Sofía Salido

Synthesis of biologically active drimanes and homodrimanes from (−)-sclareol

Abstract Three drimanes, polygodial (2), albicanyl acetate (3) and 7-oxo-8,12-drimen-11-al (5), and two homodrimanes, 13,14,15,16-tetranorlabd-7-en-12,17-dial (6) and 7-oxo-13,14,15,16-tetranorlabd-8(17)-en-12-al (7), were synthesized from (−)-sclareol (1), and their antifeedant, antitumor and antimicrobial properties tested. In most cases, 6 and 7 were found to be more active than 2.

Chemical studies of essential oils of Juniperus oxycedrus ssp. badia.

Leaf and (unripe and ripe) berry essential oils of Juniperus oxycedrus ssp. badia (H. Gay) Debeaux grown wild in Spain have been analysed by capillary GC and GC-MS in combination with retention indices. A seasonal investigation of both leaf and berry oils was also performed. Among the approximately 80 constituents investigated (representing 90-98% of the oils) 60-68 were identified (80-97% of the oil composition). The leaf oils were mainly composed of alpha-pinene (40-57%) and manoyl oxide (5-10%). The (unripe) berry oils were dominated by alpha-pinene (65%) with moderate amounts of myrcene, limonene, germacrene D or gamma-muurolene. Several differences in yields and chemical composition from a qualitative and quantitative point of view were detected when comparing all the oil samples analysed. In addition, two oil samples were examined, but found inactive, against the replication of HIV-1(III(B)) and HIV-2(ROD) in cell culture, whereas the samples were toxic for the cells at a 50% cytotoxic concentration of 106 and 123 microg/ml, respectively.

Synthesis of Ambrox® from labdanolic acid

Abstract A synthesis of the valuable amber-type odorant Ambrox® from labdanolic acid (main diterpenoid of the acid fraction of non-polar extracts of Cistus ladaniferus L.) is reported. The conversion is based on (a) the α,β-dehydrogenation of methyl labdanolate using an organoselenium reagent, (b) subsequent oxidative degradations of the side chain, and (c) final acid-promoted cyclization of the resulting tetranorlabdan-8α,12-diol. The influence of the temperature and solvent in the cyclization of the diol with p-toluenesulfonic acid is also described. Thus, Ambrox® has been obtained by a six-step procedure in 33% overall yield from methyl labdanolate.

Olive tree wood phenolic compounds with human platelet antiaggregant properties

Oleuropein and (+)-cycloolivil are natural polyphenolic compounds with a significant radical scavenging activity present in olive tree. We have investigated the antiaggregant effects of oleuropein and (+)-cycloolivil isolated from an ethyl acetate extract of olive tree wood. Oleuropein and (+)-cycloolivil reduced the ability of thrombin to stimulate platelet aggregation. Both compounds reduced thrombin-evoked Ca(2+) release and entry to a similar extent to hydroxytyrosol. This effect was greater in platelets from patients with type 2 diabetes mellitus than in controls. Thrombin-, thapsigargin- and 2,5-di-(tert-butyl)-1,4-hydroquinone (TBHQ)-evoked protein tyrosine phosphorylation, which is involved in Ca(2+) signalling and platelet aggregation, is inhibited by oleuropein and (+)-cycloolivil. oleuropein and (+)-cycloolivil are natural oxygen radical scavengers that reduce thrombin-induced protein tyrosine phosphorylation, Ca(2+) signalling and platelet aggregation. These observations suggest that oleuropein and (+)-cycloolivil may prevent thrombotic complications associated to platelet hyperaggregability and be the base for the development of antiaggregant therapeutic strategies.

Chemical Composition and Seasonal Variations of Rosemary Oil from Southern Spain

Abstract The composition of 12 essential oil samples, obtained by steam distillation of twigs of rosemary (Rosmarinus officinalis L.) harvested in four different locations from southern Spain and during three phenological stages, has been analyzed by capillary GC and GC/MS in combination with retention indices. Quantitative data relative to 53 constituents (accounting for 96.7-99.2% of the oils), 12 of which being reported for the first time in Spanish rosemary oil, are described. All samples studied belong to the chemotype α-pinene/l,8-cineole/eamphor, the main and characteristic components being camphor (17.2-34.7%), α-pinene (10.2-21.6%), 1,8-cineole (12.1-14.4%), camphene (5.2-8.6%), borneol (3.2-7.7%), β-pinene (2.3-7.5%), verbenone (2.2-5.8%), β-caryophyllene (1.8-5.1%), limonene (2.0-3.8%), α-terpineol (1.2-2.5%), myrcene (0.9-4.5%), p-cymene (0.2-3.4%), bornyl acetate (0.2-2.3%), linalool (0.3-1.0%) and terpinen-4-ol (0.4-0.9%). The effect of harvest time on the oil production and chemical composition was examined. The highest oil yields (1.6-1.8%) were recorded during the fruiting period (summer). In general, minimum amounts of camphor and maximum amounts of α-pinene were observed in winter. The concentration of 1,8-cineole was almost constant throughout the year, though other oil constituent levels varied randomly with the plant life cycle. Thus, seasonal and geographical variations on the content of representative components allowed to achieve a quality assessment of the rosemary oils and, consequently, to deduce the best period for processing rosemary in the studied area.

