Betulinic acid and poriferasterol from Eucalyptus camaldulensis and the novel antimicrobial report of the root extract

Traditional medicine practitioners have used Eucalyptus camaldulensis subsp. Acuta Brooker & M. W. McDonald leaves to treat typhoid fever, malaria, ulcers, fungal infections, cough, muscular and joint pain, blood sugar disorders, and dermatological infections. Scientific reports also indicate that the leaves and stems possess anti-dermatophyte, larvicidal, antibacterial, cytotoxic, and antioxidant properties. However, the biological potential of the roots has remained largely unexplored. In this study, the root samples of E. camaldulensis were defatted with n-hexane and extracted by maceration using ethyl acetate. The phytoconstituents and antimicrobial activity of the root extract were investigated. The extract exhibited antimicrobial activity with a minimum inhibitory concentration (MIC) of 2.5 mg/mL against several pathogens, including methicillin-resistant Staphylococcus aureus, Escherichia coli, Helicobacter pylori, Candida albicans, Candida krusei, and Candida tropicalis. Two compounds, betulinic acid (1) and poriferasterol (2), were isolated for the first time from the roots and exhibited potent antimicrobial activity, with MIC values of 0.0125 mg/mL against methicillin-resistant Staphylococcus aureus, Escherichia coli, and Helicobacter pylori. This study represents the first successful antimicrobial and phytochemical investigation of the root of Eucalyptus camaldulensis. The findings support the traditional medicinal relevance of the plant and provide a foundation for further investigation of the pharmaceutical potential of its roots.