An antimicrobial abietane from the root of Plectranthus hereroensis.

A new abietane diterpene, 16-acetoxy-7 alpha, 12-dihydroxy-8,12-abietadiene-11,14-dione, has been isolated from the acetone extract of the root of Plectranthus hereroensis and its structure established by spectroscopic means. This compound showed antibacterial activity against Staphylococcus aureus and Vibrio cholerae, and antiviral activity against Herpes simplex type II.

A rearranged abietane diterpenoid from Plectranthus hereroensis.

A new abietane diterpenoid has been isolated from the aerial parts of Plectranthus hereroensis, together with two known diterpenes. The structure of the new substance, 3 beta-acetoxy-6 beta,7 alpha,12-trihydroxy-17(15-->16);18(4-->3)-bisabeo-abieta-4(1 9),8,12,16-tetraene- 11,14-dione, was established by spectroscopic means and by comparison with closely related compounds. This diterpene showed moderate antibacterial activity.

Rapid determination of vitamin E in vegetable oils by reversed-phase high-performance liquid chromatography.

A quick and direct method for measuring tocopherols (alpha, beta+gamma and delta) in vegetable oils has been developed using RP-HPLC with UV detection. Previous extraction of tocopherols is not required. The oil is diluted in hexane and an aliquot is mixed with ethanol containing an internal standard (alpha-tocopherol acetate). The chromatographic system consists of an ODS-2 column with a methanol-water mobile phase. Tocopherols are detected at 292 nm in less than 5 min after injection. The method is precise (RSD=2.69%) and has a high mean recovery (98.14%).

Simultaneous determination of alpha-tocopherol and beta-carotene in olive oil by reversed-phase high-performance liquid chromatography.

A reversed-phase high-performance liquid chromatographic method was developed for the determination, in one run, of alpha-tocopherol and beta-carotene in virgin olive oil. The method involved a rapid saponification and a later extraction with a mixture of hexane-ethyl acetate. The chromatographic system consists of an ODS-2 column with a mobile phase of methanol-water-butanol and a diode-array detector. Linearity, precision, recovery and sensitivity were satisfactory. The main advantage of the proposed method is the speed and simultaneous determination of both compounds at the same time.

Prediction of wine foaming.

A procedure for estimating the foam properties of sparkling base wines without specifically measuring foam was developed. This method was based on mathematical equations established between the usual parameters of wine quality control (independent variables of the equations) and the wine foam parameters [foamability (HM), Bikerman coefficient (Sigma), and surface tension (ST)] obtained with the specific equipment (dependent variables of the equations). Ninety-six white wines from the Cava region produced at industrial scale were used to establish these equations. Two predictive equations that could be applied to different types of wine from different origins were obtained: one to predict the foamability (HM) and the other to predict the Bikerman coefficient (Sigma). Moreover, the database of foam parameters of the 96 wines allowed a qualitative assessment of wine foaming values.

Analgesic, anti-inflammatory, antipyretic and haematological effects of aethiopinone, an o-naphthoquinone diterpenoid from Salvia aethiopis roots and two hemisynthetic derivatives.

Aethiopinone (1), an o-naphthoquinone diterpene from Salvia aethiopis L. roots and two hemisynthetic derivatives 2 and 3 have been evaluated for toxicity, anti-inflammatory, analgesic, antipyretic, and haemostatic activities. The compounds tested showed low toxicity and a pharmacological profile similar to other NSAI substances on reducing the edema induced by carrageenan and contractions induced by phenyl-p-quinone; the most active compounds were 1 and 2. In the same way and as expected with these types of substances, the bleeding time increased. In the TPA-induced ear inflammation model, the three compounds showed a moderate reduction of edema, and 1 produced a significant increase in the reaction time against thermal painful stimuli in the tail immersion test. The results demonstrated strong anti-inflammatory, peripheral and central analgesic properties for 1, as well as antiedematose topical action and peripheral analgesic properties for 2 and 3.

From a phagostimulant natural product to semisynthetic antifeedants against Spodoptera littoralis larvae: chemical transformations of the neoclerodane diterpenoid scutegalin B.

Scutegalin B (4), a natural neoclerodane diterpenoid possessing phagostimulant activity against larvae of the lepidopteran Spodoptera littoralis, has been subjected to a series of chemical transformations obtaining several derivatives. The activity of some of these changes to antifeedant (10, 12, 16, and 17), although other derivatives are inactive (6, 7, and 15) or maintain phagostimulant activity (8 and 9) of the starting material (4). The most potent antifeedant was 16, which possesses 16,15-lactone and a (19S)-19, 2alpha-hemiacetal groups instead of the 16,15-lactol and (19R)-(19-O-tigloyl)19,2alpha-hemiacetal of the phagostimulant precursor 4. These and other structure-activity relationships are discussed, establishing that the biological action is strongly modulated by minimal structural variations.

Some biogenetic-type transformations of neoclerodane diterpenoids from Scutellaria species.

Treatment of scutebaicalin (1) with K-t-BuO yielded both the (13S)- and (13R)-8beta,13-epoxyclerodanes 2 and 3, respectively, by a Michael-type heterocyclization reaction. Identical treatment of scutalpin B (4) gave the corresponding (11E)-11-deacetoxy-12-dehydro derivative 5 by an elimination reaction. Side chains at C-9, such as those of compounds 1-5, are frequent among the neoclerodanes found in Scutellaria species, and these transformations suggest a plausible biogenetic pathway for these diterpenoids.

Structure and antimicrobial activity of diterpenes from the roots of Plectranthus hereroensis.

Two abietane-type diterpenoids have been isolated from the roots of Plectranthus hereroensis (Labiatae), one being the already known horminone [1] and the other a new substance, 7 alpha,12-dihydroxy-17(15-->16)-abeo-abieta-8,12,16-triene-11 ,14-dione [2], whose structure was established by spectroscopic means. Compounds 1 and 2 showed antimicrobial activity against Staphylococcus aureus, Vibrio cholerae, Candida albicans, and Pseudomonas aeruginosa.

Putative hepatotoxic neoclerodane diterpenoids from Teucrium species.

Fourteen neo-clerodane diterpenoids have been isolated from the acetone extract of the aerial parts of four species of Teucrium (T.alpestre, T. cuneifolium, T. divarication subsp. villosum, and T. flavum subsp. hellenicum) not previously studied chemically.