/g TPE addition. Soymilk with 0.6 mg/g TPE addition exhibited low TIA/CIA and a strong antioxidant capacity in gastric digesta, which might be good for the following intestinal digestion. A better understanding of the effect of polyphenol on the digestion of protein-based food may be beneficial to innovation in food manufacturing.

Efficacy of Sijunzi decoction on limb weakness in spleen Qi deficiency model rats through adenosine monophosphate-activated protein kinase/unc-51 like autophagy activating kinase 1 signaling.

OBJECTIVE: To investigate the efficacy of Sijunzi decoction () on limb weakness in a rat model of spleen Qi deficiency (SQD), and to study its effect on mitophagy in skeletal muscle through adenosine monophosphate-activated protein kinase (AMPK) / unc-51 like autophagy activating kinase 1 (ULK1) signaling. METHODS: SQD model rats were produced by fasting combined with forced swimming method for 15 d. After model assessment, rats were randomly divided into four groups of 10 [low/middle/high (L/M/H) Sijunzi decoction dose groups and a normal saline (S) group]. Limb holding power (HP) and body mass (BM) were measured after 2 weeks of treatment. Following euthanasia, quadriceps femoris were dissected and myofiber and mitochondrial morphology were observed by transmission electron microscopy (TEM). Mitochondrial membrane potential (MMP), adenosine triphosphatase (ATP) and reactive oxygen species (ROS) levels were determined using colorimetric methods, and immunoblot analysis of Microtubule-associated protein light chain 3 (LC3) and Sequestosome 1 (p62) was performed to monitor mitophagy and AMPK/ULK1 signaling. RESULTS: Compared with control (C) group rats, in the S group, HP was reduced, the myofiber Z line was disordered, mitochondria were scattered, and numerous vacuoles and mitophagy were observed. MMP and ATP levels were reduced, ROS levels were elevated, and LC3B expression, and p-AMPKα (Thr172)/AMPKα, p-ULK1 (Ser555)/ULK1, and p-Raptor (Ser792)/Raptor ratios were increased, while p62 expression and p-mTOR (Ser2448)/mTOR and p-ULK1 (Ser757)/ULK1 ratios were decreased. After treatment, compared with the S group, HP was improved in M and H groups but not in the L group. Mitophagy was reduced in M, H and L groups but the Z line was disordered and vacuolization remained in the L group. ATP levels were elevated in M, H and L groups, and MMPs were elevat-ed in M and H groups but not in the L group. ROS levels were decreased in M, H and L groups, as were LC3B expression and p-Raptor (Ser792)/Raptor ratios, while p62 expression and p-mTOR (Ser2448)/mTOR and p-ULK1 (Ser757)/ULK1 ratios were increased in M and H groups but not in the L group. p-AMPKα (Thr172)/AMPKα and p-ULK1 (Ser555)/ULK1 ratios were decreased in M, H and L groups. CONCLUSIONS: Sijunzi decoction improved HP, possibly by inhibiting mitophagy via suppression of AMPK/ULK1 signaling. This restored mitochondrial morphology and improved oxidative phosphorylation, which contributed to recovery of limb weakness in SQD model rats.

Folium Sennae and emodin reverse airway smooth muscle contraction.

The objective of this project was to find a bronchodilatory compound from herbs and clarify the mechanism. We found that the ethanol extract of Folium Sennae (EEFS) can relax airway smooth muscle (ASM). EEFS inhibited ASM contraction, induced by acetylcholine, in mouse tracheal rings and lung slices. High-performance liquid chromatography assay showed that EEFS contained emodin. Emodin had a similar reversal action. Acetylcholine-evoked contraction was also partially reduced by nifedipine (a selective inhibitor of L-type voltage-dependent Ca2+ channels, LVDCCs), YM-58483 (a selective inhibitor of store-operated Ca2+ entry, SOCE), as well as Y-27632 (an inhibitor of Rho-associated protein kinase). In addition, LVDCC- and SOCE-mediated currents and cytosolic Ca2+ elevations were inhibited by emodin. Emodin reversed acetylcholine-caused increases in phosphorylation of myosin phosphatase target subunit 1. Furthermore, emodin, in vivo, inhibited acetylcholine-induced respiratory system resistance in mice. These results indicate that EEFS-induced relaxation results from emodin inhibiting LVDCC, SOCE, and Ca2+ sensitization. These findings suggest that Folium Sennae and emodin may be new sources of bronchodilators.