1.Secondary Metabolites of Hemerocallis fulva var. kwanso Regel and Their PTP1B Inhibitory Potential
Thi Thanh LE ; Manh Tuan HA ; Trong Trieu TRAN ; Seung Eui MIN ; Kang-Hyun HAN ; Jungmoo HUH ; Jeong Ah KIM ; Byung Sun MIN
Natural Product Sciences 2026;32(1):76-83
A phytochemical study of the root extract of Hemerocallis fulva var. kwanso Regel resulted in the isolation and structural characterization of four lignans (1‒4), three flavanones (5, 6, and 8), one chalcone (9), and two monoterpenes (7 and 10). Enzyme inhibition assays revealed that two flavanone glucosides (5 and 6) showed significant inhibitory effect against protein tyrosine phosphatase 1B (PTP1B), with IC50 values of 31.38 µM and 51.46 µM, respectively. Further enzyme kinetic studies demonstrated that these two compounds acted as noncompetitive PTP1B inhibitors, with Ki values of 30.88 µM and 50.38 µM, respectively.
2.PTP1B Inhibitory Constituents from Dystaenia takeshimana: Mechanistic Insights via Kinetic and Molecular Docking Analyses
Manh Tuan HA ; Trong Trieu TRAN ; Thu Huong TRAN ; Jungmoo HUH ; Jeong Ah KIM ; Byung Sun MIN
Natural Product Sciences 2026;32(1):56-62
Dystaenia takeshimana (Nakai) Kitagawa belongs to the family Apiaceae (Umbelliferae) and is a perennial herb naturally endemic to Ulleung Island, Republic of Korea. Following its successful introduction and cultivation in mainland Korea, a phytochemical investigation of this plant was carried out. As a result, thirteen compounds were isolated and structurally characterized, including one flavonoid glycoside (1), two polyacetylenes (2 and3), one caffeoylquinic acid derivative (4), one aliphatic hydroxy acid (5), four phenolic acids and their derivatives(6, 8–10), one aromatic alcohol derivative (7), two carbohydrates (11 and 12), and one phytosterol (13). The structures of these compounds were elucidated based on spectroscopic analyses and comparison with previously reported literature data. To the best of our knowledge, this study represents the first report on the isolation of falcarinol (2), trans-4-hydroxy-2-nonenoic acid (5), and sucrose (11) from D. takeshimana and the evaluation of their protein tyrosine phosphatase 1B (PTP1B) inhibitory activity. Compounds 2, 3, and 5 exhibited potent PTP1B inhibitory effects with IC50 values of 10.74, 8.31, and 25.24 µM, respectively. Enzyme kinetic studies indicated noncompetitive inhibition by 2 and mixed-type inhibition by 5 against PTP1B. Furthermore, molecular docking analysis was performed to investigate the binding interactions between the active compounds and the enzyme active site.
3.A New Methoxyflavonoid Rutinoside and PTP1B-Inhibitory Phenolic Compounds from the Water Extract of Areca catechu L.
Manh Tuan HA ; Trong Trieu TRAN ; Thu Huong TRAN ; Seung Eui MIN ; Sang-Jin PARK ; Kang-Hyun HAN ; Jungmoo HUH ; Jeong Ah KIM ; Byung Sun MIN
Natural Product Sciences 2026;32(1):50-55
Phytochemical investigation of the water extract and alkaloid fraction of Areca catechu L. led to theisolation of one new methoxyflavonoid rutinoside (1), together with eleven known compounds (2−12), five of which (8−12) belong to the pyridine alkaloid class. The structure of the new compound was elucidated through extensive spectroscopic analyses, including 1D and 2D NMR experiments and high-resolution mass spectrometry.Notably, rhamnazin-3-O-rutinoside (2) is reported here for the first time from this species. The isolated compounds were evaluated for their inhibitory activity against protein tyrosine phosphatase 1B (PTP1B) using a p-nitrophenyl phosphate assay. Flavonoids (3 and 4) and stilbene (5) exhibited notable inhibitory activity, with IC50 values of 13.30 ± 0.71, 13.44 ± 0.84, and 8.68 ± 0.12 μM, respectively. In contrast, methoxyflavonoid rutinosides (1 and 2) and pyridine alkaloids (8−12) did not show significant inhibitory activity against PTP1B.These findings provide additional chemical insights into A. catechu and its constituents in relation to PTP1B inhibition.
4.Areca catechu L.: A Comprehensive and Updated Review of its Phytochemical and Pharmacological Properties
Manh Tuan HA ; Thu Huong TRAN ; Jungmoo HUH ; Seung Eui MIN ; Kang-Hyun HAN ; Yong-Bum KIM ; Jeong Ah KIM ; Byung Sun MIN
Natural Product Sciences 2025;31(4):236-250
Areca catechu L., the primary source of areca alkaloids, has long been considered the only species inthe genus containing these compounds. However, a recent study detected the same pyridine alkaloids in A. triandra, suggesting that alkaloid biosynthesis may also occur in other species of Areca. The immature fruit or pericarp of A. catechu is the principal component of betel quid, a masticatory deeply rooted in ancient oriental culture and consumed by over 600 million people globally. Its longstanding medicinal applications have attracted extensive modern research into its chemical composition, biological activities, and toxicity. This review provides a comprehensive update on the major chemical constituents of A. catechu, including alkaloids, flavonoids, tannins, other phenolic compounds, triterpenoids and phytosterols, fatty acids, glycerides, and polysaccharides, and their reported pharmacological activities, such as antioxidant, anti-inflammatory, analgesic and antinociceptive, cytotoxic, antibacterial and antifungal, hypoglycemic, lipid-regulating, antiparasitic, immunomodulatory, neuroprotective, digestive, antiviral, cardiovascular, anti-allergic, and other effects. Information was systematically collected from PubMed, Google Scholar, ACS, Web of Science, and ScienceDirect to provide an up-to-date summary of its phytochemistry and bioactivity.

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