Andrographolide targets EGFR to impede epithelial-mesenchymal transition in human breast cancer cells.

Despite the primary surgical treatment for breast cancer patients, malignant invasiveness and metastasis remain threatening factors for women with breast cancer. As chemotherapy yields unsatisfactory results, it prompted us to search for effective natural agents with few side-effects. Although andrographolide (ADGL), a natural diterpenoid lactone isolated from Andrographis paniculata, presents anticancer effects, the molecular mechanism remains unknown. Initially, on comparing the expression of proteins related to epithelial-mesenchymal transition (EMT) between nonmetastatic cancer MCF7 cells and highly metastatic cancer MDA-MB-231 cells, we found that MDA-MB-231 cells exhibit higher protein levels of N-cadherin and vimentin and lower protein levels of E-cadherin when compared to MCF7 cells. Moreover, MDA-MB-231 cells also exhibited higher EGFR expression and activity, higher STAT1 activity and abundant HDAC4 expression. To elucidate whether these proteins are closely associated with EMT, EGFR, STAT1 or HDAC4, the proteins were silenced in MDA-MB-231 breast cancer cells by their specific siRNAs. We found that silencing these proteins reduced EMT, indicating an important role of EGFR, STAT1 and HDAC4 in EMT progression. When we treated MDA-MB-231 cells with ADGL as a potential therapeutic drug, we found that ADGL treatment inhibited cell migration and invasion. Furthermore, it also recovered E-cadherin expression and decreased N-cadherin and vimentin protein levels. ADGL treatment reduced EGFR expression at a lower concentration (1 µg/mL); however, STAT1 activity and HDAC4 expression was reduced by a higher concentration (5 µg/mL) of ADGL. Moreover, we observed that the combined treatment with ADGL and siRNAs against these proteins highly sensitized the MDA-MB-231 cells to apoptosis compared to that with ADGL and control siRNA. Collectively, our results suggest that ADGL targets EGFR, thereby inhibiting EMT in human breast cancer cells.

Phukettosides A-E, mono- and bis-iridoid glycosides, from the leaves of Morinda umbellata L.

Four undescribed bis-iridoid glycosides, named phukettosides A-D, and one iridoid glycoside, referred to as phukettoside E, were isolated and fully characterized from the leaves of Morinda umbellata L. Phytochemical analysis also revealed the presence of eight known compounds. The structures were determined through extensive analysis of 1D and 2D-NMR spectroscopic and HRMS spectral data, and the absolute configurations of the isolates were deduced through ECD calculations. Biogenetic pathways for the bis-iridoid glycosides, phukettosides A-C, through intermolecular Diels-Alder type reactions, were proposed. The isolated compounds, with the exception of phukettosides B and D, were evaluated against a panel of cancer cell lines (MOLT-3, HuCCA-1, A549, HeLa, HepG2, and MDA-MB-231) and a non-cancerous cell line (MRC-5) for their cytotoxicity. None of the isolates had significant cytotoxic effects on the tested cell lines.

Antiplasmodial dimeric chalcone derivatives from the roots of Uvaria siamensis.

Four dimeric chalcone derivatives, 8″,9″-dihydrowelwitschin H, uvarins A-C, a naphthalene derivative, 2-hydroxy-3-methoxy-6-(4'- hydroxyphenyl)naphthalene, and the known dimeric chalcones, dependensin and welwitschin E, flavonoids, a cyclohexane oxide derivative, an aromatic aldehyde were isolated from the roots of Uvaria siamensis (Annonaceae). The structures of the compounds were elucidated by spectroscopic analysis, as well as by comparison with literature data. The isolated compounds with a sufficient amount for biological assays were evaluated for their antimalarial, antimycobacterial, and cytotoxic activities. The dimeric chalcones 8″,9″-dihydrowelwitschin H, uvarins B and C, dependensin and welwitschin E showed strong antiplasmodial activity with IC50 values of 3.10, 3.02, 3.09, 4.21 and 3.99 µg/mL, respectively. A possible biosynthesis pathway of the dimeric chalcones is discussed.

Two new C-benzylated dihydrochalcone derivatives from the leaves of Melodorum siamensis.

Two new C-benzylated dihydrochalcone derivatives, 4,2',4'-trihydroxy-6'-methoxy-3'(2''-hydroxybenzyl)dihydrochalcone (1) and 2',4'-dihydroxy-4,6'-dimethoxy-3'(2''-hydroxybenzyl)dihydrochalcone (2), along with six known flavonoid derivatives (3-8), a known dihydrochalcone dimer (9), three known aromatic esters (10-12), and one known aromatic amide (13), were isolated from the leaves of Melodorum siamensis. The structures of the compounds were elucidated by spectroscopic analysis, mainly 1D and 2D NMR techniques (1H, 13C, COSY, HMQC, and HMBC), as well as by comparison with literature data. The isolated compounds with a sufficient amount for biological assays were evaluated for their antimalarial, antimycobactirial, and cytotoxic activities. Compounds 1, 2, and 13 exhibited strong cytotoxicity against human tumor cell lines KB and NCI-H187, with IC50 values in the range of 0.66-7.16 µg/mL.

