Two New Myrsinane-type Diterpenoids From the Aerial Parts of Jatropha integerrima Jacq. and Their Antimicrobial Activity.

In the search for new antimicrobial agents, this study investigated the phytochemical composition of the aerial parts of Jatropha integerrima, leading to the isolation of two new myrsinane-type diterpenoids, jatrophodiones F and G (1, 2), along with seven known compounds: jatrointelone A (3), α-tocospiro A (4), 8(14),15-sandaracopimaradien-3β-ol (5), curdione (6), 5α,8α-epidioxyergosta-6,9(11),22-trien-3β-ol (7), 7-oxo-β-sitosterol (8), and 3β-hydroxystigmast-5(6),22-diene-7-one (9). The structures of these compounds were elucidated via high-resolution electrospray ionization time-of-flight mass spectrometry and infrared, ultraviolet, and nuclear magnetic resonance spectroscopy, comparing the analyses with reported spectroscopic data. Compounds 1-3 and 5-9 exhibited moderate to strong activity against eight microorganisms, including Salmonella enterica, Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, Bacillus cereus, Staphylococcus aureus, Candida albicans, and Aspergillus brasiliensis, with minimum inhibitory concentrations (MICs) ranging from 32 to 256 µg/mL. On the other hand, compound 4 inhibited only three tested Gram-positive bacterial strains and two fungi, with MICs varying from 64 to 128 µg/mL. This study is the first to investigate the antimicrobial activity of myrsinane-type diterpenoids (1, 2) and provides new insights into the potential therapeutic applications of these compounds.