NATPRO Journal

Phytochemical Profiling and Kinetic Study of DPPH⦁ Scavenging Activity of Sophora flavescens Aiton Root Extract 

Received: October 11, 2025; Revised: November 24, 2025; Accepted: November 30, 2025; Published: December 2, 2025

NATPRO J (2025) 2: 39-45

Author: Jongkeun Choi*

Department of Chemical and Biological Engineering, Chungwoon University, Incheon 22100, Republic of Korea.

https://doi.org/10.23177/NJ025.1002

Abstract: In this study, the antioxidant activity of the traditional medicinal herb Sophora flavescens Aiton root was evaluated through analysis of phytochemicals and DPPH⦁ scavenging activity of 70% ethanol extract. For chemical analysis, ultra performance liquid chromatography coupled with photodiode array detection and electrospray ionization tandem mass spectrometry (UPLC-PDA-ESI-MS/MS) was used, and six phytoconstituents, maackiain, formononetin, xanthohumol, kurarinone, lupenone and kuraidin were identified. Of these, five were classified as prenylated flavonoids. The extract, obtained by maceration in 70% ethanol at room temperature for 7 days, showed an extraction yield of 21.3% (w/w, based on dry root weight) and a total polyphenol content (TPC) of 25.4 mg gallic acid equivalents (GAE) per gram of dry root. In the steady-state DPPH⦁ assay, the extract exhibited moderate antioxidant activity with an EC50 value of 674 µg/mL compared with the positive control, gallic acid (EC50 = 2.62 µg/mL). However, in the kinetic study, the S. flavescens extract exhibited a fast initial rate. The sample was rapidly mixed with the DPPH⦁ solution, and absorbance was recorded every 0.5 s for 20 s. The initial reaction rate was then determined from the DPPH⦁ absorbance decay curve. From plots of initial rate data on the log-log scale, the following reaction orders were estimated: 1.05 for the DPPH⦁ and 0.69 for the extract. The pseudo-second-order rate constant (k2) was calculated to be 2.07 mM-0.69 s-1, which is about 19-fold higher than that of gallic acid (0.109 mM-0.48 s-1). These results indicate that the S. flavescens root extract exhibits moderate antioxidant activity at equilibrium, but very high initial radical-scavenging activity. This characteristic antioxidation activity, along with further beneficial results, demonstrates its potential for use as a fast-acting antioxidant ingredient in functional foods and cosmeceuticals, particularly for mitigating acute oxidative stress.

Keywords: Sophora flavescens; prenylated flavonoids; DPPH⦁ assay; kinetic analysis; antioxidant activity

Kaempferol Mitigates H2O2-Induced Oxidative Stress in RAW 264.7 Macrophages and Zebrafish 

Received: October 2, 2025; Revised: November 24, 2025; Accepted: November 26, 2025; Published: November 29, 2025

NATPRO J (2025) 2: 35-38

Authors: Muhammad Haroon1 and Sun Chul Kang1,2*

1Department of Biotechnology, Daegu University, Gyeongsan, 38453, Republic of Korea. 2Dr. Kang Bio Co., Ltd., Gyeongsan, 38428, Republic of Korea.

https://doi.org/10.23177/NJ025.1001

Abstract: Oxidative stress is a key mediator in numerous inflammatory diseases. This study investigated the protective effects of kaempferol against H₂O₂-induced oxidative damage in RAW 264.7 macrophages and a zebrafish model. In macrophages, kaempferol pre-treatment significantly attenuated H₂O₂-induced cytotoxicity and lactate dehydrogenase (LDH) release. It also reduced intracellular reactive oxygen species (ROS) and suppressed the secretion of pro-inflammatory cytokines, including TNF-α, IL-1β, and IL-6. Mechanistically, this protection was mediated by the activation of the Nrf2 antioxidant pathway and its downstream targets SOD1, catalase, and HO-1. Furthermore, in zebrafish, kaempferol improved survival and hatching rates, reduced ROS levels and activated the Nrf2 pathway. Collectively, our findings demonstrate that kaempferol exerts potent antioxidant and anti-inflammatory effects both in vitro and in vivo, suggesting its therapeutic potential against oxidative stress-related pathologies.

Keywords: kaempferol; oxidative stress; cytotoxicity; RAW 264.7; zebrafish

Transcriptomic Profiling of Aging Reveals Coordinated Pathway Decline and a Candidate Reversal Compound 

Received: July 11, 2025; Revised: September 22, 2025; Accepted: September 27, 2025; Published: September 29, 2025

NATPRO J (2025) 2: 25-33

Authors: Kyungmin Kim1, Bumho Yoo1, and Seong-Eui Hong2*

1HuGeX, Co., Ltd., 20, Songdogukje-daero 286beon-gil, Yeonsu-gu, Incheon, 22013, Republic of Korea. 2 4th Floor, Dream Hall, Korea Polytechnic Colleage– Seongnam Campus 398, Sujeong-ro, Sujeong-gu, Seongnam-si, Gyeonggi-do, 13122 Republic of Korea.

https://doi.org/10.23177/NJ025.701

Abstract: Aging is a complex biological process marked by widespread and coordinated transcriptional changes across multiple functional pathways. To investigate these changes, we analyzed RNA-seq data from human breast primary skin fibroblast cultured over extended passages, comparing early (P6) and late (P36) stages to model replicative aging. Differential expression analysis revealed 1,378 genes significantly altered with aging. Among these, five major pathways were consistently affected: G2-M Checkpoint, Myc Targets V1, Cholesterol Homeostasis, Interferon Alpha Response, and Inflammatory Response. To explore therapeutic implications, we integrated these gene signatures with the LINCS L1000 Chem Pert up dataset. Bosutinib, a Src/Abl kinase inhibitor, emerged as a top candidate predicted to reverse aging-associated transcriptional decline across all five functional categories. These findings highlight the utility of transcriptomic profiling combined with perturbation-based analysis to uncover biological changes linked to aging and nominate pharmacological candidates with geroprotective potential.

