Research Article Pimarane Diterpenoids from Aerial Parts of Lycopus lucidus and Their Antimicrobial Activity Jitendra Pandey , 1 Bang Yeon Hwang, 2 Hyeong-Kyu Lee, 3 and Amrit Poudel 4 1 Department of Pharmacy, Crimson College of Technology, Pokhara University, Devinagar-11, Butwal 32900, Nepal 2 Chungbuk National University, Department of Pharmacy, Cheongju, Republic of Korea 3 Natural Medicine Research Center, Korea Research Institute of Bioscience & Biotechnology, Cheongju-si 363-883, Republic of Korea 4 Department of Biodiversity and Bioresources, Satvik Nepal, Dandakonak, Kaski, Pokhara 33700, Nepal Correspondence should be addressed to Amrit Poudel; amritpoudel@gmail.com Received 17 October 2021; Accepted 18 January 2022; Published 4 February 2022 Academic Editor: Rafael M. Ximenes Copyright © 2022 Jitendra Pandey et al. is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. e ethyl acetate fraction obtained from aerial parts of L. lucidus was subjected for isolation of new bioactive compounds, which enabled isolation of five new pimarane-type diterpenoids, namely, 3β, 8β, 12β, 18-tetrahydroxy pimar-15-ene (10), 7α, 8β, 12β, 18- tetrahydroxy pimar-15-ene (11), 3β, 8β, 11β, 12α, 18-pentahydroxy pimar-15-ene (12), 12β acetoxy, 8β, 3β, 18-trihydroxy pimar- 15-ene (13), and 3β acetoxy, 8β, 12β, 18-trihydroxy pimar-15-ene (14), along with nine known compounds. e structures were elucidated by spectroscopic analysis and comparison with literature data. e isolated new pimarane diterpenoids were examined for antimicrobial activity against Gram-negative and Gram-positive bacteria strains. Among them, the compound 3β, 8β, 12β, 18- tetrahydroxy pimar-15-ene (10) was most effective, exhibiting minimum inhibitory concentration (MIC) values of 15.62 µg/mL against Staphylococcus epidermidis, 31.25 µg/mL against Staphylococcus aureus, 62.5 µg/mL against Pseudomonas aeruginosa, and 125 µg/mL against Escherichia coli. 1. Introduction e genus Lycopus of family Lamiaceae (Labiatae) contains around 16 species with wide distribution in Europe, Asia, and North America [1]. In Asia, Lycopus lucidus is widely distributed species in Korea, China, Japan, Russia, and Taiwan. It is most abundant in Korea. L. lucidus is a flowering perennial glabrous herb occurring in aquatic environment and grows up to 0.6–1.2 m height at an altitude of 320 m to 2100 m [2–4]. L. lucidus is one of the popular edible plants with its long history as a folk remedy in tra- ditional medicinal system of China, Japan, and Korea [5]. is plant has been used as both traditional and official formulations, as they are potent source of bioactive tannins, coumarins, flavonoids, terpenoids, and essential oils. Major bioactive compounds that have been isolated from this plant are flavonoid and its esters, rosmarinic acid derivatives, phenylpropanoids, steroids, pentacyclic triterpenes, essen- tial oils, oligosaccharides, polysaccharides, and diterpenoid glycosides [3, 6–8]. e leaf and stem (aerial part) of L. lucidus have been extensively used for the treatment of inflammation, cardiovascular problem, insomnia, menstrual problems, and thyroid problem, as a sedative, wound healing, pain reliving agents, herbal tea, and useful tonic [6, 8, 9]. e root of L. lucidus is known as small ginseng in China and widely used as dietary supplement [10]. Many biological activities such as inhibition of superoxide radical [4], nitric oxide scavenging effect [6], inhibition of hyper- cholesterolemia and atherosclerosis [11], acaricidal activities [10], and hyaluronidase inhibition [5] have been explored from this plant. In the current scenario, bacterial infectious diseases are a serious worldwide public health problem due to an increase in their resistance towards antibiotics, which have ultimately Hindawi Evidence-Based Complementary and Alternative Medicine Volume 2022, Article ID 5178880, 9 pages https://doi.org/10.1155/2022/5178880