Recent years have seen a growing interest in Berberine, a phytochemical with multispectrum therapeutic activities, as anti-tumoral agent for photodynamic therapy (PDT). In this context, low density lipoproteins (LDL) play a key role in the delivery of the photosensitizer in tumor cells. We correlate the physicochemical parameters of the berberine association to LDL with the influence of LDL-delivery on its accumulation in a glioma cell line and on its photo-induced activity in view of antitumor PDT. Our results evidence an important binding of 400 berberine molecules per LDL. Changes in berberine and apoprotein fluorescence suggest different fixation types, involving various LDL compartments including the vicinity of the apoprotein. The berberine association to LDL does not affect their recognition by the specific B/E receptors, of which over-expression increases the cellular uptake of LDL-preloaded berberine. Fluorescence microscopy evidences the mitochondrial labeling of the glioma model cells, with no significant modification upon LDL-delivery. Moreover, the cellular delivery of berberine by LDL increases its photocytotoxic effects on such cells. So, this research illustrates the potential of berberine as a photosensitizing agent for PDT, in particular due to their behavior towards LDL as plasma vehicles, and gives insights into its mechanisms of cell uptake.

Passiflora species presents a coevolutive relationship with Heliconiini butterflies, their primary herbivores. The Heliconiini caterpillars are able to detoxify toxic compounds produced by Passiflora, thus morphological defense strategies stand out over chemical innovations. In this framework, we highlight the presence of mimetic structures and extrafloral nectaries (EFN) as morphological strategies. Heliconian butterflies oviposit only on leaves that do not possess previous eggs, so the presence of egg mimics could prevent the oviposition. EFN are glands that offer nectar to territorial and aggressive ants, establishing mutualistic relationships. Here, we present a structural and chemical analysis of petiolar EFN and nectar from Passiflora alata and P. edulis in order to have insights about the implications of these features in deterring heliconian caterpillars. P. alata have one to four stipitate-crateriform EFN while P. edulis possess a pair of convex glands. Butterflies lay their eggs isolatedly or in up to three on leaves of both species. Our morphological results suggest that EFN from P. alata may act as egg mimics. Ontogenetic data suggest that the variation in the number of glands observed in this species is a serial homology, wherein the selection pressure for this variation is possibly the oviposition pattern. P. alata retain alkaloids, flavonoids and terpenoids inside nectariferous cells; sugars and flavonoids are found in the nectar of both species, while alkaloids are also detected in P. edulis. There is a selective retention/release of secondary metabolites from the EFN tissues to nectar. Knowing that these compounds can be dissuasive to some herbivores and inoffensive to others, we plotted this relationship in a consumer growth versus secondary metabolite concentration diagram. Our results suggest a more active role in the modulation of the gland defense from plants besides the establishment of a mutualistic relationship with ants, an important response in a coevolutive scenario.

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Antioxidant compounds can be useful to prevent several degenerative diseases or as preservative in food and toiletries. Species of the Myrtaceae family are able to accumulate phenolic substances and those are closely related to the antioxidant activity due to their capacity to scavenge free radicals, protect against lipid peroxidation and quench reactive oxygen species. These facts prompted us to investigate the antioxidant capacity of the ethanolic extracts of the leaves of four Myrtaceae plants collected of the south of Brazil: Eugenia chlorophylla O. Berg., Eugenia pyriformis Cambess, Myrcia laruotteana Cambess and Myrcia obtecta (Berg) Kiacrsk. The antioxidant potential was performed using the DPPH (a single electron transfer reaction based assay) and ORAC (Oxygen Radical Absorbance Capacity, a hydrogen atom transfer reaction based assay) assays. Moreover, the total soluble phenolic content was also measured using the Folin-Ciocalteu reagent. A preliminary evaluation of the ethanolic extracts of these Myrtaceae plants revealed high levels of phenolic compounds (343.7-429.3 mg GAE) as well as high antioxidant activity according to both methods (1338 a 3785 µmol of TE/g of extract in ORAC and SC 50 in the range of 1.70 and 33.7 µg/mL in the DPPH). The highest antioxidant activity obtained by DPPH assay was exhibited by ethanol extract of the leaves of E. pyriformis (1.70 g/mL), followed by extracts of M. laruotteana (3.38 g/mL) and M. obtecta (6.66 g/mL). In comparison with controls, in the DPPH assay, the extract of E. pyriformis was more active than trolox (SC 50 = 2.55 g/mL), while the extracts of M. laruotteana and M. obtecta were more actives than quercetin (SC 50 = 7.80 g/mL). In the ORAC assay, all species also show good antioxidant capacity (1000 µmol of TE/g). Initial HPLC-UV/DAD and ESI-MS confirmed the presence of phenolic acids constituents in the ethanol extracts. The results indicate the presence of compounds possessing promising antioxidant/free-radical scavenging activity in the analyzed extracts of Myrcia and Eugenia plants of the south of Brazil.

Pilocarpine, an important imidazole alkaloid, is extracted from the leaves of Pilocarpus microphyllus (Rutaceae), known in Brazil as jaborandi and used mainly for the treatment of glaucoma. Jaborandi leaves also contain other imidazole alkaloids, whose pharmacological and physiological properties are unknown, and whose biosynthetic pathways are under investigation. In the present study, a HPLC method coupled with ESI-MSn was developed for their qualitative and quantitative analysis. This method permits the chromatographic separation of the imidazole alkaloids found in extracts of jaborandi, as well as the MS/MS analysis of the individual compounds. Thus two samples: leaves of P. microphyllus and a paste that is left over after the industrial extraction of pilocarpine; were compared. The paste was found to contain significant amounts of pilocarpine and other imidazole alkaloids, but had a slightly different alkaloid profile than the leaf extract. The method is suitable for the routine analysis of samples containing these alkaloids, as well as for the separation and identification of known and novel alkaloids from this family, and may be applied to further studies of the biosynthetic pathway of pilocarpine in P. microphyllus.