People living long-term in areas with UV will cause premature photoaging. An abnormal reduction in autophagy is a key feature of photoaging, and p38 MAPK has been regarded as a key regulator of autophagy. Isothiocyanate is one of the main active components of Moringa oleifera Lam. seeds. Studies have reported that M. oleifera Lam. seeds isothiocyanate (MITC) has anticancer, anti-inflammatory, cardiometabolic repair, nervous system protection, blood lipid regulation and diabetes prevention properties. However, the molecular mechanisms of MITC with protective effects against skin photoaging have not been studied thus far. In this study, we aimed to evaluate the antiphotoaging activity of MITC and to investigate the effect of p38 MAPK-dependent autophagy in vivo and in vitro models of photoaging. In this research we found that MITC can reverse the intracellular reactive oxygen species (ROS) content and inhibit the activation of p38 MAPK to improve the autophagy level, reduce the expression of matrix metalloproteinases (MMPs), and finally protect against photoaging by UV. Our results will uncover the molecular mechanisms of MITC that play a role in the protective effects against skin photoaging, provide helpful information for developing MITC as an anti-photoaging plant material and improve the utilization of M. oleifera Lam. seeds.

Moringa oleifera Lam. is a Moringa genus in the Moringaceae family that is high in nutrients and has a wide range of applications. Phenolic compounds are widely found in plants and have various health benefits for the human body. With its high content and wide variety of phenolic compounds, M. oleifera Lam. has been widely studied for its health benefits. The phenolic compounds in M. oleifera Lam. (MOPCs) can be a potential source of functional food ingredients in pharmaceutical and industrial applications. Numerous studies have shown that MOPCs have antioxidant, anti-obesity, anti-diabetic, and antibacterial effects. Although the research on MOPCs has been gradually increasing, the extraction, isolation, identification, biological activities, and comprehensive application of MOPCs need a more systematic summary and generalization. Therefore, this paper reviews the isolation and extraction methods, structure identification, biological activities, and comprehensive applications to provide a further reference for the research and application of MOPCs.

In this study, a mixture of ultrasound or microwave pretreated walnut meal protein peptides and CaCl₂ was used for the preparation of walnut peptide-calcium chelate. The effects of different pretreatments on the calcium chelating capacity, structural changes and stability of walnut meal protein peptides were analyzed. The results showed that compared with walnut meal protein peptide-calcium chelate (WPP-Ca), the chelation rates of ultrasound-pretreated walnut meal protein peptide-calcium chelate (UP-WPP-Ca) and microwave-pretreated walnut meal protein peptide-calcium chelate (MP-WPPCa) were enhanced, which indicated that ultrasound and microwave pretreatments improved the calcium-chelating capacity of the peptides effectively. Using ultraviolet-visible (UV-Vis) absorption spectroscopy and Fourier transform infrared (FTIR) spectroscopy, it was found that ultrasound and microwave pretreatments mainly affected the calcium ion binding sites such as amino groups, carbonyl groups, carboxyl groups, amide bonds and carboxylate groups of walnut meal protein peptides. The results of X-ray diffraction (XRD) showed that ultrasound and microwave treatments changed the molecular arrangement of walnut meal protein peptides, thereby making the structure of walnut peptide-calcium chelate more ordered. Fluorescence spectroscopy showed that ultrasonic and microwave treatments promoted the chelation between aromatic amino acids and calcium ions. In addition, UP-WPP-Ca and MP-WPP-Ca showed good stability toward different pH values, temperatures, and gastrointestinal digestion. In short, ultrasonic and microwave pretreatments can improve the calcium-chelating capacity and stability of walnut meal protein peptides, which is of guiding significance for the processing of walnut peptide-calcium chelate and the development of calcium supplements.

