Pahangensin A and B, two new antibacterial diterpenes from the rhizomes of Alpinia pahangensis Ridley

The rhizomes of Alpinia pahangensis Ridley yielded a new bis-labdanic diterpene for which the name pahangensin A (1) was proposed along with a new labdane diterpene, pahangensin B (2). Their structures were elucidated by spectroscopic methods including, 1D and 2D NMR techniques and LCMS-IT-TOF analysis. Pahangensin A (1) was found to be an antibacterial agent against Staphylococcus aureus, Bacillus cereus and Bacillus subtilis with MIC values less than 100 lg/mL, respectively. Pahangensin B (2) exhibited antibacterial activity (MIC <100 lg/mL) against B. cereus

A new bis-labdanic diterpene from the rhizomes of Alpinia pahangensis

The rhizomes of Alpinia pahangensis yielded a new bis-labdanic diterpene for which the name pahangensin C (1) was proposed along with twelve known analogues (2–13). The structure of 1 was elucidated via spectroscopic methods including 1D and 2D NMR techniques and LCMS‑IT‑TOF analysis. Compounds 2 and 12 were isolated for the first time from the genus Alpinia. This is the second occurrence of compounds 2 and 12 in the Zingiberaceae family. Selected analogues exhibited moderate to strong inhibitory activity against Staphylococcus aureus and Bacillus cereus