Jaume Bastida

Acetylcholinesterase inhibitory activity of some Amaryllidaceae alkaloids and Narcissus extracts

Amaryllidaceous plants produce pharmacologically active alkaloids, galanthamine being the most interesting for its use in the treatment of Alzheimers disease as a cholinesterase inhibitor. The aim of this work was to test 23 pure Amaryllidaceae alkaloids and 26 extracts from different species of the genus Narcissus for their acetylcholinesterase inhibitory activity using galanthamine as a reference. Only seven alkaloids, belonging to the galanthamine and lycorine skeleton types, exhibited such an effect, sanguinine being the most active, even more than galanthamine. All the extracts with the highest acetylcholinesterase inhibitory activity contained galanthamine except that of N. assoanus, a lycorine type alkaloid-bearing species.

Identification of phenolic compounds in artichoke waste by high-performance liquid chromatography–tandem mass spectrometry

A new fast and efficient method combining liquid chromatography coupled to ionspray mass spectrometry in tandem mode with negative ion detection is described for the qualitative analysis of artichoke waste. Forty-five phenolic compounds were identified on the basis of their mass spectra in full scan mode, mass spectra in different MS-MS modes, and retention times compared with those of available reference substances. The major compounds were found to be both caffeoylquinic and dicaffeoylquinic acids, luteolin glucuronide, luteolin galactoside, quercetin, and some quercetin glycosides.

Investigation of Bolivian plant extracts for their radical scavenging activity and antioxidant activity

Fifty-four different extracts of nine Bolivian plants belonging to the family Asteraceae were evaluated for their radical scavenging activity by the DPPH*, NBT/hypoxanthine superoxide, and (*)OH/luminol chemiluminescence methods, and for their antioxidant activity by the beta-carotene bleaching test. The total phenolic content was also determined by the Folin-Ciocalteu method, and the oxidative stability by the Rancimat test. Both remarkably high phenolic content and radical scavenging and antioxidant activities were found mainly in the ethyl acetate fractions among the different plant extracts. Some ethyl acetate and even some defatted crude extracts exhibited activities comparable to those of commercial extracts/compounds, thus making it possible to consider some of the studied plants as a potential source of antioxidants of natural origin.

Structure-activity studies on the lycorine pharmacophore: a potent inducer of apoptosis in human leukemia cells.

Abstract The direct chemoselective differential functionalization of the ring-C hydroxyl groups present in the Amaryllidaceae alkaloid lycorine is described allowing for selective manipulation of the 1,2-hydroxyl groups. A mini-library comprised of synthetic and natural lycorane alkaloids was prepared and their apoptosis-inducing activity investigated in human leukemia (Jurkat) cells. Further insights into the nature of this interesting apoptosis-inducing pharmacophore are described, including the requirement of both free hydroxyl groups in ring-C.

Antioxidant Activity and Phenolic Composition of Wild, Edible, and Medicinal Fennel from Different Mediterranean Countries

Fennel (Foeniculum vulgare Mill.) is a typical aromatic plant of the Mediterranean area, long used as a medicinal and spice herb. Fennel is also well-known for its essential oil, which has been extensively studied for many years owing to its commercial importance. In this work, the antioxidant activity and the total phenolic and flavonoid contents, as well as the quantitative determination of individual flavonoids and phenolic acids of wild, edible, and medicinal fennel from different Mediterranean countries, have been determined. The antioxidant activity was measured as the free radical (DPPH), hydroxyl radical, and superoxide anion scavenging activities. Wild fennel was found to exhibit a radical scavenging activity, as well as a total phenolic and total flavonoid content, higher than those of both medicinal and edible fennels.

Bioactive alkaloids from Brunsvigia radulosa.

A phytochemical investigation of the bulbs of Brunsvigia radulosa yielded the new alkaloid 1-O-acetylnorpluviine, together with the known structures 1-epideacetylbowdensine, crinamine, crinine, hamayne, lycorine, anhydrolycorin-6-one and sternbergine. All structures were established by spectroscopic evidence. Some of the 13C assignments which were reported for crinamine and hamayne were corrected by means of 2D NMR techniques. In order to provide a further structure for biological testing, crinamine was converted to apohaemanthamine. The alkaloids were tested for activity against two strains of cultured Plasmodium falciparum and for cytotoxicity with BL6 mouse melanoma cells.

N-Alkylated galanthamine derivatives: Potent acetylcholinesterase inhibitors from Leucojum aestivum.

N-(14-Methylallyl)norgalanthamine, a new natural compound, together with five known alkaloids: N-allylnorgalanthamine, galanthamine, epinorgalanthamine, narwedine, and lycorine were isolated from mother liquors (waste material) obtained after industrial production of galanthamine hydrobromide from Leucojum aestivum leaves. The structures of N-allylnorgalanthamine and N-(14-methylallyl)norgalanthamine were completely determined by (1)H and (13)C NMR spectroscopy and two-dimensional experiments. N-allylnorgalanthamine (IC(50)=0.18microM) and N-(14-methylallyl)norgalanthamine (IC(50)=0.16microM) inhibit AChE considerably more than the approved drug galanthamine (IC(50)=1.82microM).

Alkaloids from Boophane flava

Abstract Fourteen alkaloids have been isolated from bulbs of Boophane flava . The alkaloids, buflavine, 8- O -demethylbuflavine and montabuphine are reported here for the first time. The structure and stereochemistry of these new alkaloids were established by physical and spectroscopic methods. 1 H and 13 C NMR spectra of epivittatine and epibuphanisine were completely assigned by means of 2-D NMR techniques.

Alkaloids from Brunsvigia josephinæ

Abstract Six alkaloids, 3- O -acetylhamayne, hamayne, crinamine, josephinine, ambelline and stembergine have been isolated from bulbs of Brunsvigia josephinae (Amaryllidaceae). The alkaloid josephinine is reported for the first time. Their structure and stereochemistry were established by physical and spectroscopic methods.

Callus induction, somatic embryogenesis and organogenesis in Narcissus confusus: correlation between the state of differentiation and the content of galanthamine and related alkaloids

Abstract In vitro cultures from two strains of Narcissus confusus (Amaryllidaceae) initiated from mature seeds were screened for their ability to produce alkaloids. Protocols for callus induction, somatic embryogenesis and organogenesis were established. The alkaloid contents were determined by HPLC. Undifferentiated calli produced small amounts of galanthamine, which increased with the degree of tissue differentiation. Scanning electron micrographs of the cultures at different stages of development were made. Embryogenic friable calli were maintained in culture for more than 2 years, retaining a high regeneration capability. All regenerated plants showed normal morphological characteristics.