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Abstract Food loss due to contamination caused by fungi has much impact on agriculture and leads to significant economic losses. Synthetic and natural fungicides have been used for avoiding losses of several food products due to fungal contamination. As a result, species of the genus Capsicum have been used for preserving food because of their chemical compounds with antifungal activity. Therefore, this study aimed at identifying some phenolic compounds found in both ethyl acetate extract (EAE) and methanolic extract (ME) from habanero pepper (C. chinense) ripe fruit by liquid chromatography tandem mass spectrometry with electrospray ionization (LC-ESI-MS/MS) and at evaluating their antifungal activities against fungi Sclerotinia sclerotiorum, Rhizopus stolonifer and Colletotrichum gloeosporioides. Extracts resulted from a sequential process of maceration. Antifungal activity was evaluated by the disk diffusion method (DDM) at the following doses of both diluted extracts: 25 µL, 50 µL, 100 µL and 200 µL. The chemical analysis showed that there were protocatechuic acid, gentisic acid, vanillic acid, kaempferol-3-O-robinobiosideo and naringenin in both extracts. EAE showed high inhibition of mycelial growth at both doses 100µL and 200µL against the three fungi while methanolic exhibited weak activity even at the highest dose under investigation. However, further in-depth studies are needed to reinforce their uses and practical applications to the agricultural field.

Abstract Essential oils (EO) from aromatic and medicinal plants generally perform a diverse range of biological activities because they have several active constituents that work in different mechanisms of action. EO from Citrus peel have an impressive range of food and medicinal uses, besides other applications. EO from Citrus reticulata, C. sinensis and C. deliciosa were extracted from fruit peel and analyzed by GC-MS. The major constituent of EO under evaluation was limonene, whose concentrations were 98.54%, 91.65% and 91.27% for C. sinensis, C. reticulata and C. deliciosa, respectively. The highest potential of inhibition of mycelial growth was observed when the oil dose was 300 μL. Citrus oils inhibited fungus growth in 82.91% (C. deliciosa), 65.82% (C. sinensis) and 63.46% (C. reticulata). Anti-Sclerotinia sclerotiorum activity of 90% pure limonene and at different doses (20, 50, 100, 200 and 300 μL) was also investigated. This monoterpene showed to be highly active by inhibiting 100% fungus growth even at 200 and 300 μL doses. This is the first report of the in vitro inhibitory effect of natural products from these three Citrus species and its results show that there is good prospect of using them experimentally to control S. sclerotiorum, in both greenhouse and field conditions.

Abstract This study evaluated the antibacterial and antiproliferative activities of the essential oil of Psidium guajava leaves (PG-EO), traditionally used in folk medicine. The essential oil was obtained from fresh leaves by hydrodistillation, using a modified Clevenger apparatus. The major PG-EO chemical constituents were identified by GC-MS and GC-FID as being β-caryophyllene (16.1%), α-humulene (11.9%), aromadendrene oxide (14.7%), δ-selinene (13.6%), and selin-11-en-4α-ol (12.5%). The antibacterial activity of the essential oil of P. guajava leaves was determined in terms of its minimum inhibitory concentrations (MIC) using the broth microdilution method in 96-well microplates. PG-EO had moderate activity against Streptococcus mutans (MIC = 200 µg/mL), S. mitis (MIC = 200 µg/mL), S. sanguinis (MIC = 400 µg/mL), S. sobrinus (MIC = 100 µg/mL), and S. salivarius (MIC = 200 µg/mL). The antiproliferative activity was evaluated against different tumor cell lines: breast adenocarcinoma (MCF-7), human cervical adenocarcinoma (HeLa), and human gliobastoma (M059J). A normal human cell line (GM07492A, lung fibroblasts) was included. The antiproliferative activity was evaluated using the XTT assay and the results were expressed as IC50. The essential oil showed significantly lower IC50 values against MCF-7 and M059J lines than that obtained for the normal line, showing selectivity. Our results suggest that the essential oil of Psidium guajava L. has promising biological activities and can be considered a new source of bioactive compounds.