Components ofSaussurea elegans

Isolation and Biological Properties of the Natural Flavonoids Pectolinarin and Pectolinarigenin-A Review

Flavonoids are metabolites widely distributed in plants and commonly present in foods, such as fruits and vegetables. Pectolinarin, which belongs to the flavone subclass, has attracted considerable attention due to its presence in many medicinal plants. It has turned out to be a good biological agent especially due to its antioxidant, anti-inflammatory, antidiabetic, and antitumor activities, evaluated both in vitro and in vivo. Its aglycone, the metabolite pectolinarigenin, is also known for a series of biological properties including anti-inflammatory and antidiabetic effects. In the first overview on the two metabolites here presented, their collection, isolation and the results of their biological evaluation are reported.

Effect of plant flavonoids on the volume regulation of rat thymocytes under hypoosmotic stress

BACKGROUND

Cell volume regulation and volume-regulated anion channels are critical for cell survival in non-isosmotic conditions, and dysregulation of this system is detrimental. Although genes and proteins underlying this basic cellular machinery were recently identified, the pharmacology remains poorly explored.

METHODS

We examined effects of 16 flavonoids on the regulatory volume decrease (RVD) of thymocytes under hypoosmotic stress assessed by light transmittance and on the activity of volume-sensitive chloride channel by patch-clamp technique.

RESULTS

Comparison of effects of flavonoids on RVD revealed a group of four active substances with lehmannin being the strongest inhibitor (IC50 = 8.8 μM). Structure-functional comparison suggested that hydrophobicity brought about by methoxy, prenyl or lavandulyl groups as well as by the absence of glucosyl fragment together with localization of the phenyl ring B at the position C2 (which is at C3 in totally inactive isoflavones) are important structural determinants for the flavonoids activity as volume regulation inhibitors. All active flavonoids suppressed RVD under Gramicidin D-NMDG hypotonic stress conditions when cationic permeability was increased by an ionophore, gramicidin D, with all extracellular monovalent cations replaced with bulky NMDG+ suggesting that they target volume-sensitive anionic permeability. While effects of hispidulin and pulicarin were only partial, lehmannin and pinocembrin completely abolished RVD under Gramicidin D-NMDG conditions. In direct patch-clamp experiments, lehmannin and pinocembrin produced a strong inhibiting effect on the swelling-induced whole-cell chloride conductance in a voltage-independent manner.

CONCLUSION

Lehmannin, pinocembrin, and possibly hispidulin and pulicarin may serve as leads for developing effective low-toxic immunomodulators.

Flavonoid Diversity of Saussurea and Serratula Species in Tien Shan Mountains

Nine Saussurea species, S. alberti, S. elegans, S. gnaphalodes, S. involucrata, S. konuroba, S. kuschakewiczii, S. leucophylla, S. schanginiana and S. sordida, and Serratula lyratifolia from the Tien Shan Mountains and adjacent area were chemically characterized for flavonoids. Thirty-one flavonoids and one hydroquinone were isolated from the leaves of these species and identified from mass spectrometric, UV, 1H and 13C NMR spectroscopic data, by characterization of hydrolyzates, and direct TLC and HPLC comparisons with authentic samples as kaempferol 3-O-rutinoside (1), quercetin 3-O-rutinoside (2), isorhamnetin 3-O-rutinoside (3), quercetin 3-O-glucoside (4), quercetin 3-O-galactoside (5), kaempferol 5-O-glucoside (6), kaempferol 7-O-glucoside (7), quercetin 5-O-glucoside (8), quercetin 7-O-glucoside (9), isorhamnetin 5-O-glucoside (10), luteolin (11), hispidulin (12), nepetin (13), selagin 7-methyl ether (14), selagin (15), velutin (16), luteolin 7-methyl ether (17), jaceosidin (18), apigenin 7-O-rutinoside (19), apigenin 7-O-glucoside (20), luteolin 7-O-rutinoside (21), luteolin 7-O-glucoside (22), luteolin 7-O-galactoside (23), luteolin 7-O-glucuronide (24), hispidulin 7-O-glucoside (25), nepetin 7-O-glucoside (26), luteolin 5-O-glucoside (27), isovitexin (28), apigenin 6,8-di-C-glycoside (29), isoorientin (30), luteolin 8-C-glycoside (31), and arbutin (32). The nine surveyed Saussurea species differed in their flavonoid composition. It was shown that the genus is not only morphologically, but also chemically diversified.

Chemical constituents from the genus Saussurea and their biological activities

The genus