Meroterpenoids from Daphne genkwa shows promising in vitro antitumor activity via inhibiting PI3K/Akt/mTOR signaling pathway in A549 cells.

Phytochemical investigation into the leaves and branches of Daphne genkwa afforded 25 meroterpenoids (1-16) including nine pairs of enantiomers (1a/1b-8a/8b and 12a/12b), among which 20 compounds have been reported in the present work for the first time. The structures with absolute configurations of the new molecules (excluding 10-13) were established via comprehensive spectroscopic analyses especially electronic circular dichroism (ECD) and Mosher's methods. A preliminary in vitro cell viability assay revealed remarkable cytotoxicities of selective compounds against A549 (lung), Hela (cervical), MDA-MB231 (breast) and MCF-7 (breast) cancer cells, and compound 8a showed the best inhibitory activity with IC50 values in the range of 3.12-4.67 µM toward the four cell lines. Subsequent in vitro antitumor evaluation of 8a disclosed that it could inhibit the proliferation and metastasis, as well as induce significant apoptosis and cycle arrest, of A549 cells. Further mechanistic investigations revealed that 8a could exert its antitumor activity via inhibiting the PI3K/Akt/mTOR signaling pathway.

Alterbutenolide, a new butenolide derivative from a sponge-derived fungus Alternaria alternata I-YLW6-1.

Alterbutenolide (1), a new butenolide derivative with a long-chain aliphatic acid substitution, together with seven known phenolic compounds i.e. alternariol (2), asperigillol B (3), p-hydroxyphenylacetic acid (4), p-hydroxyphenylethyl alcohol (5), methyl p-hydroxyphenyl acetate (6), 2-(4-hydroxyphenyl)ethyl acetate (7), and 5,6-dihydro-4-methyl-2H-pyran-2-one (8), was isolated from the cultures of a sponge-derived fungus Alternaria alternata I-YLW6-1. The structure of 1 was established on the basis of HR-MS, 1D and 2D NMR, as well as by comparison of the optical rotation data with the literature reported. Compounds 2 and 3 showed significant to moderate inhibitory activities against three harmful microalgae with IC50 values from 3.0 to 36.2 µg/mL, whereas compound 1 only displayed moderate inhibition against Chattonella marina with IC50 value of 34.6 µg/mL. Meanwhile, compounds 3 and 4 showed weak toxicity against brine shrimp larvae with LC50 values >100 µg/mL.

Three new bioactive diterpenoids from the roots of Croton crassifolius.

Phytochemical investigation of Croton crassifolius led to the isolation of two new halimane diterpenoids (1 and 2), a new nor-clerodane diterpenoid (3), along with three known analogues (4-6). Their structures including absolute configurations were elucidated by spectroscopic analysis, single-crystal X-ray diffraction, and CD analysis. All isolates were evaluated for their inhibitory effects on the nitric oxide (NO) production induced by lipopolysaccharide (LPS) in RAW264.7 macrophage cells, and compound 1 exhibited moderate inhibition of NO production with an IC50 value of 25.8 ± 0.9 µM.

A new prenylated coumarin and a new anthranilamide derivative from Evodia lepta.

A new prenylated coumarin (1) and a new anthranilamide derivative (2) were isolated from the aerial parts of Evodia lepta. Compound 2 represents the first anthranilamide derivative from the Evodia genus. Their structures were elucidated by spectroscopic data analysis (MS, UV, IR, and NMR). Compound 1 exhibited certain inhibition on nitric oxide (NO) production induced by lipopolysaccharide (LPS) in RAW264.7 macrophages with an IC50 value of 37.96 ± 1.7 µM.

Two new naphthoate derivatives from Morinda officinalis.

Two new naphthoate derivatives, including a symmetrical dimer (1) and a monomer (2), were separated from the roots of Morinda officinalis var. hirsuta. Their structures were characterized on the basis of spectroscopic means especially MS and NMR methods. Biological evaluations revealed that the two compounds did not show inhibition against both cholinesterases AChE and BChE, while the dimer (1) did exhibit moderate growth inhibitory activity toward one human osteosarcoma cell line U2OS with an IC50 value of 18.5 ± 1.1 µM.

Eucalyptals A-C with a new skeleton isolated from Eucalyptus globulus.

Eucalyptals A-C (1-3) with a new skeleton of 3,5-diformyl-isopentyl phloroglucinol-coupled cadinane were isolated from the fruits of Eucalyptus globulus. Their structures were elucidated by spectroscopic analysis, and that of 1 was confirmed by single-crystal X-ray diffraction. The biosynthetic pathway of 1-3 was also postulated. Compounds 1-3 exhibited selective cytotoxicity against the HL-60 cell line.

Novel antibacterial diterpenoids from Larix chinensis Beissn.

Two novel labdane-type diterpenoids, butanedioic acid mono[(13S)-13-hydroxylabda-8(17),14-dien-19-yl] ester (1) and butanedioic acid bis[(13S)-13-hydroxylabda-8(17),14-dien-19-yl] ester (2), along with the eleven known diterpenoids 3-13 and three other known compounds, were isolated from the bark of Larix chinensis. Their structures were elucidated both spectroscopically and chemically. The major diterpenoids 1-9, 11, and 13, as well as the very abundant phenolic compound 16, were subjected to antibacterial and cytotoxic bioassays. Compounds 7 and 9 showed remarkable in vitro inhibition of Staphylococcus aureus and S. epidermidis (MIC = 37-73 microM).