Fungitoxic effect and phytochemical characteristics of Brazilian Cerrado weeds against Rhizoctonia solani and Macrophomina phaseolina fungi

Abstract

The use of natural products obtained from plants, for example, invasive plants, offers a variety of allelochemicals with fungicidal potential. With this in perspective, the objective was to evaluate the fungicidal potential of ethanolic extracts of Cerrado plants on Rhizoctonia solani and Macrophomina phaseolina. The ethanolic hydroalcoholic extract of the 12 plants identified as invaders in the Brazilian Cerrado was prepared (Anacardium humile Saint Hill; Baccharis dracunculifolia DC.; Cenchrus echinatus L; Commelina erecta L.; Erigeron bonariensis L.; Digitaria horizontalis Willd.; Digitaria insularis L.; Porophyllum ruderale Jacq. Cass; Richardia brasiliensis Gomes; Sida rhombifolia L.; Turnera ulmifolia L.; Smilax fluminensis Steud)) and phytochemical screening and determination of total phenols and flavonoids were performed. To evaluate the in vitro antifungal activity, the hydroalcoholic solutions at concentrations of 800, 1200, 1600, 2000, and 2400 µL 100 mL-1 were separately incorporated into BDA agar and poured into Petri dishes, followed by the mycelium disk of the fungus. As a control, two solutions were prepared, one ethanolic solution added to the BDA medium (2400 µg 100 mL-1) and the other with BDA medium only. They were poured into Petri dishes, followed by a 0.5 cm diameter disk of mycelium of the fungus, incubated (23±2 ºC), with a 24-hour photoperiod. Among the constituents found in the plants, 75% are phenolic compounds, 58.3% are cardiotonic heterosides, 50% are steroids, 33.3% are flavonoids, 16.7% are anthraquinones, and 8.3% are alkaloids, saponins, and reducing sugars. Out of the 12 species, only the extracts of C. erecta and R. brasiliensis were active for M. phaseolina and R. solani. Thus, it is concluded that the ethanolic extract of C. erecta has the fungicidal potential to control diseases caused by fungi that are soil inhabitants. Of the other species, A. humille, B. dracuncufolia, D. insulares, C. erecta, D. insulares, P. ruderale, and R. brasiliensis have natural fungitoxic potential because they stand out in the content of polyphenols efficient in reducing the mycelial growth of M. phaseolina and R. solani.

Ethnomedicinal, phytochemical and pharmacological investigations of Baccharis dracunculifolia DC. (ASTERACEAE)

“…Frontiers in Pharmacology frontiersin.org at a concentration of 2000 µL/100 ml, inhibited by 13.5% the growth of Rhizoctonia solani (Dilkin et al, 2022).…”

“…As for biofilm formation, the extract showed better results for consolidated biofilms than new biofilms ( Assumpção et al, 2022 ). The ethanolic extract (99.8%) produced from leaves, with the presence of cardiotonic heterosides, steroids, phenolic compounds, flavonoids, tannins, coumarins, and triterpenes, at a concentration of 2000 µL/100 ml, inhibited by 13.5% the growth of Rhizoctonia solani ( Dilkin et al, 2022 ).…”

Cytotoxic, Phytotoxic and Insecticidal Potential of Achillea millefolium L. and Chaerophyllum villosum wall. ex dc.

“…These insects are one of the major causes of damage to fruits and vegetables throughout the world (Nazir et al, 2022). The search for attaining products from plants which may act as effective against certain plant diseases with less toxicity effect and less adverse effects on environment as well is being stressed upon by researchers (Dilkin et al, 2024). Plants contain the naturally occurring insecticides.…”