Protective Effect of Castanopsis sieboldii Extract against UVB-Induced Photodamage in Keratinocytes

Orientin attenuates UVB-induced skin photodamage by inhibiting ROS generation via the AMPK/Nrf2 axis

The accumulation of reactive oxygen species (ROS) in the skin following UVB exposure is a key contributor to ultraviolet-induced skin photodamage. Orientin, a bioactive flavonoid, has demonstrated antioxidant properties in previous studies. However, its efficacy in treating skin photodamage remains inadequately understood. This study investigates the effects of orientin in preventing UVB-induced immortalized human keratinocytes (HaCaT cells) and BALB/c mouse skin photodamage by activating the AMPK/Nrf2 axis. Results show that orientin protects HaCaT cell viability after UVB exposure, reduces ROS levels, and upregulates antioxidant enzymes, including SOD1, HO-1, and NQO-1, while concurrently suppressing the expression of inflammatory mediators such as COX-2, IL-6, and IL-8. Additionally, orientin promotes AMPK phosphorylation, which facilitates Nrf2 nuclear translocation, thereby enhancing the antioxidant defense of cells. This effect is diminished upon inhibition of AMPK or Nrf2. In the BALB/c mouse model of photodamage, topical application of orientin alleviates symptoms like skin roughness, scaling, and erythema induced by UVB irradiation, while also elevating antioxidant enzyme expression in skin tissues. These findings suggest that orientin mitigates ultraviolet-induced skin photodamage both in vitro and in vivo, boosts cellular antioxidant capacity, and diminishes inflammatory responses, suggesting its potential for further exploration in skin photodamage management.

Genus Castanopsis: A review on phytochemistry and biological activities

Genus Castanopsis are native to tropical and subtropical Asia, comprising about 120 species. Some species from Castanopsis have been used as folk medicines in Asia. Phytochemistry investigations of the different plant parts of Genus Castanopsis have disclosed the presences of natural products including phenolics, terpenoids, steroids, and essential oils. Phenolics exist in Castanopsis species widely, particularly, triterpene ellagitannins were found to be potential chemotaxonomic marks of this geuns. The crude extracts and chemical constituents from Castanopsis have extensive biological activities, such as anti-inflammatory, anti-oxidative, antimicrobial, etc. In conclusion, the phytochemistry and biological activities of genus Castanopsis make it a promising source of natural products for drug discovery and development. This review collected the literatures published prior to 2023 on the traditional medicinal uses, phytochemistry, and bioactivties of the genus Castanopsis by searching from several scientific databases, such as Elsevier, Sci-finder, PubMed, Web of Science, CNKI, and Baidu Scholar. The main purpose of this systematic review is to provide the available information for relevant scholars to understand the progress in phytochemistry and biological activies of the genus Castanopsis and help the further development of this genus.

A non-bactericidal cathelicidin with antioxidant properties ameliorates UVB-induced mouse skin photoaging via intracellular ROS scavenging and Keap1/Nrf2 pathway activation

Cathelicidins, a category of critical host defense molecules in vertebrates, have been extensively studied for their bactericidal functions, but little is known about their non-bactericidal properties. Herein, a novel cathelicidin peptide (Atonp2) was identified from the plateau frog Nanorana ventripunctata. It did not exhibit bactericidal activity but showed significant therapeutic effects in chronic UVB radiation-induced mouse skin photoaging through inhibiting thickening, pyroptosis and inflammation in the epidermis, while inhibiting cellular senescence, collagen fibre breakage and type Ⅰ collagen reduction in the dermis. Further studies indicated that Atonp2 effectively scavenged UVB-induced intracellular ROS via tyrosines at positions 9 and 10, while activating the Keap1/Nrf2 pathway to protect epidermal keratinocytes against UVB radiation, which in turn indirectly reversed the senescence and collagen degradation of dermal fibroblasts, thereby ameliorating UVB-induced skin photoaging. As such, this study identified a non-bactericidal cathelicidin peptide with potent antioxidant functions, highlighting its potential to treat and prevent skin photoaging.

