• Korean Journal of Food Science and Technology
• /
• v.42 no.6
• /
• pp.750-754
• /
• 2010

The purpose of this study was to investigate the antioxidant and skin whitening effects of Rhamnus yoshinoi extracts. Rhamnus yoshinoi was extracted with 100% ethanol and water. The antioxidative and skin whitening effects of extracts were determined by in vitro assays using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) method and inhibitory effects against tyrosinase activity and melanogenesis in B16F1 melanoma cells. The radical scavenging activities of the Rhamnus yoshinoi extracts were tested by DPPH assay and showed high DPPH radical scavenging activities (SC50; 21.6 ppm in EtOH, 40.5 ppm in water). As for tyrosinase inhibitory activity, the Rhamnus yoshinoi ethanol extract had the highest inhibition activity ($IC_{50}$; 256.3 ppm). In B16F1 mouse melanoma cells, the Rhamnus yoshinoi ethanol extract significantly inhibited melanin synthesis by 53.36% at the concentration of 50 ppm. These results suggest that Rhamnus yoshinoi ethanol extract has significant antioxidant activity and whitening activity.

• Journal of Plant Biotechnology
• /
• v.48 no.2
• /
• pp.106-114
• /
• 2021

We evaluated the anti-cancer activity against human prostate cancer cells and the associated molecular mechanism of extracts from the branches of Rhamnus yoshinoi (RYB). Treatment with RYB suppressed viability of human prostate cancer cells (PC-3) and decreased protein levels of both β-catenin and T-cell factor 4 (TCF4). This was reflected in reduced TCF4 mRNA, but not decreased β-catenin mRNA. PC-3 cells were pretreated with the proteosome inhibitor MG132 before treatment with RYB, which blocked RYB-mediated down regulation of β-catenin in PC-3 cells, thus confirming that RYB promotes the proteasomal degradation of β-catenin. RYB induced β-catenin phosphorylation, and GSK-3β inhibition by LiCl blocked the phosphorylation and proteasomal degradation of β-catenin by RYB. These results suggest that GSK-3β may be an important upstream kinase for RYB-mediated regulation of β-catenin. Finally, GC/MS analysis of RYB identified 18 compounds. Based on these findings, RYB shows potential for development as a therapeutic agent for prostate cancer.

• Journal of Plant Biotechnology
• /
• v.47 no.3
• /
• pp.254-259
• /
• 2020

We studied the antioxidative and immunoregulatory properties of 70% ethanol extracts from the leaves, branches, and fruit of 13 species of the Rhamnaceae collected during the bearing season (Berchemia berchemiifolia, Berchemia floribunda, Hovenia dulcis, Paliurus ramosissimus, Rhamnella franguloides, Rhamnus crenata, Rhamnus davurica, Rhamnus koraiensis, Rhamnus parvifolia, Rhamnus ussuriensis, Rhamnus yoshinoi, Sageretia thea, and Ziziphus ujube). Total phenolic and flavonoid content values were determined using calibration curves of gallic acid and rutin, respectively. ABTS and DPPH radical scavenging assays were performed to determine antioxidative potential. Anti-inflammatory effects were studied using the nitric oxide (NO) inhibition assay in LPS-induced RAW264.7 cells. Extracts of Berchemia berchemiifolia, Sageretia thea, and Ziziphus jujuba had the highest total phenol and flavonoid content values. Extracts of Berchemia berchemiifolia, Paliurus ramosissimus, Rhamnella franguloides, and Sageretia thea had the highest ABTS radical scavenging activities. Berchemia berchemiifolia and Sageretia thea had the highest DPPH radical scavenging activities. Furthermore, extracts of Berchemia berchemiifolia, Berchemia floribunda, Paliurus ramosissimus, Sageretia thea, and Ziziphus jujuba showed strong anti-inflammatory activity through inhibition of NO production. The results of this study suggest that Rhamnaceae extracts can be used as natural antioxidants and immunomodulators.

