Fungos endofíticos associados à Passiflora incarnata e avaliação de seu potencial biotecnológico
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2017-03-13
Autores
Silva, Matheus Henrique Reis da [UNESP]
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Universidade Estadual Paulista (Unesp)
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Passiflora incarnata encontra-se entre as plantas medicinais mais estudadas no âmbito farmacológico, cujas propriedades medicinais são atribuídas principalmente aos seus fitoconstituintes, tais como compostos fenólicos, alcalóides e flavonoides. Já foi constatado que os fungos endofíticos, aqueles vivem no interior de plantas, compartilhando com as mesmas uma interação simbiótica. Estes endófitos estão presentes em todas as plantas e muitas vezes partilham dos mesmos metabólitos que sua hospedeira. Devido ao seu enorme potencial de exploração, os fungos endofíticos são considerados um dos mais importantes recursos para a obtenção de novos agentes terapêuticos, pois um grande número de metabólitos estruturalmente novos e biologicamente ativos tem sido relatado para esses organismos. Neste contexto, o objetivo deste trabalho foi isolar fungos endofíticos presentes em folhas de P. incarnata e avaliar seu potencial biotecnológico, quanto à presença de compostos fenólicos, flavonoides e atividade antioxidante. Das 120 folhas analisadas, um total de 315 fungos endofíticos foi obtido; foi possível identificar 16 táxons distintos, dentre eles Aspergillus spp., Fusarium spp., Penicillium spp., Curvularia spp., Phoma spp., Neurospora spp., Trichoderma spp e representantes dos Mucoromycotina. A maioria dos isolados não apresentou esporulação. Os 60 endófitos utilizados nos ensaios produziram ao menos um composto fitoquímico, 60% (n=36) foram positivos para saponinas, 76% (n=46) para flavonoides, 93% (n=56) para compostos fenólicos, apenas 3% (n=2) para taninos, e nenhum fungo apresentou alcalóides no filtrado. O teor de flavonoides e fenóis totais do extrato de n-Butanol, determinado espectrofotometricamente revelou que a maioria dos fungos analisados foram bons produtores destes compostos, com destaque para os isolados Trichoderma sp./LMA 1684 e Aspergillus sp. 1/LMA 1720, com 213,69 mg.g-1 e 187,3 mg.g-1 , respectivamente, para flavonoides totais expressos em rutina, enquanto para fenóis totais os isolados LMA 1713 e LMA 1824, ambos fungos não esporulantes, apresentaram os teores 184,94 mg.g-1 e 187,05 mg.g-1 , respectivamente. Todos os endófitos apresentaram atividade antioxidante frente ao radical livre DPPH. O extrato butanólico do fungo Aspergillus versicolor/LMA 1705 (94%) foi maior que o padrão BHT (90,27%) e rutina (91,98%). A fração AcOEt e BuOH de cincos fungos selecionados apresentou metabólitos com atividade antioxidante, entre as amostras, a fração BuOH do fungo Trichoderma sp./LMA 1684 mostrou a atividade de eliminação do radical livre DPPH mais baixa (valor de IC50 de 304,18 mg/mL ), enquanto a fração AcOEt do fungo Chaetomium sp./LMA 1793 com um valor de IC50 de 0,21 mg/mL exibiu uma atividade antioxidante maior que os controles positivo BHT (0,42 mg/mL ), Rutina (0,25 mg/mL ), e Ácido Ascórbico (0,23 mg/mL). Foi realizada CG-EM da fração acetato de etila em cinco fungos previamente selecionados e foi constatada a presença do metabólito orcinol (3,19%) em Aspergillus versicolor/LMA 1705, 4-metoximetilfenol (4,79%), Sorbicillina (33,59%) e ergosterol (23,08%), presentes em Trichoderma sp./LMA 1684 e isopropenil-1,4-dimetil-1,2,3,3a,4,5,6,7-octahidroazuleno no endófito Fusarium sp. 4. O estudo mostrou um grande potencial de aplicação em biotecnologia dos endofíticos de P. incarnata.