Redetermined structure, inter-molecular inter-actions and absolute configuration of royleanone.

The structure of the title diterpenoid, C(20)H(28)O(3), {systematic name: (4bS,8aS)-3-hy-droxy-2-isopropyl-4b,8,8-trimethyl-4b,5,6,7,8,8a,9,10-octa-hydro-phenanthrene-1,4-dione} is confirmed [Eugster et al. (1993 ▶). Private communication (refcode HACGUN). CCDC, Union Road, Cambridge] and its packing is now described. Its absolute structure was established by refinement against data collected with Cu radiation: the two stereogenic centres both have S configurations. One cyclo-hexane ring adopts a chair conformation whereas the other cyclo-hexane ring is in a half-chair conformation and the benzoquinone ring is slightly twisted. An intra-molecular O-H⋯O hydrogen bond generates an S(5) ring motif. In the crystal, mol-ecules are linked into chains along [010] by O-H⋯O hydrogen bonds and weak C-H⋯O inter-actions. The packing also features C⋯O [3.131 (3) Å] short contacts.

Absolute configuration of fibaruretin B.

The title furan-oditerpenoid, known as fibaruretin B (systematic name: 2ß,3α-dihy-droxy-2,3,7,8α-tetra-hydro-penianthic acid lactone), C(20)H(24)O(7), was isolated from the roots of Arcangelisia flava. The absolute configurations at positions 2, 3, 4, 4a, 7, 9, 10a and 10b of fibaruretin B are S, R, S, R, S, S, S and S, respectively. In the crystal structure, the mol-ecules are linked into infinite chains along the c axis by O-H⋯O hydrogen bonds and weak C-H⋯O inter-actions.

11,12-Dihy-droxy-10,6,8,11,13-icetexapentan-1-one.

THE TITLE COMPOUND [SYSTEMATIC NAME: 14,15-dihy-droxy-7,7-dimethyl-13-(propan-2-yl)tricyclo-[9.4.0.0(3,8)]penta-deca-1(11),3(8),9,12,14-pentaen-4-one], C(20)H(24)O(3), is a new icetexane diterpenoid which was isolated from the roots of Premna obtusifolia (Verbenaceae). The mol-ecule has three fused rings: a cyclo-hexenone, a central cyclo-heptene and a benzene ring. The cyclo-hexenone ring is in an envelope conformation, whereas the cyclo-heptene ring is in a twisted boat conformation. Intra-molecular O-H⋯O hydrogen bonds generate S(5) and S(8) ring motifs. In the crystal, mol-ecules are linked into dimers through O-H⋯O hydrogen bonds. These dimers are arranged in to sheets parallel to the ac plane. C-H⋯O and weak C-H⋯π inter-actions are also present.

Redetermination and absolute configuration of 7α-hy-droxy-royleanone.

THE TITLE COMPOUND [SYSTEMATIC NAME: 7α,12-dihy-droxy-8,12-abietadiene,11,14-dione or (4bS,8aS,10R)-3,10-dihy-droxy-2-isopropyl-4b,8,8-trimethyl-1,4,4b,5,6,7,8,8a,9,10-deca-hydro-phenanthrene-1,4-dione], C(20)H(28)O(4), is an abietane diterpen-oid, which was isolated from the roots of Premna obtusifolia (Verbenaceae). Its crystal structure has been reported previously [Chen et al. (2000 ▶). Jiegou Huaxue, 19, 122-125], but the absolute configuration could not be determined using data collected with Mo radiation. This redetermination using Cu radiation shows the the absolute configurations of the stereogenic centres at positions 4b, 8a and 10 to be S, S and R, respectively. Two intra-molecular O-H⋯O hydrogen bonds [one generating an S(5) ring and one generating an S(6) ring] and a number of short C-H⋯O contacts occur. In the crystal, mol-ecules are linked into infinite chains propagating in [100] by O-H⋯O hydrogen bonds and weak C-H⋯O inter-actions.

6α-Hy-droxy-5,6-dihydro-salviasperanol.

In the title compound, C(20)H(28)O(4), a diterpenoid isolated from the roots of Premna obtusifolia (Verbenaceae), the five-membered ring is in a half-chair conformation. One six-membered ring exists in a twisted-boat conformation while the other is in half-boat conformation. The crystal packing is stabilized by inter-molecular O-H⋯O and weak C-H⋯O inter-actions, generating (001) sheets.

6-Hydroxy-salvinolone.

The title compound {systematic name: 5,6,10-trihydr-oxy-7-iso-propyl-1,1,4a-trimethyl-2,3,4,4a-tetra-hydro-phenanthren-9(1H)-one}, C(20)H(26)O(4), is a diterpenoid which was isolated from the roots of Premna obtusifolia. The mol-ecule has three fused six-membered rings; the cyclo-hexane ring is in a twisted-boat conformation and the cyclo-hexene ring adopts a sofa form. Intra-molecular O-H⋯O hydrogen bonds generate two S(5) ring motifs. In the crystal, mol-ecules are linked into infinite one-dimensional chains along the [001] direction by O-H⋯O hydrogen bonds and weak C-H⋯O inter-actions.