Cage-Monoterpenoid Quinoline Alkaloids with Neurite Growth Promoting Effects from the Fruits of .

Meloyunnanines A-C, three alkaloids with an unprecedented skeleton, were isolated from fruits of . The structures featuring a caged-6/6/5/6/5/5 ring system were elucidated by the analysis of comprehensive spectroscopic and X-ray data. Biosynthetically, meloyunnanines A-C were assigned to monoterpenoid quinoline alkaloids (MQAs), derived from monoterpenoid indole alkaloids through oxidation and rearrangement.

[Chemical constituents from roots and rhizomes of Rubia oncotricha and their cytotoxic activities].

Fourteen compounds, including rubiprasin D (1), rubiprasin B (2), rubiprasin C (3), oleanolic acid (4), methyl-5-hydroxy-dinaphtho[1, 2-2'3']furan-7, 12-dione-6-carboxylate (5), rubioncolin C (6), mollugin (7), furomollugin (8), 3-amino-2-methoxycarbonyl-1, 4-naphthoquinone (9), 1-hydroxy-2-methyl-9, 10-anthraquinone (10), 2-hydroxy-6-methyl-9, 10-anthraquinone (11), 1, 4-dihydroxy-2-hydroxymethyl-9, 10-anthraquinone (12), 2-hydroxy-1-methoxy-9, 10-anthraquinone (13), and 1-hydroxy-2-methoxy-6-methyl-9, 10-anthraquinone(14), were isolated from the methanol extract of the roots and rhizomes of Rubia oncotricha using various column chromatographies. Their structures were mainly determined on basis of NMR and MS spectroscopic data analyses. Among them, 1 is a new oleanane triterpene, and compounds 2-5, 9 and 11-13 were obtained from this plant for the first time.

Rubipodanones A-D, naphthohydroquinone dimers from the roots and rhizomes of Rubia podantha.

Four previously undescribed naphthohydroquinone dimers named rubipodanones A-D, together with 19 known quinones containing three known napthohydroquinone dimers named rubioncolin C, methyl 5-hydroxy-dinaphtho[1,2-2',3']furan-7,12-dione-6-carboxylate and rubialatin B, were isolated from the roots and rhizomes of Rubia podantha. Their structures and absolute configurations were determined mainly by NMR, X-ray diffraction, and computational methods. Rubipodanones C and D, the glycosides of rubipodanone A and a pair of C-3 epimer, are the first identified dimeric napthohydroquinone glycosides from the Rubia plants.

Clausenlanins A and B, Two Leucine-Rich Cyclic Nonapeptides from Clausena lansium.

Two new cyclic nonapeptides, named clausenlanins A (1) and B (2), were isolated from the roots and rhizomes of Clausena lansium. Their structures were elucidated as cyclo-(Gly-L-Leu-L-Ile-L-Leu-L-Leu-L-Leu-L-Leu-L-Leu-L-Leu) (1) and cyclo-(Gly-L-Leu-L-Val-L-Leu-L-Leu-L-Leu-L-Leu-L-Leu-L-Leu) (2) respectively on the basis of extensive spectroscopic analysis, particularly 2D NMR spectra taken at the temperature of 338 or 303 K and MS.

New Labdane diterpenes from Hedychium yunnanense with cytotoxicity and inhibitory effects on nitric oxide production.

Two new labdane diterpenes, hedychenoids A (1) and B (2), were isolated from the rhizomes of Hedychium yunnanense, together with four known ones hedychenone (3), forrestin A (4), villosin (5) and calcaratarin C (6). Their structures were determined on the basis of NMR (1D and 2D) and mass spectroscopic analysis. Compounds 2, 3 and 5 exhibited cytotoxicity against SGC-7901 with IC values of 14.

Rubipodanin A, the First Natural N-Desmonomethyl Rubiaceae-Type Cyclopeptide from Rubia podantha, Indicating an Important Role of the N9-Methyl Group in the Conformation and Bioactivity.

