A New Apotirucallane from Walsura trichostemon Leaves and Its Antibacterial and α-Glucosidase Inhibitory Activities.

Phytochemical investigation of Walsura trichostemon leaves led to the isolation of a new apotirucallane-type triterpenoid, 11,25-dideacetyl-16-hydroxytrichostemonate (1), along with two known apotirucallane-type triterpenoids (2 and 3), two known tirucallane-type triterpenes (4 and 5), and two known steroids (6 and 7). Their structures were identified by intensive analysis of 1D and 2D nuclear magnetic resonance, infrared, and mass spectrometry data, which were compared with data reported in the literature. Compounds 2, 3, and 5 exhibited moderate antibacterial activity against Pseudomonas aeruginosa (minimum inhibitory concentration (MIC) value: 64 µg/mL), and compound 4 showed weak antibacterial activity against P. aeruginosa (MIC: 128 µg/mL). Furthermore, compound 5 displayed activity against Bacillus cereus (MIC: 64 µg/mL). In addition, compound 4 showed stronger α-glucosidase inhibitory activity than the control, acarbose. The active compound 4 was subjected to molecular docking experiments using AutoDock4 and revealed precise interactions with the active gorge of the enzyme through hydrogen bonding, supporting the in vitro results.

A new antibacterial tirucallane from Walsura trichostemon roots.

Phytochemical investigation of the roots of Walsura trichostemon, a Thai medicinal plant, provided a new tirucallane, 3-epimesendanin S 12-acetate (1), together with four known compounds, 3-epimesendanin S (2), meliasenin G (3), ß-sitosterol (4) and ß-sitosterol glucoside (5). Their structures were characterized by intensive spectroscopy including 1 D and 2 D NMR, UV, IR and MS spectrometric analysis. The isolated compounds were evaluated for antibacterial and acetylcholinesterase inhibitory activities. Compounds 1-2 showed antibacterial activity against Bacillus cereus and Bacillus subtilis with MIC values ranging from 16-128 µg/mL. In addition, compound 3 was active against Pseudomonas aeruginosa and Escherichia coli with MIC values of 64 and 128 µg/mL, respectively.

Cytotoxic compounds from the stems of Diospyros ehretioides and their bioactivity.

A new (naphthalenyl)methyl acetate, (1,4,5-trimethoxynaphthalen-2-yl)methyl acetate (1) and (±)-4,5-dihydroxy-2-methyltetralone (2) were isolated together with five lupane triterpenes (3-7), naphthoquinone derivatives (8-13), coumarins (14 and 15) and a vanillic acid (16) from the stems of Diospyros ehretioides. Their structures were established through spectroscopic analysis, IR, 1D and 2D NMR. Both 1 and 2 displayed significant cytotoxicity against three cancer cell lines including HeLa, HCT116 and MCF-7, with IC50 values in the range of 5.05-15.90 µg/mL, while 16 exhibited moderate cytotoxicity against HeLa and HCT116 cell lines and was not toxic to Vero cells.

A new cytotoxic plumbagin derivative from roots of Diospyros undulata.

A new plumbagin derivative, 3-(5-oxohexyl)plumbagin (1), together with six known benzoquinone derivatives (2-7), four known triterpenoids (8-11) and coniferyl aldehyde (12) were isolated from Diospyros undulata roots. Their structures were elucidated by intensive spectroscopy including 1 D and 2 D NMR, UV, IR and MS spectrometric analysis. Compound 1 exhibited strong cytotoxicity against three cancer cell lines as lung cancer (NCI-H187), breast cancer (MCF-7), and oral cancer (KB) with IC50 values of 7.16, 12.85 and 28.67 µM, respectively. Moreover, it did not showed cytotoxicity to Vero cells. In addition, the antimicrobial activity of compound 1 was moderate that kill only S. aureus with MBC of 250 µg/mL while other compounds especially compound 4 showed a broader activity that kill all tested bacteria.

Phytochemical investigation and acetylcholinesterase inhibitory activity of bark of Hymenodictyon orixense.

The chemical investigation of the methanol extract of Hymenodictyon orixense bark, a Thai medicinal herb, provided five compounds. Their structures were identified on the basis of 1D NMR and MS data, as well as by comparison of the data with published values, as an iridoid glycoside: loganin (1), four coumarins: scopoletin (2), scopolin (3), hymexelsin (4) and scopoletin 7-O-ß-D-xylopyranosyl-(1→6)-ß-D-glucopyranoside (5). Compounds 1-5 showed acetylcholinesterase (AChE) inhibitory activity in the range of 13.92-34.18% at a concentration of 100 µg/mL. In addition, compounds 1 and 5 are reported for the first time from this genus.

