[Investigation of the diterpene alkaloids of Aconitum species native to the Carpathian Basin]

Aconitum species accumulate highly toxic diterpene alkaloids, which have attracted considerable interest because of their complex structure, interesting chemistry and noteworthy physiological effects. The authors carried out phytochemical analysis of two Aconitum species native to the Carpathian Basin, aiming the isolation of diterpene alkaloids. The multistep chromatographic purification of the extracts of A. vulparia whole plant and A. toxicum root resulted in the isolation of 16 alkaloids. Structure elucidation by means of spectroscopic investigations revealed the presence of 3 (acovulparine, vulparine, acotoxinine) new and 13 already known compounds (anthranoyllycoctonine, delectinine, delcosine, finetiadine, lycoctonine, N-methyl-N-deethyllycocotine, septentriodine, aconitine, aconosine, dolaconine, neoline, songorine, songo-ramine). Alkaloids isolated from A. vulparia are C19 diterpene alkaloids possessing aconitane skeleton, whilst from A. toxicum two C20 diterpene alkaloids with napelline and five diterpene alkaloids with aconitane skeleton were identified. The pharmacological testing of the majority of the isolated compounds has not been reported in the literature yet. Since some of the diterpene alkaloids are structurally very similar to compounds which were active in different in vitro or in vivo experiments, the pharmacological testing of the alkaloids reported in this article seems to be reasonable. The investigation of the compounds may help to reveal structure-activity relationships as well.

Diterpenoids and flavonoids from the fruits of Vitex agnus-castus and antioxidant activity of the fruit extracts and their constituents

From the n-hexane fraction of the fruits of Vitex agnus-castus, two labdane-type diterpenes, vitetrifolin B and C, were isolated by means of multiple chromatographic separations, together with the previously identified rotundifuran, vitexilactone and the sesquiterpene spathulenol. From the EtOAc fraction, eupatorin was identified for the first time, besides the known casticin, penduletin, vitexin and orientin. The n-hexane, EtOAc and MeOH-H(2)O fractions of the MeOH extract of Agni-casti fructus were subjected to in vitro antioxidant assays. The EtOAc extract displayed a significant concentration-dependent effect when tested by 1,1-diphenyl-2-picrylhydrasyl (DPPH) free radical assay (IC(50) = 68 microg/mL) and against the autooxidation of a standard rat brain homogenate (IC(50) = 14 microg/mL). The MeOH-H(2)O fraction was less active with 3643 microg/mL (DPPH test) and IC(50) = 125 microg/mL (rat brain homogenate), while the n-hexane phase proved to be inactive. The main flavonoid constituents of the EtOAc extract, casticin, vitexin and orientin were assayed for antioxidant activity and found that only casticin possesses a marked lipid peroxidation inhibitory effect (IC(50) = 0.049 mm) compared with that of the positive control ascorbic acid (IC(50) = 0.703 mm).

[Chemical diversity of the biological active ingredients of salvia officinalis and some closely related species]

Comparative studies on the volatile and non-volatile fractions of 6 species. i.e. Salvia officinalis, S. tomentosa, S. fruticosa, S. candelabrum, S. ringens, S. lavandulifolia of the Section Salvia (Lamiaceae) have been carried out. Both fractions provide the chemical pattern matches to the chemotaxonomic character of Subfamily Nepetoideae in Erdtmanr two subfamiliar system. S. lavandulifolia had the highest essential oil content, followed by S. fruticosa, S. tomentosa, S. officinalis and S. candelabrum. S. ringens contains volatile oil only in traces. The neurotoxin thujone content was the highest in the S. officinalis oils and in that of S. fruticosa. No thujone was detected in S. lavandulifolia. The other species, e.g.: S. tomentosa contain this compound only in moderate concentrations (less than 10%). Among the non-volatile fractions of the plant ingredients the triterpene ursolic and oleanolic acids had the highest concentration in the leaves. Despite some rare cases, ursolic acid dominates the tritepene fraction. Rosmarinic and caffeic acids were measured in similar concentrations, in all species. As the case of S. officinalis shows, these compounds vary significantly in all organs during the vegetation period. Caffeic acid is also ubiquitous in the genus Salvia but as our data suggest it occurs in an order of magnitude lower concentration than rosmarinic acid. The isolation of phenylethanolid martynoside, though obtained in a rather small concentration, is of great chemotaxonomic significance, as this is the first phenylethanolid type glycoside isolated not only from the Salvia genus but also from the entire Subfamily Nepetoideae. As pheylethanolids are rather common and accumulate in significant concentrations in plants of the Subfamily Lamioideae, our opinion that the chemical differences between the two subfamilies are less qualititative than quantitative, is confirmed. This holds true of other chemical markers like monoterpenes, ursolic and oleanolic acids, caffeic acid and now phenylethanolids. Diterpenes i.e. 7-methyl carnosoate, rosmanol 7- methylether, sageon from S. officinalis, 7alpha-acetoyroyleanone, 7alpha-hydroxyroyleanone, royleanone, 6,7-dehydroroyleanone from S. tomentosa and candesalvoquinone, candelabroquinone, 12-O-methylcandesalvone, candesalvone B methyl ester and candelabrone have been isolated from Salvia candelabrum. All of the compounds belong to the abietane type of diterpenoids and have pronounced antioxidant effect.

