is a medicinal tree used in traditional herbal medicine for the treatment of bronchial asthma and various skin diseases. As part of our ongoing search for bioactive phytochemicals with novel structures in natural products, we performed a phytochemical analysis of the methanol (MeOH) extract from needles collected in Iran. Phytochemical investigation of the MeOH extract, aided by liquid chromatography-mass spectrometry-based analysis, resulted in the isolation and identification of three labdane-type diterpenes (), including a new and relatively unique norlabdane-type diterpene with a peroxide moiety, eldaricoxide A (). The chemical structures of the isolated labdane-type diterpenes were elucidated by analyzing the spectroscopic data from 1D and 2D NMR and high-resolution electrospray ionization-mass spectrometry. The absolute configuration of eldaricoxide A () was established by employing a computational method, including electronic circular dichroism calculation and specific optical rotation. An anti- test was conducted, where compound exhibited the most potent antibacterial activity against strain 51, inducing 72.7% inhibition (MIC value of 92 μM), whereas eldaricoxide A () exhibited moderate antibacterial activity against strain 51, inducing 54.5% inhibition (MIC value of 95 μM). These findings demonstrated that the identified bioactive labdane-type diterpenes and can be applied in the development of novel antibiotics against for the treatment of gastric and duodenal ulcers.