• Journal of Plant Biology
• /
• v.39 no.1
• /
• pp.15-22
• /
• 1996

Seventy-three chromosome counts are reported from populations in 70 species from Korea, of which 34 counts in 32 species belong to Apiaceae. New species counts are in Acanthopanax chiisanensis(2n=48), Hydrocotyle japonica(2n=ca.96), H. maritima (n=12), Libanotis coreana (2n=22), Lindera sericea (n=12), Quercus myrsinaefolia (n=12), Rhamnus yoshinoi (n=12), Salix hulteni (n=19), Symplocos chinensis for. pilosa (n=11) and Vaccinium oldhami (n=12). New chromosome level for Asperula odorata (n=11), Cryptotaenia japonica (2n=16) and Sium ninsi (2n=18) is also provided. The taxonomic implications of certain of these counts are discussed.

• The Korean Journal of Ecology
• /
• v.16 no.4
• /
• pp.477-487
• /
• 1993

To investigate phenological differences among species, and relationship between phenology and air temperatures, we surveyed foliation and flowering times of several woody plants in two temperate forests, Namhansansung and Taegwallyong area, for three years, 1991, 1992 and 1993. In Namhansansung area, the leaves of Quercus mor~golica, Rhododendron mucronulatum, Prunus levezlleana and Symplocos chinensis for. pilosa expanded in the early season(about 10 April), and those of Quercus variabilis, Quercus dentata and Maackia amurensis in the late season(about 5 May). The foliation time of the earliest species(Rhododendron mucronulatum) was 27 days earlier than thzt of the latest(Maackia amurensis, Quercus variabilis and Quercus dentata). In Taegwallyong area, the leaves of Staphylea bumalda and Rhamnus yoshinoi foliated on 25 April and those of Rhus verniciflua and Fraxinus rhynchophylla on 25 May. The annual mean air temperature of Narnhansansung area was $5.5^{\circ}C$ higher than that of Taegwallyong area. Foliation times of the same species were earlier in the former: the differences between two areas were 8~24 day among species. In contrast, flowering times of the same species were 0~22 days earlier in the former. It is concluded that the budding time of leaves was related to year day index(YDI), and foliation time of leaves was related to Nuttonson's index(Tn).

• Korean Journal of Plant Resources
• /
• v.37 no.1
• /
• pp.1-10
• /
• 2024

This studied the immune-enhancing activity properties of water extracts from the leaves, branches, and fruit of 13 species (Rhamnaceae) collected during the bearing season (Berchemia berchemiifolia, B. floribunda, Hovenia dulcis, Paliurus ramosissimus, Rhamnella franguloides, Rhamnus crenata, R. davurica, R. koraiensis, R. parvifolia, R. ussuriensis, R. yoshinoi, Sageretia thea, and Ziziphus jujube). Immune-enhancing activity were studied using the nitric oxide (NO) production in RAW264.7 cells. Extracts of B. berchemiifolia, H. dulcis, R. franguloides, R. crenata, R. davurica, R. ussuriensis and S. thea showed strong immune-enhancing activity through NO production. In addition, the expression of immune enhancement-related cytokine genes (NOS, COX-2, IL-1β, IL-6 and TNF-α) were confirmed through PCR-electrophoresis. The results of this study suggest that Rhamnaceae extracts can be used as natural antioxidants and immune enhancer.

• Journal of Plant Biology
• /
• v.38 no.1
• /
• pp.63-72
• /
• 1995

The growth, size and morphology of leaves, which foliated on the same shoot and time in the early growth season, were studied in 12 woody species in temperate deciduous forests of Korea, and the equation for the index of heteromorphism of leaves was fonnulated. The numbers of leaves per shoot were from 3 to 7 in early growth season and the numbers of synchronous leafing were from 2 to 6. All the leaves on a shoot were reached maximum values of specific leaf arells at the SIlme time nearly. The differences of the length (L) and breadth (B) of leaves along leaf rank (plastochron) were conspicuous, except for Quercus variabilis. Especially, in 10 species, the ~fferences of the neighbouring leaves were significant at 0.001 or 0.05 level. The index of leaf heteromorphism was calculated from the data based on $L\;{\times}\;B$ and LIB, and similar to differences of actual leaves along leaf rank. The values of index of heteromorphism were high in Carpinus tschonosldi, Styrax obassia, Ulmus davidiana, Rhamnus yoshinoi and Symplocos chinensis for. pilosa, and low in Sorbus alnifolia and Tilia amurensis. The index of heteromorphism had no relation to other characters of the leaf or life fonn of the species. It was thought that the differences along leaf rank were related to the degree of adaptation to environment, especially to changing air temperature in early growth season.season.