Diterpenoids from Rabdosia flexicaulis / 中国中药杂志

The genus Rabdosia is famous for the abundance of diverse and novel ent-kaurane diterpenoids. However, only a few ent-kauranoids have been discovered from R. flexicaulis since the investigation on its chemical constituents is not systematic. To find novel bioactive diterpenoids, the ethyl acetate extract of the above ground part of R. flexicaulis in Daofu County, Sichuan Province was obtained by column chromatography. One new compound and five known ones were identified as flexicaulin E(1), forrestin B(2), inf-lexarabdonin D(3), 7α-hydroxydehydroabietic acid(4), 15-hydroxydehydroabietic acid(5), and pomiferin F(6) by spectral techniques. Compounds 1-3 were the ent-kaurane diterpenoids isolated from this species for the first time. Compounds 4-6, aromatic abie-tanoids, were isolated from the genus Rabdosia for the first time.

Pedalitin from isodon japonica, an inactivation of soybean lipoxygenase-1 / Pedalitina de isodon japonica, un inactivador de la lipo oxigenasa-1 de poroto de soya

Pedalitin, isolated from the aerial part of Rabdosia japonica (Labiatae), inhibited soybean lipoxygenase-1 (EC 1.13.11.12, Type I) with an IC50 of 152.5 uM. The progress curves for an enzyme reaction, pedalitin inactivate the lipoxygenase-1 in a time dependent, irreversible manner, exhibiting kinetics with a kinact/KI of 59.6 +/- 10 mM-1min-1. In the pseudoperoxidase activity, pedalitin is very slowly oxidized by the soybean lipoxygenase-1 catalyzed decomposition of lipid hydroperoxides.

Pedalitina, aislada de las partes aereas de Rabdosia japonica inhibió a la lipooxigenasa-1 (EC 1.13.11.12 tipo I) con un IC50 de 152.5 uM. La curva de progreso para una acción enzimática, pedalitina inactivó a la lipooxigenasa-1 de una manera dependiente del tiempo, de una manera irreversible, exhibiendo una cinética con una kinact/KI de 59.6 +/- mM-1min-1. En la actividad pseudoperoxidasa, pedalitina es oxidada lentamente por la descomposición de la lípido hidroperóxido de la lipooxigenasa-1 de poroto de soya.

Phytochemical and toxicological investigations of crude methanolic extracts, subsequent fractions and crude saponins of Isodon rugosus

BACKGROUND: Isodon rugosus is used traditionally in the management of hypertension, rheumatism, tooth-ache and pyrexia. Present study was arranged to investigate I. rugosus for phytoconstituents, phytotoxic and cytotoxic activities to explore its toxicological, pharmacological potentials and to rationalize its ethnomedicinal uses. Briefly, qualitative phytochemical analysis of the plant extracts were carried out for the existence of alkaloids, flavonoids, saponins, oils, glycosides, anthraquinones, terpenoids, sterols and tannins. Plant crude methanolic extract (Ir.Cr), its subsequent fractions; n-hexane (Ir.Hex), chloroform (Ir.Chf), ethyl acetate (Ir.EtAc), aqueous (Ir.Aq) and saponins (Ir.Sp) in different concentrations were tested for phytotoxic and cytotoxic activities using radish seeds and brine shrimps (Artemia salina) respectively. The phytotoxic activity was determined by percent root length inhibition (RLI) and percent seeds germination inhibition (SGI) while the cytotoxicity was obtained with percent lethality of the brine shrimps. RESULTS: Ir.Cr was tested positive for the presence of alkaloids, glycosides, flavonoids, oils, terpenoids, saponins, tannins and anthraquinones. Among different fractions Ir.Sp, Ir.Chf, Ir.EtAc, and Ir.Cr were most effective causing 93.55, 89.32, 81.32 and 58.68% inhibition of seeds in phytotoxicity assay, with IC50 values of 0.1, 0.1, 0.1 and 52 µg/ml respectively. Similarly, among all the tested samples, Ir.Sp exhibited the highest phytotoxic effect causing 91.33% root length inhibition with IC50 of 0.1 µg/ml. Ir.Sp and Ir.Chf were most effective against brine shrimps showing 92.23 and 76.67% lethality with LC50 values of 10 and 12 µg/ml respectively. CONCLUSIONS: It may be inferred from the current investigations that I. rugosus contains different secondary metabolites and is a potential source for the isolation of natural anticancer and herbicidal drug molecules. Different fractions exhibited phytotoxic and cytotoxic activities, thus providing pharmacological basis for ethnomedicinal uses of this plant.

Investigations of anticholinestrase and antioxidant potentials of methanolic extract, subsequent fractions, crude saponins and flavonoids isolated from Isodon rugosus

BACKGROUND: Based on the ethnomedicinal uses and the effective outcomes of natural products in various diseases, this study was designed to evaluate Isodon rugosus as possible remedy in oxidative stress, alzheimer's and other neurodegenerative diseases. Acetylecholinestrase (AChE) and butyrylcholinesterase (BChE) inhibitory activities of crude methanolic extract (Ir.Cr), resultant fractions (n-hexane (Ir.Hex), chloroform (Ir.Cf), ethyl acetate (Ir.EtAc), aqueous (Ir.Aq)), flavonoids (Ir.Flv) and crude saponins (Ir.Sp) of I. rugosus were investigated using Ellman's spectrophotometric method. Antioxidant potential of I. rugosus was determined using DPPH, H2O2 and ABTS free radicals scavenging assays. Total phenolic and flavonoids contents of plant extracts were determined and expressed in mg GAE/g dry weight and mg RTE/g of dry sample respectively. RESULTS: Among different fractions Ir.Flv and Ir.Cf exhibited highest inhibitory activity against AChE (87.44 ± 0.51, 83.73 ± 0.64%) and BChE (82.53 ± 0.71, 88.55 ± 0.77%) enzymes at 1 mg/ml with IC50 values of 45, 50 for AChE and 40, 70 µg/ml for BChE respectively. Activity of these fractions were comparable to galanthamine causing 96.00 ± 0.30 and 88.61 ± 0.43% inhibition of AChE and BChE at 1 mg/ml concentration with IC50 values of 20 and 47 µg/ml respectively. In antioxidant assays, Ir.Flv, Ir.Cf, and Ir.EtAc demonstrated highest radicals scavenging activities in DPPH and H2O2 assays which were comparable to ascorbic acid. Ir.Flv was found most potent with IC50 of 19 and 24 µg/ml against DPPH and H2O2 radicals respectively. Whereas antioxidant activates of plant samples against ABTS free radicals was moderate. Ir.Cf, Ir.EtAc and Ir.Cr showed high phenolic and flavonoid contents and concentrations of these compounds in different fractions correlated well to their antioxidant and anticholinestrase activities. CONCLUSION: It may be inferred from the current investigations that the Ir.Sp, Ir.Flv and various fractions of I. rugosus are good sources of anticholinesterase and antioxidant compounds. Different fractions can be subjected to activity guided isolation of bioactive compounds effective in neurological disorders.