Seleção de fungos endofíticos de sangue-de-dragão (Croton lechleri Müll. Arg.) produtores de L-asparaginase

Abstract

ABSTRACT

Croton lechleri belongs to the Euphorbiaceae family and is popularly known as dragon's blood, sangre de grado, or sangue de grado. It is native to the Amazon and is used in popular and traditional medicine to treat a variety of diseases. In addition to the plant itself, endophytic fungi living within it may possess medicinal properties, such as the production of the enzyme L-asparaginase. This enzyme exhibits antitumoral activity by breaking down asparagine into aspartate and ammonia, reducing the asparagine levels in the plasma and consequently inhibiting the metabolism of tumor cells. It is primarily used in the treatment of certain types of lymphoproliferative cancers. The objective of this study was to select endophytic fungi from the Amazonian medicinal plant Croton lechleri that are capable of producing the enzyme L-asparaginase. The endophytic fungi analyzed in this study were isolated from Croton lechleri and stored in distilled water using the Catellani technique in the Microorganism Collection of the Microbiology Laboratory at the Federal University of Acre (UFAC). For reactivation, the fungi were inoculated on Potato Dextrose Agar (PDA) medium for 7 days at room temperature. Fungi were identified at the genus level based on morphological characteristics. For L-asparaginase production detection, the fungi were inoculated in modified Czapek Dox medium and incubated at 28 °C for 7 days. A change in color from yellow to blue with visible colony growth was considered positive for L-asparaginase production. Descriptive statistics were used for result analysis. Out of the total of 48 endophytic fungi analyzed, 40 (83.33%) showed positive results for extracellular L-asparaginase production. The most frequent genera of endophytic fungi were Paecilomyces (29.2%), Penicillium (12.5%), Colletotrichum (4.2%), Phomopsis (4.2%), Xylaria (4.2%), and 17 isolates did not exhibit reproductive structures, identified as sterile mycelium (35.4%). Endophytic fungi from the Amazonian species Croton lechleri demonstrate potential for extracellular L-asparaginase production, making them a promising source for the production of this antitumoral enzyme.

Key-words: Paecilomyces, Penicillium, Secondary metabolite