Berry fruit consumption has become important in the promotion of human health, mainly due to their phenolic compounds, which have been associated with protection against different pathologies, as well as antimicrobial and other biological activities. Consequently, there has been a growing interest in identifying natural antioxidants and antimicrobials from these plants. This study aimed to characterize the phenolic chemical composition and anthocyanin profile of murta (Ugni molinae Turcz.) fruit, and to evaluate the antioxidant and antimicrobial activity of its extracts (ethanolic and methanolic). LC/MS of the ethanolic extracts showed the presence of three major compounds: caffeic acid 3-glu, quercetin-3-glu and quercetin, while in the methanolic acid extract they were cyanidin-3-glucoside, pelargonidin-3-arabinose and delphinidin-3-glucoside. The antioxidant activity of ethanolic extracts (DPPH• and ORAC assays) was higher than that of methanol acid extracts or purified anthocynins. Furthermore, the methanol acid extract showed an inhibitory activity against the bacteria E. coli and S. typhi similar to that of standard antibiotics. The results suggest that the antioxidant activity of the ethanolic extract is regulated by the high content of phenolic compounds and the fruit’s characteristic color is due to the content of pelargonidin-3-arabinose and delphinidin-3-glucoside. The obtained results demonstrated the appreciable antioxidant and antibacterial activities, providing opportunities to explore murta extracts as biopreservatives.

The platelet antiaggregant activity of 17 aqueous extracts of plants traditionally used in Guatemala for the treatment of ‘blood disorders’ and parasitic infections were assayed. The aggregation of washed human platelets induced by thrombin (0.075 U/mL) was inhibited by extracts of Tridax procumbens, Tagetes lucida, Annona reticulata, Neurolaena lobata, Bixa orellana, Rauvolfia tetraphylla, Petiveria alliacea and Tecoma stans. The other extracts did not have clear inhibitory effects, and indeed caused some platelet aggregation themselves, in the absence of thrombin. © 1997 John Wiley & Sons, Ltd.

Methanol and aqueous extracts from fi ve plant species, used in traditional medicine in Guatemala for the treatment of microbial infections, were tested in vitro for their ability to scavenge DPPH, OH(.) and O(2) (-) radicals and to inhibit lipoperoxidation (LPO) in order to establish a relationship between their antioxidant activities and their effects against infectious agents. Acalypha guatemalensis, Ocimum micranthum and Smilax spinosa possessed a significant activity against both the three free radicals assayed and LPO; Guazuma ulmifolia showed effects against DPPH and OH(.). Piper auritum showed no activity. These extracts were also evaluated for antibacterial and antiprotozoal activities. A. guatemalensis showed activity against Pseudomonas aeruginosa; S. spinosa was active against Salmonella typhi, and A. guatemalensis, and S. spinosa against Trypanosoma cruzi or Leishmania spp.

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