One new cyclic hexapeptide named rubipodanin A (1), which is the first identified natural N-desmonomethyl Rubiaceae-type cyclopeptide, together with six known Rubiaceae-type cyclopeptides (2-7) were obtained using the TLC cyclopeptide protosite detection method with ninhydrin from the roots and rhizomes of Rubia podantha. The cyclopeptide structures were elucidated by extensive spectroscopic analysis, including 1D-NMR, 2D-NMR, IR, UV and MS. The solution conformation and biological activities of 1 and RA-V (4) were evaluated, and the results demonstrated that the N9-methyl group plays a vital role in the maintenance of the conformation and bioactivity.

RA-XII inhibits tumour growth and metastasis in breast tumour-bearing mice via reducing cell adhesion and invasion and promoting matrix degradation.

Cancer cells acquire invasive ability to degrade and adhere to extracellular matrix (ECM) and migrate to adjacent tissues. This ultimately results metastasis. Hence, the present study investigated the in vitro effects of cyclopeptide glycoside, RA-XII on cell adhesion, invasion, proliferation and matrix degradation, and its underlying mechanism in murine breast tumour cells, 4T1.

A pH-responsive natural cyclopeptide RA-V drug formulation for improved breast cancer therapy.

The natural plant cyclopeptide RA-V, which was isolated from the roots of Rubia yunnanensis, was discovered to be a novel anti-cancer candidate. However, the cyclic hexapeptide exhibited poor solubility in physiological conditions, limiting its application for cancer therapy in vivo. To solve this problem, pH-sensitive polymers were developed for targeted RA-V delivery into tumor sites and for acid-triggered drug release.

Cyclopeptide RA-V inhibits cell adhesion and invasion in both estrogen receptor positive and negative breast cancer cells via PI3K/AKT and NF-κB signaling pathways.

Cyclopeptide RA-V has potent anti-tumor and anti-angiogenic activities, but its potential anti-metastatic activity is unknown. Cancer cells acquire invasive ability to degrade and adhere to extracellular matrix (ECM), allowing them to migrate to adjacent tissues and ultimately metastasize. Hence, the present study aimed to investigate the effects of RA-V on cell adhesion, migration, invasion and matrix degradation, and its underlying mechanism in two human breast cancer cell lines MCF-7 (ER-positive) and MDA-MB-231 (ER-negative).

New cytotoxic naphthohydroquinone dimers from Rubia alata.

Two novel naphthohydroquinone dimers with unprecedented skeletons, rubialatins A (1) and B (2), were isolated from the herbal plant Rubia alata together with their precursor, mollugin (3). The structures were elucidated on the basis of NMR spectra and crystal X-ray diffraction. Compound 1, a racemate, was separated by chiral column chromatography, and the absolute configurations of the enantiomers were determined by the computational methods.

Coumarins from roots of Clausena excavata.

Two new coumarins, clauexcavatins A (1) and B (2), along with seven known ones (3-9), were isolated from the roots of Clausena excavata Burm. f. (Rutaceae).

[Cyclopeptides from Rubia schumanniana].

Objective: To separate and identify cyclopeptides of tubers of Rubia schumanniana.

Method: The 70% methanol extracts from tubers of Rubia schumanniana were separated and purified by silica gel, RP-18, Sephedax LH-20 and HPLC. Their structures were identified by spectral analysis.

[Progress in the study of some important natural bioactive cyclopeptides].

Natural cyclopeptides are hot spots in chemical and pharmaceutical fields because of the wide spreading bio-resources, complex molecular structures and various bioactivities. Bio-producers of cyclopeptides distribute over almost every kingdom from bacteria to plants and animals. Many cyclopeptides contain non-coded amino acids and non-pepditic bonds.

Antitumor cyclic hexapeptides from rubia plants: history, chemistry, and mechanism (2005-2011).

Rubiaceae-type cyclopeptides (RAs), cyclic hexapeptides from Rubia plants, have shown potential antitumor activity in vitro and in vivo. Based on the review about plant cyclopeptides (Chem. Rev.

Biologically active arborinane-type triterpenoids and anthraquinones from Rubia yunnanensis.

Twelve new arborinane-type triterpenoids (1-12) and four new anthraquinones (13-16), together with 50 known compounds, were isolated from the roots of Rubia yunnanensis. The structures of 1-16 were elucidated by spectroscopic data analysis and chemical methods. All compounds were evaluated for their cytotoxic, antibacterial, and antifungal activities.