Lycopene-rich extract from red guava (Psidium guajava L.) displays cytotoxic effect against human breast adenocarcinoma cell line MCF-7 via an apoptotic-like pathway.

This study investigated a lycopene-rich extract from red guava (LEG) for its chemical composition using spectrophotometry, mass spectrometry, attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR), and computational studies. The cytotoxic activity of LEG and the underlying mechanism was studied in human breast adenocarcinoma cells (MCF-7), murine fibroblast cells (NIH-3T3), BALB/c murine peritoneal macrophages, and sheep blood erythrocytes by evaluating the cell viability with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method and flow cytometry. Spectrophotometry analysis showed that LEG contained 20% of lycopene per extract dry weight. Experimental and theoretical ATR-FTIR suggests the presence of lycopene, whereas MS/MS spectra obtained after fragmentation of the molecular ion [M]+• of 536.4364 show fragment ions at m/z 269.2259, 375.3034, 444.3788, and 467.3658, corroborating the presence of lycopene mostly related to all-trans configuration. Treatment with LEG (1600 to 6.25µg/mL) for 24 and 72h significantly affected the viability of MCF-7 cells (mean half maximal inhibitory concentration [IC50]=29.85 and 5.964µg/mL, respectively) but not NIH-3T3 cells (IC50=1579 and 911.5µg/mL, respectively). Furthermore LEG at concentrations from 800 to 6.25µg/mL presented low cytotoxicity against BALB/c peritoneal macrophages (IC50≥800µg/mL) and no hemolytic activity. LEG (400 and 800µg/mL) caused reduction in the cell proliferation and induced cell cycle arrest, DNA fragmentation, modifications in the mitochondrial membrane potential, and morphologic changes related to granularity and size in MCF-7 cells; however, it failed to cause any significant damage to the cell membrane or display necrosis or traditional apoptosis. In conclusion, LEG was able to induce cytostatic and cytotoxic effects on breast cancer cells probably via induction of an apoptotic-like pathway.

Lycopene rich extract from red guava (Psidium guajava L.) displays anti-inflammatory and antioxidant profile by reducing suggestive hallmarks of acute inflammatory response in mice.

This study investigated the anti-inflammatory activity of the extract (LEG) and purified (LPG) lycopene from guava (Psidium guajava L.), as well as some mechanisms possibly involved in this effect. The anti-inflammatory activity was initially assessed using paw edema induced by Carrageenan, Dextran, Compound 48/80, Histamine and Prostaglandin E2 in Swiss mice. A peritonitis model was used to evaluate neutrophil migration, the activity of myeloperoxidase (MPO) and reduced glutathione (GSH) concentration; while the effect on the expression of iNOS, COX-2 and NF-κB, was assessed by immunohistochemistry analysis. Results showed that oral and intraperitoneal administration of LEG and LPG inhibited inflammation caused by carrageenan. LPG (12.5mg/kg p.o.) significantly inhibited the edema formation induced by different phlogistic agents and immunostaining for iNOS, COX-2 and NF-κB. Leukocytes migration in paw tissue and peritoneal cavity was reduced, as well as MPO concentration, whereas GSH levels increased. Thus, lycopene-rich extract from red guava has beneficial effect on acute inflammation, offering protection against the consequences of oxidative stress by downregulating inflammatory mediators and inhibiting gene expression involved in inflammation.

Effect of neem (Azadirachta indica A. Juss) leaf extract on resistant Staphylococcus aureus biofilm formation and Schistosoma mansoni worms.

ETHNOPHARMACOLOGICAL RELEVANCE: There are ethnopharmacological reports supporting the use of neem (Azadirachta indica A. Juss) leaf against bacterial and worm infections. However there is a lack of studies about its effect on bacterial biofilm formation and Schistosoma mansoni worms. This study reports the in vitro effects of neem leaf ethanolic extract (Neem EE) on Methicillin-resistant Staphylococcus aureus (MRSA) biofilm and planktonic aggregation formation, and against S. mansoni worms. MATERIALS AND METHODS: Quantification of the Azadirachtin (AZA), thought to be one of their main compounds related to biological effects, was performed. The effect of sub-inhibitory concentrations of Neem EE on biofilm formation and planktonic aggregates of S. aureus was tested using the crystal violet dye method and atomic force microscopy (AFM) analysis, respectively. Changes in S. mansoni motor activity and death of worms were analyzed in vitro after exposition to the extract. Treated schistosomes were also examined using confocal laser scanning microscopy. RESULTS: It was observed the presence of AZA in the extract (0.14 ± 0.02 mg/L). Testing Neem EE sub-inhibitory concentrations, a significant biofilm adherence inhibition from 62.5 µg/mL for a sensitive S. aureus and 125 µg/mL for two MRSA strains was observed. AFM images revealed that as the Neem EE concentration increases (from 250 to 1000 µg/mL) decreased ability of a chosen MRSA strain to form large aggregates. In relation of anti-schistosoma assay, the extract caused 100% mortality of female worms at a concentration of 50 µg/mL at 72 h of incubation, while 300 µg/mL at 24h of incubation was required to achieve 100% mortality of male worms. The extract also caused significant motor activity reduction in S. mansoni. For instance, at 96 h of incubation with 100 µg/mL, 80% of the worms presented significant motor activity reduction. By the confocal microscopy analysis, the dorsal surface of the tegument of worms exposed to 300 µg/mL (male) and 100 µg/mL (female) of the extract showed severe morphological changes after 24h of treatment. CONCLUSIONS: Neem leaf ethanolic extract presented inhibitory effect on MRSA biofilm and planktonic aggregation formation, and anthelmintic activity against S. mansoni worms.

Identification of Phenolic Compounds and Evaluation of Antioxidant and Antimicrobial Properties of Euphorbia Tirucalli L.

Bioactive compounds extracted from natural sources can benefit human health. The aim of this work was to determine total phenolic content and antioxidant activity in extracts of Euphorbia tirucalli L. followed by identification and quantification of the phenolic compounds, as well as their antibacterial activities. Antioxidant activities were determined by DPPH and ABTS(•+) assay. Identification of phenolic compounds was performed using high-performance liquid chromatography (HPLC), and antimicrobial activities were verified by agar dilution methods and MIC values. Total phenolic content ranged from 7.73 to 30.54 mg/100 g gallic acid equivalent. Extracts from dry plants showed higher antioxidant activities than those from fresh ones. The DPPH EC50 values were approximately 12.15 µg/mL and 16.59 µg/mL, respectively. Antioxidant activity measured by the ABTS method yielded values higher than 718.99 µM trolox/g for dry plants, while by the Rancimat(®) system yielded protection factors exceeding 1 for all extracts, comparable to synthetic BHT. Ferulic acid was the principal phenolic compound identified and quantified through HPLC-UV in all extracts. The extracts proved effective inhibitory potential for Staphylococcus epidermidis and Staphylococcus aureus. These results showed that extracts of Euphorbia tirucalli L. have excellent antioxidant capacity and moderate antimicrobial activity. These can be attributed to the high concentration of ferulic acid.