Chemical Composition and Seasonal Variations of Spike Lavender Oil from Southern Spain

Abstract The composition of six essential oil samples, obtained by steam distillation of twigs of spike lavender (Lavandula latifolia Med.) harvested in three different locations from southern Spain during the full flowering and fruiting phenological stages, has been analyzed by capillary GC and GC/MS in combination with retention indices. Yields of the oils during flowering (1.5–2.2%) were 2.5–7 times higher than during fruiting (0.3–0.6%). Among the 56 identified constituents (accounting for 96.0–97.5% of the oils), the main and characteristic components were linalool (27.2–43.1%), 1,8-cineole (28.0–34.9%), camphor (10.8–23.2%), borneol (0.9–3.6%), β-pinene (0.8–2.6%), (E)-α-bisabolene (0.5–2.3%), β-pinene (0.6–1.9%), β-caryophyllene (0.5–1.9%), α-terpineol (0.8–1.6%), sabinene (0.3–0.8%), myrcene (0.3–0.8%), camphene (0.4–0.6%), terpinen-4-ol (0.3–0.5%) and limonene (0.2–0.9%). The volatile chemical composition and oil production of both full flowering and fruiting plants allowed to assess the type and quality of the spike lavender oils processed in the studied area.

Chlorosulfonic acid as a convenient electrophilic olefin cyclization agent

Among several sulfonic acids studied (MeSO3H, p-TsOH, H2SO4, ClSO3H, FSO3H), the scarcely used chlorosulfonic acid showed to be an efficient agent for electrophilic olefin cyclizations with internal nucleophilic termination, in a similar manner that is well-established with fluorosulfonic acid. Its availability, lower price and relatively lesser handling problems makes ClSO3H an advantageous cyclizing agent particularly for high-scale applications. The stereochemical outcome of these cyclizations has been rationalized.

Cinnamtannin B-1 from bay wood exhibits antiapoptotic effects in human platelets

Proanthocyanidins, such as cinnamtannin B-1, are polyphenolic compounds with antioxidant activity that induce apoptosis in a number of tumoral cells. We have now investigated the pro- or anti-apoptotic effects of cinnamtannin B-1 in human platelets. Platelet stimulation with thrombin induced cellular apoptosis, as detected by phosphatidylserine exposure and the activation of caspases-3 and -9. Pretreatment for 30 min with cinnamtannin B-1 impaired thrombin-induced apoptosis in platelets. Thrombin has been shown to induce H2O2 generation in platelets, which induced similar apoptotic events than thrombin in these cells. Pretreatment with cinnamtannin B-1 reduced H2O2-induced phosphatidylserine exposure and caspase activation. Finally, platelet stimulation with thrombin induced translocation of caspases-3 and -9 to the cytoskeletal (Triton-insoluble) fraction, which is important for their activation and the development of apoptotic events. Pretreatment with cinnamtannin B-1 impaired translocation of caspases-3 and -9 to the cytoskeleton and, as a result, procaspases are accumulated in the Triton-soluble fraction. Our results provide evidence for the antiapoptotic actions of cinnamtannin B-1 in human platelets.

Chemical Composition of the Essential Oil of Artemisia herba-alba Asso ssp. valentina (Lam.) Marcl.

Abstract The composition of the oil, steam-distilled from aerial parts of Artemisia herha-alba Asso ssp. valentina (Lam.) Marcl. (Asteraceae) collected from the south of Spain, has been analyzed by GC/MS. Among the 65 constituents investigated (representing 93.6 % of the oil composition), 61 were identified (90.3% of the oil composition). The major constituents detected were the sesquiterpene davanone (18.1%) and monoterpenes p-cymene (13.5%), 1,8-cineole (10.2%), chrysanthenone (6.7%), cis-chrysanthenyl acetate (5.6%), γ-terpinene (5.5%), myrcene (5.1%) and camphor (4.0%). The oil was dominated by monoterpenes (ca. 66% of the oil), p-menthane and pinane being the most representative skeleta of the group. The oil sample studied did not contain thujones, unlike most A. herba-alba oils described in the literature.

Antioxidant activity and free radical‐scavenging capacity of a selection of wild‐growing Colombian plants

BACKGROUND The replacement of some synthetic food antioxidants by safe natural antioxidants has fostered research on the screening of raw materials to find new vegetable sources of antioxidants. In this study the antioxidant activity of eight wild-growing Colombian plants was assessed by four complementary assays. RESULTS An evaluation of the antioxidant activity of ten ethanolic extracts from Baccharis chilco, Cinnamomum triplinerve, Ilex laurina, Lachemilla orbiculata, Lepechinia conferta, Quercus humboldtii, Rubus urticifolius and Tephrosia cinerea was carried out. Furthermore, the total phenolic content was determined by the Folin-Ciocalteu method, and the relationship between phenolic content and activity was also statistically investigated. Cinnamomum triplinerve, L. conferta and I. laurina were found to have the highest phenolic contents. Baccharis chilco, C. triplinerve, I. laurina, L. conferta, Q. humboldtii and R. urticifolius showed higher radical-scavenging activity (DPPH and superoxide assays) than commercial rosemary oleoresin (reference). Lachemilla orbiculata and R. urticifolius showed higher antioxidant activity (β-carotene-bleaching test) than the reference. The protection factor of all studied plant extracts was below that of the reference according to the Rancimat test. CONCLUSION On the basis of the results obtained, C. triplinerve, Q. humboldtii and R. urticifolius seem to be the most promising species for further investigation in order to identify the compounds responsible for their activity.