Anti-Photoaging Effects of Antioxidant Peptide from Seahorse (Hippocampus abdominalis) in In Vivo and In Vitro Models

Overexposure to ultraviolet (UV) radiation can lead to photoaging, which contributes to skin damage. The objective of this study was to evaluate the effects of an antioxidant peptide (SHP2) purified from seahorse (Hippocampus abdominalis) alcalase hydrolysate on UVB-irradiated skin damage in human keratinocyte (HaCaT) and human dermal fibroblast (HDF) cells and a zebrafish model. The data revealed that SHP2 significantly enhanced cell viability by attenuating apoptosis through the reduction of intracellular reactive oxygen species (ROS) levels in UVB-stimulated HaCaT cells. Moreover, SHP2 effectively inhibited ROS, improved collagen synthesis, and suppressed the secretion of matrix metalloproteinases (MMPs) in UVB-irradiated HDF cells. SHP2 restored the protein levels of HO-1, Nrf2, and SOD, while decreasing Keap1 expression in UVB-treated HDF, indicating stimulation of the Keap1/Nrf2/HO-1 signaling pathway. Furthermore, an in vivo study conducted in zebrafish confirmed that SHP2 inhibited photoaging by reducing cell death through the suppression of ROS generation and lipid peroxidation. Particularly, 200 µg/mL of SHP2 exerted a remarkable anti-photoaging effect on both in vitro and in vivo models. These results demonstrate that SHP2 possesses antioxidant properties and regulates skin photoaging activities, suggesting that SHP2 may have the potential for use in the development of cosmetic products.

Endoplasmic reticulum stress in skin aging induced by UVB

Aging is a normal and complex biological process. Skin is located in the most superficial layer of the body, and its degree of aging directly reflects the aging level of the body. Endoplasmic reticulum stress refers to the aggregation of unfolded or misfolded proteins in the endoplasmic reticulum and the disruption of the calcium ion balance when cells are stimulated by external stimuli. Mild endoplasmic reticulum stress can cause a series of protective mechanisms, including the unfolded protein response, while sustained high intensity stimulation leads to endoplasmic reticulum stress and eventually apoptosis. Photoaging caused by ultraviolet radiation is an important stimulus in skin aging. Many studies have focused on oxidative stress, but increasing evidence shows that endoplasmic reticulum stress plays an important role in photoaging. This paper reviews the development and mechanism of endoplasmic reticulum stress (ERS) in skin photoaging, and provides research directions for targeting the ERS pathway to slow aging.

Castanopsis sieboldii Extract Alleviates Acute Liver Injury by Antagonizing Inflammasome-Mediated Pyroptosis

Castanopsis sieboldii (CS), a subtropical species, was reported to have antioxidant and antibacterial effects. However, the anti-inflammatory effects of CS have not been studied. This study aimed to investigate whether the 70% ethanol extract of the CS leaf (CSL3) inhibited lipopolysaccharide (LPS)-induced inflammatory responses and LPS and ATP-induced pyroptosis in macrophages. CSL3 treatment inhibited NO release and iNOS expression in LPS-stimulated cells. CSL3 antagonized NF-κB and AP-1 activation, which was due to MAPK (p38, ERK, and JNK) inhibition. CSL3 successfully decreased NLRP3 inflammasome activation and increased IL-1β expression. CSL3 treatment diminished LPS and ATP-induced pore formation in GSDMD. The in vivo effect of CSL3 on acute liver injury was evaluated in a CCl4-treated mouse model. CCl4 treatment increased the activity of serum alanine aminotransferase and aspartate aminotransferase, which decreased by CSL3. In addition, CCl4-induced an increase in TNF-α, and IL-6 levels decreased by CSL3 treatment. Furthermore, we verified that the CCl4-induced inflammasome and pyroptosis-related gene expression in liver tissue and release of IL-1β into serum were suppressed by CSL3 treatment. Our results suggest that CSL3 protects against acute liver injury by inhibiting inflammasome formation and pyroptosis.