Radical scavenging activity of Crocus sativus L. extract and its bioactive constituents

Stimulatory effect of Crocus sativus (saffron) on beta2-adrenoceptors of guinea pig tracheal chains

To study the mechanism(s) of the relaxant effects of Crocus sativus (Iridaceae), the stimulatory effect of aqueous-ethanolic extracts of this plant and one of its constituent, safranal was examined on beta-adrenoceptors in tracheal chains of guinea pigs. The beta(2)-adrenergic stimulatory was tested by performing the cumulative concentration-response curves of isoprenaline-induced relaxation of pre-contracted isolated guinea pig tracheal chains. The studied solutions were included two concentrations of aqueous-ethanolic extract from Crocus sativus (0.1 and 0.2g%), safranal (1.25 and 2.5 microg), 10nM propranolol, and saline. The study was done in two different conditions including: non-incubated (group 1, n=9) and incubated tissues with 1 microM chlorpheniramine (group 2, n=6). The results showed clear leftward shifts in isoprenaline curves obtained in the presence of only higher concentration of the extract in group 1 and its both concentrations in group 2 compared with that of saline. The EC(50) (the effective concentration of isoprenaline, causing 50% of maximum response) obtained in the presence of both concentrations of the extract (0.17+/-0.06 and 0.12+/-0.02) and safranal (0.22+/-0.05 and 0.22+/-0.05) in group 1 and only in the presence of two concentrations of the extract (1.16+/-0.31 and 0.68+/-0.21) in group 2 was significantly lower compared to saline (1.00+/-0.22 and 4.06+/-1.04 for groups 1 and 2, respectively) (p<0.05-0.001). The maximum responses obtained in the presence of both concentrations of the extract and safranal in group 1 were significantly lower than that of saline (p<0.005 for all cases). All values (CR-1=(EC(50) obtained in the presence of active substances/EC(50), obtained in the presence of saline)-1) obtained in the presence of higher concentrations of extract in group 1, its both concentrations and higher concentration of safranal in group 2 were negative and there were significant differences in this value between propranolol and those obtained in the presence of extract and safranal (p<0.05 to p<0.001). The results indicated a relatively potent stimulatory effect of the extract from Crocus sativus on beta(2)-adrenoceptors which is partially due to its constituent, safranal. A possible inhibitory effect of the plant on histamine (H(1)) receptors was also suggested.

Chemical composition of leaf extracts of Stevia rebaudiana Bertoni grown experimentally in Vojvodina

The chemical composition of leaf extracts of Stevia rebaudiana Bertoni, grown for the first time on an experimental field near Zrenjanin, was examined by GC-MS. The tested plant material was harvested in September of 2002. To analyze the chemical composition of the lipophilic components of the plant leaves, essential oils and ethyl acetate extract were isolated. Qualitative analysis of the essential oil obtained by hydrodistillation showed that among the identified 88 compounds, the majority were mono- and sesquiterpenes (50 types identified). By analysing the ethyl acetate extract, the presence of fatty acids (present as free and as esters), n-alkanes, n-alkenes, cyclic alkanes, alcohols, aldehydes, ketones, etc. was ascertained. Sesquiterpenes prevailed among the terpenes (50 types identified). Further constituents identified in ethyl acetate extract included sterols. Nerol, ?-cyclocitral, safranal, aromadendrene, ?-amorphene and T-muurolol were identified for the first time in this species, with match values over 90 %. Taking into consideration that these terpenes were identified for the first time in this species, it is obvious that Stevia rebaudiana grown in this area possesses certain specific characteristics that can be ascribed to cultivation on a domestic plantation.

Crocus sativus L. (Saffron) extract and its active constituents (crocin and safranal) on ischemia-reperfusion in rat skeletal muscle

Saffron and its constituents have been shown to decrease ischemia-reperfusion (I/R) injury in kidney or brain tissues. In this study, the effects of saffron ethanolic extract and its constituents, crocin and safranal, were evaluated in skeletal muscle during I/R injury. Hind limb ischemia was induced using clamping the common femoral artery and vein. After 2 h ischemia, the clamp of the femoral vessels of animals was taken off and the animal underwent 1h reperfusion. Muscle injuries were evaluated by recording of the electromyographic (EMG) potentials and performing some biochemical analysis including thiobarbituric acid reactive substances (TBARS), total sulfhydryl (SH) groups and antioxidant capacity of muscle (using FRAP assay). The ethanolic extract of saffron (5, 20 and 80 mg kg(-1)), crocin (50, 200 and 400 mg kg(-1)), safranal (0.1, 0.25 and 0.5 ml kg(-1)) and normal saline (10 ml kg(-1)) were administered intraperitoneally 1 h prior reperfusion. The average peak-to-peak amplitude during I/R was significantly increased in extract, crocin and safranal groups in comparison with control-ischemic group. Following saffron, crocin and safranal administration, the total SH contents and antioxidant capacity were elevated in muscle flap. The MDA level was declined significantly in test groups. It is concluded that saffron extract and its constituents show a protective effect against lower limb I/R in rat.