title: Unveiling the mode of action of antibacterial labdane diterpenes from Alpinia nigra (Gaertn.) B. L. Burtt seeds.
abstract: The labdane diterpene, (E)-labda-8(17), 12-diene-15, 16-dial (compound A) and its epoxide analogue, (E)-8β, 17-Epoxylabd-12-ene-15, 16-dial (compound B) were isolated from the seeds of Alpinia nigra for the first time. The antibacterial activities of both compounds were evaluated against three Gram-positive and four Gram-negative bacteria, and flow cytometric analysis revealed that these compounds caused significant damage to the bacterial cell membranes. Further, field emission scanning electron microscope imaging and cell leakage analysis confirmed that the labdane diterpenes were responsible for bacterial cell membrane damage and disintegration. Our findings provide new insight into the broad-spectrum effects of two natural labdane diterpenes that may be useful in the future development of herbal antibiotic products.
authors.affiliation: Department of Biotechnology, Indian Institute of Technology Guwahati, North Guwahati, Assam 781039, India.
authors.forename: Sudipta
authors.initials: S
authors.lastname: Ghosh
authors.forename: Kiran
authors.initials: K
authors.lastname: Indukuri
authors.forename: Somasekhar
authors.initials: S
authors.lastname: Bondalapati
authors.forename: Anil K
authors.initials: AK
authors.lastname: Saikia
authors.forename: Latha
authors.initials: L
authors.lastname: Rangan
mesh_terms: D032429:Alpinia / Q000737:chemistry*; D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology*; D001419:Bacteria / Q000166:cytology / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects; D004224:Diterpenes / Q000737:chemistry* / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D012639:Seeds / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D004224:Diterpenes
keywords: Alpinia nigra; Antibacterial activity; Flow cytometry; Labdane diterpene; Zingiberaceae