Walnut green husk, a byproduct of walnut processing, is rich in polyphenols with potential antidiabetic effects. However, the antidiabetic activity of walnut green husk polyphenols (WGHP) in vivo has not been reported and their mechanism of action is still unclear. This study investigated its impact on type 2 diabetes in mice induced by a high-fat diet and streptozotocin. We found that walnut green husk polyphenols improved glycolipid metabolism, reduced inflammation and oxidative stress, and protected the pancreas and liver. WGHP also reshaped the gut microbiota, lowering the Firmicutes/Bacteroidota ratio and boosting beneficial bacteria. Network pharmacology indicated that WGHP's effects are mediated by the PI3K/AKT signaling pathway, which was confirmed by increased protein expression of p-IRS-1, PI3K, p-AKT, and GLUT4 in the liver. In conclusion, these results indicate that WGHP ameliorates T2DM by modulating gut microbiota and the IRS/PI3K/AKT pathway, providing a theoretical basis for the in-depth utilization of walnut green husk.

Isothiocyanates, secondary metabolites primarily derived from cruciferous plants, are known for their distinct flavors in food and diverse biological activities such as anti-tumor, anti-diabetic, neuroprotective, antibacterial, anti-inflammatory, and antioxidant properties. They are extensively utilized in food, medicine, and agriculture. Moringa oleifera Lam. has recently been recognized as a new food resource and has attracted increasing research attention. This plant belongs to the Brassicales order and the Moringa family. It was found to contain biologically active isothiocyanates such as sulforaphane and 4-(α-L-rhamnopyranosyloxy)-benzyl isothiocyanate (MIC-1). Considering the low content of natural products and the related environmental issues caused by chemical synthesis, synthetic biology presents a promising approach for the sustainable and efficient production of these compounds. Recently, the biosynthetic pathways of isothiocyanates in many plants have been elucidated, which can promote the heterologous production of isothiocyanates through microbial fermentation. This review comprehensively examines the bioactivity, bioavailability, and biosynthetic pathways of M. oleifera Lam. isothiocyanates, alongside recent advancements in molecular biology techniques aimed at enhancing their yield. By elucidating the functional significance of isothiocyanates, this review aims to provide a comprehensive understanding of their role and to support further developments in their utilization in functional foods. It also proposes strategies for achieving high-yield production of these valuable compounds, offering insights that bridge theoretical knowledge with practical applications in the field.

Obesity has brought great challenges to global human health, and how to effectively prevent and control the occurrence and development of obesity has become an urgent problem. The role and mechanism of 4-[(α-L-Rhamnosyloxy) benzyl] isothiocyanate (MITC), an active ingredient of Moringa oleifera Lam., in the regulation of lipid metabolism have not been comprehensively investigated. In the present study, we investigated the mechanism of MITC in inhibiting lipid accumulation in mice fed with a high-fat diet (HFD) in terms of both lipolysis and central appetite regulation mediated by the gut microbe–gut–brain axis. MITC enhanced the characteristic indices associated with HFD mice and also promoted adipocytolysis and brown fat thermogenesis. Moreover, MITC was observed to improve leptin resistance, modulate the composition of gut microbiota such as Ruminococcaceae, Parasutterella, and Acetatifactor, promote 5-HT secretion, further enhance the secretion of glucagon-like peptide-1 (GLP-1) and peptide tyrosine-tyrosine (PYY) to activate peroxisome proliferator-activated receptor (PPAR) signaling in the hypothalamus, and modulate feeding behavior to inhibit lipid accumulation in HFD mice. These data suggest that MITC supplementation can help to alleviate obesity or obesity-related diseases.

Walnut dreg protein hydrolysates (WDPHs) exhibit a variety of biological activities, however, the cyclooxygenase-2 (COX-2) inhibitory peptide of WDPHs remain unclear. The aim of this study was to rapidly screen for such peptides in WDPHs through a combination of in silico and in vitro analysis. In total, 1262 peptide sequences were observed by nano liquid chromatography/tandem mass spectrometry (nano LC-MS/MS) and 4 novel COX-2 inhibitory peptides (AGFP, FPGA, LFPD, and VGFP) were identif ied. Enzyme kinetic data indicated that AGFP, FPGA, and LFPD displayed mixed-type COX-2 inhibition, whereas VGFP was a non-competitive inhibitor. This is mainly because the peptides form hydrogen bonds and hydrophobic interactions with residues in the COX-2 active site. These results demonstrate that computer analysis combined with in vitro evaluation allows for rapid screening of COX-2 inhibitory peptides in walnut protein dregs.