Jorge Bórquez

The Passiflora tripartita (Banana Passion) Fruit: A Source of Bioactive Flavonoid C-Glycosides Isolated by HSCCC and Characterized by HPLC-DAD-ESI/MS/MS

The banana passion fruit (Passiflora tripartita Breiter, Passifloraceae) known as “tumbo” is very appreciated in tropical and subtropical countries of South America. Methanolic extracts from peel and the fruit juice of P. tripartita growing in Chile were analyzed for antioxidant capacity as well as for flavonoid and phenolic content. A chromatographic method was developed for the rapid identification of the main phenolics in the samples by HPLC-DAD and HPLC-MS. The fast fingerprint analysis allowed the detection of eighteen flavonoid C-glycosides and four flavonoid O-glycoside derivatives which were characterized by UV spectra and ESI-MS-MS analysis. Several of the C-glycosides detected are structurally related to the orientin derivative 4′-methoxy-luteolin-8-C-(6″acetyl)-β-D-glucopyranoside (31), fully elucidated by spectroscopic methods. The antioxidant derivative 31 along with schaftoside, vicenin II, orientin and vitexin were isolated from the fruit extract by high-speed countercurrent chromatography (HSCCC). A suitable method for the preparative isolation of flavonol C-glycosides from “tumbo” extracts by HSCCC is reported. The pulp of the fruits showed good antioxidant capacity (12.89 ± 0.02 μg/mL in the DPPH assay). The peel presented the highest content of flavonoids (56.03 ± 4.34 mg quercetin/100 g dry weight) which is related to the highest antioxidant power (10.41 ± 0.01 μg/mL in the DPPH assay).

Antioxidant capacity, polyphenolic content and tandem HPLC-DAD-ESI/MS profiling of phenolic compounds from the South American berries Luma apiculata and L. chequén.

Native Myrtaceae fruits were gathered by South American Amerindians as a food source. At present, there is still some regional consume of the small berries from trees belonging to genus Luma that occurs in southern Chile and Argentina. The aerial parts and berries from Luma apiculata and Luma chequen were investigated for phenolic constituents and antioxidant capacity. A high performance electrospray ionisation mass spectrometry method was developed for the rapid identification of phenolics in polar extracts from both species. Thirty-one phenolic compounds were detected and 27 were identified or tentatively characterised based on photodiode array UV-vis spectra (DAD), ESI-MS-MS spectrometric data and spiking experiments with authentic standards. Twelve phenolic compounds were detected in L. apiculata fruits and 12 in the aerial parts while L. chequen yielded 10 compounds in fruits and 16 in aerial parts, respectively. From the compounds occurring in both Luma species, seven were identified as tannins or their monomers, 15 were flavonol derivatives and five were anthocyanins. The whole berry and aerial parts extracts presented high antioxidant capacity in the DPPH assay (IC50 of 10.41±0.02 and 2.44±0.03 μg/mL for L. apiculata, 12.89±0.05 and 3.22±0.05 for L. chequen, respectively), which can be related to the diverse range of phenolics detected. The antioxidant capacity together with the high polyphenolic contents and compounds identified can support at least in part, their use as botanical drugs. From the compounds identified in both species, 3-O-(6″-O-galloyl)-hexose derivatives of myricetin, quercetin, laricitrin and isorhamnetin are reported for the first time for the genus Luma.

Diterpenoids from Azorella yareta and their trichomonicidal activities

Diterpenoids with trichomonicidal activity were isolated from the aerial parts of Azorella yareta Hauman. One was 13beta-hydroxyazorellane, together with the known constituents mulinolic acid, mulin-11,13-dien-20-oic acid, azorellanol and 13alpha-hydroxyazorellane. Their structures were determined by spectroscopic and chemical methods.