Keywords: aging, transcriptome, pathway

Structure and Bioactivity of Acidic Polysaccharides from Natural Resources 

Received: June 11, 2025; Revised: July 21, 2025; Accepted: July 22, 2025; Published: July 26, 2025

NATPRO J (2025) 2: 13-24

Author: Toshihiko Toida*

Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1, Inohana, Chuoh-ku, Chiba 263-8675, Japan

https://doi.org/10.23177/NJ025.601

Abstract: Interest in naturally occurring polysaccharides has steadily increased over the past two decades. These compounds have found applications in a variety of fields, including nutraceuticals, cosmetics, pharmaceuticals, and biomedicine. As studies of the structure-activity relationships (SAR) of glycans have progressed, the biological significance and functions of natural polysaccharides have become clearer. This progress has been fueled by significant advancements in enabling technologies, including various isolation and purification methods, chemical reactions that elucidate structures, and analytical tools such as nuclear magnetic resonance (NMR) and mass spectrometry (MS). Recent technological advances have revealed that some polysaccharides have irregular functional group patterns or branched sugar units within regular structures. This review will focus on the SAR of some acidic polysaccharides in the context of pharmaceuticals and nutraceuticals, and new concepts regarding the biological functions of polysaccharides as matrikines, with a particular focus on chondroitin sulfate.

Keywords: acidic polysaccharides, glycosaminoglycans, structure-activity relationship (SAR), nutraceutical; pharmaceutical

Substrate Specificity Determinant of C-Deglycosidase from Human Gut Bacterium Dorea sp. MRG-IFC3

Received: May 19, 2025; Revised: July 14, 2025; Accepted: July 16, 2025; Published: July 21, 2025

NATPRO J (2025) 2: 9-12

Authors: Heji Kim1, Huynh Thi Ngoc Mi1, Joong-Hoon Ahn2, and Jaehong Han1*

1Metalloenzyme Research Group and Department of Plant Science and Technology, Chung-Ang University, 4726 Seodong-daero, Anseong 17546, Republic of Korea. 2Department of Integrative Bioscience and Biotechnology, Bio/Molecular Informatics Center, Konkuk University, Seoul 05029, Republic of Korea

https://doi.org/10.23177/NJ025.501

Abstract: The C-deglycosidase from the human gut bacterium Dorea sp. MRG-IFC3 shows high substrate specificity and only cleaves the C-glycosidic bond of puerarin. To elucidate the origin of the peculiar substrate specificity of the C-deglycosidase from the MRG-IFC3 strain, the genes of the C-deglycosidase d3dgpBC were cloned from the MRG-IFC3 strain, and the amino acid sequence was compared with those from the closely related PUE strain. The primary protein structure comparison revealed that four amino acid differences at the positions of 105 and 118 in D3dgpB and at the positions of 196 and 200 in D3dgpC. Except the residue Q118B, all three were found at the surface of the X-ray protein structure of the closely related DgpBC, PDB:7BVR. The residue Q118B was found near the catalytic Mn(II) site at the substrate binding pocket. The modified C-deglycosidase, D3dgpBC with the Q118BP mutation, was prepared to investigate the substrate specificity. The modified enzyme catalyzed the cleavage of the glycosidic C-C bond of various C-glycoside including vitexin, orientin, and puerarin. Thus, Q118B was identified as a key residue preventing flavone C-glycosides from binding to the active site. This work emphasizes the genomics study of gut metabolism through high-throughput sequencing cannot fully reflect the health-promoting effects of the human gut microbiota.

Keywords: gut metabolism, C-deglycosidase, Dorea sp. MRG-IFC3, puerarin, substrate specificity

Identification of Bioactive Polyphenols from Wild-Type Phellinus linteus Using LC-MS and NMR

Received: February 19, 2025; Revised: April 1, 2025; Accepted: April 7, 2025; Published: April 14, 2025

NATPRO J (2025) 2: 1-7

Authors: Papawee Saiki1, Leo J. L. D. Van Griensven2, and Toshihiko Toida3*

1Cellular and Molecular Biotechnology Research Institute, National Institute of Advance Industrial Science and Technology, Tsukuba 305-8566, Japan

2Plant Research International, Wageningen University and Research Centre, Wageningen, The Netherlands. 3Graduate School of Pharmaceutical Sciences, Chiba University, Chiba-shi, Chiba, Japan

https://doi.org/10.23177/NJ025.201

Abstract: Phellinus linteus (L.) Quel. has been used in traditional Asian medicine for over two centuries against a variety of diseases. Many researchers have focused on the antioxidant properties of polyphenols from Phellinus linteus (P. linteus), however, this mushroom lacks identification of its polyphenols. We demonstrated the presence of nine polyphenol compounds i.e. 3,4-dihydroxybenzaldehyde, 4-(3,4-dihydroxyphenyl)-3-buten-2-one, interfungin A, inonoblin C, phelligridin D, interfungin B, inoscavin E, inoscavin C and methylinoscavin D in the ethanol extract of P. linteus fruiting bodies by LC-MS. The chromatographic separation was performed on a common reversed-phase C18 column using a water–acetonitrile with formic acid gradient program and the detection was achieved by ESI source operated in negative ion mode. Further characterization of P. linteus polyphenols was done by proton nuclear magnetic resonance spectroscopy (1H NMR) which showed strong proton resonances of 3,4-dihydroxybenzaldehyde, interfungin A, inonoblin C, phelligridin D, inoscavin E and inoscavin C.

Keywords: LC-MS, NMR, Phellinus linteus, polyphenol