Two new benzophenones (1 and 2) and four new xanthones (4-6 and 17) together with 24 known compounds (3, 7-16, and 18-30) were isolated from the roots and twigs of Cratoxylum sumatranum ssp. neriifolium. Their structures were elucidated by spectroscopic methods. Compounds 5 and 26 showed antibacterial activity against Micrococcus luteus, Bacillus cereus, and Staphylococcus epidermis with minimum inhibitory concentrations ranging from 4 to 8 μg/mL, whereas compounds 7, 20, and 26 displayed selective antibacterial activities against Staphylococcus aureus (8 μg/mL), Salmonella typhimurium (4 μg/mL), and Pseudomonas aeruginosa (4 μg/mL), respectively. The radical scavenging effects of some isolated compounds were investigated. Compounds 11 and 21 exhibited potent activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) with IC values of 7.0 ± 1.0 and 6.0 ± 0.2 μM, respectively.
The first phytochemical investigation of the stem extract of Millettia extensa resulted in the isolation and identification of six new isoflavones, millexatins A-F (1-6), together with 16 known compounds. The structures of these new compounds were determined on the basis of their spectroscopic data. Millexatin A (1) is a rare isoflavone containing three isoprenyl units on a modified A ring. Compounds 1, 6, 10, 11, and 14 displayed promising antibacterial activity with MIC values of 2-8 μg/mL.
Garcinia cowa Roxb. ex Choisy (Clusiaceae) is a Thai local edible plant, which has been used for the treatment of diabetes. The aim of this study is to discover and identify bioactive compounds related to antidiabetic properties from the leaf extract of G. cowa. α-Glucosidase inhibitory bioassay-guided isolation of the ethyl acetate extract of the leaves of G.cowa resulted in the isolation and identification of 11 compounds. Of these, a decahydro-1Hxanthene derivative, garciniacowone K (1), was identified as a novel compound. Their structures were characterized by spectroscopic data and by comparison of their NMR spectroscopic data with those previously reported.All compounds were evaluated for their α-glucosidase inhibitory and glucose consumption activities. Compound 2 showed the highest efficacy in inhibiting α-glucosidase enzyme and promoting glucose consumption activity by 3T3-L1 cells, with IC 50 values of 0.5 μM and 13.1 μM, respectively, without causing toxicity to cells.
Five new compoundstwo phloroglucinol benzophenones,
garciniacowones F (1) and G (2), and three
xanthones, garciniacowones H (3), I (4),
and J (5)together with seven known xanthones
(6–12) were isolated from the fresh
leaves of Garcinia cowa. Their structures were elucidated
by detailed analysis of NMR and MS data. Compounds 1 and 2 are phloroglucinol benzophenones containing a polyprenylated
bicyclo[3.3.1]nonane ring system, while compounds 3–5 are rare xanthones having farnesyl (3 and 5) and geranylgeranyl (5) units at C-8. Compounds 1, 3, 4, 7, 8, and 10 exhibited inhibitory effects on NO production
in LPS-induced RAW264.7 macrophage cells with IC50 values
ranging from 5.4 to 18.6 μM. Compounds 4 and 8 had α-glucosidase inhibitory activities with IC50 values of 15.4 and 11.4 μM, respectively, which were
more potent than that of the acarbose control.
Chemical investigation of Cratoxylum cochinchinense stem bark has led to the isolation and identification of a new xanthone, cochinchinone M (1), together with 12 known compounds. Their structures were elucidated on the basis of spectroscopic methods, including UV, IR, NMR and MS. Some compounds were evaluated for their antibacterial and acetylcholinesterase inhibitory activities.
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