Diterpenoids from Azorella compacta (Umbelliferae) active on Trypanosoma cruzi

The anti-Trypanosoma cruzi activity of natural products isolated from Azorella compacta was evaluated, with particular emphasis on their effect against intracellular amastigotes. Five diterpenoids from A. compacta derived from mulinane and azorellane were isolated and identified. Only two products, named azorellanol (Y-2) and mulin-11,3-dien-20-oic acid (Y-5), showed trypanocidal activity against all stages of T. cruzi including intracellular amastigotes. At 10 M, these compounds displayed a strong lytic activity. It ranged from 88.4 0.6 to 99.0 1 % for all strains and stages evaluate, with an IC50 /18 h values of 20-84 M and 41-87 M, respectively. The development of intracellular amastigotes was also inhibited by nearly 60% at 25 M. The trypanocidal molecules Y-2 and Y-5 did show different degrees of cytotoxicity depending on the cell line tested, with an IC50 /24 h ranging from 33.2 to 161.2 M. We evaluated the effect of diterpenoids against intracellular T. cruzi forms by immunofluorescent identification of a specific membrane molecular marker (Ssp-4 antigen) of the T. cruzi amastigote forms. The accuracy and reproducibility of the measurements were found to be outstanding when examined by confocal microscopy.

Antituberculosis activity of natural and semisynthetic azorellane and mulinane diterpenoids.

The antituberculosis activity of 14 natural azorellane and mulinane diterpenoids isolated from Azorella compacta, Azorella madreporica, Mulinum crassifolium, and Laretia acaulis, together with eight semisynthetic derivatives, was evaluated against two Mycobacterium tuberculosis strains. The natural azorellanes azorellanol (3) and 17-acetoxy-13-alpha-hydroxyazorellane (6), and the semisynthetic mulinanes 13-hydroxy-mulin-11-en-20-oic-acid methyl ester (13) and mulinenic acid methyl ester (23), showed the strongest activity, with MIC values of 12.5 microg/mL against both strains. The methylated derivatives 13-hydroxy-mulin-11-en-20-oic-acid methyl ester (13), mulin-11,13-dien-20-oic acid methyl ester (15) and mulinenic acid methyl ester (23) proved to be more active than the parent compounds.

Diterpenoids from Azorella compacta

In addition to mulinolic acid, a new diterpenoid, mulin-11,13-dien-20-oic acid, has been isolated from the aerial parts of Azorella compacta. Its structure was based on a spectroscopic comparison with mulinolic acid and on chemical grounds.

Mulinol, A diterpenoid from Azorella compacta

Abstract In addition to mulinic acid, a new diterpenoid, mulinol has been isolated from the aerial parts of Azorella compacta . Its structure was based on spectroscopic comparison with mulinolic acid and chemical grounds.

Mulinolic acid, a diterpenoid from Mulinum crassifolium

Abstract Mulinolic acid, a new diterpenoid, has been isolated from the aerial parts of Mulinum crassifolium . Its structure was established by spectroscopic means. Mulinolic acid has a rearranged mulinane carbon skeleton of the type which has been found in four other diterpenoids from the same plant.

11,12-EPOXY-MULIN-13-EN-20-OIC acid, a diterpenoid from azorella compacta

A new diterpenoid, 11,12-epoxy-mulin-13-en-20-oic acid, was isolated from the aerial parts of Azorella compacta Phil. (Umbelliferae). Its structure determination was based on spectroscopic comparison with isomulinic acid.

Antituberculosis activity of alkylated mulinane diterpenoids.

Natural azorellane and mulinane diterpenoids show antituberculosis activity, which is increased by methylation of their free carboxyl group. We have systematically investigated the effect of alkylation in this class of diterpenoids and found that the profile of bioactivity is relatively unaffected by the introduction of short alkyl groups, both linear and branched. In this investigation, three semisynthetic diterpenoids, 13 hydroxy-mulin-11-en-20-oic acid n-propyl ester (3) and the n-propyl (19) and n-butyl (20) esters of isomulinic acid, showed the strongest antituberculosis activity (MIC=6.25 microg/mL) against a drug-resistant strain of Mycobacterium tuberculosis.