Yujin Kim

Ilex species are important sources of high-quality raw plant materials for the production of drugs and functional foods. The precise identification of different species within the Ilex genus would greatly facilitate authentication and certification as well as forest resource monitoring in plantations. Combining DNA barcoding with high-resolution melting (HRM) analysis represents a robust strategy for species discrimination, as demonstrated in recent DNA barcoding studies. Here, using concatenated and aligned complete chloroplast genomes of different Ilex species, we conducted a sliding window analysis to identify regions of high nucleotide diversity (Pi). We optimized and validated the utility of PCR-based HRM coupled with microsatellite markers to discriminate among the four Ilex species, Ilex integra Thunb., Ilex rotunda Thunb., Ilex cornuta Lindl. and Paxton, and Ilex x wandoensis C.F. Mill and M. Kim, from wild populations in southwestern Korea. The marker trnS^UGA-psbZ produced clear melting patterns and distinct melting curve profiles for the four Ilex species using HRM analysis. We applied this protocol to commercially available Ilex accessions and consistently identified the correct species for all 15 accessions tested. Therefore, combining DNA barcoding with HRM analysis is a powerful method for identifying different species within the same genus, which could be used for quality control of raw materials in the functional food/medicinal plant industry.

Corticosterone (CORT)-induced oxidative stress and neurotoxicity can cause neuronal dysfunction and mental disorders. In the present study, we investigated the effects and mechanism of the HP-20 resin fraction of the water extract of Vaccinium bracteatum leaves (NET-D1602) and its bioactive compound p-coumaric acid on neuronal cell damage in SH-SY5Y cells and primary culture of rat cortical cells. NET-D1602 and p-coumaric acid significantly improved cell viability in CORT-induced neurotoxicity in SH-SY5Y cells and primary cultures of rat cortical cells, and increased the activities of antioxidant enzymes (superoxide dismutase and catalase) against CORT-induced neurotoxicity in SH-SY5Y cells. NET-D1602 and p-coumaric acid increased the phosphorylation levels of ERK1/2 and cAMP response element-binding protein (CREB) in cortical neurons. In addition, CREB phosphorylation by NET-D1602 and p-coumaric acid was dramatically reversed by PKA, c-Raf/ERK, PI3K, and mTOR inhibitors. Lastly, we demonstrated the neuroprotective effects of NET-D1602 (3 and 10 μg/mL) and p-coumaric acid (3 and 10 μM) via increased CREB phosphorylation in CORT-induced neurotoxicity mediated via the ERK1/2, Akt, and mTOR pathways. These results suggest that p-coumaric acid is a potential neuroprotective component of NET-D1602, with the ability to protect against CORT-induced neurotoxicity by regulating ERK1/2, Akt, and mTOR-mediated CREB phosphorylation.

The leaves of Perilla frutescens var. acuta (PFA) are commonly used as a traditional medicine in Korea, Japan, and China. We previously showed that PFA attenuates eye fatigue by improving visual accommodation through a clinical study. However, detailed mechanisms and chemical compounds have not been studied. In this study, we analyzed the active compounds in an aqueous extract of PFA involved in ciliary muscle relaxation in vitro and in vivo. NMR and MS analyses showed that the PFA extract contained mainly luteolin-7-O-diglucuronide and apigenin-7-O-diglucuronide. The composition after freeze-drying and spray-drying was similar. Freeze-dried PFA (50 µg/mL, 100 µg/mL, and 200 µg/mL) increased nitric oxide and cGMP levels in ciliary muscle cells isolated from the eyes of rats. [Ca²⁺]i decreased in a dose-dependent manner. Furthermore, Sprague-Dawley rats treated with freeze-dried PFA (200 mg/kg, orally) showed significantly increased cGMP levels compared with the control group and irradiated with white light. Our results suggest that PFA extract has the potential to reduce eye fatigue by relaxing ciliary muscles.