Bangladesh Journal of Pharmacology Volume: 18; Number 2; Year 2023 Cite this article as: Rokkarukala S, Chander MP, Mohanraju R. GC-MS analysis and antibacterial properties of the selected soft corals from South Andaman, India. Bangladesh J Pharmacol. 2023; 18: 72-74. GC-MS analysis and antibacterial properties of the selected soft corals from South Andaman, India Sir, Marine organisms consist of secondary metabolites that serve as a rich source of naturally occurring, bioactive substances with a variety of structural characteristics. Long utilized as sources of various natural chemicals with pharmacological or aesthetic value include a wide range of reef invertebrates, including soft corals (Chao et al., 2011). Alcyonacean corals are classified under the category Octocorallia, which distinguishes these from hexacorallian Scleractinia colonies by implying the presence of polyps with eight tentacles. Alcyonaceans are huge sessile invertebrates with a distinct stalk and a capitulum, or smooth, mushroom-shaped top. Their tissue contains sclerites, which support the colony. Octocorals are found in the majority of benthic habitats, where they are influenced by a variety of environmen- tal conditions, demonstrating their adaptability (van de Water et al., 2018). Sclerite classification has historically been used to identify and categorize the majority of soft coral. There are 35 species of Sarcophyton, and six more have been described (Benayahu et al., 2009). Soft corals are a highly diverse group of marine orga- nisms that contain a rich source of secondary meta- bolites. Due to the lack of efficient physical protection in the highly competitive and hostile marine environ- ment, soft corals majorly depend on their secondary metabolites for survival (Shahbudin et al., 2011). The organo-solvent extract produced from various genera of soft corals consists majorly of lipids and sterols, about 90%, and the remaining 10% of the bioactive com- pounds consists of diterpenes, sesquiterpenes, steroids, terpenoids, and alkaloids (Chao et al., 2011). Soft corals have recently received attention for their pharmacologi- cal potential as antioxidants, anti-microbials, anti- cancer, and anti-inflammatory proper-ties (Gomaa et al., 2016; Cooper et al., 2014; Marican et al., 2016). Andaman and Nicobar Islands’ marine ecosystem is unique and understudied, and may have a potential source of antimicrobial agents. There are nearly 300 islands rich in coral reefs, dominated by fringing reefs and few barrier reefs, harboring rich diversity of corals and rare marine species (Laxmilatha et al., 2021). There- fore, it was worthwhile to investigate the antibacterial properties of soft corals against human pathogenic bac- teria that often cause infectious diseases. Soft corals were collected from Burma Nallah (Lat: 11° 34.298'N, Long: 92°44.160'E) by hand-picking method during the inter-tidal survey. Specimens were transferr- ed to the laboratory in plastic containers with sufficient seawater. The released mucus attached rock particles, and sand was washed with sterile seawater. The specimen was identified based on the identification key as described by Janes (2008). The sample was chopped into small pieces, and 25 g were weighed and soaked in 100 mL of organic solvent Methanol and Ethyl acetate respectively for 48 hours. The crude extract obtained was subjected to vacuum filtration and the resulting filtrate was concentrated using a rotary evaporator (Buchi 2412V0 RII, Switzer- land). This crude extract was transferred into air-tight bottles and stored at 4°C till further use. The investigation of the antibacterial