The relaxation dynamics and thermodynamic properties of supercooled and glassy gambogic acid are investigated using both theory and experiment. We measure the temperature dependence of the relaxation times in three polymorphs (α-, β-, and γ-form). To gain insight into the relaxation processes, we propose a theoretical approach to quantitatively understand the nature of these three relaxations. The α-relaxation captures cooperative motions of molecules, while the β-process is mainly governed by the local dynamics of a single molecule within the cage formed by its nearest neighbors. Based on quantitative agreement between theory and experimental data, our calculations clearly indicate that the β-process is a precursor of the structural relaxation and intramolecular motions are responsible for the γ-relaxation. Moreover, the approach is exploited to study the effects of the heating process on alpha relaxation. We find that the heating rate varies logarithmically with T_g and 1000/T_g. These variations are qualitatively consistent with many prior studies.

Three new xanthones, garcicowanones C-E (1 − 3), and six known xanthones (4 − 9) were isolated from the roots of Garcinia cowa Roxb. ex Choisy. Their chemical structures were determined using spectroscopic technics, including HR-ESI-MS and 2 D NMR. All isolated compounds were evaluated for in vitro α-glucosidase inhibition. Cowanol (6) and norcowanin (8) had the most potent α-glucosidase inhibitory activity, with respective IC₅₀ values of 33.5 ± 0.8 and 17.2 ± 0.3 µM, compared with the positive control, acarbose (IC₅₀ 257.3 ± 4.8 µM). Graphical Abstract

We investigate the anticancer activity and human stimulator of interferon genes pathway activation by a new hydrated-prenylated tetraoxygenated xanthone, garcicowanone I (1) and two known xanthones (2 and 3) that were isolated from the root bark of Garcinia cowa Roxb. ex Choisy. The anticancer activity of each compound was evaluated by sulforhodamine B assay in immortalized cancer cell lines. Stimulator of interferon genes pathway activation was assessed by western blot analysis using human THP-1-derived macrophages. The production of pro-inflammatory cytokines from these macrophages was also evaluated via enzyme-linked immunosorbent assay. Both compounds 1 and 3 displayed moderate inhibitory effects on the cancer cells, including a cisplatin-resistant cell line, with IC₅₀ values in the range of 10–20 µM. All three xanthones activated the stimulator of interferon genes, as evidenced by phosphorylation of tank-binding kinase 1, the stimulator of interferon genes protein and interferon regulatory factor 3. Furthermore, treatment of these macrophages with compounds 1–3 led to the production of pro-inflammatory cytokines, including interleukin 6, tumour necrosis factor α and interleukin 1β. In conclusion, the isolated xanthones, including the novel garcicowanone I, displayed promising anticancer and immunomodulatory activity that warrants further research.

The Garcinia genus belonging to the Clusiaceae family (Guttiferae) has been reported to be a rich source of polyisoprenylated benzophenones, xanthones and biflavonoids with various biological activities. Garcinia fagraeoides A.Chev is an evergreen hardwood tree found only in the north provinces of Viet Nam and Guangxi province of China. Its stem bark and leaves have been used in Vietnamese traditional medicine for treatment of malaria and dermatitis diseases. In our continuing studies on chemical constituents and biological activities from the genus Garcinia, the phytochemical of Garcinia fagraeoides’s stem bark collected from Thua Thien Hue province was investigated. Repeated chromatography steps over silica gel and Sephadex LH-20 of the dichloromethane partition from the methanol extract of Garcinia fagraeoides’s stem bark led to the isolation of five compounds including one polyisoprenylated benzophenone (isogarcinol (1)), two tetraoxygenated xanthones (rubraxanthone (2), a-mangostin (3)), ferulic acid (4), and pyromeconic acid (5). Their structures were elucidated mainly by analysis of their 1D, 2D NMR spectroscopy and ESI-MS data, and by comparison with reported data. The absolute configuration of isogarcinol (1) was determined by comparison of its experimental optical rotation and NMR data with the values of its stereoisomer. This is the first reported isolation of compounds 1-5 from the stem bark of Garcinia fagraeoides.

– HCTN8: Camellia hakodae Ninh, belonging to the golden subgroup of Camellia (Theaceae), is a Camellia species native to Vietnam and primarily found in Tam Dao, Vinh Phuc province. This study aimed to isolate and identify the flavonoids from the leaves of Camellia hakodae Ninh. As a results, a new flavanone glycoside, named camehakonin A (1), was discovered alongside six known flavonoids including isoxanthohumol (2), naringenin (3), taxifolin (4), (-)epicatechin (5), macarangin (6), and 3,5,7,3’,4’-pentahydroxy-6-geranylflavonol (7). The chemical structures of these compounds were elucidated based on analysis of their spectroscopic data and by comparison with reported NMR spectroscopy data of known compounds. All isolated flavonoids were evaluated for their antimicrobial activity against various microorganisms, including Enterococcus faecalis, Staphylococcus aureus, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Salmonella enterica and Candida albicans. Compound 1 exhibited significant inhibition of the tested Gram-positive bacteria (E. faecalis, S. aureus, and B. cereus) with MIC values of 128, 64, and 256 µg/mL respectively, as well as the human-pathogenic fungus C. albicans (MIC: 16 µg/mL). Furthermore, compound 1 displayed weak cytotoxicity in vitro against two cancer cell lines (KB and Hep-G2) with IC50 values of 73.70 and 221.11 µM, respectively. Notably, compounds 1-7 were isolated from the leaves of Camellia hakodae Ninh for the first time.