Antiprotozoal Effect of Artemisia indica Extracts and Essential Oil.

Diverse solvent extracts of Artemisia indica leaves originating from the West Bengal region (India) were assessed for the content of artemisinin and characteristic Artemisia polymethoxyflavonoids, namely eupatin (1), casticin (2), chrysoplenetin (3), cirsilineol (4), chrysophenol-D (5), and artemetin (6). HPLC-DAD and HPLC-MS were used to investigate the extracts macerated by solvents of increasing polarity, i.e., petroleum ether, n-hexane, dichloromethane, acetone, MeOH, or EtOH (either 96, 80, or 60 % v/v), and hot water. Artemisinin was absent in all extracts. The acetone and EtOH extracts comprised the highest levels of polymethoxyflavonoids, whereas no flavonoid could be detected in the infusion. None of the remaining extracts contained chryosphenol-D (5) or artemetin (6), while chrysoplenetin (3) was found in all extracts. The essential oil of the plant was also obtained by hydrodistillation and analysed by gas chromatography and gas chromatography-mass spectrometry simultaneously. Of the 92 compounds detected in the oil, camphor (13.0 %) and caryophyllene oxide (10.87 %) were the major components. All solvent extracts and the volatile oil showed in vitro antimalarial activity, plus a potential malaria prophylactic effect by inhibiting at least two recombinant plasmodial fatty acid biosynthesis (PfFAS-II) enzymes. Except for the infusion, all extracts were also active against other parasitic protozoa and displayed low cytotoxicity against mammalian cells. This is the first detailed study investigating both artemisinin and polymethoxyflavonoid content as well as in vitro malaria prophylactic and detailed antiprotozoal potential of A. indica extracts against a panel of protozoan parasites. This is also the first report of antiparasitic activity of the essential oil of the plant.

Enrichment of polyphenol contents and antioxidant activities of Irish brown macroalgae using food-friendly techniques based on polarity and molecular size.

An efficient, food-friendly process for the enrichment of macroalgal phlorotannins from solid-liquid extracts (SLE) of three brown macroalgae, namely Fucus spiralis Linnaeus, Pelvetia canaliculata (Linnaeus) Decaisne & Thuret and Ascophyllum nodosum (Linnaeus) Le Jolis, has been demonstrated. The initial utilisation of molecular weight cut-off (MWCO) dialysis generated fractions of low molecular weight (LMW) (<3.5 kDa) and of high molecular weight (HMW) (3.5-100 kDa and >100 kDa) from cold water, hot water and aqueous ethanolic SLE extracts. An enhancement of the total phenolic content (TPC), radical scavenging abilities (RSA) and ferric reducing antioxidant power (FRAP) in the HMW fractions of 3.5-100 kDa and/or >100 kDa from the cold water and aqueous ethanolic extracts was observed. The initial weak TPC, RSA and FRAP observed in the LMW fractions relative to the HMW fractions were substantially enhanced following a reverse-phase flash chromatography fractionation method. Quadrupole time-of-flight mass spectrometry (Q-Tof-MS) suggests that phlorotannins of varying degrees of phloroglucinol polymerisation are present in LMW fractions of the three brown macroalgal species. The development of a food-friendly process for the extraction and enrichment of phlorotannins from Irish macroalgae is vital to facilitate the use of this valuable resource in future developments of macroalgal-based functional foods.

Bromopyrrole alkaloids as lead compounds against protozoan parasites.

In the present study, 13 bromopyrrole alkaloids, including the oroidin analogs hymenidin (2), dispacamide B (3) and dispacamide D (4), stevensine (5) and spongiacidin B (6), their derivatives lacking the imidazole ring bromoaldisin (7), longamide B (8) and longamide A (9), the dimeric oroidin derivatives sceptrin (10) and dibromopalau'amine (11), and the non-oroidin bromopyrrolohomoarginin (12), manzacidin A (13), and agelongine (14), obtained from marine sponges belonging to Axinella and Agelas genera have been screened in vitro against four parasitic protozoa, i.e., two Trypanosoma species (T. brucei rhodesiense and T. cruzi), Leishmania donovani and Plasmodium falciparum (K1 strain, a chloroquine resistant strain), responsible of human diseases with high morbidity and, in the case of malaria, high mortality. Our results indicate longamide B (8) and dibromopalau'amine (11) to be promising trypanocidal and antileishmanial agents, while dispacamide B (3) and spongiacidin B (6) emerge as antimalarial lead compounds. In addition, evaluation of the activity of the test alkaloids (2-14) against three different enzymes (PfFabI, PfFabG, PfFabZ) involved in the de novo fatty acid biosynthesis pathway of P. falciparum (PfFAS-II) identified bromopyrrolohomoarginin (12) as a potent inhibitor of PfFabZ. The structural similarity within the series of tested molecules allowed us to draw some preliminary structure-activity relationships. Tests against the mammalian L6 cells revealed important clues on therapeutic index of the metabolites. This is the first detailed study on the antiprotozoal potential of marine bromopyrrole alkaloids.