properties of the crude extracts against 12 human pathogenic bacterial species was performed by the agar well diffusion method (Chander et al., 2016). GC-MS analysis of active extracts was carried out on an Alglient© 7890, which is employed for the analysis of compounds. The peaks of the compounds representing mass-to-charge ratio characteristics were compared with the NIST library to identify the corresponding organic compounds. The results presented in Table I revealed that among the three soft coral methanol extracts, Sarcophyton trocheliophorum displayed potential antibacterial activity against the tested organisms. The methanol extract of S. trocheliophorum restricted the growth of maximum test pathogens and the highest activity was visualized against Vibrio fluvialis (29.7 ± 1.5 mm) followed by Escherichia coli (21.3 ± 0.6 mm) and Salmonella typhi (15.3 ± 0.6 mm). Cladiella pachyclados inhibited seven test pathogens, most active in the case of Shigella flexneri (20.3 ± 0.6 mm) followed by E. coli (18.3 ± 1.5 mm) and S. boydii (17.3 ± 1.5 mm). The compounds of Sarcophyton ehrenbergi were moderately effective against tested pathogens and the highest activity was found against E. coli (20.0 ± 1.0 mm) followed by S. sonnei (15.7 ± 0.6 mm) and S. typhi (15.0 ± 1.0 mm). S. typhi was found to be sensitive to all the studied soft coral extracts whereas shiga toxin-producin E. coli was found to be resistant to all the extracts. A Journal of the Bangladesh Pharmacological Society (BDPS) Bangladesh J Pharmacol 2023; 18: 72-74 Journal homepage: www.banglajol.info; www.bdpsjournal.org Abstracted/indexed in Academic Search Complete, Agroforestry Abstracts, Asia Journals Online, Bangladesh Journals Online, Biological Abstracts, BIOSIS Previews, CAB Abstracts, Current Abstracts, Directory of Open Access Journals, EMBASE/Excerpta Medica, Global Health, Google Scholar, HINARI (WHO), International Pharmaceutical Abstracts, Open J-gate, Science Citation Index Expanded, SCOPUS and Social Sciences Citation Index ISSN: 1991-0088; DOI: 10.3329/bjp.v18i2.64228 Letter to the Editor This work is licensed under a Creative Commons Attribution 4.0 International License. You are free to copy, distribute and perform the work. You must attribute the work in the manner specified by the author or licensor GC–MS analysis of methanol extracts of three soft corals revealed the presence of bioactive compounds (Table II). The most abundant compound was 1- hexadecanol, 5,8,11,14-eicosatetraenoic acid, methyl ester, (all-Z)-, naphthalene, 1,2,3,4-tetrahydro-1,6-di- methyl-4-(1-methylethyl)-, (1S-cis)-, azuleno[4,5-b]furan -2(3H)-one, 9a-[(acetyloxy)methyl] decahydro-6a,9-dihy -droxy-6-methyl-3-methylene-, γ-linolenic acid, methyl Bangladesh J Pharmacol 2023; 18: 72-74 73 Table I Antibacterial activity of methanol crude extracts of soft corals (in mm) S. ehrenbergi C. pachyclados S. trocheliophorum Pathogens 50 (µg/mL) 100 (µg/mL) 50 (µg/mL) 100 (µg/mL) 50 (µg/mL) 100 (µg/mL) E. coli 12.3 ± 0.6 20.0 ± 1.0 13.7 ± 1.2 18.3 ± 1.5 15.3 ± 1.5 21.3 ± 0.6 Shiga toxin-producing E. coli _ _ _ _ _ _ S. flexneri _ _ 13.3 ± 0.6 20.3 ± 0.6 _ 13.0 ± 0.0 S. dysentery Type S _ _ 12.3 ± 0.6 15.7 ± 0.6 10.3 ± 0.6 14.3 ± 1.5 S.boydii _ 12.3 ± 1.5 11.3 ± 1.5 17.3 ± 1.5 _ 11.7 ± 0.6 S. sonnei 11.7 ± 1.2 15.7 ± 0.6 _ 12.7 ± 0.6 _ 12.3 ± 1.2 S. typhi 11.3 ± 0.6 15.0 ± 1.0 14.0 ± 0.0 16.3 ± 0.6 11.3 ± 0.6 15.3 ± 0.6 V. cholera _ _ _ _ _ 13.7 ± 1.2 V. fluvialis _ _ _ _ 20.3 ± 0.6 29.7 ± 1.5 A. hydrophila _ _ 11.7 ± 1.2 13.7 ± 1.2 11.3 ± 1.5 15.0 ± 0.6 Table II Compounds identified from the methanol extracts of soft corals by GC-MS analysis Species