A new ecdysteroid with unique 9beta-OH and four other ecdysteroids from Silene italica ssp. nemoralis

A new natural ecdysteroid, 9beta,20-dihydroxyecdysone (1) and four related compounds 5alpha-20-hydroxyecdysone (2), 5alpha-2-deoxy-integristerone A (3), integristerone A (4) and 22-deoxy-integristerone A (5) were isolated from the herb of Silene italica ssp. nemoralis. Compound 1 is the C-9 epimer of the known 9alpha,20-dihydroxyecdysone (6) and represents a peculiar steroid skeleton. The structures of the compounds were elucidated by 1D and 2D NMR, IR and MS spectroscopy.

Two new ecdysteroids from Serratula wolffii

11alpha-Hydroxypoststerone (1) and herkesterone (2), two new natural ecdysteroids, were isolated from the herb Serratula wolffii. The former compound is the first 11-hydroxylated C21 ecdysteroid, while the latter is a new ecdysteroid with a 7,9(11)-dien-6-one chromophore. Their structures were determined using a combination of spectroscopic techniques.

Preparative Scale Purification of Shidasterone, 2-Deoxy-polypodine B and 9 , 20-Dihydroxyecdysone from Silene italica ssp. nemoralis

A suitable combination of preparative scale separation methods results in effective clean-up of the ecdysteroids of Silene italica ssp. nemoralis (Waldst. and Kit.) Nyman. The isolation of minor ecdysteroids from the partially purified extract is based on the use of both droplet counter-current chromatography and low-pressure reversed-phase liquid chromatography. The purification is completed by preparative thin-layer chromatography and preparative high-performance liquid chromatography to obtain the minor ecdysteroids, such as 2-deoxy-20-hydroxyecdysone, shidasterone, 2-deoxy-polypodine B, makisterone C, and 9alpha,20-dihydroxyecdysone.

Diterpenes from the aerial parts of Salvia candelabrum and their protective effects against lipid peroxidation

A methanolic extract of the aerial parts of Salvia candelabrum was subjected to multiple chromatographic separation under the guidance of anti-lipid peroxidation assay. From the most active fractions seven abietane and seco-abietane diterpenes were isolated by preparative TLC purification. Besides candesalvoquinone, candelabroquinone, 12- O-methylcandesalvone B, candesalvone B methyl ester and candelabrone (all reported earlier), the known candesalvone B and the new candesalvolactone were identified. The structures were established by means of mass spectroscopy and advanced 2D NMR methods. All the identified compounds were evaluated for antioxidant activity in enzyme-dependent (IC (50) values 3.49 - 10.42 microM) and enzyme-independent (IC (50) values 1.40 - 13.40 microM) systems of lipid peroxidation. All compounds displayed marked concentration-dependent effects in both tests as compared with those of authentic ascorbic, rosmarinic and caffeic acids. The differences in antioxidant capacities observed in the enzyme-independent system allowed conclusions concerning structure-activity relationships.

New diterpenoids from the aerial parts of Salvia candelabrum

The new diterpenoids, candesalvoquinone, 12- O-methylcandesalvone B, candesalvone B methyl ester with the 3,4-secoabietane skeleton, and candelabroquinone with the abietane skeleton were isolated from the aerial parts of Salvia candelabrum, together with the known compound candelabrone. The structures were established by mass spectroscopy and advanced two-dimensional NMR methods, including 1H-NMR, JMOD, 1H- 1H COSY, HSQC, HMBC and NOESY experiments.

9alpha,20-Dihydroxyecdysone, a new natural ecdysteroid from Silene italica ssp. nemoralis

A new natural compound, 9alpha,20-dihydroxyecdysone (1), and two known related compounds, 20-hydroxyecdysone and ecdysone, were isolated from the herb Silene italica ssp. nemoralis. Compound 1 is the first C-9 hydroxylated ecdysteroid with a cis-fused A/B ring junction to have been isolated from a plant source, and its structure was determined using a combination of spectroscopic techniques.

5-Alpha- and 5-beta-2-deoxyintegristerone A, a 5-alpha and 5-beta isomer pair of ecdysteroids isolated from the Silene genus

5-Alpha-2-deoxyintegristerone A and 5-beta-2-deoxyintegristerone A were isolated from the aerial parts of Silene italica ssp. nemoralis (Waldst. and Kit.) Nyman using a specific combination of absorption column chromatography, preparative thin-layer chromatography and preparative HPLC. Both normal-phase and reversed-phase modes of HPLC were employed for isolation. Structural elucidation of 5-alpha-2-deoxyintegristerone A was completed by X-ray diffraction. Both 5-alpha-2-deoxyintegristerone A and 5-beta-2-deoxyintegristerone A were firstly isolated from this plant. We propose that 5-alpha-2-deoxyintegristerone A is not an artifact but an integral part of the ecdysteroid spectrum of Silene italica ssp. nemoralis (Waldst. and Kit.) Nyman.