A 2H-tetrahydropyran derivative and bioactive constituents from the bark of Goniothalamus elegants Ast.

A new 2H-tetrahydropyran derivative, 6-epi-goniothalesdiol A (1), together with nine known styryllactones (2-10) and five known aristolactams (11-15) were isolated from the bark of Goniothalamus elegants Ast. The structures were elucidated by spectroscopic methods. The isolated compounds were evaluated for their cytotoxicity toward the KB, MCF7 and NCI-H187 cell lines as well as antimalarial and antimycobacterial activities. Compounds 4 and 10 showed strong activity against all three human cancer cell lines with IC50 values in the range of 0.538 to 4.25 µg/ml, while compounds 2, 4, 10 and 14 showed potent cytotoxicity against NCI-H187 with IC50 values in the range of 0.072 to 2.17 µg/ml. In addition, compounds 4, 6, 7, 9, 10 and 13 showed strong antiplasmodial activity with IC50 in the range of 2.28 to 5.89 µg/ml.

Antiplasmodial and cytotoxic flavans and diarylpropanes from the stems of Combretum griffithii.

Four new flavans, griffinoids A-D (1-4), and two new diarylpropanes, griffithanes E and F (7 and 8), together with two known flavans (5 and 6), four known diarylpropanes, and ß-sitosterol, were isolated from the EtOAc extract of the stems of Combretum griffithii. Compounds 3, 4, 5, and 9 exhibited weak antiplasmodial activity, with IC50 values of 15.74, 13.04, 9.66, and 14.45 µM, respectively. In addition, compounds 4, 5, and 8 also exhibited weak cytotoxicity toward one or more cancer cell lines including human epidermoid carcinoma, human breast cancer, and human small cell lung cancer cell lines.

Diarylpropanes and an arylpropyl quinone from Combretum griffithii.

Three new diarylpropanes (1-3), a new arylpropyl quinone (4), and the known 1-(2-hydroxy-4-methoxyphenyl)-3-(4-hydroxy-3-methoxyphenyl)propane (5) were isolated from a methanol extract of stems of Combretum griffithii. Their structures were elucidated by spectroscopic methods. Compounds 1, 2, 4, and 5 showed cytotoxicity against one or more cancer cell lines (KB, MCF7, and NCI-H187), and compound 5 exhibited activity against Mycobacterium tuberculosis (MIC 3.13 µg/mL).

Cytotoxic lasiodiplodin derivatives from the fungus Syncephalastrum racemosum.

Chemical investigation of fungal biomass of the fungus Syncephalastrum racemosum led to the isolation of new natural products (3R),(5S)-5-hydroxy-de-O-methyllasiodiplodin (1), 6-oxode-O-methyllasiodiplodin (2), in addition to five known compounds, de-O-methyllasiodiplodin (3), lasiodiplodin (4), (3R),(5R)-5-hydroxy-de-O-methyllasiodiplodin (5), ergosterol (6), and ergosterol peroxide (7). Their structures were elucidated by spectroscopic techniques. The absolute configuration of 1 was determined by a modified Mosher's method. Compound 1 showed cytotoxicity against cholangiocarcinoma, KKU-M139, KKU-M156, and KKU-M213 cell lines with IC(50) values in the range of 14-19 µg/mL, while 3 showed cytotoxicity against KB, BC1, and NCI-H187 cell lines with IC(50) values of 12.67, 9.65, and 11.07 µg/mL, respectively.

Prenylxanthones and a bicyclo[3.3.1]nona-2,6-diene derivative from the fungus Emericella rugulosa.

Five new prenylxanthones, ruguloxanthones A-C (1-3), 14-methoxytajixanthone (4), and tajixanthone ethanoate (5), a new bicyclo[3.3.1]nona-2,6-diene derivative, rugulosone (6), and seven known compounds, shamixanthone, tajixanthone, 14-methoxytajixanthone-25-acetate, tajixanthone hydrate, tajixanthone methanoate, isoemericellin, and ergosterol, were isolated from the fungus Emericella rugulosa. The structures of 1-6 were established using spectroscopic techniques. Compound 6 exhibited antimalarial and antimycobacterial activities, as well as cytotoxicity against three cancer cell lines.