Passiflora incarnata is among the most studied medicinal plants in the pharmacological field, whose medicinal properties are attributed mainly to its phytochemicals, such as phenolic compounds, alkaloids and flavonoids. It has been found that endophytic fungi, which are those living inside plants, share a symbiotic interaction with their hosts. These endophytes are present in all plants and often share the same metabolites as the plants they live. Due to their enormous potential for exploitation, endophytic fungi are considered one of the most important resources for obtaining new therapeutic agents, since a large number of structurally new and biologically active metabolites have been reported from these microorganisms. In this context, the objective of this work was to isolate endophytic fungi present in leaves of P. incarnata and to evaluate their biotechnological potential, regarding the presence of phytochemicals, phenolic compounds, flavonoids and antioxidant activity. From a total of 120 leaves analyzed 315 endophytic fungi were obtained. It was possible to identify 16 distinct taxa, among them Aspergillus spp., Fusarium spp., Penicillium spp., Curvularia spp., Phoma spp., Neurospora spp., Trichoderma spp. and Mucoromycotina representatives. Many showed no sporulation at all. All 60 endophytes used in the trials produced at least one phytochemical compound, 60% (n = 36) were positive for saponin, 76% (n = 46) for flavonoids, 93% (n = 56) for phenolic compounds, only 3% (n = 2) for tannins, and no one presented alkali in the filtrate. The total flavonoid and phenol contents of the n-Butanol extract, spectrophotometrically determined, showed that most of the analyzed fungi were good producers of these compounds, especially the isolate Trichoderma sp./LMA 1684 and Aspergillus sp. 1/LMA 1720 213.69 mg.g-1 and 187.3 mg.g-1 respectively, for total flavonoids expressed in rutin, and for total phenols the isolate LMA sp. 6 and LMA sp. 26 with 184.94 mg.g-1 and 187.05 mg.g-1 respectively. All endophytes presented antioxidant activity against free radical DPPH. Butanolic extract of the fungus Aspergillus versicolor/LMA 1720 (94%) was higher than the BHT (90.27%) and routine (91.98%) standard. The AcOEt and BuOH fraction of five fungi presented metabolites with antioxidant activity, among the samples, the BuOH fraction of the Trichoderma sp./LMA 1684. showed the lowest free radical DPPH elimination activity (IC50 value of 304.18 mg/mL), while the AcOEt fraction of Chaetomium sp./LMA 1793 with an IC50 value of 0.21 mg/mL showed better antioxidant activity than the BHT (0.42 mg/mL), rutin (0.25 mg/mL), and ascorbic acid (0.23 mg/mL). CG-MS of the ethyl acetate fraction was performed in five previously selected fungi and the presence of the orcinol (3.19%) in Aspergillus versicolor/LMA 1705, 4-methoxymethylphenol (4.79%), Sorbicillin (33.59%) and ergosterol (23.08%), present in Trichoderma sp./LMA 1684 and isopropenyl-1,4-dimethyl-1,2,3,3a, 4,5,6,7-octahydroazulene in the endophyte Fusarium sp. 4/LMA 1719. This study highlighted a great biotechnological application of the P. incarnata endophytes.
Passiflora incarnata is among the most studied medicinal plants in the pharmacological field, whose medicinal properties are attributed mainly to its phytochemicals, such as phenolic compounds, alkaloids and flavonoids. It has been found that endophytic fungi, which are those living inside plants, share a symbiotic interaction with their hosts. These endophytes are present in all plants and often share the same metabolites as the plants they live. Due to their enormous potential for exploitation, endophytic fungi are considered one of the most important resources for obtaining new therapeutic agents, since a large number of structurally new and biologically active metabolites have been reported from these microorganisms. In this context, the objective of this work was to isolate endophytic fungi present in leaves of P. incarnata and to evaluate their biotechnological potential, regarding the presence of phytochemicals, phenolic compounds, flavonoids and antioxidant activity. From a total of 120 leaves analyzed 315 endophytic fungi were obtained. It was possible to identify 16 distinct taxa, among them Aspergillus spp., Fusarium spp., Penicillium spp., Curvularia spp., Phoma spp., Neurospora spp., Trichoderma spp. and Mucoromycotina representatives. Many showed no sporulation at all. All 60 endophytes used in the trials produced at least one phytochemical compound, 60% (n = 36) were positive for saponin, 76% (n = 46) for flavonoids, 93% (n = 56) for phenolic compounds, only 3% (n = 2) for tannins, and no one presented alkali in the filtrate. The total flavonoid and phenol contents of the n-Butanol extract, spectrophotometrically determined, showed that most of the analyzed fungi were good producers of these compounds, especially the isolate Trichoderma sp./LMA 1684 and Aspergillus sp. 1/LMA 1720 213.69 mg.g-1 and 187.3 mg.g-1 respectively, for total flavonoids expressed in rutin, and for total phenols the isolate LMA sp. 6 and LMA sp. 26 with 184.94 mg.g-1 and 187.05 mg.g-1 respectively. All endophytes presented antioxidant activity against free radical DPPH. Butanolic extract of the fungus Aspergillus versicolor/LMA 1720 (94%) was higher than the BHT (90.27%) and routine (91.98%) standard. The AcOEt and BuOH fraction of five fungi presented metabolites with antioxidant activity, among the samples, the BuOH fraction of the Trichoderma sp./LMA 1684. showed the lowest free radical DPPH elimination activity (IC50 value of 304.18 mg/mL), while the AcOEt fraction of Chaetomium sp./LMA 1793 with an IC50 value of 0.21 mg/mL showed better antioxidant activity than the BHT (0.42 mg/mL), rutin (0.25 mg/mL), and ascorbic acid (0.23 mg/mL). CG-MS of the ethyl acetate fraction was performed in five previously selected fungi and the presence of the orcinol (3.19%) in Aspergillus versicolor/LMA 1705, 4-methoxymethylphenol (4.79%), Sorbicillin (33.59%) and ergosterol (23.08%), present in Trichoderma sp./LMA 1684 and isopropenyl-1,4-dimethyl-1,2,3,3a, 4,5,6,7-octahydroazulene in the endophyte Fusarium sp. 4/LMA 1719. This study highlighted a great biotechnological application of the P. incarnata endophytes.
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Palavras-chave
Antioxidante, Compostos fenólicos, Flavonoides, Saponinas, Antioxidant, Phenolic compounds, Flavonoids, Saponins, Secondary metabolites, Metabólitos secundários