Chemical treatments of hair such as dyeing, perming and bleaching could cause mechanical damage to the hair, which weakens the hair fibers and makes the hair break more easily. In this work, hyaluronate (HA) with different molecular weight (MW) was investigated for its effects on restoring the mechanical properties of damaged hair. It was found that low-MW HA (average MW~42 k) could significantly improve the mechanical properties, specifically the elastic modulus, of overbleached hair. The fluorescent-labeling experiments verified that the low-MW HA was able to penetrate into the cortex of the hair fiber, while high-MW HA was hindered. Fourier transform infrared spectrometry (FT-IR) results implied the formation of additional intermolecular hydrogen bonds in the HA-treated hair. Thermos gravimetric analysis (TGA) indicated that the HA-treated hair exhibited decreased content of loosely bonded water, and differential scanning calorimetry (DSC) characterizations suggested stronger water bonding inside the HA-treated hair, which could alleviate the weakening effect of loosely bonded water on the hydrogen bond networks within keratin. Therefore, the improved elastic modulus and mechanical strength of the HA-treated hair could be attributed to the enhanced formation of hydrogen bond networks within keratin. This study illustrates the capability of low-MW HA in hair damage repair, implying an enormous potential for other moisturizers to be used in hair care products.

Biosurfactants are attracting much interest due to their potential application as therapeutic agents in the medical and cosmetic field. Previous studies have demonstrated that biosurfactant such as sophorolipid (SL) exhibits immunomodulatory effects. In this article, we found the potential of sophorolipid for inhibiting histamine-induced itch and preliminarily explored its molecular basis. First, behavioral tests indicated that SL can remit the histamine-induced scratching behaviors of mice. Second, SL can suppress the the calcium influx induced by histamine, HTMT and VUF8430 in HaCaT cells. RT-PCR analysis showed that the histamine-induced upregulation of mRNA levels of phospholipase Cγ1, 1,4,5-trisphosphate receptor (IP3R), and protein kinase Cα can be inhibted by SL, suggesting that SL may impede the PLC/IP3R signaling pathway activated by histamine. In further tests, the capsaicin-induced calcium influx can also be inhibited by SL. The immunofluorescence and molecular docking analysis indicated that SL acts as an inhibitor of transient receptor potential vanilloid-1 (TRPV1) activation to decrease calcium influx against stimuli. In summary, these results revealed that SL may inhibit histamine-induced itch by decreasing PLC/IP3R signaling pathway activation and modulating TRPV1 activity. This paper indicates that SL can be a useful treatment for histamine-dependent itch.

Photoaging is common and represents one of the primary pathways for hair damage in daily life. Hydrolyzed keratin, which is usually derived from wool and consists of a series of polypeptide molecules, has been investigated as a UV damage prevention ingredient for hair care. Scanning Electron Microscopy (SEM) and fluorescent penetration experiments verified that hydrolyzed keratin can deposit on the hair cuticles to form a film and partly penetrate into the hair cortex. This film played as a UV reducer and helped hair resist surface damage and maintain a sleek and healthy morphology after UV radiation. Surprisingly, it was found that hydrolyzed keratin treatment combined with subsequent UV radiation could significantly improve the tensile properties of hair. For hydrolyzed-keratin-treated hair, tensile strength was maintained after UV radiation, while, as a comparison, it decreased by 14.32% for untreated hair. This phenomenon is explained by a UV-induced degradation–penetration mechanism. During UV radiation, an increase in free amino acid content and conductivity was observed for the hydrolyzed keratin solution, demonstrating photodegradation into smaller peptides and amino acids. The degradation of hydrolyzed keratin allowed it to more easily enter the interior of the hair cortex, thereby enhancing its tensile properties by enhancing the chemical bonds.

Photoaging is common and represents one of the primary pathways for hair damage in daily life. Hydrolyzed keratin, which is usually derived from wool and consists of a series of polypeptide molecules, has been investigated as UV damage prevention ingredient for hair care. Scanning Electron Microscopy (SEM) and fluorescent penetration experiments verified that hydrolyzed keratin can deposit on the hair cuticles to form a film and partly penetrate into hair cortex. This film played as a UV blocker and helped hair resist surface damage and maintain a sleek and healthy morphology after UV radiation. Surprisingly, it was found that hydrolyzed keratin treatment combined with subsequently UV radiation could significantly improve the tensile properties of hair. For hydrolyzed keratin treated hair, tensile strength maintained after UV radiation, while as a comparison, it decreased by 11.74% for untreated hair. This phenomenon is explained by a UV-induced degradation-penetration mechanism. During UV radiation, an increase in free amino acid content and conductivity was observed for hydrolyzed keratin solution, demonstrating the photodegradation into smaller peptide and amino acid. The degradation of hydrolyzed keratin allowed it more easily to enter the interior of hair cortex, thereby enhanced the tensile properties via enhancing chemical bonds.

Limonin is a natural compound which is rich in the fruit of various plants of the Rutaceae family and demonstrated to have a wide range of biological activities. In this work, seven limonin derivatives were successfully synthesized by hydrogenation of limonin, using different reducing agents (sodium cyanoborohydride, lithium aluminum hydride, and sodium borohydride). The chemical structure of the seven derivatives was characterized and identified by a series of techniques, including HR-ESI-MS, 1H-NMR, 13C-NMR, 2D-NMR, and IR. Among the seven limonin derivatives, six limonin derivatives were found to be new compounds which have not been previously reported. Then, the anti-inflammatory activities of the seven synthesized limonin derivatives, as well as the anti-inflammatory activities of eight known natural limonins, were evaluated and compared. Natural limonins, 30-O-Acetylhainangranatumin E and Xylogranatin A, presented significantly better anti-inflammatory activity. Xylogranatin A could inhibit LPS-induced RAW264.7 cell inflammatory factors, with a 90.0% inhibition ratio of TNF-α and 63.77% inhibition ratio of NO release in LPS-induced BV2 cells at 10 μM. Other natural limonins showed poor anti-inflammatory activity. In comparison, all the synthetic limonin derivatives showed decent anti-inflammatory activities, with the highest inhibition ratio of TNF-α of 37.8% and inhibition ratio of NO release of 12.5% in LPS-induced BV2 cells at 10 μM.