Yuhua Bai

Eight compounds were obtained from the dry fruits of Piper longum L., and their potential vascular relaxant activities were explored. The present study first revealed the access of Rosin (7) and Piperchabaoside (8) in the medicinal plant Piper longum L. The vessel tension studies showed that Piperine (2), (2E,4E,14Z)-N-isobutyleicosa-2,4,14-trienamide (3), and Piperlonguminine (6) exerted significant inhibitory effects on PE-induced mesenteric artery vasoconstriction. Furthermore, Calcium Imaging studies were applied to observe the effect of Piperine on the intracellular calcium in mesenteric artery smooth muscle cells (MASMCs). Piperine (2) was observed to promote the influx of extracellular calcium in MASMCs, and via an endothelium-independent mechanism involving Ca²⁺ entry. Piper longum L. might have a great potential to be further studied as a vascular relaxant, even to be a drug candidate of anti-hypertension.

Gerbera anandria (Compositae) was extracted with 75% ethanol and the residue was fractionated using light petroleum, chloroform and ethyl acetate. The constituents of the extracts were separated by column chromatography employing solvents of different polarity. Column chromatography of the light petroleum fraction resulted in the isolation of methyl hexadecanoate, while the chloroform fraction afforded xanthotoxin, 2-hydroxy-6-methylbenzoic acid, 7-hydroxy-1(3H)-isobenzofuranone, a mixture of β-sitosterol and stigmasterol, and 8-methoxysmyrindiol and the ethyl acetate fraction gave gerberinside, apigenin-7-O-β-d-glucopyranoside and quercetin. A new coumarin, 8-methoxysmyrindiol, was found. The chemical structures of the isolated compounds were established by MS and NMR (HSQC, HMBC). Free radical scavenging and cytotoxic activities of crude extracts and 8-methoxysmyrindiol were further investigated. The ethyl acetate phase exerted the strongest DPPH free radical scavenging activity in comparison to the other fractions. The coumarin 8-methoxysmyrindiol demonstrated cytotoxicity against multiple human cancer cell lines, with the highest potency in HepG2 cells.

Flowers of Carthamus tinctorius L. are traditionally used in China to treat cerebrovascular and cardiovascular diseases. Hydroxysafflor yellow A (HSYA), the main constituent of Carthamus tinctorius L. flowers, is known for its multiple biological activities. In the present study, HSYA was isolated from Carthamus tinctorius L. flowers by a macroporous resin adsorption chromatography method coupled with a Waters high-throughput auto-purification system and it's vasodilatation effects on pulmonary artery (PA) were explored by an assay of tension study on rat pulmonary artery (PA) rings. Results suggest that HSYA possesses vascular relaxation effects on rat PA by activating the KV channel in pulmonary vascular smooth muscle cells (PVSMCs).

Semi-preparative high-speed counter-current chromatography (HSCCC) was successfully used for isolation and purification of oridonin from Isodon rubescens by using a two-phase-solvent system composed of n-hexane-ethyl acetate-methanol-water (2.8:5:2.8:5, v/v/v/v). The targeted compound isolated, collected and purified by HSCCC was analyzed by high performance liquid chromatography (HPLC). A total of 40.6 mg of oridonin with the purity of 73.5% was obtained in less than 100 min from 100 mg of crude Isodon rubescens extract. The chemical structure of the compound was identified by IR, ¹H-NMR and ¹³C-NMR.