Pueraria thomsonii Benth-Associated Endophytes: A Multifaceted Exploration of Its Bioactive Molecules

Abstract

Endophytes associated with medicinal plants hold substantial promise as a novel source for therapeutics development. In this study, 11 endophytic fungi and 9 endophytic bacteria were isolated from the roots of Pueraria thomsonii. In the preliminary screening, the ethyl acetate extract of the Apiospora marii FG-Z21 displayed strong inhibitory effects against drug-resistant bacteria Enterococcus faecalis and Methicillin-resistant Staphylococcus aureus (MRSA) with MIC values of 1.563 and 0.098 mg/mL, respectively. Furthermore, this extract exhibited significant inhibitory effects on A549 cells with a GI₅₀ value of 0.036 mg/mL and demonstrated a good antioxidant property with an EC₅₀ value of 1.869 mg/mL. Further investigation of the active ethyl acetate extract of A. marii FG-21 led to the isolation of 4-hydroxybenzoic acid (1), 2-acetamidobenzoic acid (2), benzoic acid (3), dibutyl phthalate (4), 3,4-dimethoxybenzoic acid (5), schizostatin (6), ethyl pyroglutamate (7), and anthranilic acid (8). Notably, compounds 3, 1 and 2 exhibited significant cytotoxicity against A549 cells with GI₅₀ values ranging from 4.97 to 83.08 µg/mL. On the other hand, compounds 4, 5 and 6 demonstrated potent inhibition of E. faecalis growth with low MIC values ranging from 2 to 4 µg/mL. Our study provides a comprehensive exploration of P. thomsonii-derived endophytes and their compounds highlighting their significant bacteriostatic, antioxidative, and cytotoxic activities that may potentially contribute to drug discovery paradigms.

Graphical Abstract