Compounds Retention time (min) Molecular formula Molecular weight (g/mol) Peak area (%) S. ehrenbergi 1-Hexadecanol 31.198 C16H34O 242 15.68 5,8,11,14-Eicosatetraenoic acid, methyl ester, (all-Z)- 38.088 C21H34O2 318 8.50 Naphthalene, 1,2,3,4-tetrahydro-1,6-dimethyl-4-(1- methylethyl)-, (1S-cis) 23.092 C15H22 202 7.35 Hexadecanoic acid, methyl ester 31.949 C17H34O2 270 5.84 γ-Linolenic acid, methyl ester 34.834 C19H32O2 292 5.84 1-Octadecanol 35.053 C18H38O 270 4.51 Batilol 45.400 C21H44O3 344 4.03 C. pachyclados 1-Hexadecanol 31.013 C16H34O 242 13.46 Azuleno[4,5-b]furan-2(3H)-one, 9a-[(acetyloxy)methyl] decahydro-6a,9-dihydroxy-6-methyl-3-methylene 46.754 C17H24O6 324 11.86 γ-Linolenic acid, methyl ester 34.769 C19H32O2 292 10.57 5-(7a-Isopropenyl-4,5-dimethyl-octahydroinden-4-yl)-3- methyl-pent-2-enal 45.254 C20H32O 288 9.57 2,5-Furandione, dihydro-3-(2-tetradecenyl) 39.037 C18H30O3 294 7.44 2-[4-Methyl-6-(2,6,6-trimethylcyclohex-1-enyl)hexa-1,3,5 -trienyl]cyclohex-1-en-1-carboxaldehyde 44.788 C23H32O 324 6.96 Hexadecanoic acid, methyl ester 31.864 C17H34O2 270 5.33 Hexadecanoic acid, methyl ester 31.856 C17H34O2 270 24.06 S. trocheliopho- rum 1-Octadecanol 34.956 C18H38O 270 11.68 1-Hexadecanol 30.995 C16H34O 242 10.81 Campesterol 55.081 C28H48O 400 7.89 Thunbergol 34.343 C20H34O 290 4.80 2-Pentenoic acid, 5-(decahydro-5,5,8a-trimethyl-2-me thylene-1-naphthalenyl)-3-methyl-, [1S-[1α(E),4aβ,8aα]] 36.295 C20H32O2 304 3.22 trans-13-Octadecenoic acid, methyl ester 35.188 C19H36O2 296 2.90 Ergost-5-en-3-ol, acetate, (3β,24R)- 50.221 C30H50O2 442 2.80 ester, hexadecanoic acid, methyl ester, 1-octadecanol, campesterol, thunbergol respectively. The study results of the antibacterial assay, the bio- active compounds of three soft coral extracts inhibited the growth of human pathogenic bacteria. GC-MS analysis revealed bioactive compounds from these three soft corals, and each compound has been structurally characterized so that these metabolites can act as potential pharmaceutical products or lead structures for the development of new drugs in the future. The antibacterial properties of the soft corals from South Andaman are the first of their kind from the islands and they should be further investigated for their application in developing novel bioactive compounds. Acknowledgment: The authors express their sincere gratitude to Pondicherry University, Port Blair for providing basic infrastructure for carrying out the research work. The authors are also thankful to the Zoological Survey of India (ZSI/ ANRC), Port Blair for helping with the identification of soft coral specimens. Conflict of Interest: The authors declare that they have no conflict of interest. Financial support: Self-funded Samson Rokkarukala1, M. Punnam Chander2, Raju Mohanraju1 1 Department of Ocean Studies and Marine Biology, Pondicherry University, Brookshabad Campus, Port Blair, Andaman and Nicobar Islands, 744112, India; 2 Model Rural Health Research Unit, Khumulwng, Tripura 799035, India. Corresponding author: Email: asmohanrajupu@pondiuni.ac.in References Benayahu Y, van Ofwegen LP. New species of Sarcophyton and Lobophytum (Octocorallia: Alcyonacea) from Hong Kong. Zool Meded. 2009; 83: 863-76. Chander MP, Vijayachari P. In vitro antibacterial and anti- oxidant potentials of selected seaweeds of Andaman and Nicobar Islands, India. Bangladesh J Pharmacol. 2016; 11: 874-75. Chao CH, Chou KJ, Huang CY, Wen ZH, Hsu CH, Wu YC, Sheu JH. Bioactive cembranoids from the soft coral Sinularia crassa. Mar Drugs. 2011; 9: 1955-68. Cooper EL, Hirabayashi K, Strychar KB, Sammarco PW. 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