Phytochemistry of compounds isolated from the leaf-surface extract of Psiadia punctulata (DC.) Vatke growing in Saudi Arabia

• Published in: Phytochemistry (Oxford) 2018-11, Vol.155, p.191-202
• Main Authors: Dal Piaz, Fabrizio, Bader, Ammar, Malafronte, Nicola, D'Ambola, Massimiliano, Petrone, Anna Maria, Porta, Amalia, Ben Hadda, Taibi, De Tommasi, Nunziatina, Bisio, Angela, Severino, Lorella
• Format: Article
• Language: English
• Subjects: Antimicrobial activity; Asteraceae; Kaurane; Psiadia punctulata; Trachylobane
• ISSN: 0031-9422; 1873-3700
• DOI: 10.1016/j.phytochem.2018.08.003

The surface extract of an accession of Psiadia punctulata (DC.) Vatke (Asteraceae) growing in Saudi Arabia was investigated for its phytochemical composition. A bio-guided investigation of the extract led to the isolation of thirteen ent-kaurane and trachylobane diterpenes and seventeen compounds previously described, including nine flavonoids and eight diterpenes. Three flavonoids and one ent-kaurane diterpene showed antimicrobial activity with MIC100 values ranging from 25 to 150 μg/ml. The extract showed antibacterial activity against Staphylococcus aureus (MIC100 = 180 μg/ml) and antifungal activity against Candida albicans (MIC0 = 130 μg/ml). The isolated 3′,4′,5,7-tetramethoxyflavone, at a concentration of 40 μg/ml, displayed the ability to reduce biofilm formation of S. aureus and C. albicans by 50% and 90% respectively. [Display omitted] •The surface extract of Psiadia punctulata from Saudi Arabia was investigated.•Thirteen previously undescribed ent-kaurane and trachylobane diterpenes were isolated.•Nine known flavonoids and eight known diterpenes were also isolated.•The antimicrobial activity of the extracts, fractions and isolates was evaluated.