Anti-Inflammatory Effects of Alphitolic Acid Isolated from Agrimonia coreana Nakai Extracts Are Mediated via the Inhibition of ICRAC Activity in T Cells

Agrimonia pilosa Ledeb., an important medicinal herb in traditional East Asian medicine, is primarily used to treat abdominal pain, dysentery, and hemostasis. There are ten other reported species of Agrimonia plants, including Agrimonia coreana Nakai-a naturally growing species in South Korea-and Agrimonia eupatoria Linn. Although recent studies have isolated numerous active constituents and investigated their effects, the medicinal utility of this herb is not yet fully explored. Through patch-clamp recording, a previous study reported that Agrimonia plant extracts inhibit the function of Ca2+ release-activated Ca2+ channels (CRACs). Herein, we aimed to identify and isolate the main compounds in A. coreana responsible for CRAC inhibition while assessing the anti-inflammatory effects mediated by this inhibition. We demonstrated for the first time that alphitolic acid isolated from A. coreana has a dose-dependent inhibitory effect on CRAC activity and, thus, an inhibitory effect on intracellular calcium increase. Furthermore, analysis of human CD4+ T cell proliferation via the carboxyfluorescein diacetate succinimidyl ester method revealed that alphitolic acid inhibited T cell proliferation in a concentration-dependent manner. Our findings provide a theoretical basis for the potential therapeutic use of alphitolic acid in the treatment of inflammatory diseases.

Protective skin aging effects of cherry blossom extract (Prunus Yedoensis) on oxidative stress and apoptosis in UVB-irradiated HaCaT cells

Extracts of the cherry blossom plant have been reported to exert various biological effects on human cells. However, no previous investigations have examined the antioxidant and anti-apoptotic effects of these extracts on ultraviolet B (UVB) radiation-induced skin aging. This study explores the underlying mechanisms of the antioxidant and anti-apoptotic effects of cherry blossom extract (CBE) in human keratinocyte (HaCaT) cells. HaCaT cells were treated with CBE at concentrations of 0.5, 1.0, and 2.0% for 24 h and then irradiated with UVB (40 mJ/cm²). CBE effectively and dose-dependently decreased the levels of reactive oxygen species and malondialdehyde, while increasing the activities of superoxide dismutase and glutathione peroxidase. Pretreatment with 1 and 2% CBE attenuated UVB-induced DNA damage by reducing the formation of cyclobutane pyrimidine dimers and 8-hydroxy-20-deoxyguanosine. Furthermore, CBE also prevented UVB-induced apoptosis and significantly downregulated B cell lymphoma 2 (Bcl-2)-associated X, cytochrome-c, and caspase-3 expression, while upregulating Bcl-2 expression. Taken together, these results indicate that CBE protects HaCaT cells from UVB-induced oxidative stress and apoptosis and suggest that CBE could be a potent antioxidant against skin aging.

Skin protective effect of guava leaves against UV-induced melanogenesis via inhibition of ORAI1 channel and tyrosinase activity

Ultraviolet (UV) irradiation is a major environmental factor affecting photoageing, which is characterized by skin wrinkle formation and hyperpigmentation. Although many factors are involved in the photoageing process, UV irradiation is thought to play a major role in melanogenesis. Tyrosinase is the key enzyme in melanin synthesis; therefore, many whitening agents target tyrosinase through various mechanisms, such as direct interference of tyrosinase catalytic activity or inhibition of tyrosinase mRNA expression. Furthermore, the highly selective calcium channel ORAI1 has been shown to be associated with UV-induced melanogenesis. Thus, ORAI1 antagonists may have applications in the prevention of melanogenesis. Here, we aimed to identify the antimelanogenesis agents from methanolic extract of guava leaves (Psidium guajava) that can inhibit tyrosinase and ORAI1 channel. The n-butanol (47.47%±7.503% inhibition at 10 μg/mL) and hexane (57.88%±7.09% inhibition at 10 μg/mL) fractions were found to inhibit ORAI1 channel activity. In addition, both fractions showed effective tyrosinase inhibitory activity (68.3%±0.50% and 56.9%±1.53% inhibition, respectively). We also confirmed that the hexane fraction decreased the melanin content induced by UVB irradiation and the ET-1-induced melanogenesis in murine B16F10 melanoma cells. These results suggest that the leaves of P. guajava can be used to protect against direct and indirect UV-induced melanogenesis.