The growth of fungi during pre-and postharvest of fruits may cause spoilage and result in a reduction in quality and quantity. The aim of the present work was to investigate the efficacy of four extracts (n-hexane, dichlorometane, ethyl acetate, and methanol) and the essential oil of Piper auritum Kunth and P. holtonii C. DC. on the growth inhibition of three important postharvest pathogens of fruits (Colletotrichum acutatum, C. gloeosporioides, and Botryodiplodia theobromae). The in vitro antifungal activity was assayed following the poisoned food technique. The results showed that both n-hexane extract (HE) as essential oil (EO) displayed a relative good control against the three pathogens, being the originating materials of P. holtonii the most actives. Mycelial growth of C. acutatum, C. gloeosporioides, and B. theobromae was significantly inhibited at 400 µg mL -1 . Additionally, the chemical composition of the bioactive materials was analyzed by gas chromatography-mass spectrometry (GC-MS). Safrole (64.54/56.88%) and apiol (64.24/57.20%) were the major constituents of the EO/HE from P. auritum and P. holtonii respectively. Structural identification was also confirmed by nuclear magnetic resonance. Both compounds exhibited significant antifungal properties. It can be concluded that EOs/HEs from P. auritum and P. holtonii, and their major constituents, have interesting applications to control plant pathogenic fungi.

Propolis, a natural product collected by honeybee from exudates of plants, is widely used in traditional medicine due to its known therapeutic properties. In this paper, the quality of ethanol extracts of propolis (EEP) from different regions of Antioquia (Colombia) is compared through the determination of flavonoids and total phenolic compounds content, and thein vitro antioxidant activity, using three assay systems: radical scavenging activity by means of the DPPH• (1-diphenyl-2-picrylhydrazyl) and ABTS•+ (2,2’-azino-bis 3-ethylbenzthiazoline-6-sulfonic acid cation) assays, and ferric reducing antioxidant power (FRAP). Determinations of total phenolic compounds content are found between 22.11 ± 0.54 and 75.22 ± 1.35 mg GAE/g of EEP, and total content of flavonoids between 4.75 ± 0.01 y 34.50 ± 0.07 mg QE/g of EEP. The radical scavenging activity varies from 33.9 ± 9.7 to 324.6 ± 15.0, and from 455.5 ± 7.8 to 1091 ± 17.3 μmol TE/g of EEP (TEAC) in the DPPH and ABTS system, respectively. In the FRAP method, the activity is found between 40.9 ± 13.3 and 338.4 ± 22.4 μmol AAE/g of EEP (AEAC). Results show a positive linear correlation between antioxidant activity and total phenolic content. The antioxidant activity of some propolis indicates its potential role as nutraceutical.

Biocatalytic processes may offer a cheaper alternative to natural production of flavours. The biotransformation of cinnamyl alcohol is investigated using the plant pathogenic fungus Colletotrichum acutatum as a biocatalyst. Results show that substrate is converted to 3-phenyl-1-propanol, 1-phenyl-1,3- propanediol, 2-phenylethanol, 1-phenyl-1,2-ethanediol, 3-phenyl propyl acetate, and hydrocinnamic acid. The structures of the metabolic products are elucidated on the basis of their spectral data. 2-phenylethanol has a sweet, floral odor and a wide variety of applications, especially, for the perfume and food industries. A time-course experiment demonstrates that 2-phenylethanol appeared after 120 hours, reaching almost 8% of relative abundance. Additionally, the influence that the culture broth has on the conversion capacity is investigated. It has been discovered that cinnamyl alcohol is converted faster when the substrate is incorporated in a Sabouraud medium; under this condition, 2-phenylethanol is the most common product after 288 hours reaching about 90% of the relative abundance. Biotransformation of cinnamyl alcohol using C. acutatum in a Sabouraud medium can offer a simple and efficient way to obtain 2-phenylethanol with high yield.

The development of biocatalytic methods has allowed the preparation of a wide variety of products with high added value through simple, selective, economical and environmentally friendly processes. In this work, the microbial transformation of arylpropanoide substrate trans-cinnamaldehyde using the fungus Aspergillus sp. was investigated. The process is carried out in liquid media culture Sabouraud y Czapeck- Dox to an average temperature 24oC, relative humidity between 45 and 60%, and with agitation at 120 rpm on a orbital shaker. The biotransformation of the substrate generated mainly the metabolic products 3-phenyl-1-propanol, cinnamyl alcohol, 3-phenylpropanal, 3-phenylpropyl acetate, cinnamyl acetate,benzylic alcohol, 1-phenylethanol, and 2-phenylethanol. From the results it is concluded that the fungus Aspergillus sp. initially converted the trans-cinnamaldehyde by reduction reactions, and later modified the products resulting through esterification and decarboxylation. In the process, several compounds used as raw materials in different industries were generated. The metabolic pathway and culture medium effect on substrate transformation are discussed.

Anthracnose of tree tomato, caused by the fungus Colletotrichum acutatum, is the major postharvestdisease of this crop in Colombia due to its widespread distribution and economic loss. In the presentwork, antifungal activity against C. acutatum specie with the essential oils (EO) of thyme (Thymus vulgaris), lemon grass (Cymbopogon citratus), and the main components of the EO, thymol and citral, isevaluated. Experimental result indicates that thymol at a concentration of 125 mg/L and citral at 300mg/L, inhibits completely the mycelial growth during eleven days. Spore germination is affected 100%with lemon grass oil at 350 and 400 mg/L, thymol at 100 and 125 mg/L, and citral at 250 and 300 mg/L,during the period of evaluation of twelve hours. In addition, thymol at 125 mg/L and citral at 300 mg/L,inhibits completely the sporulation of the fungus whereas thyme oil at 350 mg/L shows a lower degreeof affectation. Phytotoxicity evaluations of all materials by applying drops located at the leaf surface ofSolanum betacea to concentrations between 150 and 5000 mg/L, demonstrate that treatments do not induceany apparent damage. Also, foliar spraying complete and systematically every 2 days, for the period of2 months with constant concentration of 1500 mg/L for each evaluated materials, produces no sign ofwilting, deteriorating growth or alteration of the overall development of the plants.